Thanks for the link Dave. I don't have a Tap-X but have looked at them longingly. I have a DIY Welborne Zephyr passive preamp with caddock resistors and remote source switching capability and it's hard to justify what might be a slight sonic improvement, if at all, to go with the Bent preamp. The Tap-X is undoubtedly a pretty slick preamp if your system can support a passive preamp. The impedance matching issue is also less critical if you go with the autoformers.