Amp and preamp on same outlet?

As usual, Almarg nails it.

Using separate outlets, especially if they are on separate runs back to the breaker panel, will reduce the amount of amplifier-generated electrical noise that may couple back into the preamp. On the other hand, doing that may increase susceptibility to ground loop issues, including high frequency electrical noise as well as low frequency hum. If the connection between preamp and power amp is balanced, the likelihood of ground loop issues is considerably reduced.
02-09-15: Almarg

Hi Al,

The late Al Sekela, an EE, used to post on the AA Forum why decoupling the power supplies of audio equipment by using separate dedicated circuits benefited the SQ of audio equipment. Especially decoupling digital equipment from analog equipment.

As for ground loop problems I would say most ground loop problems caused from the use of multiple dedicated branch circuits is due to the choice of the materials and wiring methods used.

Worst wiring method is a single conduit run with multiple single current carrying conductors with insulated safety equipment grounding conductors pulled in the same conduit.

Dedicated branch circuits should never occupy the same conduit, or cable.

Best branch circuit wiring practices for dedicated branch circuits is the use of 2 wire with ground NM-B cable, (Romex is a Trade Name for NM-B cable), or 2 wire with ground MC Cable with an aluminum outer armor. The construction of the two cables cancels the EMF effect from inducing a voltage onto the safety equipment grounding conducting by the magnetic fields of the hot and neutral current carrying conductor caused by the connected load.

When Romex is used for moderate to long parallel runs of the cable they should be separated by at least 6 or 8 inches to prevent voltages from being induced from the hot and neutral current carrying conductors of one dedicated circuit onto others plus the safety equipment grounding conductors. Keeping them separated also, imo, helps prevent EMI/RFI noise transfer from one Romex cable to the other. Especially when one of the Romex cables will be used to power digital equipment.
Jim

I have always had my amp plugged straight into the wall and use a power conditioner to isolate the rest of my gear. I currently use a Furman Elite 15 PFI and it works well with my Audio Research equipment. It also protects my gear from spikes and noise while not having a negative effect on the sound. I don't know what ARC models you have. My Ref 110 has a max of 800 watts and the rest of my gear maybe 400 watts at most. There should be no problem with everything plugged into a 15 amp outlet. An extension cord can effect the sound. The only way to find out for sure is to try it and see.

I will not even read the other post!, NO!, do not ever do that.

Thanks, Jim (Jea48). Excellent points, some of which are further emphasized and explained on pages 31 to 35 of this excellent paper, which you had called attention to a while back.

Wrm, thanks also. Best regards,
-- Al