Help with double board Xotic AC-Comp please

[sonolink]

A friend has this Xotic AC Booster-Comp Custom Shop that gets dirty very soon on the gain knob. He has asked me if I could change it so that it would saturate "later".
My guess was it uses Linear pots so replacing the gain pot with a logarithmic one would probably do the trick.

When I opened the pedal I found myself with this:



So before doing anything silly I thought maybe I would seek some wisdom first

I guess bending the boards open is out of the question, so do I have to unsolder all the connecting pins or maybe I should try to unsolder and replace from the top?

Any other ideas?

Thanks for your help
Cheers
Sono

 

[Khron]

If it's just that single row of pins, I'd just cut them, and replace them with pieces of resistor legs, when reassembling. Or pieces of solid-core cat5 cable, etc.

Or, if you wanted to get "fancy", and in case those pin connections are not structural / mechanical support, you might even dig up some appropriate-pitch ribbon cables, to allow for flexibility later (if needed).

 

[sonolink]

Thanks for your reply

I have the impression it is structural indeed, but I can replace the pins as you suggest.

The log pot would do the trick, right?

Cheers
Sono

 

[Khron]

That's a big, definite "maybe" - depends entirely what that potentiometer does in the circuit, how it's connected etc.

 

[sonolink]

Would this schematic help with that "big definitive maybe"?



If the log would work, would this one be ok?
https://www.musikding.de/Pot-9mm-1M-log-Print-vertical

Thanks a lot for your time and help
Cheers
Sono

 

[Khron]

Very much so, indeed ;D You might want to perhaps simulate that part of the circuit and see if you want a log pot there, or perhaps an antilog / reverse-log one (C-taper). It's almost midnight here and i've been up since before 6am, so my brain can't figure that one out right now

On second thought, probably log / audio taper after all. Mic preamps often use a reverse-log taper, and the gain increases as the resistance decreases. The case here is the opposite of that (greater resistance -> more gain).

 

[sonolink]

Ok I'll get a log and a reverse log and try that. I didn't need an instant answer hehe thanks a lot for your help and get some rest

Cheers
Sono

 

[sonolink]

On second thought, probably log / audio taper after all. Mic preamps often use a reverse-log taper, and the gain increases as the resistance decreases. The case here is the opposite of that (greater resistance -> more gain).

Actually you are most probably right: this pedal used to have an earlier version with a 500k Gain pot that was later increased to 1M precisely to increase maximum gain. I'll definitely go for the log pot then 8)

Thanks a lot for your help!
Cheers
Sono

 

[ruffrecords]

If the log would work, would this one be ok?
https://www.musikding.de/Pot-9mm-1M-log-Print-vertical

Thanks a lot for your time and help
Cheers
Sono

Just check the shaft diameter of the existing pot first. These pots come in both 6mm and quarter inch diameter shafts. For the existing knob to fit you need to pick the right one.

Cheers

Ian

 

[sonolink]

Thanks for pointing that out Ian! 

Cheers
Sono