Since I’m building another thermionic distortion aka be-od. Any mods I can do instead of the usual parts on the documentation? Thanks
variety kind sir since I already have 3 of the same. IN4158 it is. Any other mods to make it sound different?The mod you make depends on the sound you're trying to achieve. I don't mod pedals just because I like modding them, I do it to get a particular sound. If the Thermionic does what you want, then I'd leave it alone.
That being said, D2-D5 should be something other than 1N5817 IMHO. The other Friedman pedals use 1N4148.
Asymmetrical diodes can produce more even-order harmonics. The effect can be pretty subtle. If you do mess with the diodes, I'd suggest replacing D2 with a short and/or D5 with an LED. Maybe try sockets for those so you can experiment.
I’d like a harsher distortion this time around and a bit more bass on this next build.I would be careful if you alter R9 or R11. R10 and R12 each make a clean bleed for that stage. Notice how they are matched to R9 & R11. Hard to believe that you would want more gain from this circuit, but if you do, try it in small increments. All of the usual high-gain caveats apply. Keep the input wiring away from everything else. Make sure you have very good grounds between the jacks and case.
You could also retune the tone controls. You haven't told us what tone you're seeking, only that you want it different. So why not just build a different pedal? If you're after high-gain, consider the Valhalla, Malachite, Tyrian or Sanguine.
Try these:I’d like a harsher distortion this time around and a bit more bass on this next build.
Sweet, I'll give this a tryIf I may make a suggestion, try reducing C12 to 15nF and make C13 470nF. You'll have a 25dB peak at 57Hz and more bass than stock from 20Hz on up. IC4.2 is actually a bandpass filter. The ratio of C13 / C12 sets the gain, the product of C12 + C13 sets the peak freq.
Just what I happened to grab. Been using them in place of 1N4148 in some hard clipper circuits, so they were on top of the pileD1-D4 - This change should make very little difference. Why zeners?
The 6002s seem to be fine in this and a Sweet Honey I built recently. Probably try some other chips. Nothing wrong with TL072, other than I don't currently have any on hand. Current stock of dual op-amps I have are NE5532, MCP6002, TLC27M2, CA3240, CA3260, LM358, and MC1458NE5532 has pretty high bias current which may interfere with operation as IC2 & IC3. Other stages should be fine. MCP6002 is rated for 7V max. It might be ok at 9V or it might die at any time. What's wrong with TL072?
I like the 1n4740 instead of silicon for a little extra volume. As hard clippers, they sit in between red LEDs and 1n4148 with Vf of 1.2. probably could've just gone with 2 red LEDs for that stage, but I'm happy with it now.Wired that way, the zeners just act like regular silicon diodes. We've seen that done in other pedals, like the Disarray, probably for the same reason.
Replacing one of the 4 diodes with a jumper or LED would make asymmetric clipping, which could be interesting.
Semiconductors usually have no problem running a little bit outside the maximum ratings, but there is no guarantee they will meet spec or work at all.