6G3 preamp thoughts

[cminor9]

Building a 6G3. I don't need a two channel amp, it's a waste of a triode in my book. I never use the second channel on my 5E3. Never. So I am going to build a one channel 6G3. Here is what I have come up with for the extra triode:

1) run the two stages in parallel for a "fatter" sound (dunno what exactly that means, but I read it here on m-e-f!). I cannot figure out what that would do to the signal. It wouldn't double the voltage. Would it double the current? Some weird flanging thing? Whatever it does, what effect would that have on the sound?

2) keep them separate and use one at a time (via a switch on the cathode->ground connection), each triode tuned differently. This seems pretty straightforward to me. Heck, I could even switch em both on if I did that.

3) what I am leaning towards, having a HI and LO input. One just hits a stock input stage (25uF cap, 820 resistor for one cathode, since stock is 1500 for both.) The other hits a hot input stage (2.2k resistor, 4.7uF bypass cap) and then the stock input stage. Think THD Uni-Valve, if you've ever seen or played one.

I realize this is a bit subjective, and I am not asking which I would prefer. What I am interested in is this: what exactly does scenario 1 do? Does scenario 3 seem practical (or will I create too much gain which will mess something up later down the line?)

Also, if you have ever done something similar to one of these circuits, what were your thoughts about it?

[zhyla]

From my own messing around this week with preamp biasing I think you might find cold and hot triodes to be interesting. You could also modify the low-pass cutoff by lowering the RC combo to modify the bass response - one channel with "thump" and one without.

[tubeswell]

Or build a single channel 6G3 (makes the 2nF plate bypass cap switchable) and use the extra triode as a CF stage with your bias vary trem (like a 6G16 or a 5G9) - will make for incredible trem.

[cminor9]

Tubeswell with the cool fourth option, nice!

I'll have to give that some thought. I could probably start by looking at the 5G9 and comparing them to see what you mean.

One thing: would that cause any unintended consequences with part of the trem circuit that close to the input stage? Or should I bump everything down a tube (so the tone stack follower gets the second triode of the first tube, and so on)?

At any rate, it's something to consider.

[txstrat]

I didn't think of using the second channel of such an amp either, but since I built my 6G3 I find it very interresting to tinker around with the interaction of the two channels.
While playing the bright channel and turning up the normal channels volume pot will add lots of bass to the bright channel, hence way more sound options.
Or you could use a simpe A/B stomp box to switch between the two channels for different sounds OR different volumes. Not unappealing IMHO.

[tubeswell]

should I bump everything down a tube (so the tone stack follower gets the second triode of the first tube, and so on)?

Yep that's what I envisaged. Keep the subsequent gain stages in the same bottle as far as possible, so you'd use a 12AX7 for the first two stages either side of the vol/tone, and another 12AX7 for the LTP, and the 3rd 12AX7 for the trem with CF