distance from amplifier to preamplifier question?

EMI (electromagnetic interference)from the power supply of the amp can pollute the delicate signal path of the preamp.

this effect would vary from product to product depending on the design of the circut and level of shielding. EMI is not the only potential thing that needs to be considered but the main one regarding proximity. noise in your power grid and RF are likely the other 2 main electrical issues (and grounding).

I agree with Mike Lavigne, magnetic interference from the power supply of the amp can harm the preamps performance. That's why Lamm asks for separation between the two.

On the Treo 650, I have that same phone and the interference is caused by it operating on the GSM network.

My wife's Samsung and son's Motorola RAZR phones do the same thing because they too are GSM phones. Anytime these phones "check in" with the network (ours is Cingular) everything near them gets the raspy noise through the speakers.

This includes our AM-FM desktop radio, all four of our hard wired AT&T land line telephones, my stereo system (listed here), the FM car radio in my truck, my Macintosh computers sound system and my sons Windows based computer sound system.

I know that FCC regulations state electronic device may not interfere with other products, but this appears to be the exception. Perhaps GSM phones are exempt or were not held to the same standard as other devices.

Ditto to the comments made by Albert and MIke

Having said that however I have a Lamm ML 2.1 monos used with an ARC Ref3 which sits no more than 2 feet away from the left channel Lamm ML 2.1. It has been in this position for the past one year. Perhaps I am fortunate and/or have taken appropriate steps in grounding as I have absolutely no degradation of signal or EMI/RFI in the output.

Bob,

it's likely not the output signal from the pre (which the amp is then dealing with) that is the issue. it is more likely the power supply of the preamp is affected by the EMI from the amp's power supply. this EMI would cause noise in the preamp which then gets added to the signal path.

the power supply from the amp does not pollute itself.....or at least no more than it is designed to.

just a SWAG based on my personal experience.

maybe an EE or Phd in Physics can shed light on theory here to explain it from a factual perspective.

Mike

again I agree with you...regardless of this, I have absolutely no noise in my signal path and (as stated) my preamp is less than 2 feet from my left channel amp.

Oneobgyn,

I don't think grounding will help if it is EMI/RFI that is the worry. Only adequate sheilding will prevent this and perhaps your ARC has such sheilding. It is this same type of sheilding that one looks for when purchasing a center channel speaker for HT.

For folks like me who still insist on a CRT HDTV it can be quite a problem. I must keep my A/V receiver at least 3 feet from my TV or it effects the action of the photon gun. Only moving the receiver away and de-gaussing remove the effects.