Can you identify this 6SN7 / 300B circuit?

[ElArte]

Do you mean an SRPP driving a 300B? Cary, Wavelength and other 300B amps use (or used) an SRPP to drive a 300B. Gordon Rankin's Bugle is an SRPP design, so is the Baby Ongaku. It's a very common circuit.

I don’t see the SRPP in this circuit.

 

[ElArte]

This may be of interest: https://www.diyaudio.com/community/threads/diy-300b-monoblock.403801/post-7465849

Yes, it’s interesting, but not the same circuit at all.

 

[grovergardner]

I don’t see the SRPP in this circuit.

Posts #27 and #34 are an SRPP driving a 300b. Were you refering to a different schematic?

 

[andyjevans]

EIArte - could you give us some idea of what you actually want to build? This seems to be going round in circles.

 

[ElArte]

EIArte - could you give us some idea of what you actually want to build? This seems to be going round in circles.

I am looking to build a 2-stage power amp, with 6SN7 as driver, 300B as power tube, SE, ~ 8W, H2 dominant, capable of driving both 4 and 8 ohm loads, from 90 dB of sensitivity and above. As low part count as possible.

I will order the board that is claimed to implement the schematic in post 1, even though the schematic in post 1 cannot match the board, since the board has no pentodes on it.
Just because I am curious and I won’t let it rest.

 

[chrisng]

It seems there's more than one version of those boards, the schematic of the blue one is like post #27 and a black one is like post #28.

 

[ElArte]

I ordered the black board.

 

[Michael C]

Agreed a 6sn7 is a vacum tube and needs plenty of volts to sing.

 

[jakruby]

6SN7 in SRPP ain't gonna give you lots of gain - you'll only get about x10 which means you'll need at least 5V RMS input for full power?

 

[andyjevans]

I am looking to build a 2-stage power amp, with 6SN7 as driver, 300B as power tube, SE, ~ 8W, H2 dominant, capable of driving both 4 and 8 ohm loads, from 90 dB of sensitivity and above. As low part count as possible. I will order the board that is claimed to implement the schematic in post 1

Using that board you have a 3 stage power amp. But that's OK. It's a cheap experiment.

A true 2 stage 300b SE amp is done in many ways, all on threads here:

• pentode front end
• pentode in triode, or triode front end
• DHT front end like 47 or 26 or 10Y with a 1:4 step-up transformer in front.

Good luck with your build and figuring out the PCB and circuit.

 

[ElArte]

Good luck with your build and figuring out the PCB and circuit.

It’ll probably be 2 weeks before that board arises. 2 days to reverse engineer it into Spice.
Then we will know what it is for sure.