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.
