Those lopsided, "half" waveforms?

[frozenintime]

I figure this is something I should know by now, but... I don't.

I'm running a Peluso 47 tube mic > it's power supply > UA 610 pre amp > Digi003.

Had the mic for 1.5 years, the pre for more like 6. The UA has been serviced once, a couple years ago.

Now, all of a sudden I'm getting some weirdness somewhere in this chain. Occasionally, the mic will sound sort of distorted - grainy, and no more top end, like there is some wool over it. Recording like that creates those lopsided, half waveforms that are more or less only on the bottom plane.

By fiddling with chords and/or turning the pre way up and back down I seem to be able to pop things back into working order but I feel like the above description is indicative of something specific, and I'm curious what it is for future reference.

thanks!

[GarryJ]

Can you post a picture of one of the dodgy waveforms?

As a rough guess I'd say you've got a fault in the input chain that's rectifying the signal, or shorting either the hot or cold signal to ground. Cable is the prime suspect.

[NeglectedFred]

Tubes? Did they swap out tubes when the 610 was serviced? Maybe the tube in the mic?

Is it completely random, or is it when the amplitude goes beyond a certain threshold?

[frozenintime]

i took a screenshot but for the life of me can't figure out how to upload an image...

[frozenintime]

the problem in the 2-610, as i remember it was simply that it wouldn't turn on or pass signal at all, and replacing the fuse myself didn't fix it.

the problem now with the funny waveforms and crappy sound seems random in that sometimes i turn everything on and signal sounds lovely, and other times it needs to be prodded back to life. perhaps that involves some high SPL level to clear out the cobwebs, hard to say thus far (i haven't been to scientific).

if it's tubes i'd assume the problem is the 2-610, as the peluso was new 1.5 years ago and hasn't been used anywhere near as much as the UA, which has been my bedrock for home overdubbing for years.

i'll try replacing all the xlr cables (not the mic > power supply - i don't have a spare) but it seems like it may be something else, in my own foggy estimation.

[johnny1000]

Check your cables.

Years ago I was having problems with similar half chopped wave forms and grainy sound on a session and eventually figured out it was a poorly seated cable in the patch bay.

[casey campbell]

there is a slight possibility that one of the potentiometers (volume controls) on the ua might be dirty or going bad.