Looking for advice on these speakers

Charles, yes, I think it all depends case by case as usual when it comes to what is good or good enough versus not as good....a lot is always a judgement call plus no two combos are exactly the same.

The key is always knowing what your goals are and working to achieve them. Lots of ways to skin the cat. You never know for sure until you hear.

Mapman,
You summed it up succinctly and I agree with you. This audio quest is an individual pursuit for certain.
Charles,

If I may weigh in. . . There are SETs and then there are SETs; there are too many variables to lump all SETs together. I have Zu Def IVs and am happy with my Ancient Audio 300b SET (using Takatuski 300b) that seems to be able to drive these speakers successfully. (I have very eclectic tastes in music that include both solo instrument and fullscale orchestra, jazz, classic rock, female vocals, etc.) I started with a 45 SET and then tried a 2a3 SET; both sounded underpowered in my large space. I have also tried higher powered amplifiers, but was not impressed. On the other hand, Phil (213Cobra) swears by his Audion 845 SET with his Def IVs and his Audion 300b PSET with his Druid Vs and considers a 300b SET underpowered with insufficient drive for Zu speakers.

My post may be better suited for the amplifier forum, but since it is related to this discussion, I hope you'll indulge me.

My 180-watt tube monoblocks have a switch for ultralinear and triode operation. When I first got them a few years ago, I settled for the ultralinear mode and never thought to re-audition the decision, I guess since the mode was arguably the best compromise between low distortion and most power. This thread made me go back and revisit my choice and oh my. Perhaps there was something in the air today and it will disappear, but it was a revelation. The sound may have lost a fraction of the punch with rock music, but I just can't get over the overall improvement. Hard to describe it, but it's as if the sharp edges have been smoothed out, and a new quality to the sound emerged and made familiar recordings sound so revived and fresh they became literally intoxicating. In an A-B comparison, I could tell some difference, without a clear preference, leaning toward the triode mode, but not to the degree that the subsequent listening confirmed.

My amplifiers are obviously not SETs, but I'm curious to understand why switching to the triode operation made such a positive difference. Am I getting a taste of a true SET amplification with my 180-watt amps operating in the triode mode?

Hi,
I can relate to your revelatory experience. I had two Push pull amps that
were switchable between modes.
1) 40 watt UL and 20 watt triode.
2) 100watt UL and 60 watts triode.
In both of these amplifiers I much preferred the triode mode as the sound
was simply better/more natural IMO. It gets even better if you use true
triode tubes ( rather than pentodes strapped as triodes). I'm bias toward
DHT(directly heated triode) tubes which are very linear(and can get by with
little or no NFB added). When used in a SET or push pull configuration (if
good design and implementation) can further what you've described. It
must be emphasized that a proper speaker must
be chosen to extract the full potential sound that SETs are capble of.
I think you're headed in a good direction. The 300b is a very popular DHT (
but there's other good alternatives as well). My amp is SET, Al's VAC
Renaissance 70/70 is an excellent example of 300b push pull amplifier.
Just depends on what you want/need to drive your speakers.
As Gsm18439 alluded to, all SET amplifiers aren't created equal.
Once you find your desired amp-speaker combo I belive you'll be amazed
and very pleased.
Charles,