Sound Skulptor forums

Build help and troubleshooting => MP566 Tube microphone preamplifier => Topic started by: TomT on November 16, 2025, 11:44:42 PM

Title: MP566 no DI sound
Post by: TomT on November 16, 2025, 11:44:42 PM

Hi,

I assembled my (second) MP566.
Everything works fine, except for the DI.

When I insert a jack, I keep receiving the sound of the Mic Input.

I read somewhere at the forum, it could be that the Q1 is damaged?

How can I find out?

Thanks in advance!
Tom

Title: Re: MP566 no DI sound
Post by: JPK on November 18, 2025, 03:30:11 PM

It is very likely Q1. It is a device which is very sensitive to static electricity before being soldered. It could be damaged.
Check if the voltage across D2 drops from 24V to 0V when inserting a jack plug. If not, change Q1. Handle the new one with your body grounded (no shoes on). If the voltage does drop then it is the relay.