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Eminent Technology LFT-8b in Harry's system

I recently signed up for the V.P.I. Industries newsletter, and today received my first such. In it, Harry Weisfeld reviews a Grado phono cartridge, but this post concerns one of the speakers he listed as being those he uses to listen to music and evaluate recordings through. All but one are traditional dynamic cones/domes in a box designs, only one being a planar/dipole. That planar is the Eminent Technology LFT-8b. I'm pretty sure Harry could, if he so chose, have instead as his sole planar a pair of $6000 Magneplanar MG 3.7i's, or even $14,000 20.7's. But nope, he instead chose the $2500 ET LFT-8b, imo the greatest value in a loudspeaker on the market. I compared it to the 1.7i, and the difference was dramatic.
128x128bdp24
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bdp24 OP
9,821 posts
 

I know what an OTL is, ya big silly ;-). I had a pair of Atma-Sphere M60’s for years, which I bought for driving my old Quads. One cool thing about them is you can take out half the output tubes, to create a 30 watt version of the amp, perfect for the easily-overdriven Quads.

You’re right, an ESL speaker with a direct-drive tube amp has not only no output transformer in the amp, but no step-up transformer in the speaker, eliminating two sources of distortion. I know Modjeski’s current ESL speaker/D-D amp product is designed and built that way, as I believe the Beveridge was. I think it was to accomplish that that Mr. M was hired by Mr. B. I think they were both in the Santa Barbara area at that time, a beautiful city on the California/Pacific Ocean coast, just north of Los Angeles. Modjeski relocated to the San Francisco bay area a couple of years ago, where he runs Music Reference and teaches a course in amplifier design at a local adult education school. Wish I still lived in San Jose!

When I bought the TranStatics in ’81 (for $400, out of The Recycler, a weekly S. California paper), one of them had a generic oval woofer instead of a B139. I called ESS in Sacramento, and they had one, and only one, left. I paid all of 39 bucks for it! The B139 ESS used in the speaker wasn’t the standard version---not having the four "ears" through which mounting bolts pass---just a perfect oval. I first heard the speaker in ’71, but being a starving musician couldn’t come close to buying a pair. They retailed for $1200 in ’71, the Infinity Servo-Static $2000. Ten years later I was happy to find the TranStatics, and could now buy them. Still have 'em, but man are they heavy---140 lbs. apiece

lewm
13,110 posts
 
bdp24, Sorry for the pedantic discourse on "OTL".  You would be surprised at the number of audiophiles who do not know the differences in meanings of the terms: OTL, balanced, push-pull, single-ended, and direct-drive.  My main point was, as you know, that your Atma-sphere amplifiers could not directly drive the screen of an ESL, but they are OTL.  However, once in a while, Ralph Karsten makes noises about building a direct-drive amplifier; I am sure he could do it.  I use a pair of MA240s to drive my Sound Lab speakers, in my "main" system.  Joe Curcio, I think, also claims to have a tube-based input circuit mod for the original Bev amplifiers.  The originals, like mine, use solid state input circuit, and yes yes yes, they are direct-drive.  (Bev speaker Models 1, 2, and 2SW are directly driven.)
bdp24's avatar
bdp24 OP
9,821 posts
 

No apology necessary Lew! To assume ignorance is not a bad idea ;-).

Modjeski’s new ESL is sold as an integrated speaker/direct-drive tube amp---no output transformer in the amp, no step-up transformer in the ESL. A stand-alone direct-drive amp is impossible, as a universal model/design can’t take into consideration the different nature/characteristics/needs of all the speakers it may be asked to drive. A direct-drive amp must be designed for a specific speaker, and for that speaker alone. I’ll bet the Beveridge was Roger’s first attempt at such a design, and I wonder how his new one differs from it. He did also design a "normal" OTL, the rights to which he sold to Counterpoint, who manufactured and marketed it as the SA-4.

Your KEF driver project was very advanced for a hobbiest, Lew. Transmissionlines are not easy to build, requiring a lot of knowledge of acoustical theory, speaker enclosure design, and cabinet building. I’m impressed!

bdp24's avatar
bdp24 OP
9,821 posts
 

A new review from Harry arrived today---HW Review #2 (07-03-2017). The subject of the review is the Modwright 150 Phono Section, but here a couple of quotes from the review regarding one of the speakers Harry listened to the Modwright through---yes, the Eminent Technology LFT-8b:

"A $2500 wonder."

"I typically find the ET's to have the best mid-range I have ever heard from any speaker."

The other speakers mentioned in the review are KEF Blade 2, JBL Everest, and Joseph Audio Pearl 3.

kot
133 posts
 
@ rotarius "I really don’t want to rain on anyone’s parade but like every speaker I have tried, the LFT-8B have a few flaws and they can be quite intrusive. I had them paired to my Belles 150a amp. The bass from the woofer was never quite right in my room. Way to under-damped and boomy. The other issue was the panel itself. They are supposed to be crossed over at 180 Hz but I wished that wasn’t the case because at moderate volume, with bass heavy stuff (think Patricia Barber), the panel would distort, panel slap is what I have heard it called. So, they are nice, very nice for classical but not up to the reference quality some people here claim. I liked my Martin Logans I got after that a little more."

Well, sorry to say that, but your Belles amp probably is not a good match for the LFT 8bs to say the least (some would say it is distinctly mediocre, but we all hear differently I guess) .... That is a first time I hear panel distortion of the LFT 8s, or the bass issue you have described, and I ve heard about dozen of ET 8bs and ET 6 installations. The room and improper placement is usually the culprit. Also people using jumper cables instead of true bi-wiring affects their sound to the worse. Did you tighten the panel with hex screw driver as per ET/or your dealer instructions? The tightening (but NOT OVER tightening) makes a HUGE difference in the overall sound quality of the LFT 8bs... If you like solid state amps you should try once in your lifetime to buy used Electron Kinetics EKSC 2a stereo amp and pair it with LFT 8bs...

I ve pretty much heard all Martin Logans ever since late 80s, and the only pair that would match or better the LFT 8s (not to mention the superior, sadly long discontinued model 6s) in overall coherency, wholesomeness , realistic timbres, the ability to portray recording venue with realistic proportion, the freedom from having to sit smack in the middle with once’s head firmly affixed in one position was that model that features wide panels plus woofer towers, a la Infinity IRS... and those were about 25 grand back in early 90s....

The only speakers in my (NON) humble experience that would match or exceed the LFT 8bs performance in spatial, tonal and dynamic nuance would be Apogee Divas, and Apogee FRs, and Eminents own 6s... in a very large room.... The LFT 8bs can be magical even in small to medium size rooms...

Being one of those obsessive music lovers that like to own as many different speakers as possible, I was considering the purchase of new Bowers Wilkins 802d3, or 800D3.... So I went, and I listened, and I listened, and I liked what I heard ALOT... Then I returned home and after hearing the same music on my ET 8bs even in my second, less than ideal, small listening room, I could hear that the most excellent B&W were NOT as fast, natural, delicate, open and spacious as the LFT panels.

.... There is an audiophile in princeton, nj that has ET 6s with the Nestorovic subs with two pairs of german Symphonic Line 4 monoblocks with separate crossovers in a spatial room.... I ve travelled far and wide all over the world for work, and was able to listen to systems at different audio shows, and to the million dollar systems in homes of Russian oligarchs, but none of those were organic enough, or able to match this Princeton Eminent Tech based system.... . Bruce Thigpen IS a genius!!!!!!

So, yes, in essence the Eminent Tech 8bs are reference speakers, for ALL the possible musical genre as my 20 000 albums collection can attest.... if you know what the properly recorded music sounds like ;)
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