# tubes



## abusiveDAD (Jan 7, 2009)

lookin at a receiver for one room to drive my record player,,,,
hopefully tube what should choose? (AFFORDABLE, but nice/quality)

speakers will get chosen accordingly


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## chad (Jun 30, 2005)

Where to start........


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## Dryseals (Sep 7, 2008)

abusiveDAD said:


> lookin at a receiver for one room to drive my record player,,,,
> hopefully tube what should choose? (AFFORDABLE, but nice/quality)
> 
> speakers will get chosen accordingly


I would have to ask, Why tube?

Having grown up on tube amps, I can say they do have a different way of coloring sound. I like the sound, but I have long since left them because of the lack of available supply and now the new supply at what I would call, way over priced. But if you heart is set on having a tube amp, pay close attention to the output transformer, that's where the real signature sound comes from, not the tubes them self. Granted you could play with screen and grid voltages and get a sound your looking for, but you could also do that with a good eq.

And remember, tubes are not high power compared to what is available from our silicon buddies, so your speakers have to be a tad more efficient than what they normally sell today, think horns.

If you really want a deal, do a little searching for an older Silvertone amp, console type. Flea markets, Goodwill and what ever you can find. And modify it yourself. Or an old heathkit. Doesn't have the prestige of an old Crown or Luxman, but also not near the price.


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## chad (Jun 30, 2005)

And dynaco.... And scott.


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## thehatedguy (May 4, 2007)

It's easier to choose which amp and tubes if you know what speakers you are using.


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## trigg007 (Feb 24, 2010)

thehatedguy said:


> It's easier to choose which amp and tubes if you know what speakers you are using.




x2

AND many of the lower efficiency speakers can be run with tubes, just depends on what your expectations are (background music versus house party). Generally 90db and up will work; they don't have to be horns. 

You might consider a hybrid (tube pre with transistor output). Vincent makes a really good one. 

Audiogon would be a good source to pick up something used for a low price, since many in that crowd are dumping equipment due to the economy.

Tubes will generally provide a more realistic presentation (*IMO*), but depending on topology they can be prone to breakdown. 

If reliability is a concern, maybe consider a vintage McIntosh, Accuphase or Luxman 

Good Luck...


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## jpswanberg (Jan 14, 2009)

Jolida integrated. I have a 502 for my second system. Very happy with it.

JPS


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## chad (Jun 30, 2005)

IIRC AFFORDABLE was mentioned in the original post


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## Lexus1 (Feb 18, 2010)

I'd recommend a vintage Fisher receiver, if a receiver is what you're looking for. Find an 800B or -C. Fisherdoc offers rebuild and upgrade kits at very reasonable prices, and they've got tons of power. Keep an eye out for them at garage sales and thrift stores; it's amazing how often they show up even these days! I will warn you though DON'T just plug the one you find into the wall right away! The capacitors inside them will have dried up and shorted out, which could wreck the power supply before the fuse pops! Rebuild it first, which goes for any vintage gear 25-30 years old or older. Don't ask how I know.... :blush:


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## chad (Jun 30, 2005)

often times you can reform caps with a variac, it's worth a shot. kinda tough with a tube rectifier, grab a SS plug in type rectifier to re-form with.


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## Lexus1 (Feb 18, 2010)

chad said:


> often times you can reform caps with a variac, it's worth a shot.


Yes. But with caps being relatively inexpensive, I like to replace them. Quite often one can buy a replacement cap of similar physical size, but has a higher value, and discharge rates, peak current, and ESR specs that would've been science fiction back in the day. That equals a happier, better sounding amp in most cases!


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## chad (Jun 30, 2005)

ummmmmm... OK.

Inexpensive... No, unless you go under the chassis and mod for modern caps.

Going up in value...... ONLY VOLTAGE, do not increase capacitance, remember that this is calculated in conjunction with the PS choke and that increasing capacitance can drive plate voltage levels UP past dangerous design levels. Changing cap values in tube gear IS NOT like changing values in SS gear.


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## Lexus1 (Feb 18, 2010)

chad said:


> Inexpensive... No, unless you go under the chassis and mod for modern caps.


I almost never replace the FP type cans unless it's a hyper-accurate restoration, and I often gut the original can and use regular caps inside, carefully placed, unless there's loads of room to place them under the chassis.



chad said:


> Going up in value...... ONLY VOLTAGE, do not increase capacitance, remember that this is calculated in conjunction with the PS choke and that increasing capacitance can drive plate voltage levels UP past dangerous design levels. Changing cap values in tube gear IS NOT like changing values in SS gear.


The change in plate voltage with increased capacitance depends on the impedance of the transformer winding, as much as the change in value. For instance: My Citation II amp that I have in the home system originally had two 200uf / 250v caps in series in the voltage doubler, for an effective capacitance of 100uf. In the rebuild I substituted them with 1200uf / 300v caps with no change in plate voltage. The very low impedance of that transformer means very little to no change. HOWEVER: older, less expensive transformers, or those meant for tube rectification, with a higher impedance, CAN have that issue; generally you don't want to exceed about 100uf on the input to the choke, and no more than about 150uf on the output. There's both an arc-over of the rectifier danger and a voltage change. Generally the voltage doesn't go up a huge amount in any case, unless one goes nuts with cap values, but that'll fry a rectifier! However if you do find a rise in voltage a simple change in resistor values will bring it down. The choke/cap tuning can be adjusted with some straightforward calcs. 
Let's say the Fisher 800 I recommend is purchased. It has a solid-state power supply, no choke. 450uf caps will be a great upgrade and there won't be a problem with it's low-impedance windings. Better bass response will result. Not night and day, but an improvement nonetheless. Many mfrs back in the day wildly undervalued capacitance in their designs to save money, so that's why there's often a noticeable improvement.
Sorry for the long-winded reply, but I've been restoring and designing tube amps for almost 20 years now, and I love to write about them! :blush:


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## chad (Jun 30, 2005)

Lexus1 said:


> I almost never replace the FP type cans unless it's a hyper-accurate restoration, and I often gut the original can and use regular caps inside, carefully placed, unless there's loads of room to place them under the chassis.
> 
> 
> The change in plate voltage with increased capacitance depends on the impedance of the transformer winding, as much as the change in value. For instance: My Citation II amp that I have in the home system originally had two 200uf / 250v caps in series in the voltage doubler, for an effective capacitance of 100uf. In the rebuild I substituted them with 1200uf / 300v caps with no change in plate voltage. The very low impedance of that transformer means very little to no change. HOWEVER: older, less expensive transformers, *or those meant for tube rectification*, with a higher impedance, CAN have that issue; generally you don't want to exceed about 100uf on the input to the choke, and no more than about 150uf on the output. There's both an arc-over of the rectifier danger and a voltage change. Generally the voltage doesn't go up a huge amount in any case, unless one goes nuts with cap values, but that'll fry a rectifier! However if you do find a rise in voltage a simple change in resistor values will bring it down. The choke/cap tuning can be adjusted with some straightforward calcs.
> ...


Bingo, and word to your mother 

I often just leave the can for looks and build underneath for restorations. Sometimes I just get sick of restorations and like to just build, I am however a fan of tube rectification, which is likely why my first comment was so quick to fly.

Last one in a while for restoration....





































IMHO the only thing that makes it cool is that it matches this:




























There's a story behind that combo, not unlike any other classic guitar.


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## Lexus1 (Feb 18, 2010)

Sweet! I've never done a guitar amp. HiFi is my thing, although I keep threatening myself to do one! 
I'm working on a 6SN7-based preamp right now. Projected bandwidth is 4hz to 80khz and virtually perfect square-wave and sine-wave response. What happens in the real world is another story, but handling audio frequencies will be old hat for it no matter what!


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## chad (Jun 30, 2005)

I started in hi-fi, went to guitar, and back to hi-fi. Guitar is fun because you are literally voicing it...... the "Fi" goes right out the window


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## WmAx (Jan 1, 2009)

OP: Seriously, this idea of choosing an amp and building the speaker system around the amp is a very poor way to target high SQ.

You can add in EQ that the tube amp normally would due to it's high output impedance by adding a high power dummy load resistor in line with the amp/speaker or by using a precision parameteric EQ to make the response changes. If you want to emulate the sound of a SET tube amp that has THD in the %5-%7 range, you can buy studio processing tools that allow you to mix in any level of distortion into your signal from a tube, and you can even swap the tube for different models, to vary your harmonic distortion profile(distortion signature).

It's best to just get a high power, low impedance stability SS amp that can transparently drive any speaker.

The speaker(s) and room acoustic(s) are by far the most important things affecting SQ, aside from the recordings, of course.

-Chris


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## chad (Jun 30, 2005)

WmAx said:


> It's best to just get a high power, low impedance stability SS amp that can transparently drive any speaker.
> 
> 
> -Chris


well that ain't no fun.


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## abusiveDAD (Jan 7, 2009)

"The speaker(s) and room acoustic(s) are by far the most important things affecting SQ, aside from the recordings, of course."

-Chris 

100% agreed 

never heard a TUBE in a standard environment, only in a more controlled ---
professional environment. but really enjoyed it, so i am trying to do something cloe and somewhat cheap for one room,,,

THANKS EVERYONE FOR ALL THE SUGGESTIONS


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## Dryseals (Sep 7, 2008)

chad said:


> well that ain't no fun.


Tubes and fun?

When I keft for Australia, I had four tube type Bogen 100 watt mono block type amps stashed in my bed room of my mothers house. A year and a half later, I returned. My mother thought they were old trash, I did pack rat a few things here and there. She chunked them while I was gone.


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## chad (Jun 30, 2005)

ouch. 

We were gutting a movie theater and I found a pair of Altec 260A's.. WOOT.

I put them aside and said DO NOT THROW THESE AWAY and put a sign on them. they were balls heavy so i figured nobody would move them. I was going to pick them up the next day because I drove a motorcycle there that day.

They tossed them that evening and the trash guy came the next morning. Talk about something VERY valuable and cool slipping out of your hands.

Dudes, Altec 260A's... TWO mafuggin sixty A's! TWO OF THEM.....
like this: ALTEC LANSING 260A Vintage Tube Amplifier+Peerless

Damn 813's in them... I should have just pocketed the flippin tubes that day.


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## chad (Jun 30, 2005)

just one more for memory lane http://www.triodeel.com/al260a.gif

just look at the plate voltage on that red-boned **** hound.


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## trigg007 (Feb 24, 2010)

OP...you really didn't define "affordable"...but here's a good one:

Music Reference rm10 mk2 For Sale | AudiogoN


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## chad (Jun 30, 2005)

they are really pushing those 84's to get 35W/Ch.. thankfully they are using 84M's.
\I'm partial to 34's/6CA7's, 6550/KT88's. Good tubes to build around.

Speaking of which. have you considered a kit? Are you handy with **** like that or enjoy doing it?


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## jasondplacetobe (Jun 15, 2009)

is that true its the output transformer that privider the warmth?


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## chad (Jun 30, 2005)

I don't know if I would call it the provider of warmth but personally I think it's one of the most important, if not THE most important part of a good amp.


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## subwoofery (Nov 9, 2008)

Try to do some research... 
Affordable$$Audio :: The E-zine For Frugal Audio Enthusiasts - not really DIY spirit, but still in the DIY wallet spirit  

Kelvin


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## jpswanberg (Jan 14, 2009)

even ordered hamonic distortion = warmth
odd ordered harmonic distortion = cold/sterile

from what I have remember from the converstaions I have had with Eveanna Manley


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## chad (Jun 30, 2005)

she's a damn cool chick.


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## tyort1 (Jun 2, 2010)

Rebuilt Dynacos are a good place to get a proven design for not too much money.


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## chad (Jun 30, 2005)

tyort1 said:


> Rebuilt Dynacos are a good place to get a proven design for not too much money.


Or grabbing dynaco transformers and rolling your own.


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## stereo_luver (Oct 30, 2007)

OP says he is looking for a receiver to use with a turntable. Most of the later models of intergrated tube amps don't have a phono stage. Personally I like my CJ gear the best but its not intergrated. For the best/better bang for the buck look for something like a Fisher 500C or 800C, Dynaco SCA-35, Sherwood S-5000. All these have a nice phono stage and you can roll some 12AU7's and 12AX7's around in the phono section to get the sound that suits your needs. But as mentioned speakers should be what drives your choice in what amp/receiver you buy.


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## trigg007 (Feb 24, 2010)

:rimshot:


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## 99chevy7.4L (Sep 25, 2010)

Affordable reciever find a Sansui 500 or sansui 1000 nothing more needed.


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