Bad practice?

[~arph]

Hi,

I'm working on a tremolo (there is a lot of us lately) and I think my methodology for changing the volume is bad practice, but it works so well!
What I'm doing is at the end of the output stage (basically a mosfet boost) AFTER a 10uF electrolyte I have an LDR to ground. This means the output impedance (correct me if I'm wrong) is anywhere between ~ 1 Meg and 500 ohms. (the LDR range) This is basically a dynamic high pass filter, but since 500 ohms and 10uF gives me a corner freq of around 30Hz this should not have an audible effect on guitar (not too noticable on bass too I guess). Still somehow I have a hunch that fooling around with the output impedance is a bad idea. So far I haven't run into any problems on my amps and in combination with other pedals.
Maybe I'm wrong, because this is what we usually do for controlling output volume too.
Does anyone have a definite word on this?

Thanks,

Arnoud

[alanlan]

but it works so well!

I think you've sort of answered your own question!

I can't see a "problem".  All you are doing is forming a potential divider between the output impedance of the MOSFET booster and the LDR.  You could probably put the LDR anywhere, I suppose, to shunt the signal.  I don't think you'll do any damage if that's what you are worried about.

[~arph]

Thanks,

This forum is wonderful and full of similar minded helpfull people. 
Yes I did kind of answer my own question, but I was having this nagging feeling that it might cause problems to equipment you put after it. I did try the LDR in many positions in the signal path, this one by far sounds the best. All that remains now is too see if the little remaining noise is breadboard related or should be filtered out, after that make the PCB and hire some elves to make enclosures. (no Zach, not your elves)

[~arph]

Hi it's me again,

After reading the pedal impedance article on AMZ I concluded that a resistor to ground is not affecting the output impedance, it merely passes a part of the signal to ground. A resistor in series with the output would affect it. So my conclusion is it's fine to do this.. happy now. 

[Meanderthal]

 Yep, you're right... that LDR to ground at the output is about the same as the more common pot to ground volume control.