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Fat Boostered Bass & Gain controls not working

Started by KaBi, September 18, 2013, 09:55:18 AM

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KaBi

hi all,

I recently finished building the Fat Boostered using the layout on the below thread:

http://www.madbeanpedals.com/forum/index.php?topic=905.0

The problem is that the Bass and Gain controls don't seem to work, turning those pots appears to have no effect at all. Volume seems to work fine (I have an overall boost even before reaching the middle position, say around 10 o'clock) and so does the Treble control (it reduces Treble significantly around 2-3 o'clock onwards)

I used stock values for everything described on the pdf file, except for the Gain pot where i used the same value but the opposite taper (LOG instead of LIN if memory serves). I triple-checked my soldering for bridges and removed any solder residues, I replaced all transistors one by one in case there's a faulty one and I have checked all the connections both on the pots and on the PCB side, everything looks absolutely fine.

Any suggestions on what could be causing this and where to focus at this point (any specific parts or PCB area)? Has any other builder had a similar experience with this circuit?

Any help would be extremely appreciated. Thanks :-)



kothoma

Quote from: KaBi on September 18, 2013, 09:55:18 AM
The problem is that the Bass and Gain controls don't seem to work, ...
... seems to work fine (...) and so does the Bass control ...

I'm confused. So does Bass work or not?

KaBi

Quote from: kothoma on September 18, 2013, 10:38:02 AM
Quote from: KaBi on September 18, 2013, 09:55:18 AM
The problem is that the Bass and Gain controls don't seem to work, ...
... seems to work fine (...) and so does the Bass control ...

I'm confused. So does Bass work or not?

Yes sorry, it was just a typo. I meant that the Treble control works ok. Corrected now

kothoma

Bass control. Of course you checked the values of C1 and C2? Also R2 (and R3)?

Is the board still in the box?

KaBi

#4
Yes i've checked all components but i will triple-check when i get home tonight

The board is still boxed but I can easily flip it over by desoldering a couple of wires

KaBi

#5
Gain and Bass controls still not working. I double-checked all values and everything looks ok

Am i right to assume that since those two controls are interacting with each other the problem may be the connection between them? (ie Gain lug 3 connects to Bass Lug 1 according to the schematic, is that correct?)

To my understanding they are both behaving like they are not part of the circuit, perhaps they are grounded somehow?