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Hi BlueCrab; thanks again for your input, it is clear to me that you know your stuff! As your entry #275 shows, I still measure 60 VAC. The White Oak mods call for the ctr tap to be connected to the chassis at one point only; the screw formerly holding the terminal strip between the left channel heat sinks. I have just measured the assembled amp again; 60 VAC is on the chassis when the line cord ground N/C.
B
BlueCrab
Hi Peter. There is no reason to connect the signal ground (which is the center tap of the secondary) to the chassis. If you isolate the signal ground from the chassis (that screw) and make your measurement from the chassis to line cord ground, there should be 0 vac (and 0 vdc) since the chassis is now completely isolated from all circuits. The amp will still work fine.
B
BlueCrab
And you can now connect the chassis to the line cord ground if you desire. You will, of course, want to check which configuration gives you the least hum pickup. But make that measurement with the inputs shorted (not open) to signal ground (not the chassis). Hope this helps.
Still running around, been a busy year, nice to have time to visit areas of interest. Drop me a message if you like.
With reference to the dual 500, did you install a soft start? I ask because I've done a fair amount of research on inrush current on 700's and haven't seen a need for it there. I tend to think the impedance of the transformer limits the current to safe values. Note that the stock rectifier can withstand more than 150 amps.
grapplesaw
grapplesaw
Hi Don. I have not done the soft start yet. I have some kits coming to do it including remote on off built in.
The reason why I am doing it is I have updated to 50 amp bridge rectifier and 33000uf caps. When you turn it on I had to go to slow blow fuses and the sucker busses for a bit.
As for 700 ‘s I want to try one as it has built in safety low voltage DC thermal temp switches. This replaces the 110v switch
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