100k and 220/150k in the same amp - the best of both worlds?

[dave g]

All this talk of the 100k vs 220/150k non-hrm amps really got me thinking, do we absolutely have to limit ourselves to one voicing per amp? For my next non-HRM build I was planning on changing the preamp layout a bit so that I'd be able to use an additional toggle switch on the back of the amp to change the plate and cathode resistors on V1 and V2 along with the cathode bypass caps and coupling cap on CL2 back and forth between the 70's and 80's values. Anyone given this a try before?

[chris_sanford]

All this talk of the 100k vs 220/150k non-hrm amps really got me thinking, do we absolutely have to limit ourselves to one voicing per amp? For my next non-HRM build I was planning on changing the preamp layout a bit so that I'd be able to use an additional toggle switch on the back of the amp to change the plate and cathode resistors on V1 and V2 along with the cathode bypass caps and coupling cap on CL2 back and forth between the 70's and 80's values. Anyone given this a try before?

I think it's a great idea in theory, however the implementation of all that switching would be problematic, imo. How are you going to handle switching the high voltage, for instance? I can imagine a scheme using two coupling caps per preamp stage, so that you wouldn't have to mess with B+ voltages, OR perhaps have two discreet overdrive (or preamp) tubes so you could kick them in or out of the circuit... but that is still a lot of pain for perhaps not so much gain (no pun intended).

I believe that you can have your cake and eat it too (great clean AND dirty tones) with one properly tweaked d-style circuit.

chris

[Normster]

Sounds like you're describing a Glaswerks. I have no idea how Gary accomplished his switching, but in looking at the gut shots of his amps, I think I'll stick to the "simple" dumble circuit.

[dogears]

Gary does not switch plates or cathode resistor values. He does switch other stuff that can get all kinds of sweet tones. And, the cleans are stellar.

Sounds like you're describing a Glaswerks. I have no idea how Gary accomplished his switching, but in looking at the gut shots of his amps, I think I'll stick to the "simple" dumble circuit.

[Funkalicousgroove]

Just build yourself a couple amps!!

[Bob-I]

I figure it'll be easier to build an amp switcher than all this inside the amp. You'll have too many issues to deal with in there. These amps are complex enough already. JMO

[dave g]

Yeah, I think you guys are right. I worked out a way to do it with lots of optocouplers, but I don't know if it's even really worth it then.

[Funkalicousgroove]

If it were me, I'd do an 80's with 100K/1K5, and an HRM and use a lehle switcher.