"Tube Sound" Tube Sound Fuzz

[Bill Mountain]

So, I haven't drawn anything up yet but I've been having visions of a Tube Driver type circuit with CMOS stages instead of opamps.  Logic chips clip more convincingly and the tube is really just there to do some filtering of the signal.  I don't have time to try every project that comes to my head so I was hoping someone had done it or someone will try it at some point.

At 9-12 volts I'd probably go with a Valvecaster style back end.  Anything higher and I'd go with a Tube Driver circuit (with the 12AX7) but you'd have to check the max voltage on the Chip and you'd have to devise a more complicated power supply.

Maybe you could do the heaters in parallel and use the 6.3 volts to run the Chip as well (at its preferred lower voltage) and then you could take the B+ as high as you want to go.

Thoughts?

Criticisms?

Better Ideas?

[brett]

Hi
I wonder whether you'd be getting much colour out of the tube?
If you haven't yet built a distortion with CMOS "TSF" stages, then I suggest you start with that on it's own.
From building several variations, I suggest putting a mild booster (e.g. JFET, gain of 5) in front of the CMOS stages. Generally, two stages = mild and three stages = wild.
Also, the smaller the feedback capacitors, the "sharper" the clipping.
But if you have messed with CMOS stages before...go for it. The CMOS stages will certaily load the tube as much (or more) than you want.
cheers

[Bill Mountain]

I built a Tube Sound Fuzz a while back and I just dug it out to run some comparisons with a FET distortion and it did surprisingly well for such a simple circuit.  That's what led me to think of new things to do with it.  There is a little too much fizz stock so I'm gonna to try out some EQ circuits as well.