Single ended amp...with 2 power tub

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bluesbear
Hey get your own solder
Posts: 309
(1/20/04 11:01 am)
  Single ended amp...with 2 power tubes!
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 Hi! After having built several amps, all different in both approach and sound, I think maybe the single ended Champ type amp is my favorite. Trouble is, the just aren't powerful enough. I'm going to try a couple of approaches to beat this problem and see which I like better. This hereby begins number one!
I have seen single ended transformers advertised that use 2 or even 3 power tubes run in parallel. Does anyone know where I can find a schematic to see how this is done? I'd like to try running 2 6V6's like this. If any of you more learned people could sketch something up real quick, I'd sure appreciate it. It would be something that should probably go into the archives since there is so little info available, at least that I've been able to find.
Thanks!!!!
Dave
 
eddiejg
Senior tube assistant
Posts: 194
(1/20/04 11:28 am)
  Single ended amp...with 2 power tubes!
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 Dave-
Angela (www.angela.com) has a super single ended that does exactly what you are talking about in the how to section.
At the same time, I have built a few 5F2A Fender Princetons set up to use 1 6L6, which increased the power output.
I build mine using a 270DX (275-0-275) Hammond & set them up so they can use either the 6L6 & 5AR4 or the 6V6 & 5Y3.
I get around 375 volts on the plate of the 6L6.
If you used a 272BX (300-0-300) or maybe even 273X (350-0-350) with only 1 6L6, you could alter the dropping resistors & get a much higher output.
Also, a higher rated OT will increase the output also.
-Ed
 
ernie jr
Junior tube assistant
Posts: 64
(1/20/04 11:35 am)
  PRINCESTON
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 ED, I WAS THINKING OF DOING THE SAME THING, ONLY USING A LEFT OVER 6550 THAT I HAVE, (ONE IN THE PAIR BROKE) WHAT OTHER CHANGES DID YOU NEED TO MAKE IN THE CIRCUT?
THANKS
ERNIE
 
eddiejg
Senior tube assistant
Posts: 195
(1/20/04 12:04 pm)
  PRINCETON
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 Ernie-
If you're only going to use the bigger power tube, you would want to adjust the dropping resistors in the power rail.
The 1st dropping resistor to the screen can be reduced in value.
You then will also have to increase the value of the dropping resistors to the preamp, otherwise, you will wind up with much higher voltages on the plates of the preamp tube- 150+.
Of course, you might like it that way.
You can spend a whole week changing out the resistors to see what gives you what voltage & how it affects the sound (I know I have).
-Ed
 
bluesbear
Hey get your own solder
Posts: 309
(1/21/04 3:45 pm)
  Re: PRINCETON
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 Thanks, Eddie, that's just what I need to get this show on the road. I'll report back with progress.
Dave
 
Moosehead2
Junior tube assistant
Posts: 43
(3/15/04 9:19 am)
  any luck
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 I am also building a champ with parralel 6V6's and treble boost. Should be running tonight.
 
wayneosdias
Senior tube assistant
Posts: 262
(3/15/04 11:26 am)
  Re: any luck
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 if you guys are into that amp you should get TUT3, Occonor goes pretty deep into that thing, beefing up power supply, 4+ power tubes, cathode/fixed bias switching, adding preamp tube, fender/marshall voicing.

wayen
 
Moosehead2
Junior tube assistant
Posts: 45
(3/15/04 1:42 pm)
  i second that
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 Yeah thats where i'm getting my ideas for SE mods
 
LooseChange
Senior tube assistant
Posts: 217
(3/15/04 6:04 pm)
  Re: i second that
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 What type of output transformer are you using for this amp.
What are the specs??
Thanks!
 
Moosehead2
Junior tube assistant
Posts: 47
(3/15/04 7:23 pm)
  xformer
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 i am using a hammond 125DSE

Here is the link to the specs www.hammondmfg.com/125SE.htm
 
LooseChange
Senior tube assistant
Posts: 218
(3/15/04 8:15 pm)
  Re: xformer
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 What is your primary impedence? What secondary leg did you use??
 
wayneosdias
Senior tube assistant
Posts: 263
(3/15/04 8:51 pm)
  asdf
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 i used the 125d universal, for the standard champ design w/a 6l6. i sold the amp some time ago and cant remember what exact taps i used, but i rember the most appropraite 1ary/2ary setup cuased the amp to fart when slapping the E w/the volume cranked. i raised the 2ary Z and it sounded great w/no probs.

wayne
 
Moosehead2
Junior tube assistant
Posts: 48
(3/16/04 9:07 am)
  re
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 I used 5000 primary for a 8 ohm load. This would be the yellow wire.
 
 
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