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Left Channel Out Primaluna Dialogue Premium

Hey folks.  So I turned on the stereo last night ready to listen to some tunes when it was clear there was no volume at all coming from the left speaker.  Right channel sounds just fine.  I did some speaker/cable/source switching and swapping and determined it was the integrated amp.  It’s a Primaluna Dialogue Premium which is the predecessor to the EVO 300.

I swapped out all the tubes, still nothing.  Did some research and stumbled on some info regarding the fuse.  I can replace that today but if it was the main fuse, wouldn't both channels be out?  
 

I came across a similar thread on here from @whacky who mentioned a left and right channel fuse.

”There are separate fuses for the right and left channel. Not just the main fuse. they are contained on inside a small fuse holder on the left and right side after you open up the underneath.”

Problem is, I can’t seem to locate an internal left or right fuse.  Nor can I locate any kind of PL schematic that shows where this fuse might be.  I have a message into Upscale and maybe they can point me in the right direction but I thought I would reach out to all the fine folks here for some assistance. 
 

Any other thoughts as to what the problem might be?  If it is a left channel fuse, where is that guy located?  Thanks for your help!

paulietunes
paulcreed
553 posts
 

I would think you need to turn amp upside down and remove some screws and check the fuses that protects the circuit in case of a tube failure. I don’t have a Primaluna but would think all tube integrated amps may be similar. 
 

I have a Conrad Johnson cav45 S2 and had same exact thing happen. I watched one of the left power tubes red plate and left channel went out. Right channel never skipped a beat and kept on playing. 
 

I called Conrad Johnson next day and explained what happened. They told me to replace fuses with very specific fuse and there is nothing to worry about. I told him it was a shame I lost one of my 1960’s Mullard fx2. His reply was tubes red plate sometimes and take out fuses just plug the fx2 back in. I was very skeptical about my tube. I ordered about 10 fuses. When fuses came in I plugged in fuses and tube that red plated and it’s been running no issue for almost a year. Good luck I’m sure you will have it up and running very soon.

pangeek
21 posts
 

@paulietunes 

If you have “spare” or extra 12AU7 tubes, try to spot which of the left three 12AU7 tubes is not lit up and replace that (power off and after 5 minutes of course).  If you don’t have spares, I would swap the left 3 12AU7s with the right.  Taking note if numbered 1-6 from left to right, swap 1 and 6, 2 and 5, 3 and 4.   See if now the Right channel doesn’t work.  Like what BrianNguyen said, turn off all the lights and see which tube isn’t lit up on the left side.   Good luck brother.  I have the same exact PL Dialogue Premium and love my amp.   

paulietunes OP
66 posts
 

@paulcreed unfortunately this model only has one main fuse so I can think that’s the problem.  
 

@pangeek thank you for the good wishes and yes, it’s an amazing amp!  I really love it!  Sad it might be out of commission for a short time but hopefully not long.  I will try your suggestion later tonight when I’m home again.  I do have four spare 12AU7 tubes so maybe I can narrow down the issue with them.

 

paulietunes OP
66 posts
 

Meant to say “I don’t think that’s the problem”. 

tablejockey
3,856 posts
 

I've owned the PL HP for 6 years. 

Channel went out and it was an auto bias board. It's one of the suspects that will make a channel go out.

Take it to an authorized tech. Mine fortunately happened to during warranty period.

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