Recent content by Chuck D. Bones

Most of the compressors we run into are feedback-type compressors. The output level is sensed and that is used in a feedback loop to adjust the gain. The Engineer's Finger compressor is a feed-forward type. The input signal level is sensed and that is used to adjust the gain. There is no...

Good questions. There is no hysteresis. but there is a slow-ish release. At first, I was concerned about the long time constant between R15 & C6/C7 (my schematic). It's a trade-off between release time and ripple. If we shorten the release time too much, by reducing R15 or C6/C7, then there...

Yes. No difference when using just the OTA. The Darlingtons come in handy in filter circuits but are not needed here. Close. The OTA (U2A) acts like a current-controlled resistor. The peak detector (Q2-Q5) outputs a current proportional to the peak amplitude at the output of U1B. That...

Back when I was a young lad, my friend & roommate Richard bought a Black Finger. As per usual, I would cajole him into letting me take it apart & trace the circuit with the the promise that he'd get it back intact. A very interesting circuit indeed. Years later he sold it to me and I still...

I'll keep that in mind. I bought a matched pair of JJ's.

Don't pay too much for them. Shop around. I bought some from a guy in the UK thru eBay.

Every time you change a transistor, you should check and adjust the biasing. This is especially true with Ge. Otherwise you're changing more than one thing when you swap out a Ge transistor. Q3's bias has a major effect on tone. Q3-C should be around 4.6V.

The two leakage currents I measure are Iceo and Ices. Ices is basically the same as Icb since E & B are shorted together when measuring Ices. The one I pay the most attention to is Iceo (collector current with B not connected to anything). How much is not enough? How much is too much? How...

Yes.

Getting the right amount of light on the LDR is the critical. LDRs are EXTREMELY sensitive to light. It is easy to put too much light on the LDR and if that happens, then it recovers (resistance goes up) very slowly. A diffuse LED is better because it spreads the light more evenly over the...

Correct. The DC bias can come from anywhere, as long as it's the right voltage. Check out the biasing in the Big Muff II. Stage 1 biases stage 2. Stage 2 biases stage 3.

Dear God, you can't rotate the pic on your phone? :LOL: We're talking about R3 & R4, yes? Opamps need a DC bias source for every input pin. In other words, every input pin must have a DC path to somewhere. The output of that opamp, or another opamp, or GND or Vref, whatever is appropriate...

I think we've wandered far enough off topic. ;)

In theory, yes. And it might work in some cases. Do you ever wonder why Boss & Ibanez put buffers before and after their FET switches?

Nope. But they can be purchased in an SMD package. So can a 555.