Anyone listen to Zu Audio's Definition Mk3?

Phil,
I`m curious would a 2 watt 45 amp or say a 6EM7 tube amp drive your Def IV speakers? or perhaps a 2A3 amp? I ask because 100 db is really high sensitivity and a Xoverless design is an easy load(at least in theory).

I see posts by other gon members who use these types of amps to effectively drive Fostex single driver speakers(usally 97 db ) as well as Lowther based speakers. These listeners seem happy with the results within reasonable limits.Your 845 tube amp seems like plenty of surplus power for a true 100 db speaker.
Regards,

Charles,

I have this "2 watts" discussion all the time.

Look, it certainly works and 45 amps like the Yamamoto are revered by some who gravitate to flea power triodes. The tonal realism, immediacy and beauty can be arresting -- for awhile. I don't recommend this route however. The reason is that even at 101db/w/m efficiency, the dynamic limits of such a small amp are still quite noticed, even in a modest room, and that constant sense of grazing the ceiling -- or banging your head right through it -- is distracting. I find the 45 adherents forced to listen within dynamic limits that are excessively restrictive.

These 2w amps aren't cheap either. So instead, a well-executed 300B amp ala Audion Silver Night or Golden Nights can deliver all the tone, nuance and subtlety, but with acceptable dynamics. I consider a 300B's 7-8 w or perhaps a PX-25's 6-7w the practical lower limit for pairing Zu to an SET amp with true-tone attributes and acceptable dynamic range.

Better yet is a well-executed 845, but we've already discussed that.

Gerritt at Zu (the man you generally get when you dial them up) loves the Yamomoto 45 amp on his speakers, and recommends it unequivocably. I think if you are the kind of audiophile who has a small inventory of high quality amps in rotation, it's worth having a 45 like the Yamo or something similar among them. You'll love it some of the time. But if you have one amp only, I advise against 2w amps for Zu, as being too dynamically limited for general satisfaction. On balance for me, 2w amps give up too much in dynamic ease and headroom to gain what's lovely about them. Others may disagree.

There is one interesting way to justify it however. Are you a headphones listener? EddieCurrent has a sub-$3000 2a3 headphone amp that also has speaker outputs. Into speakers it outputs 3w/ch. Justify it for headphones and tap that flea power for speakers when you feel the urge to switch a few cables.

Phil

Phil,
Thanks for your reply. Like I mentioned I asked out of pure curiosity. My 8 watt 300b works well with my 94 db speaker with multiple genres of music. So I thought 2 watts with a 100 db speaker would roughly be equal. I experience no sense of 'bumping' against a dynamic ceiling. Of course all flea powered amps(5 watts or less) are`nt created equal so there`s likely some range of varying sucess among them.
Thanks,

So Phil, I know you have some familiarity with my Hovland HP200 tube pre and Radia 125W/ch pow amps. They've served me well with my Def2s, and softness in sound occasionally perceived I've come to the conclusion is more to do with the 2s' tweeter reticence.
So with the Def4s more complete Radian tweeter and better performing FRDs, do you believe this softness will recede, to be replaced by a more dynamic sound thru higher frequencies and in fact do you still believe there will be good synergy between the 4s and my Hovlands?
I know you have very opinionated views on amp choice and really value your input.
Btw, I hear my Def4s are almost ready at the Zu factory...

Although I have not tried a 45 or 2a3 with the Zu Def 4s, I did try both with my Zu Def 2s and agree with Phil. I eventually found them restrictive and too much of a compromise.