Gamut M250 MK3


I got a pair of Gamut M250 Mk3 mono-blocks that went in place of a D200 mk3. They were installed yesterday, and worked fine for a day. This morning I turned on the amps to warm up. A bit later I went back to the listening room and heard a very loud hum. First I looked out the window for a garbage truck; then put my ears against the speakers. Nothing there. It was coming from the amps. Power-cycle of both amps confirmed that both were making that noise, though one was louder than the other. About 10 minutes later the noise was gone. I have a feeling that this might be one of those intermittent problems that's difficult to track down, but I do want to get to the bottom of it while they're in warranty. To other owners of the M250, have you ever experience such a problem?
ping2357
Thanks for your answer.
The big differences between the D200 and M250 are more power and channel separation ? No big difference in sound, for example bass control or extension ?

What was the problem with the Pass : could you explain a bit more ?
M250 of course bass control and extension is better than D200,also micro dynamic is better than D200.
Thanks for your answer.
SO, the M250 is worth the upgrade even if my speakers are easy to drive : Tannoy GRF ?
I can have a pair of M250 for a fair price.
I never use and listen Tannoy GRF,so i don't know.but i think if you can have a M250 mklll for a good price,i think it's worth because you don't need change amp on future.M250 mklll can drive most of speaker in the world.
Do you have compared the Gamut with Pass amps, like the X350.5 or the new XA.5 series ?