Unison Smart 845 big problem

[enriquerb]

Good morning , friends .

First of all , sorry for my bad english.

This is my first post and it´s a help requirement from your experience with a serious problem about a monophonics Unison Smart 845 power amplifier I recently purchased .
From the first moment, a month ago, one of then present a breath noise that lasts a few minutes and stops. Again It begins and again stops, and so ..
Sometimes after a few "cycles", noise disappears and works fine. Others the noise don´t go away, i get bored and turn it off.
The worst is that the other day when connecting, issued a tremendous beep (capable of destroying the speakers) and turned off immediately. I tried again and the same thing happened .
Already in the service, it presents unpredictable behavior : Sometimes the breath that comes and goes , sometimes the tremendous buzz and other works fine. We are totally lost ....
preamp ? power tubes ? capacitors ? microphony ?
Any help is welcome .
Thank you in advance and best regards from Spain .

 

[Palustris]

Replace the ECC82 and ECC83 and if that doesn't solve the problem I think that it would be best to contact Unison Research about the problem.

 

[enriquerb]

Replace the ECC82 and ECC83 and if that doesn't solve the problem I think that it would be best to contact Unison Research about the problem.

Thanks Palustris. We´re going to replace them. It´s a cheap way to discard something. The seller told me that tubes were in good state, but who knows...
Maybe tubes were damaged in transport . When I opened the boxes, the two lampshades arround 845 tubes were broken.
Thanks again and we'll see if the problem is solved.