Yes R1 is just a discharge path for any floating voltage when switching, the anti pop thing. 2M2 is Way to high to have any effect on the input Z of U1A and it's isolated via C5.CheapPedalCollector wrote: ↑17 Dec 2022, 06:32 Thanks phatt, excellent info.
I think the pulldown resistor in the input is just to stop the switch from clicking from capacitive buildup of voltage since the LED is also going through it, or maybe backwards charge potential on the input cap, I remember popping being some issue with it.
Regards to R2 & R6.CheapPedalCollector wrote: ↑17 Dec 2022, 06:32 I'll try building the circuit with a buffer transistor and see how much less noise it makes, should be able to lower R2/R6 also to 4.7k and 100k to retain the same gain but less noise yes?
I really need to buy a copy of art of electronics...
No this one does the gain by altering the resistance of R3.
(not ideal in my experience as all the gain might be close to the end of the sweep)
Better to make R6 a 500k pot and just ground R3. R3 does not have to go to Vb it can go to either Vb or Comm.
Frankly just use the values of the TS circuit then tweak till you find a sweet spot.
With the buffer you will need to up the value of C5 to 1uF or higher, see TS circuit.
Experiment by changing values of C4 & C6.
Also R3 but below around 500R it may just squeal like a pig be warned.
I was lucky that someone gave me a copy of a free sim program and *Art of Electronics*. Circuit maker Prg was very basic but for pedals it was all I needed to see just how it works.
BTW, All this was before I had internet. (shows my age group )
So I had a breadboard on the bench and a sim program on the screen.
So change a value on the screen and then do it to the actual circuit.
Really sped up my understanding.
I've worn out 5 breadboards in the last 30 plus years.
and I'm too old now to go back to uni to learn stuff I may never have time to use.
So now i have a good pedal and Amp setup and tend to play guitar far more than soldering stuff.
I urge anyone wishing to learn how to make pedals,, get yourself familiar with sims, They won't tell you everything but nothing like a plot on the screen and then hear it live to speed up just where tone is won and lost.
Phil.