2. amps-preamps
  3. 149214-112130

PRIMA LUNA DIALOGUE PREMIUM - 20 minutes and then loud pop and buzzing in 1 channel

Hopefully someone can help.

Amp is virtually new. The amp will operate wonderfully for 20 minutes and then a loud pop , and then buzzing from the right channel. I shut down the amp and then it repeats.  I switched some tubes and it is still there.  I switched the cables and know for sure it is only one channel, the right one. The buzzing does not increase with the volume increased. . 
It is the amp and not the Prima luna preamp.  Cables and connections are fine.   Pushing Focal Kanta No2's . 

Any help would be very much appreciated. I'd rather not send a 68 pound piece of equipment through the mail. 

Thanks lot - Craig 

vespacraig1966

Showing 3 responses by newbee

newbee
4,795 posts
 
BTW, I did not overlook your comments about switching 'some tubes' I was recommending you switch all tubes. If it were a tube, IMHO, it would probably be a small tube, unless you were tripping the bias circuit protection when you heard the pop. Another question, is the buzz superimposed over the (sound) signal or does the right channel just buzz? Anyway, switching the entire set of tubes should show if it is a defective tube or not. If not, pack it up and send it back to PrimaLuna for warranty work. FWIW, assuming you bought this new and have the packing I wouldn't worry much about shipping - the tripple boxing and Styrofoam lining are fairly bombproof. 
newbee
4,795 posts
 
Could be a bad tube. You might try switching the tube set from the right channel to the left channel and see if the problem follows the switch. BTW, did the protections circuit activate when you heard the pop?
newbee
4,795 posts
 
Craig, It sounds like you have done enough to rule out a faulty tube as being the source of your problem. That said you are really going to have to have a tech diagnose and repair the problem. If you did not buy this from a dealer I doubt that Deal is going to repair it. He wouldn't work on one of my units which I bought second hand. He did, however, refer me to a tech in the LA area to whom I sent the unit and had it repaired promptly and at a fair price. These units should be easy service so if you have a tech in your area who knows tube amps you could probably have it done locally.
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