@gdnrbob 

Bob,

Thanks for the kind words.

Jim

@nyev

I assume you live in the US...

Solid core #8awg 600V insulated power wiring hasn’t been made in years. Insulated #10awg is the largest solid core wire made...

For a 50ft run, length, #10 should be more than adequate. I doubt if pushing the amp hard playing music with high dynamics will cause any VD, (Voltage Drop), on the branch circuit wiring.

Here is a review quote from Six Moons on the amp:

Gryphon are purists. For electronics that’s fully balanced, dual mono, DC coupled, high bandwidth and zero NFB. With 200W idle and 1’900W max power draw

I am not sure if the 1900W is continuous or short, quick, draws of current that would be caused from pushing the amp hard playing music with high dynamic passages. 50ft of #10awg should handle the load without any AC Line VD. Power amp’s power supplies like a steady state AC mains voltage.

As for the type of branch circuit wiring to use I would recommend 10-2 solid core with ground MC, (Metal Clad), aluminum armor cable. * MC, NOT, AC armor cable *... 2nd choice 10-2 with ground NM-B, (Romex Trade Name), sheathed cable.

Breaker size 20 amp

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Mike,

He can use a plastic box and still be code compliant...

Jim

@nyev 

I would not feed the amp with 240V.

Probably the biggest reason you couldn't use aftermarket 120V plug power cords.

(A 240V branch circuit will require a 250V wall receptacle...)

@ditusa 

I suggest you read NEC 210.6 (A)(2)

"Branch-Circuit Voltage Limitations"

@nyev 

I gotta ask. Is your electrical panel mounted sideways? Horizontal instead of vertical? What's with that?

Jim

jea48 said:

Where was your reference point used for the measurement? At the electrical panel?

ieales response:

Where else?

Usually the no load voltage is checked at the last outlet on the branch circuit. No loads are connected to the circuit. If a difference of potential, voltage is present it will be the same as the applied voltage at the feed end. In this case the branch circuit breaker to neutral bar voltage.  If 120V at the panel it will measure 120V at the end of the branch circuit that has no load connected to it. (Add load and then measure again for VD.)

Why? Simple Ohms law. You need a load to have a VD. No load no VD. The internal resistance of a typical DMM is about 10M ohm. 

     jea48 said:

What type of volt meter did you use?

ieales response:

calibrated Fluke.

10M ohm internal resistance. 120V / 10M ohm = 0.000012 amp.

Jim

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@kijanki

+1

Please explain what happens if the power transformer’s secondary winding voltage is lower feeding the rectifier, due to a quick AC mains VD event, and the electrolytic capacitors voltage is higher. Just going from memory the rectifier will not conduct and the caps do not get recharged for that "(millisecond pulse)" in time.

Jim

@richopp

An Overview of Audio System Grounding and Interfacing

Take note of page 16.

Read pages 31 thru 36.

Note the chart on page 35. AL armored MC measured the second best. Number one being the best where the hot and neutral conductors are twisted together the entire length of the branch circuit. The EGC is ran along side the twisted pair.

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Do not increase the wire size beyond 12 ga. as this is a code violation

Not true...

FWIW:

National Electrical Code 90.1 Purpose:

(A) Practical Safeguarding. The purpose of this Code is the practical safeguarding of persons and property from hazards arising from the use of electricity. This Code is not intended as a design specification or an instruction manual for untrained persons.

(B) Adequacy. This Code contains provisions that are considered necessary for safety. Compliance therewith and proper maintenance result in an installation that is essentially free from hazard but not necessarily efficient, convenient, or adequate for good service or future expansion of electrical use.

NEC could care less how your audio system sounds. It could care less if you have ground loop hum. No where in the code is it mandated voltage drop shall be a consideration . NEC is bare minimum electrical safety standards.

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