Suitable tubes for Gomes output

[Ceglar]

Hi,

Thinking about this here;
Gomez Vs XPP Amplifier

Would like to try it, but wondering what sort of tubes are best suited for this circuit from 5687, 6922, 12AT7, 12AX7...

Are the requirements for the (how to explain..) the left hand side of the cct different from that of the right hand side? (top and bottom, left and right)

Any ideas would be helpful.

Thanks,
Shane

[Ceglar]

So far as what tubes to use, I'm trying to figure out how it actually works.

Looks to be SRPP input but then it gets tricky. The second 'stack' upper element is fed an amplified out of phase signal, the lower element of the second stack is same as source.

Does this suggest that all the tubes must be the same?

If so, wouldnt it be more elegant (assuming Rp of 'the tube' was suitable) if the actual output was taken from the plate of the lower tube in the second stack??

That way the signal at the cathode of the upper tube in the second stack would be the same in amplitude as the plate of the the lower tube in the second stack.. which makes me wonder if there is an error in this schematic?!!

I dunno.. but I'd like to :-)

Shane

[waltube]

The best, for me, 6H6 (6N6) soviet.

I have written an article about line stage using Gomes schema with 6H6 tube; it is very good in all parameters on Audiocostruzione in Italy
Tha Va was about 240 Vdc; the output impedance is 100 ohm.

Bye

Walter

[DF96]

The valve choice, as always, would depend on the application.