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Tube Amp Maintenance Tip...

Interesting maintenance tip story.....My C-J LP66S amp has been creating a 'variable volume sign wave' type hum in my speakers lately. The hum did not go away with warm up. I pulled the 4 power tubes and 3 signal tubes out of their sockets. I blew out each socket and pin with Can-O-Air. I also pulled the two fuses & blew out the holders /holes. Then I applied a very thin coating of Di-electric grease to each tube pin hole. Finally, I crossed the 4 power tubes (6550) left to right and just rotated one position each of the three signal tubes. Performed a re-bias once the amp powered up. No new parts involved, let's just call it a 'dusting & cleaning'. Long story short, issue resolved. Not sure what I did to correct the noise or why it even started. Perhaps a mote of dust in the wrong place? Moral: If your having some noise issues with your tube equipment perform some basic cleaning procedures prior to going into any type of panic mode. Hope this helps someone in the future!
quincy
theo's avatar
theo
2,698 posts
 
I agree with Zd542, di-electric grease would reduce contact surface for each pin. In my business, truck and truck equipment sales, we use di-electric grease to protect electrical connections from moisture infiltration.
When I clean my system each year I use Caig cleaning brushes in each hole on each pin with Cardas Contact Cleaner, and feel I get good results.
Just my opinion of course
xti16
1,525 posts
 
Keeping the pins in the socket tight is the best tip I can think of especially if you roll tubes. Also reseating the tubes can clean off some oxidation.
quincy OP
356 posts
 
Yes, I had some reservations in regards to the di-electric grease, but it is a good conductor and used on very sensitive electrical connections in automobiles. (connectors on oxygen sensors for one example). The input is appreciated and hopefully some members will remember this in the future. Perhaps sans the grease application.
steuspeed's avatar
steuspeed
501 posts
 
A lot of guys use Walker Audio Super Silver Treatment SST.
jetrexpro
506 posts
 
I clean resistor leads, capacitor leads, internal hook up wire, tube sockets etc, with 99% alcohol. About once every two months.
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