I read somewhere that 12AU7 can run with 12v, so i tried to make a 1959 preamp model in LT Spice with 12AU7 with 12v power supply. It seems to sound good with a guitar signal input.
To use it with an IR cab or in front of a tube clean amp I had to add a low pass filter on a VST eq. That's why I added one in the schematic but value are still to define or choose according to your tastes.
Maybe the filter is not necessary with the return of an effect loop.
Could someone tell me if it's a ridiculous idea or correct the mistakes or improve the schematics and draw a vero because its too difficult too me ?
I tried the same with JCM800 preamp but it doesn't seem to be OK... Maybe better with lower gain as JTM45 or fender ones.
I built something very similar to this only used 60 to 90 vdc charge pump and 12v regulators for heaters.I got very impressive results.I'm still expirementing with the circuits but must say its really worth the effort just to learn as you go while tweaking things.I will be boxing the 2 I made sometime in the future.
Most tubes have an optimum operating plate voltage. The main thing is to make sure that the filaments get the correct voltage. You can run the plates at reasonably low voltage but the sound will get very compressed at lower voltages. The lower the plate voltage the easier they will break up but too low it's just too mushy. Personally I like dirt with as little compression as possible so if i use a tube overdrive I like amp-like voltages on the plates.