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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. 
128x128baf5289
baf5289's avatar
baf5289 OP
3 posts
 
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 

yogiboy's avatar
yogiboy
5,724 posts
 
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!
baf5289's avatar
baf5289 OP
3 posts
 
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. 
czarivey
5,946 posts
 
It seems that logical adaptive auto-bias board needs attention.
There's an instruction page   http://www.primaluna-usa.com/index.php?option=com_content&view=article&id=118&fb_comment_id=fbc_287873517993116_2045910_394667337313733#f22d93128


atmasphere's avatar
atmasphere
11,861 posts
 
It does sound like a power tube; a power tube failure would reduce output, but not kill it entirely.

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