Got any suggestions for my new pedal?

Started by henrymop, September 18, 2012, 02:43:20 PM

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henrymop

Program located here: http://www.falstad.com/circuit/

Here's the schematic:
http://imageshack.us/a/img854/6655/44213732.png

I havn't built it yet, was just designing it. Just wanted some comments on what you thought.

Prototype name is Black Silk, for now. Will change when I build it.

Has clipping switch and pot for how much clipping you want.
Beta for both transistors are 200.
Top waveform dry signal and bottom is distorted signal.

Wondering about the distorted signal. Why is it only positive voltage? I tried biasing the transistors, but I guess I did them wrong.

LucifersTrip

maybe breadboarding a Knight Fuzz will give you some comparison and/or help



always think outside the box

Quackzed

tack a 100k resistor from the output to ground... that should center the waveform. adding a 100k volume pot at that spot and taking the output from the middle lug would also work there...
a mod you could try is to take either one of the diodes and remove it from the side of the pot its on and move it to the other side of the same pot, just one of em. for a hard/soft clip setup that has a kinda tubey sound... as an option.

nothing says forever like a solid block of liquid nails!!!

henrymop

#3
I really appreciate your replies. Thank you.

Here's an update:
http://imageshack.us/a/img43/574/27809159.png

It takes 2 seconds for the waveform to center as it is in this picture.
Evidently something is discharging, and I think it is the 4.6 cap at the end. When I lower the value on that cap, it seems to have helped center it some, but of course I don't want to change the sound until I start breadboarding this.

I changed the last cap from 10u to 4.6u. This last cap acts as a high-pass filter and some sort of protector, right?
I also changed the caps inbetween the transistors.

I also added 2 100k resistors after each transistor output cap. That helped, but only when I did it for both.

Quackzed

QuoteIt takes 2 seconds for the waveform to center as it is in this picture.
Evidently something is discharging, and I think it is the 4.6 cap at the end. When I lower the value on that cap, it seems to have helped center it some, but of course I don't want to change the sound until I start breadboarding this.

I changed the last cap from 10u to 4.6u. This last cap acts as a high-pass filter and some sort of protector, right?
I also changed the caps inbetween the transistors.
yes , basically that cap and the resistor to ground that you added form a high pass filter. also the cap/resistor allow the cap to discharge through the resistor and slowly bias itself inbetween the power rails.
because of this slow bias shift you may want to use a smaller cap / smaller caps. with a .1uf / 100k the rolloff of bass is still below the guitars lowest note, so ALL of the signal still gets in, just not as much that is below the guitars frequency range, this will also speed up the 'bias' time, as the smaller cap discharges faster... try .1 /100k after each transistor and see if that helps.
also try raising the 15k at the base of your first transistor to say 50k-100k might not be what you want, it will change how the circuit sounds i think, but its something to try, a 100k(instead of the 15k) will bias the base to about 1/2 way btween the + and - power rails. see how that works, the resistor from q1 base to ground is almost equal to the resistance from q1 base to 9v+ if 100k. so its biased inbetween the rails( around half way)...
with 15k, its closer to ground and signals will clip at ground on one side sooner... becouse 15k isnt equal to 100k...

nothing says forever like a solid block of liquid nails!!!