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.