• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Stereo Buffer with a single twin triode

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Was doing some further reading.

This resistor after the output cap keeps the cap charged. It creates a small voltage to maintain the charge of the cap. hence it was bass shy as it was charging.

Is this correct?

I currently have a 500K to ground. If I reduce this it will charge up the cap a little faster?

I see on some headphone designs (Bruce Bender on Headwise eg) with big output caps there is a low 22K resistor to ground. This makes sense.
 
Brit01
Without a res to ground the output voltage will rise towards the 170v you have on the cathode. Big Bang if you connect that to an amp input. The res is there just to keep the output at 0v, value is not critical but with a 1uF cap you could go a lot lower 100k. Too low and the stage will roll off the bass, too high and it will take longer for the output voltage to fall to 0v. cheers
 
B+ and cathode current controls

Just a thought.

Now if I want to use different 9 pin tubes, 6N1P, 6N6P, 6N2P etc... I could incoporate a variable resistor on the first RC junction (to adjust the B+) of my psu and another for the cathode resistor.

Also to add small meters to measure the B+ and Cathode current so I can fine tune and adjust for different tubes with ease.

I'd have a controlled range for the psu resistor so I don't exceed the limits of the 6X5GT recitifier in this case.

Sounds like a good idea?
 
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