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In Reply to: RE: Premature judgement posted by Lew on June 18, 2020 at 13:42:36
I measured the speakers when all this started. From stators to screen the resistance is infinite. There is 1.5nF of capacitance from one stator across to the other, and as one would expect, there is about 3nF of capacitance between each stator and the screen. I bought some 6kV rated, 3nF capacitors off eBay with the idea to create a dummy load (inside an insulated box, of course). I'm a little afraid of trying that, however. Two caps in series where the stators connect at each end of the chain, and the screen attaches to the junction between the two capacitors. (On these speakers, the screen is low impedance and held at zero potential and is driven by signal voltage.) Each stator is at +/-3200V and also driven by signal voltage.
Follow Ups:
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When installed, the amplifier is the the base upon which a 6-foot speaker cabinet rests. You can't see the tubes or anything else that is going on. You have to go on funny noises, either from the speaker or from the amp chassis.
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The amp connects directly to the speaker via HV banana plugs. The stators receive +/-3200V. Can you imagine a "safe" cable for that? I've got 20kVDC wire, but not enough of it. I remember seeing a photo where some guy in Europe inverted his Beveridge speakers, so that the amplifier sits on top. Then he removed the "bottom" part of the clam shell chassis (which becomes the "top" part when the whole speaker/amplifier is inverted). Thus he could see and access the amplifier while playing music, if he stood on a step ladder, because the speaker alone is at least 6 ft tall. I honestly don't want to be standing on a step ladder next to +/-3200V that is riding on a structurally "tippy" cabinet. I guess for test purposes, you could lie the speaker on its backside and use 20kV wire terminated in HV banana plugs on the amplifier end and HV banana jacks on the speaker end, to link the banana jacks on the amplifier, which would be sitting on the floor next to the speaker, to the relevant male banana plugs on the speaker.
Up to 10kv test prod wire is readily available. You will be able to run 6-8' of cable between the amp and panel with banana plugs and jacks.This is what RM detailed to me when he was building and repair amps and testing with open panels.
I run about 6' of cable to my DD amps with high voltage silicone wire in as similar way
https://canada.newark.com/pomona/6733-0/test-lead-wire-silicone-18-awg/dp/63H2513
Edits: 06/26/20
Yes, I am sure that COULD be done, but I wouldn't want to do it except in the case where I am trouble-shooting. Otherwise, I find it nice and neat and safer to have the Beveridge amplifiers serve as the base for the speaker with no external wiring. This system is in our finished basement which I like to keep only dimly lit while listening to music. As it is, the IC from the preamp to the L hand Beveridge travel across the floor between me at my listening position and the speakers. More than once I have tripped on that particular IC on occasions where I was turning the system on or off. I'd hate to do that with speaker cables carrying +/-3200VDC.
Is there a particular reason why you have chosen to use external speaker cables? I guess it may be inherent to the fact that you converted Model 3s to DD amplification.
I'm only suggesting this as method to troubleshoot.
For my Model 3's the DD amps were never part of the structure so I use HV cable to tie the amps to the panels.
I appreciate your input greatly.
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