Xotic EB Booster Acting as volume cut instead of boost

[maurice]

I just built the Sabro Xotic EP Boost (http://www.sabrotone.com/?attachment_id=3185)

When the effect is activated, the knob acts as a volume cut (but not completely silent).  Pot all the way to right is same level as clean tone (No boost).

Any ideas what could be the problem?

I substituted the C10k pot with a B100k as it's all I had.  Would that be causing the issue?

[Elijah-Baley]

Are you sure you're not confusing the pot's lugs?
Check the contacts of the wires and them position on the board. Start with this.

[maurice]

Thanks for the suggestion, but yes I just double checked.  Lugs are correctly connected.

I also just swapped the pot to a B47k and tried alternate wiring of the lugs but same problem persists.

Any other suggestions?

[Elijah-Baley]

Post some pictures of your board, if you can.

[maurice]

No worries.  I'm uploading them to http://imgur.com/a/A1IHp

Thanks for taking the time to look!

I couldn't really get the top of circuit but let me know if it's advantageous to de-solder and get better pics.

On a side note, I used two small ceramic caps  for c1 & c5 whereas I've seen other people use different types. Could that be an issue?

[Kipper4]

1 It's a great idea to test your circuits before boxing them.
  Debugging is easier out of the box. Less to debug too. (Switching, led indicator, Jacks etc)

2 Have you insulated the board?
  It's all too easy for the componant or solder side to short out inside the box.

3 Did you know you can put a resistor in parallel across a pot to alter the pots resistance
  See the secret life of pots @ Geofx and a parallel resistor calculator if needs be.


ceramics should be fine for C1 & C5.

I cant see the board very well in the photos. Sorry I cant be more help with debugging but these tips might help you in future.

[Gus]

First

http://www.diystompboxes.com/smfforum/index.php?topic=29816.0
Transistor voltages will help

[maurice]

Thanks, more pics of the circuit at http://imgur.com/a/dls6t

Will get the voltages later today

[maurice]

Seems that my previous imgur upload didn't work  http://imgur.com/a/p16W3 is the correct pics for the more detailed circuit view.

Voltages for transistors are:
Q1:
D: 3.3
S: 3.8
G: 8.4

Q2:
E: 8.1
B: 1.46
C: 1.5

[intripped]

R5 and R6 are swapped in your circuit

[maurice]

You my friend are an eagle eyed genius! Problem solved

Pedal works great!