ogeva
New Member
Posts: 6
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Post by ogeva on Feb 10, 2020 10:26:56 GMT -7
Hi, My Z-Lux is producing soft, somewhat random crackling or hissing noises about the floor noise. Not something extreme, but some un even noise sound. It starts some 30 or 60 seconds after starting to play, not immediately. I thought that was just tube microphonics, and I tried replacing V1 and V2, with no help. I think V3,4,5,6 are irrelevant if I turn off reverb and tremolo and are out of the circuit. Am I right? I can swap a 12AX7 in each one by one, but I won't be easy to get the V3 one here.. Can it be the power tubes? Something else?
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ogeva
New Member
Posts: 6
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Post by ogeva on Feb 10, 2020 10:44:51 GMT -7
Made some progress - it seems that its related to the power amp. The crackling remains with the volume all turned off, but stops when i lower the master. Before I go and replace the power tubes - does that make sense? How do I replace the power tubes? Do I need a matched quad? Those are difficult to get around here. If I get two pairs of matched couple, how do I place them? This is the sound: Crackling
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Post by purpletele on Feb 10, 2020 11:43:49 GMT -7
The audio didn't play, but I would wager that the power tubes are going south, I had just replaced Power Tubes in my Z-Plus after I started getting floaters that made a crackling noise as well.
If you can get you hands on a Matched Quad they can be dropped right in, the amp is Cathode Based Biasing so no need to worry about trying to adjust the bias.
BV
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ogeva
New Member
Posts: 6
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Post by ogeva on Feb 10, 2020 13:38:35 GMT -7
Thanks, I only see matched pairs at local dealers currently. Can i use 2 matched pairs? How should i place them? Or should I go for a matched quad, which may take some time to get here and clear customs etc.
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Post by purpletele on Feb 10, 2020 15:45:39 GMT -7
Thanks, I only see matched pairs at local dealers currently. Can i use 2 matched pairs? How should i place them? Or should I go for a matched quad, which may take some time to get here and clear customs etc. This is a question to be taken further, If you can talk to a dealer the has the matched pairs and see if he has similar current ratings on the tubes. I am sure it will be safe if the current rating for one pair was say 35 and the other pair was 43. Those are just random numbers BTW don't look for those numbers specifically. I believe the amp can go into an oscillation if the voltages ratings are hugely different. Can someone verify that 2 pair philosophy?
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