Cracks on high gain on guitar knob

Hi, when I finaly tried to play in concert with my pisound based guitar multieffect (KleagMFX Documentation), I discovered that when the gain knob of my guitar is pushed too far, there is a lot of terrible cracks and noises, that do not sound at all like a saturation effect, even with a clean sound. And in fact, the input led of the pisound turns red very early when turning the knob.

How could I solve the problem ? It is not great to have to keep the gain in the lower half. I suppose there can be a lot of reasons, but I don’t know where to start.

Does it happen in your regular environment of using the multieffect box? I would initially suspect the power supply and wiring - some cables could pick up external electrical noise (like 60Hz hum) that could cause issues like that.

Ideally, you should aim to keep the Pisound’s input gain knob set to the lowest possible level, while turning up the output volume of the device providing the input signal, so that when you play the loudest, the clip LED on Pisound won’t turn on.

Thanks for your answer. The alim is a Raspberry Pi one (27W, 5A). But the wiring is a mess. How can I reduce its influence?

I will try the settings you describe, but then I have difficulties obtaining a volume high enough on the output.

The device providing the input signal is an electric guitar, so its volume setting is the mic gain knob. Is there a pin or an api where I can read clipping signal? In normal use, the pisound is directed toward the ground in the enclosure. The bottom is transparent but it is still not easy to see it.

Did you notice the audio difference when playing in your regular environment (studio?) compared to when you played in a concert venue?

The Pisound’s input on your box is on the edge of your device, which is good. You have to be careful where the cable between your device and the guitar goes (avoid laying it over other electric equipment), and it should be shielded (most proper audio cables are shielded). The wiring inside the box might still have some impact, but at least not much of it seems to be particularly close to Pisound.

If configured otherwise, and the red LED lights up, then the signal is getting distorted. If you need ‘quiet’ performance to be more audible, maybe a compressor plugin in MODEP could help boost the low signals?

It’s not available… Unless you’d make a wire connection of a unused GPIO to the anode of the LED (the LED side closer towards the edge). It’s low when there’s no clipping and high when distortion is detected, using OR logic for both stereo channels.