Chop shop 2M resistor substitute...

[The Gator]

Looking at the circuit, there are a couple of 2M resistors to ground off the input.
I did not pay close enough attention to the shopping list and missed these. I have some 2.2M, or I guess I could series some 1M if it needs to be that accurate.

I could use the opinions if those who are more knowledgeable than I.

Thank you...again

Gator

 

[The Gator]

Oops. I rudely asked for help and forgot to add the picture of the schematic.
Here it is

 

[Bricksnbeatles]

2m2 is fine. R1 is just a pull-down, and r3 is forming a voltage divider with R2— 2M2 will just make it so the signal being fed into Q1 is attenuated just a tiny bit less than if it was 2M

 

[Snicksound]

I routinely sub 2M2 in place of 2M. A 10% up or down is typically not a big deal except in a few key spots.

In this case, the idea was pretty much to keep a 1M input impedance despite having a resistor before and after the input cap (a common practice in pedals). The 33k is almost irrelevant, it's more of a "gate stopper" for the JFET.

Using 2M2 means a 1M1 input impedance, which won't make a difference. As for the R2/R3 voltage divider, you'll be going from a 0.14dB reduction to a 0.13dB reduction.

 

[KR Sound]

I couldn’t find my 2M2’s so I tented some 1Ms.

 

[The Gator]

Thank you very much for the responses!
Especially thank you for the explanation of the purpose. I felt like it did not matter, but the specifics are extremely helpful.
I hope to have this working tonight.

 

[The Gator]

Ok. I could start another thread if the moderator believes I should, but I want to make sure I understand the biasing method for this new version of the chop shop circuit.
The sag pot turned all the way CCW (should make it lowest resistance reading) then measure from the provided pad on top of the trimmers. Measure from the pad to ground I assume. Fine tune each trimmer until 6 to 6.6v is achieved?

I did this and the pedal works. However turning up the sag pot just cuts the sou d out rather quickly. It was also very, very touchy to tune in the trimmers. It goes from .4V to 7.4V when I barely touch the trimmer

 

[KR Sound]

Ok. I could start another thread if the moderator believes I should, but I want to make sure I understand the biasing method for this new version of the chop shop circuit.
The sag pot turned all the way CCW (should make it lowest resistance reading) then measure from the provided pad on top of the trimmers. Measure from the pad to ground I assume. Fine tune each trimmer until 6 to 6.6v is achieved?

I did this and the pedal works. However turning up the sag pot just cuts the sou d out rather quickly. It was also very, very touchy to tune in the trimmers. It goes from .4V to 7.4V when I barely touch the trimmer

That’s exactly what I did and I was able to get each one right at 6V, but I had a lot of wiggle room. In fact, one was right on perfect to start, and the other took almost a half turn from starting at about 1v to get 6.

My Sag control has a lot of room to it- I’d say the full spectrum of the knob.

 

[LukeFRC]

My Sag control has a lot of room to it- I’d say the full spectrum of the knob.

mine too, it drops the volume a bit but you can make it up with the volume

 

[The Gator]

Sounds like I need to start a thread in the troubleshooting forum with some more info and pics.