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What's the greatest bargain in SET these days?

Hi, Gang,
I response to my recent review of the Reference 3A De Capo BE speaker, someone wrote that if you really want to hear them sing, you should try them with a SET amp, or words to that effect.
That got me thinking. The De Capo's are 92 db efficient, which (correct me if I'm wrong) seems kind of borderline for low-power SET amps.
In any event, right now I'm running mine with a pair of Manley Mahi mono-blocks. They are switchable from triode (20 watts) to "ultra linear" (40 watts). I run them in triode all the time, and in my room, the volume knob almost never goes past 9 o'clock; more would just be too loud.
All that said, what do you guys think of running the De Capo's with a SET amp? And if I did, what's the best bargain in SET's these days?
Thanks!
rebbi
almarg's avatar
almarg
9,670 posts
 
11-25-14: Larryi
If the De Capo is easy to drive, that is actually more important than the efficiency rating. I have heard low wattage tube amps driving the very easy load 15 ohm Rogers LS3/5a speaker that is extremely inefficient (low 80's for efficiency) and the combination worked well even in a big room. On the other hand, the Wilson WP7 has a mid 90's efficiency, but even 40-50 watt tube amps would find that speaker to be a beast because of its very challenging load characteristics.
Excellent comments as always, Larry, as are the responses from the others. The impedance characteristics of the de Capo (magnitude and phase) are shown in the graphs near the bottom of this page, which I had linked to earlier in the thread. They strike me as being indicative of an easy load, the worst case probably being the combination of a 7 ohm impedance and a phase angle of around -32 degrees which occurs just in the immediate vicinity of 100 Hz.

My Ulysses, btw, have extremely benign impedance characteristics, although their nominal impedance is 6 ohms. That may have been a little less true, though, in the version of the Ulysses which existed at the time Jazdoc left the comment I quoted.

Best regards,
-- Al
darkmoebius
900 posts
 
Alamrg, I think this Positive Feedback review excerpt could help explain why Jazdoc's PX-25 "ran out of gas at mid-high listening levels" with his Daedalus Ulysses:
Although I know that Lou did not design this speaker specifically for low-powered tubes, the Ulysses can certainly deliver when driven by them. Is your passion the gorgeous sound of low power tubes? If so this speaker can accommodate you, though within limits. I felt at the 12-watt push-pull Audio Space amp was probably at the lower limit of power you could use and still get realistic dynamics. The 28-watt 845 Consonance SET performed very nicely.

How about mid- to high-power solid-state or tube designs? The Ulysses was built for high power. When I used 15 watts of class D power I loved the unlimited realistic dynamics that made the music seem so natural. My only regret was I didn't have a chance to try this speaker with some high-power tube amps.

Which type of amplification/source did I prefer with the Ulysses? Usually, whatever I was listening to at the time. Pressed for a decision on one, I have to give the nod to the Consonance Cyber 845, and my analog rig (VPI Scoutmaster, Shelter 501, and Aqvox Phono 2Ci, Gingko Cloud 9) which together gave me some of the most extraordinarily cohesive sound my room has ever been graced with. If you read Lou Hinkley's quote "coupling high efficiency with high power handling makes for effortless reproduction of music" it is obvious that he prefers a high-power amp for these speakers. I look at the Ulysses low-power affability as a big plus. This chameleon-like transducer is friendly to many different types of amps, and it truly lets you enjoy the characteristics of each and every amp. Rare indeed and a dream for audiophiles who enjoy the sound of more than one type of gain device.
mapman's avatar
mapman
22,689 posts
 
More so then tonal imbalances that would be associated with a "difficult load". if there is a problem, I think it will be related more to a flea powered SET "running out of gas" sooner due to the DeCapo combo of low end extension and moderate efficiency and resulting in (soft) clipping that has to impact dynamics. It exponentially takes more power to produce lower frequencies with smaller speakers/drivers, , so even modest bass extension can have significant impact.
mapman's avatar
mapman
22,689 posts
 
Dark,

Good to hear from you. IT's been awhile.

I do not think any good speaker designed for high power amps can perform equally well with low power. It might transform in a still musically desirable way in some case, but there will be an inevitable loss of "accuracy".

But no speaker vendor will willingly tell you this. They will say their speakers work well with most anything within certain parameters at best because, well, they need to sell speakers and its a pot shot to predict whether a customer will be happy or not before the fact.
almarg's avatar
almarg
9,670 posts
 
11-25-14: Darkmoebius
Almarg, I think this Positive Feedback review excerpt could help explain why Jazdoc's PX-25 "ran out of gas at mid-high listening levels" with his Daedalus Ulysses....
Thanks very much for the reference, Darkmoebius. Note, though, that it was not the PX-25 which Jazdoc tried with his Ulysses. It was the "high current" version of the Jota, which is rated at 24 watts.

Best regards,
-- Al
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