I use isoproply alcohol and Mr. Clean magic eraser on tube pins. Don't trust most new manufacture tubes, NOS from reputable sellers the way to go. Another issue these days is some manufacturers run tubes hot, higher plate voltages increase tube plate dissipation which shortens life span. Filament/heater voltages can also be a concern, especially with amps that are stated to run a variety of tubes.
Strange Behavior for New Tubes in Preamp
A while back I had a tube get noisy in my Van Alstine T-10 RB pre-amp. It uses two of the JJE88CC and I ordered a new pair of their stock silver pin JJE88CC directly from Audio by Van Alstine. The new tubes arrived quickly and sound great and the noise (high pitched squeal) is gone.
In the meantime I have consulted the AVA website and this pre-amp can also use: 6922, ECC88, 6DJ8, 6CG7, and 6N1P tubes. I confirmed these numbers with someone at AVA and they said that using these numbers will not void my warranty, as long as they are 6 volt tubes. After some research and asking questions I ordered a balanced and matched pair of JJE88CC Gold Pins, a pair of 6922, and a pair of matched 6N1P Voshkod Rockets.
I used an interdental brush dipped in CAIG D5 cleaner, then tapped to remove excess to clean the tube sockets, even though my preamp is just shy of a year old. I install the Gold Pin JJE88CC and wait as they warm up. This is when things get weird. As they are warming up the slight noise (that sounds like steady static) gets louder and louder. At first I have to put my ear to the speakers to hear it but after 20 seconds I can hear the noise in my listening position eight feet away. It increases in volume each second until I shut off the preamp. This is with the preamp volume turned completely down. I thought maybe there was D5 cleaner residue causing trouble in or near the sockets but I had carefully used a blower and thought I did a good job removing residual cleaner. So I re-installed the stock JJE88CC tubes I received from AVA and everything sounds like normal. Normal has been a slight static noise with my ear close to the speakers.
Today, after a week of using the same stock JJE88CC tubes, I try again the new Gold Pin JJE88CC tubes and same thing.... with the preamp volume turned clear down the noise starts out barely audible but builds until it can be heard across the room... at which time I shut off the preamp. I let the tubes cool and remove them. I install the new Voshkod Rocket 6N1P and they sound great with the normal hiss that I'm used to if I put my ear to the speakers.
I let the preamp cool and replace the two 6N1P with the two new 6922. Same increasing loud noise but sounds more like a slightly crackly static instead of a steady monotone static or hiss.
I'm fairly new to tubes so I hope you folks have some ideas why it effects just the gold pin JJ and the 6922. Thanks.
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Had a response all typed in and phone refreshed, damn it, lost it all! Bottom line in my experience sometimes there is simply a compatibility issue with certain tubes and gear. I’ve decided that if they work and you like the sound, just stop! Cost, brand, version, age, are all variables that affect compatibility. Sometimes it simply cannot be explained. |
"I used an interdental brush dipped in CAIG D5 cleaner, then tapped to remove excess to clean the tube sockets" any residue of contact cleaner inside tube sockets could cause noise similar to what is described. you may try no residue cleaner, or ionized water to wash tube sockets. tube sockets must be absolutely clean & dry! |
@markmendenhall I agree and that's gonna be my new policy also! I like the present sound and I'm gonna stop here. Over the weekend I carefully cleaned the tube pins and sockets with isopropyl alcohol, and made sure everything was dry. I also let everything rest an hour before assembly and power. Unfortunately the noisy 6922 gold pins and JJ gold pins are still noisy. |
@foamcutter Sounds like bad luck with tubes. |
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