David: My tweak is that I use two of the Radio Shack units as dual mono's. This requires twice as many rechargable batteries but is a simple way of beefing up the power supply (by asking it to do less work). I also use shorted RCA plugs and ones crossed with 100 ohm resistors in the unused inputs/outputs, but this may not be needed (I just did this to block any stray RFI and the parts were only $6). When I have the energy I will replace the internal hookup wire (including the battery leads) with something better, but for now they sound very good and are "dead" quiet due to the battery power supplies. The dual mono configuration is a step up, though a single unit will suprise you. As with anything, plan on running it in for 50+ hours, or so, for it to open up. I like them so much that I purchased a pair of backups. The model # is 42-2111 and though these are probably still out of stock @ RS they are available on Ebay and from other online sources.
