Recent content by JTEX

MLCCs (with an X5R/X7R dielectric) are fine in the audio path (certainly as far as pedals go, at least) as long as any voltage across them is far less than their rated voltage. This avoids voltage-dependent loss of capacitance and distortion. I use 10% tolerance X7R rated at 50V (or more) and...

Check R44 if the ICs don't get power. Also, make sure it's 100 ohms and not 100k.

I feel that this style is the most reliable of them all, but it needs a bit more space than other designs:

The caps do not contribute noise. The 3 circuits have the same output level and frequency response. Not sure I understand the last question.

I thought the most common, garden variety log type is 10% at mid travel. Is this not the case?

The first 10 probably means that you get 10% of the total value when it's at the half rotation point, measured between the CW lug and middle (it's the opposite of a log pot, which would be 10% measured from CCW to middle)

yes

Resistors make noise. Thermal (Johnson) noise. The higher the value, the more noise. If you simply go with convenient, common values without paying attention to their noise contribution, you can easily swamp an op amp's self noise with the surounding resistors' noise. The following 3 circuits...

As drawn, the R2/R3 divider (Vbias) will send half of any noise/ripple from your 9V supply straight into the opamp input. Hope you're using a battery! A better way to do it is something like this:

It helps the manufacturers charge more for the pedal, is what I meant :rolleyes:

It helps them charge more. Perceived value. More to look at, and brighter colors (compared with, say, SMD). Makes duck all difference soundwise, assuming the correct parts are used in both cases. Placebo with benefits (for the maker...). There, I've said the quiet part out loud.

You gave up too easily :)

BTW, the final-final (I swear!) iteration of the RockBrain is Rev2 (renamed to RockEngine) and you can find it here. It's a little bit more polished and comes with a datasheet: https://www.jtex.ca/products/discontinued/re

That's probably a leftover symbol from when I was still experimenting with the internal grounding arrangement. Should be a filled triangle (mid-supply), which I actually corrected in a minor revision. (Rev1.1+).

I did hand-pick MMBFJ201s. It was easy though: the batch I got were very consistent and roughly in the ballpark for this circuit. YMMV of course. BTW if I had to do something like this again, I'd replace the compressor with something completely different, like a THAT-based design with a proper...