# Zapco/BSG/Ebay deal



## chad (Jun 30, 2005)

I tore into the BSG amp last night and thought I'd share some thoughts and pics. I did not get to hear it because I was running late but did get a break out box built and took some static measurements.

Here is the bad Oscar: 


And the preamp/ mic Pre/ CROSSOVER!



The amplifier runs on bipolar (duh) 14.8V rails. The power supply is a PWM switching type unit and is NOT cross-compatible for use in the car; it would be VERY difficult to convert. There is a switch in the power supply that I believe sets it up for 220V operation. Next to the power switch and HV rectifier, tucked in there is the Fuse, it's a 6.3A puck style commonly seen in European gear, they are not going to be found at rat-shaq so probe carefully, you will need to order spares from an electronics wholesaler like Mouser or Digikey. I plan to grab some in the next order I make, I'll get a part number.

The finals are 2N6488 and 2N6491 made by ST and Moto respectively. There is one each per channel; they are driven by TIP31 and TIP32 devices that are driven by Central CEN-U57 and CEN-U07 transistors. There is a lot of drive here with little gain, the amp should be pretty stout, the finals are 15A/80V devices so they are certainly running in their SOA.



The amp is fused at 6.3A the manual states that it can consume 420 watts, if the amplifier were 70% efficient this would mean that in theory, all channels driven, one could get 49W/Ch out of it, if it is 80% efficient (there IS a PWM supply) then theoretical output all channels driven would be 56 watts. 

The manual states that it IS ok to run a 2 ohm load (they say 4 (X) 8 Ohm speakers per channel) 

All this is only true if the power supply is up to the task, these are just figures. The HV pulse voltage of the PS is 166V, rectified and filtered right off the AC line. This is then pulsed and stepped down to the rail voltage previously mentioned.

Getting separate inputs...... My unit was sent with 2 audio cables, fortunately, after demolishing a PS/2 keyboard it was found that my specific keyboard did not have all 6 wires in it, just 4 and a shield. I chose to hack up ONE of the cables and save the other.


I used a small bud box and put 6 RCA females into it, I also installed 2 DPDT switches that gang channels 1&2 to 3&4 and 3&4 to 5&6, this way I can use 2, 4, or 6 inputs. I just did a pigtail end for wiring; I was going to not sacrifice a cable and put the jack out of the preamp in it but decided not to.

Here's the unwired box:



Breakout with the switches wired:


Totally wired:



Here's the finished product:



Big problems arose when becoming confused while looking at the manual for wiring color codes, the manual is screwed. They state the color coding as follows:
Ch1=Red
Ch2=Yellow
Ch3=Blue
Ch4=black
Ch5=White
Ch6= Black!!!!! (WTF)

2 blacks? and there is no white or blue!

Here's the correct wiring!!!

Ch1=Black
Ch2=Brown
Ch3=Red
Ch4=Orange
Ch5=Yellow
Ch6=Green

^^^^^CORRECT^^^^^^

Kinda looks like the resistor color codes eh? Whoda thunk it?

The second method of doing this eliminates the BOB and cable, you will need to drill 6 holes in the amp, I would do this under the speaker outputs, you will not need ground as chassis and signal share common ground. It does not render the stock input useless, it allows for an either/or operation.

IF YOU SUCK AT SOLDERING THIS METHOD IS NOT FOR YOU!

Near the female DIN connector you will see 6 SMT resistors labeled in this order:
R89
R90
R98
R105
R112
R116

See:


With a maximum of 1/16" chisel or screwdriver tip quickly tack 6 wires onto these resistors on the side closest to the input connector. GO FAST with the heat, too much heat will melt the other side and knock the resistor loose, they will re-attach but if you have never worked with SMT stuff it will anger you quickly!

The other ends of these wires will attach to the center conductor of the RCA's you just mounted. The order is as follows:

R89=CH3
R90=CH5
R98=CH1
R105=CH2
R112=CH6
R116=CH4

Now you have 2 different methods of inputting to the amp. Don't use both at the same time as the preamp won't like having signal applied to the outputs!


So there you have it!

Time for a reward!


Enjoy

Chad


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## sqkev (Mar 7, 2005)

wait...how/when did I miss out on this?

so this is a home amp + preamp? is it fullrange on all 6 channels? how does it sound so far??

I'd be a great bedroom tester amp for me.


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## chad (Jun 30, 2005)

For commercial use (resturant, etc)

6 channels 30W per at 4 ohms. 1-4 are HP'd 5-6 are LP'd at the control unit, the control unit has volume, bass, treble, mic gain and ducking. The amp itself is FR, I don't plan to use the preamp.

$42.45 shipped and it came F-A-S-T!

Chad


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## sqkev (Mar 7, 2005)

so with your mod, you have 6 inputs and 6 fullrange outputs now? (for the loss of volume control right?)

How does it SOUND?


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## rekd0514 (Sep 24, 2006)

Dang we got some smart people here. Very cool! It looks a lot easier once you figured out all the work. haha Nice Work!


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## chad (Jun 30, 2005)

sqkev said:


> so with your mod, you have 6 inputs and 6 fullrange outputs now? (for the loss of volume control right?)
> 
> How does it SOUND?



Yep, 6 in/6 out. Via switching I can par channels down to the point where I have 1 stereo pair coming in and 3 stereo pair out. Wiring the switches differently woulld allow for easy bridging without Y connectors.

I did not get the chance to listen to it yet, maybe tonight, it depends.

Chad


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## azngotskills (Feb 24, 2006)

In your wired BUD box, is the ground of the PS/2 cable soldered to the chasis of the BUD box?


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## chad (Jun 30, 2005)

azngotskills said:


> In your wired BUD box, is the ground of the PS/2 cable soldered to the chasis of the BUD box?


There's a ground lug included with each RCA female, I used one and tied the ground to that, the metal box takes care of the rest.

You can see it in the pic of the wired box, the ground is in clear heat shrink and tied to #1 (black on the PS/2)

I have tried to solder to a bud box.... it don't fly. they are aluminum and lead/tin solder simply will not stick, I tried real damn hard too 

Chad


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## ~Magick_Man~ (Jul 11, 2006)

i ordered my pair on friday, paid over the weekend and have heard nothing from the seller at all.

~Magick_Man~


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## chad (Jun 30, 2005)

It will be there soon, via USPS, it made it here very fast.

Chad


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## ~Magick_Man~ (Jul 11, 2006)

did you get a message from the seller letting you know they had shipped or did they just show up?

~Magick_Man~


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## fej (Feb 8, 2006)

Hmm tempted. How much for the "chad" upgrade package?


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## 300Z (Mar 20, 2005)

I also missed on this...  

Is this deal still available? If so, where? I need an small amp to replace my T amp and this seem like it would be perfect for my active setup... 

Can it be bridged at all? 5ch would be awesome for my application.

Leo


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## ca90ss (Jul 2, 2005)

Still available and yes it can be bridged.
http://cgi.ebay.com/ws/eBayISAPI.dl...Sell_LogicX&refwidgettype=cross_promot_widget


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## 300Z (Mar 20, 2005)

Awesome. Thanks!


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## tyroneshoes (Mar 21, 2006)

Thats perfect chad.

Is there any way you can help a simpleton create one stereo input and two bridged stereo outputs and a bridged sub output?

Would you be willing to sell the switchbox/ps/2 setup?


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## ArcL100 (Jun 17, 2005)

tyroneshoes said:


> Is there any way you can help a simpleton create one stereo input and two bridged stereo outputs and a bridged sub output?
> 
> Would you be willing to sell the switchbox/ps/2 setup?


Ditto all that - that's how I'd be using it - and/or off the computer soundcard like the way scott_fx mentioned in the original thread. I honestly know nothing about this stuff (like what the hell a ps/2 cable is for starters lol), but bought one anyways, haha.

I'm not sure if my ratshack solderer is up for that kind of soldering anymore =/

-aaron


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## chad (Jun 30, 2005)

~Magick_Man~ said:


> did you get a message from the seller letting you know they had shipped or did they just show up?
> 
> ~Magick_Man~



Yes, I got a "payment received and will be shpping today" message. The seller is a very good guy and seems very honest. Shoot him a message.

Chad


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## coffee_junkee (Jul 13, 2006)

chad said:


> Yes, I got a "payment received and will be shpping today" message. The seller is a very good guy and seems very honest. Shoot him a message.
> 
> Chad


Hey Chad, when you made your BO box, which wire is the signal ground for all the channels? I got the 6 color coded positive wires figured out, but the ground has me all tripped up.


IMO, this unit rocks! I bridged the four full range channels, hooked it up to my B&W 705 monitors and it sounded damn good. Plenty of juice to piss off the neighbors and my fiancee..


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## chad (Jun 30, 2005)

coffee_junkee said:


> Hey Chad, when you made your BO box, which wire is the signal ground for all the channels? I got the 6 color coded positive wires figured out, but the ground has me all tripped up.
> 
> 
> IMO, this unit rocks! I bridged the four full range channels, hooked it up to my B&W 705 monitors and it sounded damn good. Plenty of juice to piss off the neighbors and my fiancee..



There's a bare wire in there, it's a common ground for all channels.




See the wire going to ground lug the first RCA? (black wires connected) That's it! But I shrinked it in clear shrink tube.

Chad


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## coffee_junkee (Jul 13, 2006)

Chad, 

Ok, I'm an idiot and mistook that bare wire for plain shielding. Now, does that ground need to be split and soldered to all channel's grounds' or just channel 1? My BO box has no switches for bridging signals, just FR to all the channels.

Also, mabye you can clarify something in the manual that's somewhat confusing. It doesn't say exactly what each channel is capable of driving with regard to impedance. Is it 2ohm stable, stereo? The instructions mention that it's capable of four, 8ohm speakers in parallel.. 

Ugg.. My brain isn't working today. Need more coffee...


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## STI<>GTO (Aug 8, 2005)

More information here --> http://www.pesupport.com/cgi-bin/config.pl?read=314066
and here --> http://xlobby.com/forum/viewtopic.php?t=5066&postdays=0&postorder=asc&start=0

Both several pages with some more good info. I also have a couple coming soon.


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## chad (Jun 30, 2005)

coffee_junkee said:


> Chad,
> 
> Ok, I'm an idiot and mistook that bare wire for plain shielding. Now, does that ground need to be split and soldered to all channel's grounds' or just channel 1? My BO box has no switches for bridging signals, just FR to all the channels.
> 
> ...



2 ohms per single channel stable, have not tested output yet into 2 ohms. If your box is metal and you tighten the **** out of the connectors you will only need to attach to one point. If you want to install all the lugs and tie them together then knock yourself out 

Chad


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## chad (Jun 30, 2005)

STI<>GTO said:


> More information here --> http://www.pesupport.com/cgi-bin/config.pl?read=314066
> and here --> http://xlobby.com/forum/viewtopic.php?t=5066&postdays=0&postorder=asc&start=0
> 
> Both several pages with some more good info. I also have a couple coming soon.



The cat in the first link has never dealt with "pre bridged amplifiers before" only "QSC" that is a pro amp.

If you do it like he says you will be grabbing 2 inverted channels and it won't work, you need to mono a PAIR (which is an inverted and non-inverted to do this. ONLY an even and an odd, not two evens OR two odds.

Yall are in the know how "pre-bridged" amps work right?

Chad


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## STI<>GTO (Aug 8, 2005)

chad said:


> Yall are in the know how "pre-bridged" amps work right?
> Chad


I didn't pay much attention to his instructions, as I don't have one infront of me yet, but to bridge you hook it up like most car amps right? For example: L+ and R-, or ch1+ and ch2-

Is that correct?


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## coffee_junkee (Jul 13, 2006)

chad said:


> 2 ohms per single channel stable, have not tested output yet into 2 ohms. If your box is metal and you tighten the **** out of the connectors you will only need to attach to one point. If you want to install all the lugs and tie them together then knock yourself out
> 
> Chad


After a large cup of Honduras finest, I feel like a moron. I should know better than to ask questions before being fully caffienated.. :blush: 

Looks like I'll be soldering all the lugs as my box is plastique! Knew I should have grabbed the alumi one..  

Thanks Chad..


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## chad (Jun 30, 2005)

This goddamn forum is not allowing me to quote today so i gotta do it old-skool

STI GTO Sed:
I didn't pay much attention to his instructions, as I don't have one infront of me yet, but to bridge you hook it up like most car amps right? For example: L+ and R-, or ch1+ and ch2-

Is that correct?


Me Sez:
Yep, 

Here's how it works......

All amplifiers use 2 positives (driven) for bridging, all (most) amplifiers have a positive (driven) and a ground for the speaker. The negative of the second channel is actually the INTERNAL driven lug and the positive is the GROUND.

Here's why.

Bridging works by inverting the phase on one channel, you can still use two speakers wired correctly, they will be out of phase, wire the second backwards and they will be In phase and IN absolute phase. By going to the two positives you are doubling the voltage at the outputs (one channel is swinging up while the other is swinging down) in this app both speaker terminals are "live" and there is no ground reference.

Pro amps do this with a switch, the switch simply comes off the preamp stage of channel A, inverts it and drives channel B with that, this ensures the same gain on both channels, it's mono, driven with only one channel of preamp, you then go off the two positives for a voltage double, Chb's preamp just pisses in the wind, often thru a resistor to prevent internal oscillation.

Car amps are "pre bridged” although they are labeled +-+- they are wired internally +--+. The phase of channel B is flipped from the get go and chB's output labeling is backwards. This was hinted at in the original post of this amp when I suggested driving headphones then finding out I had to invert one channel. So when you wire + chA and -ChB you are actually wiring + and + internally and bridging happens by simply monoing the inputs and matching gains. Some amps have a bridge switch which is simply a summing network.

There is a couple reasons this is done and has proven in the pro world to make a difference. The technical reason is that most LF information is mono anyway. Let’s say it is hooked up "conventionally" and you get a kick drum hit. Since amplifiers are bipolar and half of a channel amplifies the positive pulse and the other half does the negative side, both speakers pull off of the positive and negative section of the power supply at the same time. By bridging the amp or flipping the phase of one side, during the exact same impulse each speaker is pulling from different sides of the bipolar supply. So on a positive swing chA is pulling from the positive side of the PS but chB is pulling from the negative side, flip the phase of the speaker and both cones move in the same direction but the power supply is effectively balanced. This has been proven to increase headroom.

So on these amps ch's 2,4 and 6 have the phase inverted naturally so bridging channel one needs to take place between ch2, 4, or 6. It won't work by bridging between another odd number. 

The input section needs to be modified to mono odds and evens on this amp, no biggie, switch 2 wires or curt two traces and re-route.

Here's another explanation of the power supply thing 

http://www.prosoundweb.com/live/articles/daverat/amptricks.shtml

Enjoy everyone, let me know if I blew you out of the water, I'll assist, it's important to know this stuff!

Chad


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## azngotskills (Feb 24, 2006)

Hahaha...i think im more confused now :blush: What is the proper way to bridge this amp? Or do we just bridge it like a car amp +ch1 and -ch2? A diagram would merit brownie points but a how-to would be perfect


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## STI<>GTO (Aug 8, 2005)

Thank you sir. You're the man!


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## chad (Jun 30, 2005)

azngotskills said:


> Hahaha...i think im more confused now :blush: What is the proper way to bridge this amp? Or do we just bridge it like a car amp +ch1 and -ch2? A diagram would merit brownie points but a how-to would be perfect



I don't have provisions for doing diagrams except MS paint, and I would then do a worse job than my 6yr old 

Yes it's as you said and described in the manual, BUT ch1 and 2 have to be level matched and driven in mono, the existing preamp does not have the provisions for driving chs 1and 2 as the left then 3 and 4 as the right. It's wired LRLR on the input plug. If using the supplied preamp you would have to swap the wiring between ch's 2 and 3 inside the amp or preamp.

That being said. What do you all use for diagrams? Or if I wanted to take a picture, draw lines to **** and put labels on them to explain things? I SUCK at photo editing and still draw my schematics by hand! Believe it or not I find drawing them by hand to sink into my thick skull better (see drug use thread) If i draw them I can visualize them like trying to go to sleep etc, if I have software do it it's in one ear and out the other 

Chad


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## shinjohn (Feb 8, 2006)

Chad,
Thanks for your writeup. I'm getting to loath this forum as it's made me spend way too much money on audio recently! 

I had originally decided to pass on this one, but your pictures of the internals and the work you did to create an input box inspired me to use this for an audio project of my own.... Dang it, I just bought one!!!! 

My wife must think I'm going crazy. I just had 5 different boxes arrive on my doorstep yesterday evening, all audio related stuff. And I'm still waiting for my Alpine ring radiators too from PAC Parts! LOL!


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## chad (Jun 30, 2005)

I get home before my wife  Then burn the boxes  And always have an excuse cooked up and ready. Thank god she does not spend much time out in the shop!

Chad


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## azngotskills (Feb 24, 2006)

LOL...instead of your wives its my parents :blush:


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## coffee_junkee (Jul 13, 2006)

chad said:


> I get home before my wife  Then burn the boxes  And always have an excuse cooked up and ready. Thank god she does not spend much time out in the shop!
> 
> Chad


LOL..

A couple of months ago, my fiancee asked me what I would ever do with fifty Precision Power car amplifiers.. Mind you, she wasn't mad, just curious and of course I didn't have a good answer. So I asked her what she would ever do with all the pairs of shoes in the closet? She had no idea. We just stood there and laughed about it. I have my gear and she has her shoes..


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## chad (Jun 30, 2005)

Well, I have male genetalia but...... WTF are you going to do with 50 PPI amps? 

My vice is music, I have to look into the structural soundness of the area where I will put my music collection. 

Chad


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## coffee_junkee (Jul 13, 2006)

chad said:


> Well, I have male genetalia but...... WTF are you going to do with 50 PPI amps?
> 
> My vice is music, I have to look into the structural soundness of the area where I will put my music collection.
> 
> Chad


Well, for awhile there I was restoring them with the intent to resell. More for fun than profit because I'm a whiz at airbrushing and blending. That didn't work out so good because once they were perfect again I couldn't sell 'em. It was all downhill from there..  I have all the white Sedona's from the 50 all the way up to the 500ix. Complete set of white Arts from the A100 to the A1200 minus the Ax404. Complete set of white ProMOS and an extra MOS450. Besides that I have: Ax606.2, ProArt50, 5075DX, 4200AM, 2050AM, 2030AM, A200, A204 and probably 12 or so Sedona amps of various years/colors/wattages. Processors... gosh lots of them...20 or so. And one PPI Pro 10" sub. I have a thing for Xtant too, but let's not go there!


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## demon2091tb (May 30, 2005)

You's peoples are god.

I got 2 of them sitting at the house waiting for me to go pick them up and play with them, it'll be a few weeks though, mabey yall will have it all XLR'd up and 2 amps bridged.....mabey for connection to DCX-2496?


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## ~Magick_Man~ (Jul 11, 2006)

well i got my pair in today, and man they are sexay.
i cant wait to get them hooked up to something.

~Magick_Man~


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## niceguy (Mar 12, 2006)

I've had mine for a few months now IIRC, ever since ScottFX linked them in OT....I hooked it up to a pair of Goldwood poly cone 7" auto midbasses and a pair of the Tangband 1" neo tweets and they did pretty well sitting in cardboard baffles on the floor....

I was thinking they actually had adjustable xovers but since they don't, I've stashed it in the closet. No time to build custom passives for PC speakers and I can't find a Creative soundcard that doesn't wreak havoc w/my PC...

Neat little unit though....time for a garage sale...

Jeremy


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## chad (Jun 30, 2005)

The goldwoods with the silver cone? Those have always sparked my eye for a door install, they look too good to be true spec-wise.

Chad


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## tyroneshoes (Mar 21, 2006)

chad said:


> The goldwoods with the silver cone? Those have always sparked my eye for a door install, they look too good to be true spec-wise.
> 
> Chad


I got those 5.25 goldwoods (its actually a clear cone)for a passive install in my friends hyndai doors. Mated with a passive JL crossover and some quart tweeters I had laying around.

At first I was suprised, they performed well, especially in the midrange area. Midbass s typical of a 5.25 woofer meaning highpassed at 120 hz. two weeks into the install, the tinsel leads snapped on one. Build quality is not so great. Fixed with solder but for 10 bucks, expect an average speakers with average results. For ten bucks, what do you expect?

For this amp, I plan to use roman's microbes. I just finished them and they sound amazing.










Perfect for 30-60 watts. Plan to use a 6.5 tang sub for the bridged 5+6 channel. 

Design for microbes here


http://www.rjbaudio.com/Microbe/microbe.html


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## 300Z (Mar 20, 2005)

Just ordered mine too... along with a JBL 1500GTi.  
Now I need to get me an active crossover and some waveguides with a set of compression drivers and I'll be set. 

Thanks for the find guys!

Leo


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## niceguy (Mar 12, 2006)

Chad, yeah the 'silver' ones, that tyrone mentioned, but 6.5".....only limited aspect is the 2.5mm? xmax but running them free air w/about 30w rms on them from the amp, they didn't bottom out. I was more afraid of blowing the little TB new tweets w/no xover on them....

I've been meaning to try them out but am still running the Silverflutes in my van doors IB (love them though I just kicked a small dent in the cap)...

You said the amp does have a hp/lp depending on the channles? I may wait till I get a new PC and try a soundcard that has xover/eq ability so I can use the amp to drive a nice little PC speaker setup...

Jeremy


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## chad (Jun 30, 2005)

niceguy said:


> Chad, yeah the 'silver' ones, that tyrone mentioned, but 6.5".....only limited aspect is the 2.5mm? xmax but running them free air w/about 30w rms on them from the amp, they didn't bottom out. I was more afraid of blowing the little TB new tweets w/no xover on them....
> 
> I've been meaning to try them out but am still running the Silverflutes in my van doors IB (love them though I just kicked a small dent in the cap)...
> 
> ...


Yes 1-4 are HP and 5-6 are LP Mono, Preamp does the XO, the Freqs are darn near unuseable. I'll know more after putting it on an analyzer.

Chad


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## niceguy (Mar 12, 2006)

Can you get a soundcard that actually allows you to electronically xover mids/tweets? As in slap a mid and tweet in a small enclosure with no passive, and tune/set from the computer?? That would be awesome....

I just don't have the time to buy, try and retry passives so some kind of PC xover would be necessary for me...

Jeremy


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## tyroneshoes (Mar 21, 2006)

niceguy said:


> Can you get a soundcard that actually allows you to electronically xover mids/tweets? As in slap a mid and tweet in a small enclosure with no passive, and tune/set from the computer?? That would be awesome....
> 
> I just don't have the time to buy, try and retry passives so some kind of PC xover would be necessary for me...
> 
> Jeremy


Im thinking that with Chad's box design you could just use fmods.

http://www.partsexpress.com/webpage.cfm?&WebPage_ID=3&manufacturer=265


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## demon2091tb (May 30, 2005)

How would one go about connecting external processing so 6 FR Ch's would be needed, how would one also go about linking the 2 amps together for [email protected] usage?


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## chad (Jun 30, 2005)

demon2091tb said:


> How would one go about connecting external processing so 6 FR Ch's would be needed, how would one also go about linking the 2 amps together for [email protected] usage?



Just build the break out box for 6 Ch's. As for linking 2 you could use the same BOB, hang 2 link wires off of it, then wire 1/2 to an RCA then 3/4, 5/6 and on the other amp 1/2 (7/8) 3/4 (9/10) and 5/6 (11/12) Wola 6 RCA's 12 channels utilized to derive 6 bridged up channels. I'll bet you that they make some potent heat at 4 ohms bridged according to another forum linked.

Chad


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## chad (Jun 30, 2005)

Remember if you have soldering chops you can put the connections on the amp and forget the box, I can help you thru it. Bridging can take place internally so only 3 RCA's are on the amp.

Chad


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## demon2091tb (May 30, 2005)

chad said:


> Just build the break out box for 6 Ch's. As for linking 2 you could use the same BOB, hang 2 link wires off of it, then wire 1/2 to an RCA then 3/4, 5/6 and on the other amp 1/2 (7/8) 3/4 (9/10) and 5/6 (11/12) Wola 6 RCA's 12 channels utilized to derive 6 bridged up channels. I'll bet you that they make some potent heat at 4 ohms bridged according to another forum linked.
> 
> Chad


Where is that link and is this bad heat?


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## chad (Jun 30, 2005)

In this big-ass thread http://xlobby.com/forum/viewtopic.p...der=asc&start=0 One person complains of it running hot. These folks are using them in home distribution, he may be running it balls to the walls 24/7 and using L-pads in the rooms. Then I would suspect it to run a tad warm 

I haven't had the time lately to wander out to the shop and really beat it up, hopefully tomorrow/Monday.

Chad


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## tyroneshoes (Mar 21, 2006)

chad said:


> In this big-ass thread http://xlobby.com/forum/viewtopic.p...der=asc&start=0 One person complains of it running hot. These folks are using them in home distribution, he may be running it balls to the walls 24/7 and using L-pads in the rooms. Then I would suspect it to run a tad warm
> 
> I haven't had the time lately to wander out to the shop and really beat it up, hopefully tomorrow/Monday.
> 
> Chad


Well, mines to arrive shortly so if you dont mind Chad, I may be pming you with a bunch questions about bypassing the preamp and creating one rca input and hopefully a stereo and a mono output bridging all the channels.


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## chad (Jun 30, 2005)

I'll start looking into combining networks to mono out to one channel. 1 input meaning one stereo input right (as in 2 RCA's?)

Chad


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## tyroneshoes (Mar 21, 2006)

chad said:


> I'll start looking into combining networks to mono out to one channel. 1 input meaning one stereo input right (as in 2 RCA's?)
> 
> Chad


Yes I need to use my preamps stereo (r and l rca) output into the amp and then have 3 channels of output ( 60x3) considering Ill be bridging all channels. Two will be stereo speakers and one channel will be for a small sub. Easiest way is best for me, so I dont mind use of y adaptes and passive crossovers if necessary.

Thanks
TS


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## chad (Jun 30, 2005)

Specs from a torture session......

Ran it at the verge of clipping, sine wave, 100% duty, in this config for 30 min then took measurements..

1/2 bridged at 8 ohm
3/4 bridged at 8 ohm
5/6 bridged at 4 ohm

came up with....
1/2 39.47W / 17.77VRMS
3/4 39.47W / 17.76VRMS
5/6 76.30W / 17.47VRMS

Not half bad. It got pretty damn hot but never shut down, all voltages were the same at 10Hz, 500Hz, 1KHz, and 25KHz. So she'll make it way above and below where we can hear.... No clipping.


The 5/6 side got hot QUICK! but I'll run it again tomorrow at 4 Ohm on 1/2 to make sure it was not that section of the power supply getting hot. After time the whole heatsink leveled out to about the same temp (about 10 Min). 

I'll also do a long term 1/3 power test, 100% duty for ****s and grins to check for heat in a more realistic condition.

Chad


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## azngotskills (Feb 24, 2006)

thanks for your input on these amps...got mine in but havent decide how im going to use them yet  I know im building a breakout box for RCAs like your though


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## azngotskills (Feb 24, 2006)

Im am trying to get parts together in order to build the pre-amp RCA box, are these the right Female RCAs? Sorry never built something like this before :blush:


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## chad (Jun 30, 2005)

Those will work, these are cheaper and perform the same task 

http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=090-280

Chad


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## azngotskills (Feb 24, 2006)

Thanks Chad...i was looking for the ones like yours but couldnt find them but now I have 

PS: Is a similar BUD box that you have, available on partexpress.com? I just want to make one big order. Thanks and sorry about the noob questions and troubling you :blush:


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## ~Magick_Man~ (Jul 11, 2006)

http://www.partsexpress.com/webpage...orderby=1&sm=1&so=1&search_type=main&desc=ASC

the HAMMOND project boxes look to be what he has.
i am not sure what size he used but there is quite a selection.
i will probably be ordering a pair myself soon so i can wire up the 2 amps i got.

~Magick_Man~


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## niceguy (Mar 12, 2006)

Tyrone....thanks for the F Mod suggestion....haven't used those in over 10 years and didn't even think of 'em....I may be able to actually put to use something I've bought on impulse, how nice...  

I'm thinking of trying to port the Goldwoods though they and the tweets are 4ohm...never tried using car audio speakers for home though I guess it's no worse than doing the reverse, as long as the amp will handle it...

Thanks guys

Jeremy


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## azngotskills (Feb 24, 2006)

~Magick_Man~ said:


> http://www.partsexpress.com/webpage...orderby=1&sm=1&so=1&search_type=main&desc=ASC
> 
> the HAMMOND project boxes look to be what he has.
> i am not sure what size he used but there is quite a selection.
> ...


Thanks man....i need to learn how to search the PE site better


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## SQ_Bronco (Jul 31, 2005)

niceguy said:


> Tyrone....thanks for the F Mod suggestion....haven't used those in over 10 years and didn't even think of 'em....I may be able to actually put to use something I've bought on impulse, how nice...


rather than spending all that money on f-mods (which use low quality components, and are not precise) you can diy your own:

http://www.t-linespeakers.org/tech/filters/passiveHLxo.html

the toughest part will be figuring out your amp's input impedance.


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## chad (Jun 30, 2005)

azngotslills, the Hammonds will be fine, go with the aluminum ones they are insanely similar to the bud boxes. Be careful drilling them, the bit will want to catch... BAD!


SQ
I think the way F-mod gets around the impedance thing is by making the inline device have a final "input impedance" (but actually an output impedance) by dropping a resistor across the output. Then the relatively high input of the amplifier has little effect on the final crossover frequency, although it does have some tolerance issues. Lets say the amp has an input impedance of 10K and you adjust the crossover for 1K and drop a 1K across the input of the amp. The 10K will have little effect. You dig? or did I just talk myself in a circle?

Chad


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## SQ_Bronco (Jul 31, 2005)

chad said:


> I think the way F-mod gets around the impedance thing is by making the inline device have a final "input impedance" (but actually an output impedance) by dropping a resistor across the output. Then the relatively high input of the amplifier has little effect on the final crossover frequency, although it does have some tolerance issues. Lets say the amp has an input impedance of 10K and you adjust the crossover for 1K and drop a 1K across the input of the amp. The 10K will have little effect. You dig? or did I just talk myself in a circle?


yup, that sounds like a good way to make it work without having to measure anything.


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## Preacher (May 8, 2006)

Hey Chad, 

On those passive line level xovers are you suggesting the roughly equivalent to a zobel network. That sounds like a great idea.


----------



## niceguy (Mar 12, 2006)

Has anyone found where the Preamp crosses the channels at??


----------



## chad (Jun 30, 2005)

niceguy said:


> Has anyone found where the Preamp crosses the channels at??



Too damn high for subs, too low for anything else. No imperical measurements yet. I'd love to have a schematic for the preamp so we could swap out components in the XO circuit!

Chad


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## chad (Jun 30, 2005)

Preacher said:


> Hey Chad,
> 
> On those passive line level xovers are you suggesting the roughly equivalent to a zobel network. That sounds like a great idea.



Ummmm, yeah, kinda. You are not doing any reactance correction, just lowering the "input impedance of the amp" yourself so that the actual input impedance of the amplifier does not mess with your chosen crossover point as much. making the input impedance more predictable) There will be loss, but after hooking up the amp and listening to it I can attest you can drive it with about anything. when cracked wide open it's pretty darn sensitive! I would not worry about a couple dB of loss.

an example....

If the amp has a 10K input impedance with a 1 K strapped across it the final input impedance would be 909.091Ohms

If it had an input impedance of 20K and a 1K strapped across it the final impedance would be 952.381Ohms

As you can see DOUBLING the input impedance has little effect on the final impedance with a 1K strapped across it, granted there IS a difference but that's where the tolerance issues with F-Mods come into play. Darn near any source unit can drive a 1K input impedance with ease if these were real numbers.

Chad


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## 300Z (Mar 20, 2005)

Just received my amp today. Ordered it last weekend and received today... and the guy is only 30-some miles away from me..  

Just tested the amp bridged channels 1+2 left 3+4 right and 5+6 sub.  works great. Except the FR and crossover is all screwed up.

Chad, you think we could bypass the crossover and EQ on the Pre-amp while retaining the volume control? That would be perfect for me for the time being.

Later down the road I'll need the 6 individual inputs for when I get the new crossover and the compression drivers.  

Oh, you think the amp can handle subbass duty on bridged 5+6ch driving the 1500GTi? I tested it with my 1000GTi for about 45min and the amp never even got warm.  

Leo


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## 300Z (Mar 20, 2005)

300Z said:


> Just received my amp today. Ordered it last weekend and received today... and the guy is only 30-some miles away from me..
> 
> Just tested the amp bridged channels 1+2 left 3+4 right and 5+6 sub.  works great. Except the FR and crossover is all screwed up.
> 
> ...


Chad?


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## chad (Jun 30, 2005)

OOps! Sleepin at the switch :blush: I played Rokstar all weekend so I'm just catching up 

I was going to do more work the amp project this weekend but got sidetracked on this weekend's impulse buy/project. Should be finished with it by Tuesday night, I'll get a pic up, it's pure 'lektrik sex! I HAVE to get it done before next weekend and have a lot of soldering to do! I do However have heat figures for posting that I brought today and I'll get them up soon.

I kinda gave up on the preamp for the time being. it's an SMT dual sided board with THIN traces. It's going to take a fine tip iron, a steady hand, and some drive to do what you want. I decided a straight path would be best for me. You can always obtain a 250K-500K dual gang pot (linear or audio taper it's up to your preference, I prefer linear though) and wire it up as a stereo volume control. This will make the preamp go bye-bye including the possible noise from the Mic Pre, tone controls and gain stages. The amp can be adjusted to be heinously sensitive, you don't need any more gain IMHO. 

Anything is possible, it's just going to take some time at the bench probing around. The crossover needs to be bypassed as well as the channel 5/6 summing (possibly putting the summing on some kind of switch) Not having the service docs SUCKS!

You can see the crossover section in the upper right hand corner, see the op-amps and support caps, etc? You will see more caps/op-amps in the lower center, that's the tone circuit.

Pic: 

It's just going to take a bit of time I guess, I'd also like the Mic Pre gone unless yall are karakoe fans 

As for the 1500GTi... Go for it! It's probably the best driver for the task, it's an easy load and is quite efficient. It will make the most of what you have. In fact, I'd do it or still may if/when I bastardize a 2226 Recone kit  I have it on my shop speakers bridged, using 4 of the channels and it gets louder than I thought it would before noticable distortion, verah cool!

Chad


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## 300Z (Mar 20, 2005)

You're right. I just opened mine and the traces are really too thin. Neither of my soldering irons tips are fine enough.  Oh well, screw that thing...  

I'm just gonna get a cheap Behringer CX2310 crossover for the time being, that should do the trick I suppose... Unless you recommend against the Behringer unit.?

Leo


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## chad (Jun 30, 2005)

The Behringer will do just fine. Another cheapo but good analog crossover is the samson S-3way.

Chad


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## chad (Jun 30, 2005)

Here are the results of heat after testing the amp at 1/3 rated power for 8 hours.

The room temp was 68.4 deg F +/-2 degrees

I ran the amp bridged 2 channels of 8 ohm and 1 channel at 4 ohm. So in theory 4 of the channels were seeing a 4 ohm load and 2 of them were seeing 2 ohm.

The temp readings were the same from side to side when i moved the 4 ohm load around so no worries about one side being better for the bridged channels due to power supply component mounting.

The side with 2/2/4 ohms ran at a temp of 155.4 Deg F average with a high of 161 Deg and a low of 146 Deg

The side with4/4/4 ohms ran at 148.7 Deg F with a high of 153 Deg and a low of 138 Deg.

Yes it ran hot but never thermaled out you certainly could not comfortably keep your hand on it! The temp did rise and fall and the rise and fall was perododic, dunno why, possibly a self adjusting bias scheme? There are some small transistors on the sink and sometimes those (MPSA93 If I remember right) are used for thermal tracking. But that's a shot in the dark.

Chad


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## solacedagony (May 18, 2006)

Any idea what the thermal max before something melts down is? Even a guesstimate?


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## chad (Jun 30, 2005)

Hell if I know, but I've felt amps run a lot hotter for a longer time 

Thing is that the WHOLE amp gets hot since it's a brick of aluminum and nicely bolted together, it nicely ironed (pressed) the carpet on my bench 

Chad


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## 300Z (Mar 20, 2005)

chad said:


> The Behringer will do just fine. Another cheapo but good analog crossover is the samson S-3way.
> 
> Chad


The cheapest place I found for that Samson is about $60 more expensive than the Behringer still...  But I haven't looked hard enough... 

Never used/worked with any Samson gear before, Are they decent?

Thanks.

Leo


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## chad (Jun 30, 2005)

The samson is about the same as the behringer quality wise IMHO. It has metering, phase reverse per channel, mute per channel, and limiting although i don't care for the limiters, the release is too slow. It's also got CD horn EQ but i don't use that either. i like the samson because of it's WIDE Xo freq selection. I got a helluva deal on it at the time 

Chad


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## 300Z (Mar 20, 2005)

Oh, cool. But I just need a 2 way + sub. Would the S 2 way work too?

Leo


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## chad (Jun 30, 2005)

Didn't know there was a S-2 way 

The 3 way does 2 way, 3 way or mono 4 way with all options of mono subs also, very versatile unit.

Chad


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## demon2091tb (May 30, 2005)

So guys how is this little amp turning out, i have 2 sitting at home and i'm going to pick them up this weekend to start messing around with. What can i expect from them, i have 2 and i want to pretty much run a 3way stereo setup in the future.

First off though i think i'm going to modify slightly my bookshelfs to run them active by the dcx2496 i'm going to buy.

How would i eventually go about bridging both amps to a 3way mono signal on each amp, so each amp would run each side for the 3channels .

Also is this truely a zapco styled or origin amp, What would be some background on this particular amp as well as the BSG/zapco connection.


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## chad (Jun 30, 2005)

Turning out well, it play's suprisingly loud, is free of any strange noises and will do quite well in your situation. Read around, there's a couple ways of making the channels work or PM me and I can give you the skinny. It bridged nicely albeit you have to accurately set the levels, there's no ganging switch so a good voltmeter and tone are in order. 

Chad


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## demon2091tb (May 30, 2005)

chad said:


> Turning out well, it play's suprisingly loud, is free of any strange noises and will do quite well in your situation. Read around, there's a couple ways of making the channels work or PM me and I can give you the skinny. It bridged nicely albeit you have to accurately set the levels, there's no ganging switch so a good voltmeter and tone are in order.
> 
> Chad


Will do when i get a few minutes, hitting the books pretty hard right now.


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## tyroneshoes (Mar 21, 2006)

Ok, I got mine up and going and I have to say, Im impressed. Very good sound quality and decent power. More than enough for my apartment and setup.

I have mine set up as a 3 channel amp. 1 left, 1 right and 1 mono rca input. All the channels are bridged. I didnt have to buy anything but a female rca input set at radio shack for 4 dollars. You dont even need the female input if youre ok with 3 stereo channels. It was very easy so I'll break it down for those who want a similar setup.

First thing to do is unscrew the worthless preamp and open it up. Then remove the circuit board inside. We only need one part of that but we'll use the box as the preamp chassis.

We are going to use the provided rca inputs on the preamp and the box the preamps in. Disconnect the red rcas from the circuit board. Youll see where to cut. Then your board should look like this










You dont need the board again and its not going back in the box. Now cut the ps2 cable and strip it. Youll have 6 colored wires and a bare wire. This cable enters through the ducking level opening on the preamp cover.

Ok, so now we solder following Chads guide on color.

For a stereo and mono input: 

Reattach the rca input to the preamp cover with the screw. Make the rca's soldering points attachents visible. Youll see the input is the nice long tab you have to solder on the upper part of the rca and the ground is underneath. we solder channels 1 and two to the red rca input (the top connection on the rca) then solder channels 3 and 4 to the white rca. Solder the bare wire to the grounds of both rca inputs. 

Then get a female rca input, (I just went to radio shack and got a gold set for $4) and attach it to the preamps cover in the "output" hole. You probably have to find a washer as the hole is too big. I found a bolt that worked well. Solder channels 5 and six to the same input and run a wire from the stereo input's ground to the mono rca ground. This pic should help explain and show you appropriate colors. Excuse the sloppy solder. I had to resolder when I added the mono channel.










Then screw back the cover and your preamp is ready. It should look something like this.










I used some brushed aluminum contact paper I had (found at lowes) and just covered the rear preamp cover with it. No more holes and it made a nice finish if you want this to be visible. Otherwise this preamp could be hidden.










Here it is in its home powering my left and right and center (mono) using my Marantz recievers 7.1 preouts. 










Make sure all the gains match. 

The sound quality is excellent and far superior to my marantz reciever's built in amp. Much more detail and seems clearer. Suprisingly loud and powerful at the 60x3 its rated for. No problem powering my speakers.

You might first get a horrible buzzing noise when you first plug in your amp and connect it to speakers. Thats because your reciever and the amp uses a different ground. Get a 3 prong to two prong adapter, or just pull off the ground prong and the noise will be gone.

Hope this helps some people. So far I have to say this is the best ebay deal as of yet.


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## chad (Jun 30, 2005)

JR DIY Alert!!!!! Yall are gonna be proud!

We got our 6 year old son a boom-box for Christmas, the standard Sony Fare with Radio Cd, Etc. He was stoked for a bit but he thought it sounded bad, and it does. We have bred ourselves a mini-audiophile 

In the quest for something better I told him he would have to work to get what he wants and that we would use things that I purchased cheap, traded for, or were lying around. And off we went this weekend. We have been trading Labor services for equipment, gotta teach them commerce early  And you can now eat off the shop floor, and for months to come 



Keep in mind that this gizmo was COMPLETELY designed, assembled, and painted by a 6 YEAR OLD! Since he can't read fractions on a tape measure (hell, he can barely read) he used the actual devices or a dowel to measure cuts for the table saw. He set the saw up and I made the cuts, in fact the only thing he did not do was guide the router and make the cuts on the table saw. There's 5 chunks of wood here total, all measured by the components or a 1/4" dowel  He did all the gluing, clamping and brad nailing. Then after shooting a few brads where they shouldn't have gone he did the bondo work after I ground the brads out into the wood. Fleckstone paint was used to cover imperfections and it did not turn out too bad. So here is his creation!




We used a surplus switch mode charger originally intended to charge Lead-Acid cells. I modded it to make it think it is a power supply and it makes 12.5V at 3.5A, more than enough to power the headunit, the amp has a built in supply. paired it up with the Insignia speakers (50 bucks a pair) and Wola! His new Rig........ Almost... (read below)




Now for the Almost..... He wants a sub (lets see him measure that box out with a Dowel  )

He wants to do some horse trading, he has in his possession the Breakout box I made up for this amp and a spare stock preamp (no spare interconnect cables other than the "phone plug") I plan to just install RCA's on the amp so the break out box is not needed. He is wanting to work out some sort of trade for a 10" or larger 4 ohm or dual 2 ohm sub driver that MUST be rather efficient, work in a vented enclosure, and not look "girly," The Girly thing is straight from his mouth. Anyone need a breakout box and have a spare driver lying around? We can work on Shipping charges since the driver is much heavier than what we are shipping.

Chad


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## 300Z (Mar 20, 2005)

Man, this is super badass.  

If this was a little while ago when I was giving stuff away I would find a way to ship you one of the subs I had. I gave away a SS exact 10 4ohm and a Diamond Audio M5 10" DVC4, both work very well in small ported boxes.


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## chad (Jun 30, 2005)

A day late and dollar short


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## 300Z (Mar 20, 2005)

If I only knew...


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## shinjohn (Feb 8, 2006)

Chad,
That is awesome! Great job by your son! You must be really proud! 

I just pulled out a Boston Rally 10" (4 ohm) sub from an old install of mine. It's in a nicely tuned bandpass enclosure (designed & built by me), is very efficient, and sounds pretty darn good IMO (for what it is). I had told another buddy that I would sell it to him; but let me double check with him on that. (I haven't talked to him in awhile) I'll get back to you, but this might be an option.


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## ArcL100 (Jun 17, 2005)

Your 6 year old > me.

-aaron


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## chad (Jun 30, 2005)

MaMa was sick this weekend = Crabby = Men in the shop/garage cutting wood and tearing **** up 

He's pretty handy with his hands and can pretty much put together/draw (roughly) what he visualizes, that helps. It's fun to watch him go at something because a youngster's thought process is so much different than ours, and sometimes makes more sense. For example, to cut the bottom/amp shelf what do you do? Slap the amp on the table saw and cinch the gate down. Next, sandwich the H/U between the wood, take your trusty dowel mark how high you want the sides to come up, holler at dad to cut the dowel with the miter box, use the dowel to measure the gate for the table saw, cut two peices and grab the clamps! Caveman style, not one measurement taken that involves numbers. Recess the headunit? Sure! Slide the unit in (damn there is a gap) slide it over, measure the little square off to the side (2 more dowels), measure, cut, slip that in, glue, clamp, nail. While that dries slip the head in trace the trim ring and it's "careful time" with a small chisel and hammer.

The drawback is the "now factor" with a kid, glue and paint needs to dry, thankfully he has an imeasureable love for the shop vac, he cleans up, I whip up a power supply. Off for dinner, screw around for a bit, work on the "mousetrap challenge" (don't ask) and it's paint time, paint it, whip up a drying rack from scraps, and bedtime.

How to keep a kid busy 101 

Chad


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## SQ_Bronco (Jul 31, 2005)

Lol, that's awesome.

FWIW the deal of the day at parts express is a 10" 4 ohm Audax woofer for $29. Seems like a decent deal.


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## tyroneshoes (Mar 21, 2006)

I hate when kids are better than me.

That kid has some serious aptitude.


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## toolfan91 (Dec 7, 2005)

I have a SB Audigy 2ZS, is there any software out there so I could just actively crossover the independent channels?


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## chad (Jun 30, 2005)

I swear this the last mod 

No more need for the breakout box! Here's why and how.

Why? It's clumsy and there's enough room inside to work 

Here's what you do (the second type of mod from the first post.) I only needed 3 inputs but by drilling 3 more holes you can have 6, and yet 3 more holes then you can do bridging/un-bridging via little toggle switches.

I'd like to preface this by saying more precautions need to be done here, the solder points are very small and a well controlled iron/small tip are needed. I used a Weller WTCPT station and a Weller 1/16" "screwdriver" tip and a steady hand. Also you will be drilling and finishing Aluminum, it can get everywhere, the amp is comprised mainly of SMT stuff and even a metal filing laying across a component or wedged in some op-amp legs can have devastating effects. So do this after you take the bottom off!!!




That's right, mask off the area where you will be drilling, then cover and mask all the internals. an air supply can be handy to GENTLY blow stuff off as out work while holding the amp "open part down."

Punch your hole guides:



Drill and install RCA's See the metal shavings I was talking about? I like to drill a pilot hole then go at it with a unibit, I pretty much always drill everything but unibit holes on the drill press so the unibit saves oodles of time, the RCA needs a 1/4" bit. The Chassis is signal ground, no grounding is needed.




Now, this where you will need "The Knack" see: http://video.google.com/videoplay?docid=2021369175979347037 You will be soldering to surface mount components, it's not fun but with the right tools you'll be OK. At least the amp was not expensive eh? Mua Ha Ha Ha  Measure out the length of wire you will need to go from the SMT resistors by the original input to the RCA's These resistors:




Then strip one end at about 1/32 of an inch and the other at about 1/4" Tin them. the 1/32" is the more important to do right, you will want great solder penetration and a little blob on the end without the little "DairyQueen" sharp point protruding made of solder (love those engineering terms.) Next locate the input side of the resistor (side closest to the original connector) Add a small amount of solder to the input side of each QIUCKLY as to not heat the whole device and pop it off the board. You will want a shiny "blob" there about twice the size of the original. Go fast and keep a steady hand. The order of the inputs on these resistors is in the first post of this thread, note that it is rather unconventional but makes sense if you know the pinout of a PS/2 connector. Work from the top down, it's easier. Approach the new connection with the 1/32" stripped and nicely tinned wire, just before you touch the SMT pad apply heat to the wire and the instant it penetrates the blob on the board remove the heat. Hold the wire steady as it cools. Give it a tug (lightly) to make sure it's on there and then wire the RCA up (much easier) The tug and moving while wiring the RCA will give it a good test to make sure it's gonna hold. 

If you have never done this before and want something to practice on then use the preamp, if you are not going to use it. Just practice tacking wires to your little heart's content.

So "rinse lather and repeat" the other 5 input resistors and you will have something like this: 



I used the signal conductors from some scrap Gepco 61801 I had laying around after I copped a bunch of the drain wire for another project, you will want to use some pretty small stuff, I recommend stranded, and NOT gutted network cable, I've had bad luck with the solder holding and the wire breaking on that stuff.

When you are done you will have this (or more RCA's):




Women will flock to you and you will gain popularity at the lodge/golf course.

Chad


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## chad (Jun 30, 2005)

Copped from the PE Forum, why we are probably getting these so cheap 

http://www.thesmokinggun.com/archive/machado1.html

Chad


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## solacedagony (May 18, 2006)

If you're bridging, say channels 1+2, do both channels need input, or do you only need to input on channel 1, or 2?

Edit: Also, for those of us that suck at soldering (read: me), would it be possible to pull off that metal sheath over the 6-pin input and just solder onto the wires in there, instead of the board itself?


----------



## chad (Jun 30, 2005)

solacedagony said:


> If you're bridging, say channels 1+2, do both channels need input, or do you only need to input on channel 1, or 2?
> 
> Edit: Also, for those of us that suck at soldering (read: me), would it be possible to pull off that metal sheath over the 6-pin input and just solder onto the wires in there, instead of the board itself?



(1 AND 2) not (1 OR 2) and the levels have to be matched really well (preferably with a scope or voltmeter) for best efficiency. Since you will be using the two internal positives of the amplifier (to double voltage) each channel will need to receive the same signal (the even channels are already phase inverted).

Pulling the 6 pin out would be a rough job, the amp board will need to come out of the sink at which time you risk damaging the Sil Pads for heatsink conduction and pulling your hair out. Count on HOURS of work for this. If you decide to go the "get-er dun" route and force/break the connector out then you risk damaging the board and you are in worse shape then screwing it up. If you are truly bad at soldering or don't have the tools, the break out box is for you. The boy (my kid) has one for trade  If you can get the sheath off without damage (i think it's soldered to the board) then knock yourself out, it will work fine!




See the solder point for the sheath right next to the right-most 10K pot? It's ground for sheilding purposes.

Chad


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## Marbles_00 (Jan 31, 2007)

Hey guys,

I just chimed in here from the Xlobby forums, where we've been discussing this amp...more towards connecting to it without the AIP. Most of us are using it in a music distribution setup. One guy has set it up in a DIY projector system as well. Pretty cool.

Chad, I just wanted to say, great job on the review and the mods you've done to the amp, and your son is very talented indeed. Also thanks again for letting us know over in the Xlobby forums of this post here. Excellent read.


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## chad (Jun 30, 2005)

Marbles_00 said:


> Hey guys,
> 
> I just chimed in here from the Xlobby forums, where we've been discussing this amp...more towards connecting to it without the AIP. Most of us are using it in a music distribution setup. One guy has set it up in a DIY projector system as well. Pretty cool.
> 
> Chad, I just wanted to say, great job on the review and the mods you've done to the amp, and your son is very talented indeed. Also thanks again for letting us know over in the Xlobby forums of this post here. Excellent read.



Thanks and congrats on joining, feel free to gander around, please. There are some sharp cookies here as on your forum, even if car audio is not your bag. It's nice to have you, enjoy your stay. We sometimes wander off into home and pro audio too 

Chad


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## azngotskills (Feb 24, 2006)

Bring this to the top....BUY MINE http://www.diymobileaudio.com/forum/showthread.php?t=9571 [/shameless plus]


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## shinjohn (Feb 8, 2006)

Chad,
Thanks again for the input/config info. I did the mod, mouting the jacks as per your second mod. Works great. Some pics:
































Figured I'd show a pic with the cheapie 10/25W pencil soldering iron I used, which with a steady hand, got the job done great!

And about the amp's sound: it does seem to have reasonable power, but to me the amps sounds like it boosts the low end just a tiny bit, which I guess isn't a bad thing if you are running small speakers.... Compared head to head to my Adcom, I don't think it really compares at all, but considering the price, it's a nice little amp.

Thanks again, Chad!


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## 300Z (Mar 20, 2005)

Chad have you ever done FR measurements of the amp?


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## chad (Jun 30, 2005)

Nah, it made full power from way lower than 20Hz to way above 20KHz. The amp is really straight ahead, the preamp is a different sory, I gave it about an hour befor I decided I was not going to use it


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## 300Z (Mar 20, 2005)

Cool, thanks. 
I'm also only using the amp, I only hooked up the pre-amp just to take a quick listen and ditched it.


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## bmaupin (Feb 22, 2006)

I finally started using my BSG/Zapco amp. I am currently only using 1 channel to power my center channel - which consists of 2 Hivi BS3's mounted in their original packaging (yah!  ) My plan is to use 3 of the channels to run the final version of my center channel triamped that will be a 2.5 way - 4 BS3's and a tweeter yet to be named (the single 27TDFC I have is the front runner as of now) - and 2 other channels for rear left & right surround speakers (also yet to be built).

I created an input box from the first preamp that I received that had bent & broken control pots. I used some copper circuit board for connectivity and that allowed reusing the rear 4-input connector as a means to connect inputs 1-4 to each other in any way desired (and not require using y-cables).


































The amp and the Hivi's sound good - even with the carboard enclosures. I wish I would have bought a few of these amps since they are so versitle, have 6 channels and can be placed behind other components in my already full entertainment system cabinet.

The bonus of being able to bi-amp or tri-amp the 2.5 way center channel is that I can run the inner and outer mids paralleled and have 6db of increased output capability over having to run the inner and outter mids in series and then paralleled if I was going to be running 1 channel of amplification.

Thanks to Chad for the correct channel wiring color coding!

Has any one tried bi-amping with theirs?

- Brad


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## 300Z (Mar 20, 2005)

bmaupin said:


> Has any one tried bi-amping with theirs?
> 
> - Brad


Been running mine 4ch bridged down to 2ch powering the mids and the other 2ch powering the tweeters since I got my amp.

Leo


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## chad (Jun 30, 2005)

Get this shat... I have yet to use mine :blush: 

I used it to test a pair of speakers once  

Chad


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## bmaupin (Feb 22, 2006)

300Z said:


> Been running mine 4ch bridged down to 2ch powering the mids and the other 2ch powering the tweeters since I got my amp.


Leo,

How do you make the connections for bridging? I am only familiar with how home audio amplifiers do this - invert one signal (done internally off an opamp or similar) to feed the second channel and then take the outputs from the + on the main channel and the - on the inverting channel.

Thanks, Brad


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## chad (Jun 30, 2005)

bmaupin said:


> Leo,
> 
> How do you make the connections for bridging? I am only familiar with how home audio amplifiers do this - invert one signal (done internally off an opamp or similar) to feed the second channel and then take the outputs from the + on the main channel and the - on the inverting channel.
> 
> Thanks, Brad



That is explained in this very thread I believe.....

But it's just like a car amp but you have to drive the 2 channels with the exact same signal. They are already phase inverted, CH 2,4,6 is already out of polarity in a driven/non driven sense, the markings on the amp depict 2 channel operation.


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## bmaupin (Feb 22, 2006)

I see - the paired channel has its + output connected to ground, inverts the input and the driven/amplified output is the -. 

I read the previous posts that mentioned this, but it was not clear to me - it seemed to indicated that you could bridge any 2 channels. I now understand that you can bridge between any odd (+) and even (-) channel.

thx!


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## chad (Jun 30, 2005)

bmaupin said:


> I see - the paired channel has its + output connected to ground, inverts the input and the driven/amplified output is the -.
> 
> I read the previous posts that mentioned this, but it was not clear to me - it seemed to indicated that you could bridge any 2 channels. I now understand that you can bridge between any odd (+) and even (-) channel.
> 
> thx!


You got it man! Go nuts!


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## 300Z (Mar 20, 2005)

Just test it report back. 

This amp was an awesome find btw.
When I first got it I had it powering my mids and tweeters + the sub all active and it was pretty nice. The low end output was perfect at my listening position but in the other room it sounded like I had a Quad of 18" with 1kw on each due to the paper thin walls in this app, it was crazy so I had to ditch the sub and honestly I haven't missed it much. 

Leo


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## sensibull (Jul 22, 2007)

> I finally started using my BSG/Zapco amp. I am currently only using 1 channel to power my center channel - which consists of 2 Hivi BS3's mounted in their original packaging


Hey guys. Funny coincidence, as I was just thinking about using this amp in a portable boom box for my Zune player, with some Hivi B3Ss or B3Ns and the mighty little 5" Tang Band sub. I'm thinking a 150Hz crossover would be about right, given the Hivi's inability to go much lower than that.

Am I remembering it right that the preamp's crossover for this amp is right around there?

Would I be stupid to use the preamp, and not build my own crossover (having never done so before, I am a little leery)?

Any feedback is much appreciated.


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## Ge0 (Jul 23, 2007)

I'm going to assume this deal is long gone. So, does anyone want to sell me a few of these little beasties?

Ge0


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## chad (Jun 30, 2005)

I have one I may let go of, it's drilled out for 3 RCA's, It's the one you see in my thread. I need to find it.


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## Ge0 (Jul 23, 2007)

chad said:


> I have one I may let go of, it's drilled out for 3 RCA's, It's the one you see in my thread. I need to find it.


Hmm, I could use that. And, I have some pretty nifty foo foo panel mount RCA adapters to populate there. Now I just need a few more channels. Hmm, perhaps a cheap 2 channel amp from ebay?

Ge0


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## chad (Jun 30, 2005)

Ge0 said:


> Hmm, I could use that. And, I have some pretty nifty foo foo panel mount RCA adapters to populate there. Now I just need a few more channels. Hmm, perhaps a cheap 2 channel amp from ebay?
> 
> Ge0


It wired and ready to go for 3 ch operation, if you want to go 6 channel I have the **** to do that too (break out box), but you will have to go inside and snip some wires, think you can handle that?  It's tough work, not for the timid 

I have to locate all this stuff tho, what are you building?


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## Ge0 (Jul 23, 2007)

chad said:


> It wired and ready to go for 3 ch operation, if you want to go 6 channel I have the **** to do that too (break out box), but you will have to go inside and snip some wires, think you can handle that?  It's tough work, not for the timid
> 
> I have to locate all this stuff tho, what are you building?


I purchased Npdangs old super computer / audio processor a while back and have added some substantial enhancements. I want to start toying around with it to see what I can come up with. But, not outside in freezing temperatures over the winter. Inside my warm and cozy house with a glass of whiskey next to me 

I am going to build a setup in my office similar to what is in my vehicle at the moment (processor, amp channels, speaker placement, etc...) so I can monkey with sound field processing.

Yes, I have a cheap 5.1 channel speaker system set up on my main PC. But, I don't want to tie this up for this function. I want a totally separate system.

I have a few beat up old 2 channel receivers laying around. I have buttloads of car amps. But, that would be a bastardization of gear to set this system up. For some dumb reason I wanted something slick looking and compact. That's where these little Zapco/BSG amps looked so attractive.

Ge0


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## chad (Jun 30, 2005)

I'll look around tonight, You know, if you did not want to spend the money, you could borrow it, like for the winter, it has been "modded" for 3 ch but comes with a BOB for 2/4/6 ch use. All RCA in. It's been sitting but is all most too cool to sell, if you know what I mean 

It's even set up for whiskey drinkin 



















You would just have to cut out the wires gooing to the RCA's on the amp itself:



















Chad


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## MIAaron (May 10, 2005)

Hey Geo,
I have one that I'm not gonna use. I was planning on using it to run an extra room of audio in my house, but I ended up buying something different.

Let me know and we'll get it worked out.

Aaron


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## Ge0 (Jul 23, 2007)

MIAaron said:


> Hey Geo,
> I have one that I'm not gonna use. I was planning on using it to run an extra room of audio in my house, but I ended up buying something different.
> 
> Let me know and we'll get it worked out.
> ...


My god, is there anything you do not have?

I'll PM you...

Ge0


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## Ge0 (Jul 23, 2007)

chad said:


> I'll look around tonight, You know, if you did not want to spend the money, you could borrow it, like for the winter, it has been "modded" for 3 ch but comes with a BOB for 2/4/6 ch use. All RCA in. It's been sitting but is all most too cool to sell, if you know what I mean
> 
> It's even set up for whiskey drinkin
> 
> ...


Would you be interested in trading it for a brand new 1KW Tripath amp module? The Tripath amp has it's own coolness factor. I'll just never get around to building it like I thought I would...

Ge0


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## MIAaron (May 10, 2005)

Ge0 said:


> My god, is there anything you do not have?
> 
> I'll PM you...
> 
> Ge0


Yeah, the time to finish any of my projects! haha


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## boarder124 (Mar 16, 2006)

I finally want to get around to adding some dpdt switches to my breakout box. What kind should i be getting, on-off-on, on-on-on, or on-on? I know this is a few years late ha.


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## boarder124 (Mar 16, 2006)

After thinking about it a little more i picked up some On-On DPDT's.


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