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  1. JTEX

    when to use mlcc capacitors

    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...
  2. JTEX

    Voltage Supply Question

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

    What are the most rugged 1/4" jacks people are using?

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

    Resistor values and Noise

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

    What kind of pot is this?

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

    What kind of pot is this?

    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)
  7. JTEX

    Resistor values and Noise

    yes
  8. JTEX

    Resistor values and Noise

    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...
  9. JTEX

    Critique my circuit

    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:
  10. JTEX

    Stuff you wanted to know but were afraid to ask

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

    Stuff you wanted to know but were afraid to ask

    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.
  12. JTEX

    Rock Mania / RockBrain

    You gave up too easily :)
  13. JTEX

    Rock Mania / RockBrain

    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
  14. JTEX

    Rock Mania / RockBrain

    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+).
  15. JTEX

    Rock Mania / RockBrain

    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...
  16. JTEX

    Queen Brian May Fans - Deacy Pedal Project

    I suspect you can't get the real Deacy sound without using the proper, cheapo speaker and cabinet.
  17. JTEX

    A new-production BBD, with added features!

    The S/N spec is pretty underwhelming for such a short delay. Gets even worse if daisy chaining a few
  18. JTEX

    Do you pay any attention to Capacitor ‘Life’ ratings?

    I'd say you can bend them about twice before they break.
  19. JTEX

    Do you pay any attention to Capacitor ‘Life’ ratings?

    I've never seen an 18v rated elcap in my life. It's either 16V or 25V as far as I've seen. Now, you can have leaky caps (there was an "electrolyte gate" scandal), and those will corrode traces on the PCB, causing untold grief. This is why I only buy elcaps from well known brands.
  20. JTEX

    Do you pay any attention to Capacitor ‘Life’ ratings?

    The rated life is given at the maximum temperature. For every 10°C decrease, the life expectancy doubles. So if you buy a cap rated for 1000 hours at 105°C, it should be good for 128k hours at 35°C, which is warmer than the typical temp inside a pedal. Basically don't worry about elcap life in...
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