use a low input impedance buffer to retain volume knob cleanup?

[Alex C]

Well, geez...   

John-
I meant no disrespect by my post, just good-natured ribbing.  I think I didn't properly convey the friendly tone that was intended. 

I thought your circuit was pretty clever, and it seems to me that it would indeed allow for adjustment of the input impedance while keeping gain at unity.  I can appreciate the tendency to over-complicate things, but I don't really see this as "overkill"- that's a pretty low parts count for a circuit addition that could really increase the versatility of setups that include input-impedance-dependent effects like fuzzes.

-Alex

[frank_p]

I think you should not be embarassed too, John.  Ideas are habitually a good thing.

[tehfunk]

So if the approximate resistance of the first stage of a FF is 22k, how do i make a buffer, or use an output resistor on the effect before it to make it the right impedance to make it seem like there is no pedal running before it. (i am referring specifically to the case of the wah into the ff) i saw that doug used a 47k output resistor, but would it be better to have it be 22k? I really don't understand all the electronic theory, I plan on learning.

[brett]

Hi

Envelope detector drives an LED, and the input bias resistor to gain stage is an LDR... maybe.  Neat idea.

If you used this circuit, and
1 replaced the 100k input resistor with an LDR
2 replaced the mosfet with an LED (luckily, both "turn on" at 2 to 3 V)
3 and replaced Q1 (and associated resistors etc) with an inverting opamp

you'd have something close. 

In this circuit the pot is a "compression" control, and Q2, the 1N4148, the cap, the trimpot, etc are a very flexible envelope follower.  The 470k resistor controls "voltage bleed"/ decay.

Anyone going to try?

[earthtonesaudio]

MOSFETs as variable resistors are my favorite!