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Tube power amplifier low static on one channel

Hi all I have an Audio Note Kit EL34 power amplifier. When the music is off I can hear a static sound from the right channel. It is not constant it gets louder then quieter then nothing then back again. I switched the non power tubes right to left and the static stayed on the original channel.  

If it was a tube it would have switched to the other channel correct?

If it was electro interference it would come out of both channels correct? 

Thoughts on what to check next?

Thanks

jh

johnah5
yogiboy's avatar
yogiboy
5,661 posts
 

Try swapping the power tubes

johnah5 OP
235 posts
 

Ok great idea. I did some research and the sound a bad filter cap makes is a hum. I don't have a hum it is a changing low level static. 

Will do the power tubes and update the post.

jh

blisshifi's avatar
Ag insider logo xs@2x
blisshifi
1,183 posts
 

It could be two other things - 

- Dirty or loose tube sockets. Inspect, tighten and clean the contacts in the tube sockets

- If you have digital electronics adjacent, such as a router, WiFi modem, satellite, etc, that could be causing the static out of just one channel. Make sure anything of that sort is at least 3-5ft away from tube electronics.

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elliottbnewcombjr
5,361 posts
 

Don't trust your memory, make notes

All cables and connectors are good? IOW, make sure you are not hearing the random result of a poor connection elsewhere.

Switch L/R inputs 1st, that way, if the noise moves, it is coming from a different piece of equipment prior to the amp

Switch speaker wires, noise moves, it is that connected side, noise doesn't move it's perhaps in the speaker's crossover

How old is the unit?

If the noise does not move with the tubes (swap one at a time, keep track of original locations) it's time to check the entire unit, not just find one thing.

Another reason a simple tube tester is good to have. 

Power tubes get biased, how does your unit handle that?

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