Soundskulptor MP573 Problem

Hi All

Haven't been here much lately, but unfortunately today I need help.

Have just built TWO MP573 Preamps. They are BOTH showing no phantom power.

My solders are very clean, and I just can't see any visible issues with where i've put stuff.

I've done the post build tests, and calibration of the bourns pot to 3v. Everything checked out on the tests.

So really stumped. Any help greatly appreciated.

Matt

Both no Phantom Power? Are you sure the slots they are in do have phantom power?
Do you have any other module with phantom power you could put in that slot?

Hi Volker

I have a VP26 working fine. Its a full 51x rack, with GDIYPSU powering it

This is a build problem I think. I am pretty certain i've soldered something in the wrong place.

Have to say, it is very weird that both are doing the same exact thing.

I will be having another look at it today

Matt

Looking at the schematic there isn't much for 48V.
A broken switch, or forgotten R1 (or R2 & R3).

Sorry for this late reply, we were closed until today for our summer shutdown.
The problem could be caused by a reversed C1. Also double check the value of R1 (270 ohms).
Make sure that, if you are using a 51X rack, the back connector is correctly lined up, the golden fingers are not making unwanted contact with the next contact.
You can also check that the 48V voltage is present on the SW1 switch (on the low pin). It should also be present on the center pin when the switch is ON.