Blue Magic MOSFET Resistor/Cap Query

[Luqqas]

It's possible that R4 in the Blue Magic Project (by Jake Nagy, available at General Guitar Gadgets) can cause a pop noise when switch on the effect?

R4 (1K) is between ground and the Source of the Mosfet (BS170)

What happen if that resistor is modified in his value?

Link to the project: http://www.generalguitargadgets.com/diagrams/bmagic.pdf?phpMyAdmin=78482479fd7e7fc3768044a841b3e85a

[Luqqas]

Ok, sorry for this nonsense. I've realized that the 6.8 cap in parallel with R4 may be the cause of the pop when the effect turns on.

I've applied all the advices about the pull-down resistors and LED pop's and all the threads about pop noise.

Just wondering if a MOSFET characteristics may produce a pop noise.

[PRR]

> It's possible that R4 ... can cause a pop noise when switch on the effect?

No.

All single-supply circuits pop at turn-on. Q2's drain rises instantly from zero to +4.7V, POP.

> R4 (1K) ...What happen if that resistor is modified in his value?

Try it. With R4 very low, say under 100 ohms, the MOSFET will suck R5 to ground, no signal can pass. R4 large, maybe over 5K, MOSFET drain will slam to +9V supply, no signal can pass.

R4 with R1 R2 and the MOSFET's parameters set MOSFET and R5 current. The usual goal is to set Q1's drain about half-way up the supply voltage. Say 3V to 7V on a 9V supply.

[PRR]

Did you add a 2Meg resistor to ground, left of C1?

[Luqqas]

Did you add a 2Meg resistor to ground, left of C1?

Yes, I did it. Put 2M2.

I get a pop and also try wiring the 3PDT with input and output to ground when effect is off. I've made all the tricks that you can imagine and still the pop. All.

But then, read somewhere that by MOSFET characteristics you can get a pop, So that's what I'm wondering.

I feel that the question is in R4 and the parallel cap. of 6.8 uF