Tube Buffer 6J1 / 5654 (6AK5)

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

astouffer said:

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

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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.

You could make it larger if you wanted, but with power on, the input impedance is something like half a meg, so why bother?

Does anyone know what voltage the transformer secondaries are? I've got one to play with but need 240v tranny rather than the supplied 110v.

I wasn't sure what the value said - that's great, thanks!

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

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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

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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.

btw. Here's a link to the Datasheet

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?