big muff help

[adapt]

i've built a few before, but this one is giving me trouble. it sounds really like, mid-rangey. like, lower-mids. i used the black russian layout, except i subbed 10uf tantalums for input and output (like the pharaoh, and it sounded just as middy before anyway), 100 ohm resistors on Q2 and Q3, 680 ohm resistor on Q1.

everything else is the same, according to kit rae schematic. 10k limiting resistors, 470k/470pf feedback parts, etc etc. the only thing i can think of that might be off:

i used a 20k resistor/10n cap in the tone section (tone 1 side) as per kit rae schematic though 20k seems really low. i also used ME4003 transistors, could this be the problem?

it's driving me crazy.

[adapt]

welp. guess i'll figure it out. thanks.

[induction]

Gutshots and/or voltages would give us somewhere to start.

[Frank_NH]

Right.  To debug something we need more info, and what really helps are: (1) images (lots of closeups, front and back of the board), (2) voltages at key points in the circuit.

Also, read this for all of the essential debugging tips:

http://www.diystompboxes.com/pedals/debug.html

[Frank_NH]

Also - if you have a schematic, that is very helpful for debugging.  I assume this is what you're working with?



If you're playing with the tone stack, you may want to check out the Duncan tone stack calculator to see if any of your changes would result in a midrange hump.

Finally, if you've built this before and your current build is somehow off, check your component values.  Sometimes, you think you've used a 4.7nF cap when it really was a 47nf cap (don't ask me how I know this ).  In fact --- I recent fixed my ROG Thor circuit when I noticed that the reason that the J201 wouldn't bias was because I had used a 5K trimmer versus a 50K trimmer!   (Yes, the Bournes trimpots read 502 = 5K, 503 = 50K etc.  Guess which one I used?). Lesson learned...