• 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.

Tube Buffer 6J1 / 5654 (6AK5)

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The Yaoin Tube buffer...:

Arne K
 

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astouffer said:
330uf seems a little big for coupling to a grid. Maybe try 1uf or even 10uf at the most.

Probably should be nF, not uF.

The 30k resistor is bootstrapped so that it seems like it's really about mu times bigger.

Arne: The connections look fine. The suppressor grid is attached to the cathode internally and is accessed by pin 2.
 
Right...looking at datasheet, pin 7 and 2 are internal connected...

I will try better caps, and a smaller for input.

I still find it strange with the 30k, as signal passes easily thrugh when powered off...

Arne K
 
Cobra2 said:
2 x 100nF + 2 x 4,7uF caps, 2 x 120K(replaced 30k) and a pair NOS GE 5654 later;
It sounds pretty good now, actually useful for my cheap "play-all-formats" DVD.

Arne K

Hi Arne,

I just purchased the Yaoin and telefunken 6AK5's are on their way.
Replacing the 30K for 120K resistors is clear to me but instead of what did you replace the 2 x 100nF + 2 x 4,7uF caps? And what caps are of good quality?
I'm a newbie here and have been reading this forum for a while.
Hopefully you can help me out. Thank you in advance.
 
Cobra2 said:
The (signal)caps in mine were cheap Philips X2 types, changed to some other "junk-box" samples.
Try what you find...
Arne K

I have ordered standard X2 type 100nF caps but I found some 4,7 uF caps specially meant for high-end audio. They are made by 'AMPOHM WOUND PRODUCTS' and seem to be new.
Unfortunately they have only caps from 1000nF and higher.
 
Hey, sorry to revive such an old thread.

I just wanted to double check something, since I've recently came into pocession of one of these buffers.

When replacing the caps, the 330uf caps should be replaced with ones under 10uf, and the ones following those should be replaced with 100nf ones?
 
The input cap (in mine) was 330nF (not uF).
You can probably use a smaller cap without problems. Do not need to be high-voltage, but is often an advantage soundvice.

Output cap was 1uF, I guess anything from 1-4,7uF will work, must be more than 60V

Arne K