FYI, from another forum.
> I had another question for you.
> Do those inline ground isolators perform the same
> function as the transformer you specified (see links below)?
> My guess is that they would not deal with the impedance mis-match.
The specs are pretty vague but what I gather from the descriptions, the Radio Shack and Wal Mart units are the same and are designed for line level connections. Note the Radio Shack disclaimer about not hooking up to speaker lines. They are probably high impedance 1:1 transformers. The Crutchfield one looks like it is designed to match a headphone jack (relatively low impedance, less than 1 watt). Hard to say what the output is designed to match to. Jim