dingebre
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I hear hum. Very faintly at a comfortable level for music listening. I've done my homework, reading the articles on this site and others, searching my old and newly purchased text books regarding hum particularly in tube circuits, and did the required experimentation.
I've also had an excellent discussion with Steve Deckert, thank you again Steve. In the end, Steve thought the hum was probably normal after hearing some samples I sent him. I am happy to accept that conclusion.
I'm not sure exactly what the source is and after all I've done and Steve's great help, I don't think I much care anymore. It really doesn't affect the music.
What I want to discuss is the general concept of hum in a tube system.
I'd love to hear from others, however, to help me establish a context for what hum is normal, acceptable, reasonable, etc. I haven't owned a tube amplifier since I was a pre-teen in the late 60s and my memory was that there was hum in a tube amplifier, low level, but still there. So, why would a new design using the same tubes and basic construction techniques be any different?
So, on a subjective level (or objective, measurement level) what level of hum should I be willing to accept and how far do you go to minimize what's there?
Thanks David
For the curious, not really looking for help on this...
Some background: I just bought a new/old turntable (Thorens TD-165 like the one I owned in the 70s) and a brand new turntable (Thorens TD-309), a ZP3, a CSP3. and a Thorens solid state phono stage.
I hear low level hum through the ZP3 with both turntables. I tried new interconnects, moving equipment and cables, EBTECH Hum Eliminators, MU-Metal sheets, swapped all the tubes in the ZP3, everything I could imagine. When nothing is connected to the ZP3, dead quiet.
The SS phono stage, no hum with either new or old turntable.
CSP3 connected to the Thorens phono stage and either turntable, almost scary quiet (excellent job Steve).
So, difficult to blame the ZP3 or the turntables. I think it's just the way it goes.
Thanks. David
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