BBE Sonic Stomp -(Aion Lumin) Problem

[Nio28]

Hi folks,

This is my first post in this forum... and I am starting with a problem.
I built the "Lumin", a BBE Sonic Stomp clone by Aion electronic, bought at Musikding.de (here is the Building description https://aionelectronics.com/wp-content/uploads/2019/03/lumin_documentation.pdf)
I´m a DIY newbie, and therefor not really experienced in debugging.
The Pedal is used for processing/EQing Bass, Mid and Treble. After finishing and mounting the PCB, Bass and Mids are working fine, but the Treble Poti (called "Process") as well as the High Frequency switch don´t do anything when beeing changed.
Also the sound looses high frequencies when the pedal is engaged.

The high frequency/Process poti is fine when measured with a mulitmeter.

Can somebody please give me a hint how to proceed in finding the bug?

Thanks,
Nio

[garcho]

...the Treble Poti (called "Process") as well as the High Frequency switch don´t do anything when beeing changed... Also the sound looses high frequencies when the pedal is engaged.

could very well be a simple wiring issue, if the high frequency control is shorted in some way it could potentially be stuck in the "all the way down" position, which could be why nothing changes yet the highs are attenuated when you actuate the pedal.

double check C10 value, it should be 100pF, usually labeled 101 on the actual cap

[Nio28]

Hi,

The C10 is labelled 101, should be OK. I forgot to mention one possibly important issue: Initially I mounted the Process-pot the wrong way and hard a hard time removing it.
Possibly I fried the PCB there?
Is there a way to bypass the PCB route and wire the lugs directly?

Process pot:
Lug 3 to R17
Lug 2 ?
Lug 1 to R10

[garcho]

Possibly I fried the PCB there?

yes, or the pot. take a pic and post it, or if you have a DMM, do a continuity test.

Lug 3 to R17

Yes, R17, as long as it's the lead that's connected to the inverting input (pin 6 of IC3B) and not the lead that's connected to the output of the op amp (pin 7). You want the junction of lugs 3 on all pots, pin 6 of IC3B, C10, and R17.

Lug 2 ?

hard wired to lug 1 so you have a variable resistor instead of a true potentiometer. trust the schematic! as long as you trust the person who drew it, anyway...

Lug 1 to R10

yes, as long as it's NOT the lead that's connected to the output of IC3A (pin 1) or R8 and R11.