Intermittent loss of volume with Art Tube MP

[dcoz]

When I record vocals with my Art Tube MP I frequently (usually at least 10 seconds during a 3 minute recording session) experience an extreme loss of signal, the vocals are barely audible in the recording. A minute later everything appears fine. Does this sound like a problem with the preamp? Perhaps the Tube MP cuts out if it is overloaded?

Thanks for any ideas or comments.

Here is my setup:

Shure SM58 -> Art Tube MP -> (1/4" to RCA) -> M-Audio Audiophile 24/96 Line In.

Also, I just replaced the 12AX7 and the problem remains.

[woolybooly]

I used to have an ART SGE and it had similar problems. I must have sent it back 5 times to get fixed. Finally I gave it to my uncle to play with. I believe it had something to do with the heatsink. Does it run hot at all?

[dcoz]

I don't recall it ever getting hot but I've honestly never monitored it that closely. It did get shipped across the country years ago so perhaps it was damaged. I think it may be the invisible hand of consumerism telling me to buy a new and better preamp.