Melody EL34 amp sudden drop in Volume and loud buzz.

The other night I was watching a movie with the sound going through this amp and all of the sudden the sound just dramatically decreased and started sounding horrible. The next day I tried listening to an album and it was audible but very quiet even when turned up to levels which previously were very loud and again the sound was terrible. In addition, there is now a loud buzz coming from both speakers. I tried replacing all the 6sn7 tubes with the originals as one of my newish northern electric tubes was going bad and i thought that might be the problem but no dice. The amp uses a 101d tube but I am not sure why and if this could be the problem. Issue is these are expensive and so I'd rather not buy one only to find out that there's no way this could be the issue. (my amp is similar to this but uses el34 tubes for the power

Hopefully, someone can shed some light on this. I know phil(213 cobra) has experience with these amps so maybe he will be able to weigh in. thanks in advance.
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...which leaves the 101D voltage regulator. Sounds like a dry solder joint issue. I assume you've checked the interconnects and preamp. 

I had a similar symptom in my tube integrated but only one channel and it was diagnosed as a bad output transformer. In your case it could be the power transformer affecting both channels.
A power transformer sound like a very expensive fix,no?
Sorry I was in a hurry when I replied & yes power tube would affect only 1 channel..
As I think about this I agree with reply from noromance that the possible culprit is the 101D which is used for Voltage Regulation..If that were going bad it would display as a lowered output....However the BUZZ points to a transformer..
Have you tried contacting Melody?
If other avenues to solve your problem do not pan out, probably worth it to buy a used 101D on ebay for $70+/-