Solid State Guitar Amp Forum | DIY Guitar Amplifiers

Solid State Amplifiers => Tubes and Hybrids => Topic started by: Fossilshark on July 13, 2016, 04:24:58 PM

Title: 6v6 power amp circuits
Post by: Fossilshark on July 13, 2016, 04:24:58 PM
How many watts is a single 6v6 tube power amp typically, like in the fender champ. And is there a way i can use multiple to get 30-40 watts. Does anyone have a schematic for this?
Title: Re: 6v6 power amp circuits
Post by: DrGonz78 on July 14, 2016, 01:46:30 AM
The 6v6 data sheets are your best friend. 6V6GT in a champ Single Ended is roughly about 5 watts and this can vary slightly. If you have two 6V6 tubes in push/pull AB it is conservatively about 10-14 watts, but it can be higher like 15-18 watts. Some claim that they can get 24 watts out of a pair 6v6 push/pull AB. My feeling is that you'll be eating through tubes if you push the thing that far. I guess a 40 watt amp is not out the question (push/pull AB) running 4 6v6gt tubes, but I am having trouble finding a decent schematic to reference.
Title: Re: 6v6 power amp circuits
Post by: DrGonz78 on July 14, 2016, 03:45:16 AM
Also here is a jim Kelly amp that uses 4 6v6 tubes on the output...
(http://www.themusiczoo.com/images/4-09-13/15489_Kelley_Tolex_Head_a.jpg)

http://www.themusiczoo.com/product/15489/John-Suhr-Amplifiers-Jim-Kelley-Single-Channel-Reverb-Amplifier-Head/ (http://www.themusiczoo.com/product/15489/John-Suhr-Amplifiers-Jim-Kelley-Single-Channel-Reverb-Amplifier-Head/)

Still not finding any schematics but would not be hard to design this amp. Finding a good match for the Output Transformer would be my greatest concern right off the bat. 

I attached the schematic...
Title: Re: 6v6 power amp circuits
Post by: Vitrolin on July 14, 2016, 03:36:49 PM
according to datasheet, 280V plate voltage you should give you around 14W per pair with a 8k output transformer.
with 4 output tubes you want a 4k OT.
look for an OT for el34 that will get you pretty close..

3k6 a little low
http://www.tubeampdoctor.com/en/shop_Output_transformers_Output_Transf_for_Marshall/Output_transf_for_Marshall_50W_2x_EL34_4_8_16_Ohm_165 (http://www.tubeampdoctor.com/en/shop_Output_transformers_Output_Transf_for_Marshall/Output_transf_for_Marshall_50W_2x_EL34_4_8_16_Ohm_165)

4k5 probably better
http://www.tubeampdoctor.com/en/shop_Output_transformers_Output_Transf_for_Marshall/Output_transf_Marshall_for_40W_DSL401_1368 (http://www.tubeampdoctor.com/en/shop_Output_transformers_Output_Transf_for_Marshall/Output_transf_Marshall_for_40W_DSL401_1368)

remember that the output power claimed is depending on the THD level accepted, 24W maybe be with how much distortion?
Title: Re: 6v6 power amp circuits
Post by: DrGonz78 on July 14, 2016, 04:46:20 PM
remember that the output power claimed is depending on the THD level accepted, 24W maybe be with how much distortion?

24 watts at 10% THD or higher would be my guess.
Title: Re: 6v6 power amp circuits
Post by: Fossilshark on July 14, 2016, 11:23:20 PM
thanks! would you have any suggestions for a single tube circuit at 40 watts? using a different tube obviously.
Title: Re: 6v6 power amp circuits
Post by: g1 on July 15, 2016, 03:31:29 PM
A single ended class A power amp is not very efficient.
You get around 30 to 40 percent of the max rated power for the tube.
So you would need a power tube rated for 100 to 120W max.
The largest commonly used tube in guitar amps is probably a 6550, rated for 42W max.
Title: Re: 6v6 power amp circuits
Post by: DrGonz78 on July 15, 2016, 03:54:42 PM
Just have to ask what you are planning to build? Seems we are jumping around a bit on the tube type questions with little information for what this tube amp's designed purpose will serve. There is your intended use for what you want to build or research and that is what is most important really.
Title: Re: 6v6 power amp circuits
Post by: Vitrolin on July 16, 2016, 12:00:34 PM
that gonna be hard to obtain, a KT120 might get you there.

but there i a reason most mid to high power amps are with a push pull output or when single ended with paralleled output tubes

but why must it be with only one output tube, it going to need a massive power transformer to get around 40W output.

remember that the output power claimed is depending on the THD level accepted, 24W maybe be with how much distortion?

24 watts at 10% THD or higher would be my guess.
yes hardly comparable to someone who accepts 5%

Title: Re: 6v6 power amp circuits
Post by: Fossilshark on July 16, 2016, 12:55:09 PM
I was just wondering how feasible it would be seeing as 1 tube is every so slightly less work then 3 or 4 lol. Im working on building my first full tube guitar amp. Im going to build a fender champ clone first then replace the preamp section with a marshall preamp circuit i found. I didnt know if i should just keep the single 6v6 power amp or go for a little bit more power so i could play with some friends.
Title: Re: 6v6 power amp circuits
Post by: blackcorvo on July 16, 2016, 07:27:20 PM
I was just wondering how feasible it would be seeing as 1 tube is every so slightly less work then 3 or 4 lol. Im working on building my first full tube guitar amp. Im going to build a fender champ clone first then replace the preamp section with a marshall preamp circuit i found. I didnt know if i should just keep the single 6v6 power amp or go for a little bit more power so i could play with some friends.

I'd recommend you check out AX84.com if you wanna get some nice ideas of tube amp designs, and they even have "bulding block" projects, that you can use to mix-and-match preamps and power amps as you see fit.