Small Clone/Heladito Volume and Tone Filtering

[YouAre]

Hey Guys,

Just built the tonepad Small clone ( http://www.tonepad.com/project.asp?id=8 ) and I love the sound, but I'm not 100% happy.

One issue is the overall volume boost. I figured I could throw on a volume control at the end (replacing the 100k resistor at the output with a voltage divider), or I could mess with the 10k resistor feeding into pin 6 of ic1b. Do you guys think that lowering the gain of the output summing amp will mess with the small clone sound?

I also think that the pedal cuts off too much lows for my liking, making it sound slightly thin. I see a lot of low pass filters feeding into Q1, so those must not be the issue. The 1uf capacitor at Q2's emitter along with the 220k resistor to Vref sets up a high pass, but the filter cutoff is .7hz, so I don't think it's that. There's a lot of bass being cut off SOMEWHERE, can anyone give me insight as to where?

Thanks for the help guys!

[PRR]

> The 1uf capacitor at Q2's emitter along with the 220k resistor

220K _AND_ the 22K, 20K, 10K network.

But that's surely over 25K effective (20K+(22K||10K)) so under 7Hz, and not your problem.

At IC1a, 6.8K against 0.01uFd is unity-gain below 500Hz and 5:1 boost above 2,500Hz. Since phase-tickle works beast and higher frequencies, while strong bass uses-up BBD headroom, this makes sense; but you could explore other values.

[YouAre]

I messed with the .01uf cap, and doubled it's size. Didn't seem to change the bass content that much.

Do you think increasing the input cap to say .1uf might thicken up this pedal?

[YouAre]

Welp, I gone and done some legwork and have stuff to report!

Changing the input cap does indeed add some fullness. I swapped the .033uf input cap to about .1uf. It's not as "sparkly" sounding, but it's a nice fuller sound that almost "whistles." Not in a bad way of course.

I also changed the 10k resistor going into pin 6 of ic1b to about 22k-27k. 27k seems to bring it to unity, but filtering in the pedal makes it seem apparently less loud. 22k is still a significant boost. So maybe a 10k resistor in series with a 25k trim? Basically 22-27k seems like the magical unity gain sweet spot.

Happy modding, boys!