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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
bdp24's avatar
bdp24 OP
4,908 posts
 

Wow, a new pair of LFT-6’s! I’m gonna look into that.

Bruce includes a chart of the LFT-8’s impedance curve in both the owners manual and on the ET site, and the inductance of the dynamic woofer does cause an impedance dip. But the panels themselves have a very even, and for magnetic-planar and ribbon drivers, very high impedance characteristic, making them a good candidate for bi-amping and tube amplification, if that’s what one desires. Maggies, in contrast, present a 4 ohm and lower load to the amp, a real challenge for a tube design. The lifespan of tubes is greatly shortened when asked to drive low impedance loads, inefficient ones even more so.

Another point worth mentioning is that some consider the LFT-8’s dynamic woofer, though optimized for and blending well with the panels, to be the speaker’s weak point. If one desires more (or "better") bass output capability, the rather low 180Hz x/o frequency between panel and woofer allows one to use a sub of one’s choosing in it’s place. I am about to try just that with the bass panels of a pair of Magneplanar Tympani-IVa’s, an idea I became aware of recently on the Planar Speaker Asylum Forum.. Should be interesting

tommytom
12 posts
 
I first had the LFT8 and the woofer would distort with heavier bass passages so I was going to upgrade ($200) with Bruce's LFT8b woofers but I ended up getting a pair of 8b's (2011 vintage) off Audiogon for $1200. My favorite speakers by far because of all the reasons described here. I had previously; MGIIIA's, MG1.6, Legacy Focus, Dahlquist DQ-20.
The Focus obviously had the greatest dynamics with the 3 12" woofers and at around 98db sensitivity but overall the 8b had greater transparency and naturalness to the sound. The key thing here I believe that led to their great sound for me was running them with a Moscode 600 hybrid amp. At 300wpc and a Mosfet output stage, it gave those panels what they needed.
Fast forward to 2015 I wanted to try something different so I sold the Moscode and bought the Quicksilver V4 monoblock tube amps at 120wpc. As good as they sounded with the 8b's I don't think they had quite the same bass control and overall tighness that the Moscode had.
So then I see a pair of Alon IV for sale and still having the Dahlquist DQ-20, and knowing how good those speakers are, I purchase the Alon IV's.
As good as the bass was with the 8b's/Moscode combo, and even with the 8b/V4 combo, the bass from the Alon's was way deeper and more dynamic, and the mids and high frequencies were very good as well, although not as tall and wide of a soundstage as the 8b's. So now I end up selling the 8b's and am currently using the Alon IV/ Quicksilver V4 combo.
I say all this because as a crazy adiophile, I am thinking about getting another pair of LFT-8b's, selling off the V4 amps and Alon speakers, and buying a high current either hybrid tube/ss or maybe even a class D amplifier like the Rogue Pharaoh or Audio Alchemy amps. My goal is to bring back the overall cohesiveness and transparency that the LFT8b's have, but this time pairing it with and amplifier that can bring out those qualities.
Any suggestions?
bdp24's avatar
bdp24 OP
4,908 posts
 
One great thing about the LFT-8b is that it's low 180Hz x/o frequency allows it to be used with a high-quality sub in place of it's stock woofer. Then a good tube amp can be used on the midrange magnetic-planar midrange driver and tweeter, which present an 11 ohm load to the amp. The sub's woofer is driven by the plate amp integral to most subs.
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brucefrederick
7 posts
 
Has anyone bothered upgrading the caps in the crossover.......Well I have.  
Tweeter cap : Rike S cap 2.2uf
Mid cap: Audyn  true copper 2.2uf
470uf replaced with Clarity cap TC 220ufx2 bypassed with Rike PIO Qcap 3.3uf x2

All I can say it was well worth it.  Everything across the board improved significantly.  I was never quite satisfied with the tone these SOTA drivers gave, but now I am quite sastified. 

Class D SDS470C  modded extensively (previously owned the 350a)
Ming Da MD-6 passive  transformer preamp
Doge 6 CD player


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