Phase Linear Dual 500 Diagnosis Assistance Requested

Quick question about how these are supposed to be run...

If this will be run on 4 ohm speakers, should I leave the amp on High Z, or manually set it to low z for this application?
 
Ok you need to understand how this puppy works.
First it has high 120V and low 80V rails by way of a double wound transformer.
This high low switching can be done two ways. First by pressing the front pannel button. The second the amp can flip its self from high to low for various safety reasons (all in the manual).

So why would you use this In low “Z”?
Because you are giving the components less stress by running at low. If you only need 200 /8 ohm watts or less then run it their. Basicly its jus a PL400 with double the outputs running this way. But if you want Head Room , right Lee, then run it in high. If you have a true 4ohm load it should do just fine. If you want to run it to max at 4 ohms then I suggest you use the old Pink Floyd trick and pack the heat sink with dry ice.
 
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Thanks again Grapplesaw.

I was aware of the dual rail voltage, but I wasn't sure what the intention was for it. I assumed it was similar to other amps that I have used where you set a selector switch on the back of the amp depending on the final load. My NAD switches between 4/8 ohm for low or 8-16 ohm for high.
 
My Spec 2's are selectable between 4 and 8 ohms, more for the proper operation of the protection circuit than anything..
 
Sorry to cut in, but once I saw the pictures of the dual mode LED display, I just had to comment, I also like the bar-mode display setup. Makes me want to try it on my D-500. I wonder if it's possible to modify the current D-500's setup similar to the 700 boards from Joe. ?? I guess anything is possible with these led displays and a little rewiring. Thanks for the pictures.. You guys are the best..
 

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Quickcarl said:
Sorry to cut in, but once I saw the pictures of the dual mode LED display, I just had to comment, I also like the bar-mode display setup. Makes me want to try it on my D-500. I wonder if it's possible to modify the current D-500's setup similar to the 700 boards from Joe. ?? I guess anything is possible with these led displays and a little rewiring. Thanks for the pictures.. You guys are the best..
Click to expand...
See post #93. And see what the meter board looks loke

You would have to create a new meter board assembly for the 500’s. Only time and money is required. I mean lots of both. I hope you can get someone to do it.
 
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