Avalon Eidolon Diamond vs WATT/Puppy 7

As a Diamond owner, the only thing that the WP7 does better is macrodynamics. In every other attribute, including bass presentation, the Diamond is a better performer as it should be given that its retail price is significantly more. The Diamond, offering more natural transparency, will be more revealing of source components. The WP7 is a more difficult load as measured by the impedence curve. Also because the bass of the Diamond is much more accurate, it can work well in smaller rooms- the WP7 can be overpowering here.

Kurt, two things to consider when assessing drivability are sensitivity and efficiency. Sensitivity is measured in db/1m/1w; but most would argue that efficiency as measured by resistance in ohms (i.e., loading characteristics) is more meaningful. You are absolutely correct in that both speakers present 4 ohm nominal loads but it is more instructive to look at impedence minimums (i.e., dips and where on the frequency spectrum these dips appear). These dips impose huge current delivery requirements on amplifiers. Both the Diamond and Eidolon have 3.6 ohm minimums- not significantly different than their nominal loads. Wilson (at their website) does not publish impedence minimums. Now when was the last time you heard WP owners (and Thiel as another example) using tube power amps successfully. I regard the Eidolon as on the cusp, higher powered tube amps that have decent current capability will work successfully.