Korg Forums

Hi.
This my first time asking for help on this forum, and I hope someone can advise. I couldn't find satisfying answer to my problem in the archives.
Few days ago, I connected left output from M50 to Scarlet 4i4 interface using stereo jack cable. It didn't work. Coincidence or not, when I replaced the connection with mono jack cable it worked, but the output sound wasn’t clean anymore. As soon as I hit a key bit harder or play a chord, I get distorted sound. This also includes headphones output. Any ideas? Is it possible that I damaged something with stereo jack cable?

Thanks
Alex

Is it possible that the 4i4 phantom power was turned on?

.

Hi.

It wasn't. I'm 100% sure.

Not an easy issue to troubleshoot. Distortion can be caused by a fault in the mute circuit. The mute circuit keeps the M50 outputs low until the M50 circuitry has stabilised after power on, to prevent possible damage to ears, amplifiers and speakers. A fault could be caused by a high voltage transient being applied to the M50's output e.g. by phantom power, hence my question, or by two different bits of equipment being connected whilst powered on. I've known laptops with "grounds" or chassis to be sitting at well in excess of 100V AC relative to mains supply ground, during operation using their mains power supply, and any connected equipment, such as the Focusrite, would be sharing that ground via the USB ground connection.

It would be useful to determine if the distortion is present on the main Volume potentiometers, and then go from there. This could be a job for a keyboard tech.

.

I had the same problem and fixed it. It was caused by a bad electrolytic capacitor in the muting circuit that caused it to only partially release. It is in the area of the IO board between the output jacks and the power switch.

I had the same issue.
I changed 2 capacitors: C27 (220uF) and C93 (22uF) for regular electrolic capacitors (not SMD).

Solved!!