I've experienced similar sounds with tubes. If it goes away, or is intermittent, you should be ok. The tube rush sound will only get worse over time, but usually takes a long time to get there. If you can hear the tube rush from say, 2 to 3 feet from the speaker, not much of a problem. If you start hearing it at the listener's position, it might be time for replacements. IMO
tube noise - 2 questions
Q1: Three months ago, I installed two matching NOS 6DJ8’s in my preamp. Sounded great up until a week ago. Barely audible tube rush on startup - and then totally quiet. Three months later, one started making crackling noises. Only intermittently. It will crackle for a few minutes - then all is well again for days. But, this repeats every so often. Does this intermittent problem mean that tube is soon to be history?
Q2: With a different preamp, a NOS 12AU7 had crackling & popping noises from the get-go. The noise never went away - even after 100 hours of burn-in. I tried the same tube in my DAC, zero noise - ever. Why might that be?
Q2: With a different preamp, a NOS 12AU7 had crackling & popping noises from the get-go. The noise never went away - even after 100 hours of burn-in. I tried the same tube in my DAC, zero noise - ever. Why might that be?
8 responses Add your response
Q1: the tube has an intermittant problem. Giving it a good whack on the side might shut it up for a while. Eventually that will get old- just change it out. Q2: This depends on the gain of the circuit. In a DAC, the gain is relatively low, but if you use that same tube in the front end of a phono section it might be quite noisy. If its not a problem further upstream or in the DAC, that's probably where it should stay. |
@steakster You can count on it coming back again... Its giving you plenty of warning that you need to find another tube. |
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