Tube amp buzz (amp, not speakers)


Hello - 

Almarro a318b makes buzzing sound at random: sometimes it does, sometimes it doesn't, completely unpredictable. The buzz comes out of the amp itself, like a transformer buzz; the sound out of speakers is completely clean. 

I'll appreciate any ideas - what causes it, what to do?
boriso
Run with the cover off and when buzz starts, touch various parts of the transformer and chassis and see if you can identify what is vibrating. Once you locate that, you can address it. 
Your a318b uses extremely high voltages.

As there is no guarantee that it is not still holding such high voltage, even days after being powered off/unplugged, only knowledgeable people should access the inside for diagnostics/repair.

DeKay
I used to own that amp. Holographic sound for sure. I always got a system "hum" when switching it on, even with a dedicated line and a power conditioner. Occasionally a transformer would buzz and I'd just unplug the unit and power up another time. I owned the Almarro about 3 years.
Post removed 
Thank you all so much. I don't know the first thing about electronics, so it seems like I have two options: getting an Emotiva CMX-2  or taking it to a technician, at least for a comparable cost if not more. What would your inclination be? 

@tuberist - what does "holographic sound" mean in this context?