I am going nuts pondering whether the 6-8dB raise of hum noise when I engage the serial fx loop of my boogie Mark IV is normal. Even if I just connect a patch cable to send and return there is that circa 8dB loss of dynamic range because of the sleight humming noise. Even with no instrument connected. Tried different power outlets with only the amp plugged in and no other appliances connected to the amp.
Somebody told me that amps like the Mark IV have a "make-up" stage after the effects return, so some increase in noise is to be expected. True?
If it wasn’t for my home recording ambitions I wouldn’t mind. Still, with about 45-50 dB of headroom you can do a lot. Yet, I would expect different from an amp like the Boogie Mark IV. Agreed, that within 20 years parts may age or deteriorate...
But ! How about doing it the other way and thus avoiding the Mark IV's fx loop ?
Any objections to the following setup: Close mic'ing my Amp with and fusing (from the DAW) it into the effects unit (Line 6 M13) by creating an effects loop from the DAW rather than using the serial fx loop. The RME Fireface UC should have enough adjustment possibilities to meet the right output and input levels.
It might be even superior because by having the chance to adjust the dry and wet signal in the (DAW) mix I would have –in effect- a parallel fx loop !
Then again, I find it strange to look the mic’ed signal through an “old school” floor board fx unit like the M 13….
I own a Mark IV and a Mark IIC+. No problems with the fx loop here. You may be due for a service. I always record dry, and insert/create aux/monitor any fx through my DAW....that is unless there is an effect critical to the song, I may print that live...I only use the fx loop when gigging live.