On the DIY issue, I've used resisters myself in a preamp out, that needed a subwoofer out also, but never tried speaker out. This was done on disposable gear also. Some of these adapters use what appear to be isolation transformers. Others have just resisters I think. I've never tried one for home audio, because I don't feel safe not knowing what they may have going on inside them. Link for a transformer one (below) that I don't think I'd use either, but at least may provide isolation, if needed. But it may also short, or have its own impedance characteristics. For this reason (to many unknown variables), I never no of any to recommend. [http://www.sonicelectronix.com/item_18735_Absolute-HLA600.html]
