tube buffer values

[trancy]

helo everybody....

maybe this is not real place for my question, but there is a half of schematic (joes amp) regarding chip amp...other half is tube buffer, and that is a part that i need...basicly....which values of resistors and caps can I use and of course which is the best transistor to use????

my english is bad....

thanks

[Nuuk]

Trancy, that is Joe's commercial VBIGC (or something very similar).

Unless Joe stands out in the sun for too long, don't expect him to post his commercial secrets here .

The VBIGC that most people build is the DIY version that Joe 'gave' to us. details on

his site

and more on how I built mine Here

[trancy]

"this might be some commercial secret" it was my first thing when i first time seen a schematic, but maybe, maybe.....you never know

[w00t]

Originally posted by Nuuk
Trancy, that is Joe's commercial VBIGC (or something very similar).

Unless Joe stands out in the sun for too long, don't expect him to post his commercial secrets here .

The VBIGC that most people build is the DIY version that Joe 'gave' to us. details on

his site

and more on how I built mine Here

Hmm.. there's 2 tubes in your VIGC. Is this another secret?

[Nuuk]

Hmm.. there's 2 tubes in your VIGC. Is this another secret?

No secret, just building separate buffers for each channel, as much for the aesthetics as anything else.

[trancy]

can i use that kind of buffer to drive a class mosfet amp (zen)?? should i modify something??

[Nuuk]

can i use that kind of buffer to drive a class mosfet amp (zen)?? should i modify something??

What you are really asing is will that buffer make a suitable preamp for another type of power amplifier.

I don't have enough experience of valve circuits to say for sure but I can't see why not. It may not be ideal but as Joe pointed out, it is a low voltage circuit suitable for beginners.

[trancy]

Originally posted by Nuuk


What you are really asing is will that buffer make a suitable preamp for another type of power amplifier.

I

exactly....

[Shoog]

If you go with this approach be very aware that you are introducing DC into the Zen as the buffers warm up. In mine it went from 20V at the speakers and dropped to about 100mv over about 30 seconds. This could be damaging to the type of speakers which tend to partner Zens. There are ways round this problem.

Consider using a FET buffer. NUUK considered this to be about the same in effect with none of the disadvantages associated with the Valve buffer.

Shoog

[Nuuk]

Consider using a FET buffer. NUUK considered this to be about the same in effect with none of the disadvantages associated with the Valve buffer.

Just to clarify that, I still found some DC offset while the opamp buffer powered up but nowhere near as much (and for so long) as with the valve buffer.

It should go without saying that anything you build should be measured for DC offset on thge output and suitable precautions taken to protect the next item in the chain whether that be power amp and/or speakers.