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High value, high efficiency speakers for SET amps

Hi, Gang,
I know that some of what I want to discuss here has been dealt with in other threads, some of them quite old, but I wanted to see if any of you fine, knowledgable folks are willing to help update and consolidate some of this info in a more current thread.
I am currently running my new Audio Note Kit 1 300B SET amp with a pair of Reference 3A De Capo speakers. I think it's a fine pairing and I am really enjoying what the 300B SET experience brings to the table in terms of musicality and emotional connection.
Still the De Capo, while supposedly an easy load due to its crossover-less design (only 1 cap on the tweeter with the mid-woofer directly coupled to the amp), is "only" rated at 92 db efficient, and based on the most recent Canadian NRC specs, that rating may be optimistic.
So, I am toying with the idea of trying a pair of more efficient, deliberately SET-friendly speakers in my rig, something that might also play lower and with greater dynamic swing than the De Capo's. Note that the De Capo's have served me well and I am very fond of them, but I can't help but wonder if my lovely Kit 1 would shine even better coupled to a VERY easy to drive speaker.
Devore and Audio Note are obvious options - the O/96 looks really tasty. Unfortunately, both of those choices are out of my budget, which I'm thinking maxes out (for real) at around $1500. I am willing to consider used equipment.
Tekton Lore 2.0: This is the speaker that Eric Alexander of Tekton has recommended when we've spoken on the phone, based upon my medium-small listening room and amp. I've read the epic "Lore vs. Zu" thread elsewhere in this forum, and clearly Tekton has its enthusiastic fans here. What I wonder is whether the Lore 2.0 has the refinement of the De Capo in terms of resolution, sweet high end and imaging. Audiogon'er Mikirob has pointed me to the many rave reviews of Tekton's speakers and I'm definitely interested.
I've corresponded with the Sonist folks (who are super nice) but their really high-efficiency, nearly-full-range floor stander is out of my budget.
Then there's the "vintage" route, going after some used JBL's or other high-efficiency "classics" from the 80's (or '70's). I am not inclined to go in this direction, but mention it because it's been suggested to me.
And then there's Omega. I spoke to Louis some time ago and he recommended his 7XRS hemp cone model. But I know all the raps on single driver designs and I'm cautious, although I would like to hear from any of you who own or have owned Omega's.
I'm in no rush to make a switch but I am very interested in your thoughts. Thanks, folks!
rebbi
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almarg
9,670 posts
 
04-26-15: Lewinskih01
I guess my bottom-line-question is whether the vanishing distortion at lower output level that is a trait of SETs is also a trait of SEPs, like the Dynamo?
Hi Lewinski,

Ralph can most likely provide the best answer to that question, but pending his response I'll say that the vanishingly low distortion of SETs under small signal conditions is presumably due to a combination of two things: Absence of crossover distortion, resulting from the single-ended operation, and the inherent linearity of good triodes, especially under small signal conditions.

The Dynamo, being single-ended, will provide the first of those benefits, so the question becomes the degree to which the linearity and distortion characteristics of an EL34 operated under small signal conditions can approach those of a good directly heated triode such as the 300B. I don't know the answer to that question, but I think it's worth reflecting upon the fact that a lot of very highly regarded amplifiers over the years have used the EL34 in a push-pull configuration, crossover distortion included.

Best regards,
-- Al
rebbi OP
1,326 posts
 
Saki70,

You know what they say:

"A thread's not a thread until it hits 500 posts."

:-)
cymbop
315 posts
 
Rebbi, I'll augment Veroman's input: at RMAF I was stunned by the tonality and frequency extension of Audio Nirvana's single-driver setup, which showcased their 12" cone and an EL34 push/pull if I recall correctly.
atmasphere's avatar
atmasphere
11,894 posts
 
This is very interesting, Atmasphere. Is this true for SEP as well? True for a Dynamo 34SE?
That was an insightful observation.
Thank you!

The 20% thing applies to SETs, which typically make about 10% THD at full power. However below about 20% their distortion is quite low, and if one thinks an SET measure poorly one should try to measure the distortion at the lower power levels and then they don't look bad at all. Its understanding how they are to be used that is in short supply.

SEPs are a little different- and because of their inherently higher distortion I would expect that you would want to run them at even less power.

Again, speaker efficiency is key: otherwise you simply are not hearing what the amplifier can do.
lewinskih01
909 posts
 
Thanks Ralph.

I asked Coincident's Israel Blume about Dynamo's THD and he replied "1% @ 8W , .8% at 1 watt"

Seems the difference in THD from 12.5% power (1W/8W) to full power is not much. Should I conclude there is no much gain from running this amp at lower power % then? No vanishingly low distortion at low power in this design, it seems.
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