Weird Popping issue

Hey all,

I have a primaluna stereo amp and have been having some issues with it lately and was hoping to get some advice on what action to take next to try and resolve the issue. 

Each time I turn on the amp, the amp warms up, the audio signal comes through, and then maybe a minute after it has warmed up and started the audio, i hear a couple loud popping sounds from the right channel and then i lose all sound from that speaker. The audio keeps coming through the left and the sub however. The only way to remedy the situation is if you turn off the amp again, wait a little, power the amp back on and then i don't have any issues with either channel. 

pretty new to tube amps but haven't had any problems with my gear before this.

any help that you could provide would be more than appreciated. 

let me know if there is more info i can provide to help you understand my situation. 

Thanks a lot. 
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The first step is to swap the left and right channel tubes,if the popping moves to the left channel then you will know it is a bad tube.
The chances that this is a bad tube are pretty high. My guess is it will be one of the smaller tubes- not one of the power tubes.

The tube is likely developing a cathode/filament short or similar. Quite often the short will heal temporarily if the tube is cycled off and then on again.
thanks you guys. i swapped the tube and it did switch the problem to the left channel. i think @atmasphere, that you are correct. i had to replace one of them before. can you recommend any good brands or places to get new tubes? also, do you think its a good idea to replace all of the smaller tubes so to avoid issues in the future or is that overkill?
FWIW: When you have tube gear you should always have a spare set. I buy all my new tubes from Tube Depot . It would be overkill to replace all the smaller tubes. The smaller tubes last for years !
If you have a Primaluna I would start with Kevin at Upscale Audio.

You might also look on ebay- that can be a good source if you know what you are looking for.

Also try CE Distrubution in Arizona.

Of course, a lot depends on what tube type it is and how much you are willing to spend!
thanks again you guys, I swapped the pre-amp tubes back to original configuration and left the power tubes swapped. ended up getting the pop sound on the left again. does this mean that it is in fact a power tube and not a pre-amp tube?

the tubes i have right now are,
 4 Primaluna KT88
2 Primaluna 12AU7 
2 Tung-Sol 12AX7 

Just swap the power amp tubes and if the pop moves to the right then you have proved that it is one of the power amp tubes that is bad! Report back with the results!
So, i waited a bit longer and turned on the amp again and this time. still with the same configuration as above. all pre tubes in the original position and the power tubes in the swapper position. this now results in there being a pop but i don't lose all of the sound on the left channel but the same pop is heard it just doesn't cut out the signal completely. im going to get some new primaluna KT88s from upscale audio. 
It seems that logical adaptive auto-bias board needs attention.
There's an instruction page

It does sound like a power tube; a power tube failure would reduce output, but not kill it entirely.