Nsgarch, Do I recall correctly that the 'old Svetlana tubes, now also referred to as SED's, Winged C's, and even before that I think they had a big 'S' logo on the bottle, were made in St Petersburg? I've always been a bit confused over the sale of the use of the name "Svetlana" in some but not all countries. Hard to keep up with all of the name changes and licensing agreements. :-)
Tube Replacement: Single, Pair, or Quad?
Hello, can anyone help me?
I have a new (to me) pair of Cary SLM-100s. Without fail one of my amps will blow a "tube" fuse after approximately 45 minutes of listening. Immediately prior to the fuse blowing, two of the tubes (positions 3&4) become very bright. After this happened a few times, I switched Tube #4 in one amp with Tube #4 in the other amp with similar results in that amp.
I am using Tesla KT88 power tubes (not JJ Tesla.) I have them biased to approximately 150ma.
My initial diagnosis was that I have a bad tube. However, my question is, if the tube is OK, why would it continue to operate correctly in 45 minute increments? Could something else be wrong? If I need to replace the tube, do I have to replace tubes in pairs (e.g., 3&4) since this is a push-pull design? Do I have to replace all four? Can I just replace the one bad tube?
Also, the original owner did not have this problem. Further, when I installed the tubes I did so randomly not knowing which tubes he had in which amp in what order he had them in. Is this relevant?
Thanx in advance for your assistance.
I have a new (to me) pair of Cary SLM-100s. Without fail one of my amps will blow a "tube" fuse after approximately 45 minutes of listening. Immediately prior to the fuse blowing, two of the tubes (positions 3&4) become very bright. After this happened a few times, I switched Tube #4 in one amp with Tube #4 in the other amp with similar results in that amp.
I am using Tesla KT88 power tubes (not JJ Tesla.) I have them biased to approximately 150ma.
My initial diagnosis was that I have a bad tube. However, my question is, if the tube is OK, why would it continue to operate correctly in 45 minute increments? Could something else be wrong? If I need to replace the tube, do I have to replace tubes in pairs (e.g., 3&4) since this is a push-pull design? Do I have to replace all four? Can I just replace the one bad tube?
Also, the original owner did not have this problem. Further, when I installed the tubes I did so randomly not knowing which tubes he had in which amp in what order he had them in. Is this relevant?
Thanx in advance for your assistance.
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- 10 posts total
- 10 posts total