SOLVED Cross Contaminator Bias Pot Trouble

[finebyfine]

Finished a cross contaminator today. Sounds great and everything as expected other than that anything but diming the bias pot kills the sound. Triple checked transistor pinouts and component values. Confirmed with DMM that bias pot pin 1 is connected to R7. If it is something with the potentiometer itself and I should replace it, how can I confirm this with a DMM? Only thing I hate worse than desoldering components in general (if the screw terminals don't give that away) is desoldering pots.



Edited (much later): Had the wrong value pots placed.

 

[fig]

You can measure the resistance across the pot when dimed to see if it is within spec. I'm guessing at full CW, it's just pumping too much current to the transistors. Does it sound right other than that behavior?

 

[zgrav]

interesting choice to use screw terminal connections between the board and footswitch. sort of a head scratcher for me, but a neat looking build.

 

[finebyfine]

You can measure the resistance across the pot when dimed to see if it is within spec. I'm guessing at full CW, it's just pumping too much current to the transistors. Does it sound right other than that behavior?

Yeah the resistance readings across the pot really don't make any sense, I'm gonna swap it out. Other than that it sounds perfect.

interesting choice to use screw terminal connections between the board and footswitch. sort of a head scratcher for me, but a neat looking build.

I've convinced myself it makes debugging builds easier, whether or not it actually does is certainly up for debate.

 

[fig]

If you are doing it based on my suggestion I would add that any resistance or load will effect the reading and I am not an expert!. It's a 5K pot and I've checked them out of the bin at <3K before. I often go up a value and add resistors to "dial in" the pot to the correct value if it is a sensitive adjustment.

 

[finebyfine]

Different 2n1711s came in the mail and still have the same problem. Gonna kick the can down the road until I have another b5k to swap out