# My (semi-) DIY 8 channel amp, with pics!



## SQKid89

Seeing as I really don't have too much to contribute elsewhere (many of you guys have a much more in-depth understanding of this hobby than I do), I figured I'd throw in the project I'm currently working on.

Being in the northeast without a garage, its wayyyy too cold to work on the car, so we turn our sight indoors. I've been wanting to upgrade my HT for a while now. The receiver does everything I could need currently and the new TV handles all the video without issue, but I could go for a matched set of speakers. The current plan was to go with a Triune 5.1 setup, but my receiver is not capable of delivering 4ohms continuously. I know I could go to the 8ohm version, TriTrix, but what if I want to upgrade again later? So in comes the project.

I started over at DIYAudio in the class D section. Aparently there was a company selling 4ch amp modules on eBay for $50. Figured it was worth a shot. So how about a chassis? back to eBay, awesome all aluminum chassis for $100 shipped (steel chassis available for under $50). RCA's and binding posts? ebay again, $10 for 10 rca's and $10 for a set of 4 binding posts. Switchmode power supply? guess where, eBay again.

So time for me to show some pics. Its not done, so bear with me, but everyone loves progress pics  









this is the chassis as it arrived. from everything i could find, it was built better and cheaper than many of the other available options.









yes, 1/4" thick front panel. this thing looks good.









10 minutes later (I don't waste any time on this), the case all together. All the necessary hardware was included and all the holes had pressed in nuts, so no worries of stripped aluminum.









Here is the layout I'm going with, cept the PS will be on the opposite side. Nothing's bolted down, just checking for room.









the in's and out's. awesome quality for the money, quickly received (got them in 2days from Cali to Mass). I made an oops and ordered only half as many binding posts as i needed. more on the way.

So here is where I stand thus far. Beeing sick and working long hours makes progress slow, but I did start drilling out the rear panel for the hardware. Need to get some more screws, etc for mounting the boards, but otherwise everything is here. Oh, need to get a decent IEC socket, something thats maybe fused and filter, but who knows. Still trying to figure out how to get a Bulgin vandal switch (check google, you'll like what you see) to work as a power switch, but thats something for later.

Always open to suggestions and feedback


----------



## JayBee

A) What kind of power are expecting from this unit?

B) What color switch are you going to use? (those swithes are pretty sweet looking.)


----------



## SQKid89

they are "rated" at 100w @ 4ohm per channel. With all the math in place and running at 24-26v, I should see somewhere around 50-60w or so.

as for the switch, I'd really like to go blue. nothing on the front but that switch, centered & toward the bottom. simple and elegant. maybe come up with some kinda of logo to go one step further.


----------



## demon2091tb

definently needing some listening impressions when you capable, this looks to be a safe project.


----------



## SQKid89

i did a test run with both amps just to make sure everything was working. unfortunately, one channel gave up the smoke ( ), but the other 7 work fine. speaking with the seller currently on their warranty policy. they seem to do pretty well, but there is a slight bit of noise if you put your ear up to the speaker. some people have done some mods to be rid of this noise, so i'm looking into that as soon as i get the thing together and at least do some quick listening. i understand $50 isnt going to buy the best amp in the world, but for my uses (mainly home theater and gaming) it should work well.


----------



## Diru

Looks like a clean lay out .


I would place one UV Purple LED[everyone does the blue, just ask Chad] on the face and thats all. Put the switch on the back.


You got links to these amps? 

Whos power supply is that? Link?


I see the heat sinks are on the amp boards and the power supply appear to have a fan. Are you going to do forced air cooling on the case?


----------



## SQKid89

as for suppliers, here's the rundown:

amp modules and SMPS: Sure Electronics
chassis: biglawhk
rcas and binding posts: cnso138

some of the best pricing I've found online and great communication with everyone but Sure (and they aren't bad per se, but not quite as quick to respond or work with me like the other two).


----------



## Diru

SQKid89 said:


> as for suppliers, here's the rundown:
> 
> amp modules and SMPS: Sure Electronics
> chassis: biglawhk
> rcas and binding posts: cnso138
> 
> some of the best pricing I've found online and great communication with everyone but Sure (and they aren't bad per se, but not quite as quick to respond or work with me like the other two).



ok so this modual?

http://cgi.ebay.com/4-100-watt-4ohm...5064919QQihZ013QQcategoryZ14973QQcmdZViewItem

http://www.sure-electronics.net/rf,audio/AA-AB009.pdf

Info, bingo











This your supply

http://cgi.ebay.com/24V-DC14-6A-350...9QQihZ022QQcategoryZ58286QQrdZ1QQcmdZViewItem


















Useing One power supply your going to be a little short on the current [ 5 to 10 amps, depends on volume and load]. Can you do 2 power supplies?


OR [ give me a second here]

2 of these

http://cgi.ebay.com/SIX-6-NEW-ELECT...ryZ73132QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

or one of these

http://www.apexjr.com/capacitorsR.html

47,000 Mfd 
80V 
2 1/2" Dia X 4 5/8" Tall + 1/8" w/ screws new stock Hitachi image $17.50ea

adding the large assed caps will help on high peak currents, and help clean up the output of that power supply


----------



## SQKid89

yessir. the SMPS I grabbed was their 24v, 14.6a piece. maybe not optimal of all channels are being driven, but chances of all 8 going full tilt (which wont be anytime soon as it will only be powering 5 speakers) is slim enough that it should do for now.


----------



## Diru

Make sure you fuse the input ac and dc outputs on that thingy


----------



## Ge0

Kick ass project man. Keep it up and learn all you can.

I did a similar project a few years back. Bought up a dead ADCOM GFA-555II on ebay for around $80 shipped. Outputs were fried but the linear supply was good. I originally just bought it for the sexy chassis but ended up using the supply too. It is now a sub amp based around a Tripath 1KW (bridged) amp module. Pounds the bejeezus out of two Mass 2012 subs in my living room. I've never got around to measuring true output but my best estimate it will deliver a clean 800W into 4ohm.

I did a writeup on this project a while ago. However, can't find the log book for the life of me.

Ge0


----------



## chad

It runs on a single ended power supply? Not Bi-Polar?


----------



## Diru

chad said:


> It runs on a single ended power supply? Not Bi-Polar?


Yepper, I was thinking that to. But hell its a nice looking kit


----------



## chad

Diru said:


> Yepper, I was thinking that to. But hell its a nice looking kit


No ****! That looks cool!
here's the power supply source I was looking at last night.....

Just throwing it out, looks strikingly similar eh?

http://stores.ebay.com/Electronic-Kits-and-Parts-Store_Power_W0QQcolZ4QQdirZ1QQfsubZ14QQftidZ2QQtZkm


----------



## Ge0

chad said:


> It runs on a single ended power supply? Not Bi-Polar?


What do you mean? I see right on the back panel that it has positive volts and negative volts .

Ge0


----------



## SQKid89

i think he's referring to +24 0 -24, but you may be just joking with me  .
the gainclones i did before were like that, but this one is just +24 and 0.

i may look into getting a more powerful psu sometime, but for now this will at least get me going. i'll definately look into getting one of those caps, just need to see if i've got room.....

chad - that PS is only 2A, so not the best choice for running more than one or two channels.


----------



## chad

SQKid89 said:


> i think he's referring to +24 0 -24, but you may be just joking with me  .
> the gainclones i did before were like that, but this one is just +24 and 0.


He's just messin with me 



SQKid89 said:


> i may look into getting a more powerful psu sometime, but for now this will at least get me going. i'll definately look into getting one of those caps, just need to see if i've got room.....
> 
> chad - that PS is only 2A, so not the best choice for running more than one or two channels.


You did not look around  They sell 500 watters and they will configure to what voltage you want 

Chad


----------



## SQKid89

thats what i get for jumpin the gun. sorry bout that.


----------



## chad

SQKid89 said:


> thats what i get for jumpin the gun. sorry bout that.


I'm on the edge of buying a 13.8V 500 watter as the grunt in building a PS for the car for the garage and possibly show. I'll let you know how it performs


----------



## durwood

chad said:


> I'm on the edge of buying a 13.8V 500 watter as the grunt in building a PS for the car for the garage and possibly show. I'll let you know how it performs


You thinkin of bringin out the civic to some sound shows this year perhaps?


----------



## chad

durwood said:


> You thinkin of bringin out the civic to some sound shows this year perhaps?


If I can find that goddamn rattle in my headliner that's driving me nuts and do some work on door treatment   

I may do some rattle chasing tonight, my little wrench monkey is itching to take stuff apart.

Chad


----------



## durwood

chad said:


> If I can find that goddamn rattle in my headliner that's driving me nuts and do some work on door treatment
> 
> I may do some rattle chasing tonight, my little wrench monkey is itching to take stuff apart.
> 
> Chad


Sweet!

Check where the headliner meets the windsheild. I've had problems there before.


----------



## chad

durwood said:


> Sweet!
> 
> Check where the headliner meets the windsheild. I've had problems there before.


It's back by where the sunroof mech is I'm sceart that it may be the mechanics itself.

Project ideas tonight are 50/50 decision between..... Find the noise and de-stink the car or work on the Smaart tutorial.

Chad


----------



## durwood

chad said:


> It's back by where the sunroof mech is I'm sceart that it may be the mechanics itself.
> 
> Project ideas tonight are 50/50 decision between..... Find the noise and de-stink the car or work on the Smaart tutorial.
> 
> Chad


ah didn't know you had a sunroof. 

Put your wrench monkey to work and do the smaart tutorial while supervising.


----------



## chad

durwood said:


> ah didn't know you had a sunroof.
> 
> Put your wrench monkey to work and do the smaart tutorial while supervising.


I can only do 2 things at once.... and drinkin' is one of them


----------



## 300Z

chad said:


> Smaart tutorial.
> 
> Chad


Tell me more about that please! 

Leo


----------



## CBRworm

My sun roof mechanicals rattle. I thought about slathering everything with thick grease, but as hot as it gets here it would probably end up dripping on my head.


----------



## SQKid89

A quick little update. Here's the almost complete rear panel. I miscounted how many binding posts I needed, but the rest are on the way. I also dicovered I'm not the greatest at drilling the holes quite as evenly as I hoped, but oh well, it wont be seen anyway...


----------



## Diru

What, you still haven't turned it on yet.


----------



## chad

I looks allright, I feel your pain on drilling but one thing that works for me is drawing a line that everything goes on and then measure yout holes on that line. USE A PUNCH, Mine is spring-loaded nad you puish down and POP it leaves a nice little punch divet.On aluminum, if i do it on my short carpeyt on my bench it teaves a tiny dent that guides the bit right to the divet. I start with a very small pilot hole then drill the real one. After a bit of time you will get them straight as ever, it just takes practice.

If it's more than 2 rows I mark it out on graph paper then punch thru the paper that I affix to the stock.

chad


----------



## SQKid89

yeah, i covered the panel with masking tape and measured all the lines and marked all the spots, just had a couple of oops' along the way. 

this thing should be all together as soon as i get some more nuts and bolts to mount the boards. 'cept losing my debit card yesturday puts me in a not so fun spot right now. so no buying until monday...


----------



## Inferno333

Very cool project.

I'm looking forward to listening impressions.


----------



## SQKid89

almost there. just waiting on the last of the hardware and need to solder the connections....


----------



## Diru

You figure what your going to use for your input hook up wire?


You going to hard wire to the board connector or to the board RCA connectors?

Oh oh oh , you getting a big cap to put in there?[like the ones I tossed out there]


----------



## SQKid89

the cap idea will be kept in mind, but i mounted the boards so far forward in case something did get added later on (such as a circuit to switch power on by momentary button, or a cap ). as for connections, the board has screw terminals for the input, output, and power, so the on-board rca's can be bypassed. I will probably gut some cat-5 cable for the input, some 16-14 ga for the power (there's 3 terminals per 12v/gnd, may use two just cause i can), and probably the same for the outputs. The boards are raised up so i can run wiring underneath them or who knows.


----------



## chad

SQKid89 said:


> but i mounted the boards so far forward in case something did get added later on (such as a circuit to switch power on by momentary button, or a cap )


oohhh I like the switch idea


----------



## SQKid89

ok, ok, I get the message. everyone want to know what it sounds like.  
so I got in the first testing phase after everything was mounted. the psu had multiple outs, so I used em all. figured a few runs of smaller wire (18ga was all I had laying around) was better than one. Also didn't want to risk blowing a good set of speakers if something was wrong with the board, so I used a pair of left over speaker I had from an old HTiB. As a source, I'm using my trusty $80 Zune (thank you Woot). The speakers are 8 ohm, so I'm not getting full power from the amp, but it gets loud as is. I was only able to put the player up to half way before the speaker started to max out. There is still the background noise that I mentioned before, but it can only be heard if its dead silent and I am within 2-3 feet of them. Still havent tried any of the tweaks to be rid of the noise, so it was to be expected. The heatsink on the amp is barely even warm, nothing really noticable. Here a pic of the testing, including my lab partner.


----------



## Diru

chad said:


> oohhh I like the switch idea


I like the cap better.[maybe a blue LED]

////////////////////////////

So thats cool cat5, done some crazy **** on cat5 before. you'll be fine I'm sure.


----------



## chad

Diru said:


> I like the cap better.[maybe a blue LED]


Turquoise LED  that's what he needs 

Dunno about the cap, Methinks since it's a switcher with no audio reviews, I'd be just as happy to see a coil there to knock off any switching parasitics if they exist.


----------



## Diru

So whats this thing look like today ehhhhhhhhhhhhhhhhhhhhh


----------



## SQKid89

ehh, she's still in the same state, kinda. all i really need to do is solder the connections and it'll be ready. just been busy with other things of recent. Haven't really needed it quite yet, as I have yet to build the speakers that "need" it yet and have no room on my current entertainment center for it. What is nice is that the company i bought the boards from was kind enough to send a replacement for the board that had a dead channel. Think i may play around with the bad one to see if i can get the channel working, may be useful as another stereo setup elsewhere in the house.


----------



## pahhhoul

excellent project! can't wait to see everything done!


----------



## annoyingrob

Nice power supply. I have a SP-480-15 lying around that I used to use for TECs.

Is that enclosure you got rack mountable?


----------



## spydertune

SQKid89 said:


> There is still the background noise that I mentioned before, but it can only be heard if its dead silent and I am within 2-3 feet of them. Still havent tried any of the tweaks to be rid of the noise, so it was to be expected.


This is a great project and I truly want this thing to kick ass for you! I looked at these modules ~1 year ago but could never get the company to reply to questions on them. I was curious about S/N, channel separation, & distortion specs but they never answered me. What kind of noise issue are you getting? Is it "hiss"? If it is, it could be the modules or it could be noise because the amps are not buttoned up in the enclosure, etc. I will be very interested to know if it gets better when you've completed everything. I do agree though that you will likely not notice it at all when you are using it.

Re: SMPS, when I did some searching on DIYaudio about them for amp use, the prevailing comment was the lack of headroom they have. When you hit the limit of what they do, they collapse completely. What was proposed IIRC is getting 2X what you think you need. I may have missed it but did you buy 2 SMPS? (It looked like you had 2 in the chassis with the 2 modules.) So, you are probably fine and if you are using them with a high-pass crossover & no deep low-end, I'd bet you don't ever run into trouble with these either.

One last question, how was Sure-Electronics to deal with for you?


----------



## SQKid89

I'm not sure if the enclosure can be mounted, as there are no provision for the rack screws, but at least it looks the part . Sure was so-so to work with. Communication was not the best, but they did replace one of my boards free of charge when one channel burnt out on first use. So I do have 3 boards now and plan on trying to fix the broken one (most people say its the zobel network, worth a shot for a couple bucks in parts). I've still got this project on pause for multiple reasons, but may finish it soon. All thats left is soldering the rcas and binding postings.


----------



## Spasticteapot

You might have a grounding issue, or you might just need more power supply filtering. Have you considered placing some really big capacitors in parallel with the power supply?


----------



## King Nothing

I hate to bring a dead thread back to life like this, but I have a question. in the ad it says "It supports dual channel amplification and can readily be powered by any DC power supply ranging from +10 to 36V" If It can be powered by any DC power supplf rom 10-35v, could it be powered off a car electrical system? See where Im going here? DIY car amps


----------



## SQKid89

wow, this is an old post. Unfortunately, the project took a back seat when I moved and never was completed. I know I'm sooo close to being done, just got buried in the boxes, yet to get dusted off. I don't see any particular reason why you could not use this in the automotive world; its really small, its got its own heatsink included, and it will run off a basic 12v & ground setup.


----------



## Diru

You know you still have to stick a big ass super bright blue LED <3 to 5 watt class> in there for Chad.


----------



## blamus

Interesting, i just read through the whole thread. I have been thinking about DIY amps for a while, and nearly bought the sure electronics 2*100W T-amp board. I just love T-amps. 

I've also considered and dug around about trying to use that in the car, powered directly off the car battery. I'm still not sure if thats a good idea (noise issues etc.) but my first problem would be that simply using 12V would only give me very low power (so I was told, about 20-30W) which is not enough. So now more research needs to go into building/finding a good power supply for the car application. For the home its simple, I have 10000s of 12-30W PSUs from laptops, battery chargers, etc. And ironically, I only need 20W in the home (I am happy with the sonic T) but in the car, i need POWAHHH!


----------

