grungy noise

[jwschaff]

I just finished doing a remote recording of a jazz band this weekend using eight channels of SCA pres through an apogee AD16X into Nuendo on a mac. Unfortunately, I had no way to monitor the input other than by watching the rather crude DAW meters in Nuendo. All looked fine.

When I got back to the studio and ran the tracks, there was a low-level static-like growly grunge on ever single channel. The audio itself was pristine, but the noise was present on every channel. Close examination of the tracks showed that it was recorded on the individual tracks. More specifically, the sound is identical to that being made when there is a minor short or poor connection.

Since the audio was great, I'm not sure that there existed any short between the pres and the AD converter (using an apogee 8X snake with a DB25 connector). Nonetheless, the noise entered into the signal of all eight pres, which indicates that somehow there is some internal noise being generated internally to the SCAs (the power supply?) that would impact all eight signals after they entered the units from the mics but before they left the units on their way to the AD16X. The only other source I can think of would be a problem with the DB25 connection at the AD unit, but I'm hard pressed to understand how a poor connection there would affect all eight signals.

My last thought is that the unit was plugged into the clubs outlets (through my filtered power supply) and there were light dimmers being used on some of the overhead lights. If this was interference from dimmers wouldn't it impact the entire signal and not just add dirty noise to a clear audio track (I used my restoration software to remove the grunge and the audio is pristine)?

Any thoughts would be greatly appreciated.

John

[goldcut]

My last thought is that the unit was plugged into the clubs outlets (through my filtered power supply)

what exactly you had to filter your ac?