12AT7 vs AX7 in V1 for dynamics?

[Steve A.]

Hi Steve~ embarrassingly, I don't know the circuit on my 6G15 RI!! It usually has an AX7, an AT7 and a 6V6.

Me too! I just looked at the schematic and the 12AT7 is the initial preamp tube for the reverb section while the dry signal goes to one stage of the 12AX7 from which it is blended with the wet signal.

Steve

[deci belle]

ok, so 1/2 of the ax7 amplifies the dry signal and sends it to the output mixer pot.

That means I'm using an au7 to do the ax7's job and its other 1/2 to send the wet signal to the tone and mixer pots.

So the at7 I'm using sends the soon to be wet signal to the pwr tube then the OT's SE 2ndary to the reverb tank.


And that's where the au7 recovers the wet signal from the tank.

Some day I'll make a real 6G15 and put it in the RI cabinet! I am having an aluminum chassis bent for that now but I wasn't planning on actually doing any time soon.

What a cool little circuit. Now I understand it better— thanks, Steve!

[Mick Bailey]

I'll also throw in the 12BH7 for discussion. More in the 12AU7 area for gain, and higher heater current. Sounds good in some amps - I've used it to tame gain for jazz players.