Pyrocumulus - Sustain knob mostly effects tone last half of the sweep?

Idlebeach

Member
Hey! Sorry for asking for help so frequently! I appreciate you all.

I built this Pyrocumulus (Thorpy Fallout Cloud) for a friend and I'm not confident about the way the sustain knob works. It definitely increases gain but most of what is happening toward the end of the sweep is it's adding a fair amount of lows. Kind of sounds a tiny bit like a clean guitar and muff at the same time? Could just be the tonal changes tricking my ear. This could be as designed or I messed up somewhere. I've reflowed every joint and added some solder to a few but it didn't make a difference. I've also cleaned off the back of the board with IPA and a toothbrush.

I took a photo in case someone with fresh eyes can spot a wrong resistor or cap but I took my time as I built it. All other controls work as expected.
IMG_5434.jpg

Oh and here is the build doc link : https://docs.pedalpcb.com/project/Pyrocumulus-PedalPCB.pdf

If someone else has built this one and can verify the sustain knob adds low end as you turn it up - then that's probably all it is. Doesn't sound quite like the demos I heard though. Thanks!
 
I’ve made a fair number of pedals where the volume knob (usually at the end of the circuit) attenuated the lows as you turn it down. It’s just the nature of the circuit block (look into R-C filters to see what I mean). The sustain stage is essentially no different albeit a little tamer in terms of low end. Can you share a sound clip? Your phone may or may not capture it very well.
 
I’ve made a fair number of pedals where the volume knob (usually at the end of the circuit) attenuated the lows as you turn it down. It’s just the nature of the circuit block (look into R-C filters to see what I mean). The sustain stage is essentially no different albeit a little tamer in terms of low end. Can you share a sound clip? Your phone may or may not capture it very well.
Good idea! I recorded this through an ACS1 so hopefully the low end is more apparent as the gain is turned up.



Thanks!
 
I can't be of any help. But I gotta say, it sounds pretty @!#?@! grat through my laptop speakers. The low end issue is not discernable from here.

The bees are super cute as well. Nice build. Hope you get it how you like it!
 
Idlebeach, very nice build!! One question to you and all other people who built this pedal... did you measure the hfe of the bc549c did you use??
Thanks!!
 
Sounds like mine, my dude/ette, so if it's a thing, it's a consistent thing. Definitely this circuit has a tone "separation" where the lows and highs seem to be layered and clear under the fuzz. I like that!

I also think some circuits will shunt different parts of the signal to ground in attenuating through the pots and that will affect the tone (this def happens in guitars) as well as what parts are clipped, so it's not a weird thing for the bass to be more present when the signal is wide open/fully clipping, i don't think.
 
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