Electrostatics and tubes

Right you are @gumbedamit. He says the same in his reviews of both the LFT-8b and 8c. It can be argued that the opinion of ESL’s by one who doesn’t like ESL’s is of no value. Just as an opinion about a, say, horn loudspeaker by one who doesn’t like horns (I admit to being one such person) is meaningless.

Still, I find it of interest that Guttenberg characterizes the sound of the ET LFT-8 (both b and c iterations) to have the best traits of both ESL’s (transparency) and planar-magnetics (very well known in the Magnepan designs), with less of their faults.

I understand Guttenberg’s reservations about the ESL sound, though I don’t agree with his dismissal of the design. All speakers are a combination of strengths and weakness, and every listener must decide what his or her priorities are, and look for a speaker that provides he or she with the most of what they are looking for at a given price. I find the ET LFT-8 to offer a nice balance of attributes at a very modest price, and remain mystified that the speaker is not more well known and owned.

It took Guttenberg 30 years to get around to reviewing the LFT8! Robert E. Greene also reviewed the LFT-8b in TAS, and there are several reviews in UK mags, all very enthusiastic. I encourage @hotrod6871 to consider the 8b ($3200) or 8c ($4500) before making a purchase.

@bdp24 I've owned Maggie's from MGIIIa's up to my current 20

1's. A friend of mine once owned a set of Acoustat Spectra 11's.  I was amazed how well they imaged compared to my then MGIIIa's.  The bass sucked, but the imaging was great. A few years ago I had the opportunity to get a set of Acoustat Spectra 33's and build on that. The larger panels and the seemless integration gave a much better sound over the 11's with increased imaging and bass response. I use a sub for the bottom end which helps with slam and SPL.  Do they sound better than the Maggie's,  no just different.  FYI: I don't need a sub for my Maggie's.

Enjoy the Music  

I heard the Sanders Model 10 ESL’s at two Stereophile shows, and considered the sound they produced to be the best at the shows. At one of the shows I also heard a gigantic pair of SoundLabs ESL’s, but there was definitely something wrong. Amplifier clipping?

The advantage ESLs have over other kinds of speakers is the fact that the Modus Operandi  of operation is powered. In a conventional speaker the voice coil moves when current is put through it in response to the magnetic field that is present. That magnetic field sags a bit when this happens,resulting in compression. In addition the voice heats up slightly with power, resulting in something called thermal compression.

ESLs don't have this problem so are one of the more dynamic speaker technologies out there. The real issue is driving them because they don't adhere to the Voltage rules which most speakers do. In that rule where the speaker is 'Voltage driven', its expected that the amp can behave as a Voltage source, which is to say it can put out the same Voltage regardless of the speaker load impedance.

ESLs have an impedance curve isn't based on a driver in a box. So there's no box resonance although there typically is an impedance peak in the bass region like many box speakers. But unlike box speakers they need to have power in that peak; in a box speaker this impedance peak is a resonance (a region of higher efficiency) so you want to throttle back the power so as to not play too much bass. If the amp behaves as a Voltage source then this happens.

So ESLs work better with amps that do not behave as a Voltage source. That's one of the reasons they can often work better with tubes. But ideally the tube amp should make constant power with respect to load and to do that the amp has to be either zero feedback or have equal amounts of Voltage and current feedback (which is rare; I don't think any such amps are in production today).  

Obviously this makes finding the ideal amp for an ESL a bit tricky. But once you have the right combination they can be pretty hard to beat at any price.

To add to Ralph’s (atmasphere) expert commentary, probably the most transparent music reproduction I have ever heard was a pair of QUAD ESL’s driven by a pair of his M-60 OTL amps.

Roger Modjeski was also a huge fan of the QUADs, and used that loudspeaker as one of the loads in the development of his Music Reference RM-10 power amp. Roger then took the ESL/tube pairing to it’s ultimate realization: he developed an amplifier in which the tubes directly drive the ESL stators, bypassing the input transformers of the QUAD. He made only a very few pairs of that amp before Cancer ended his life in 2019. I can only imagine how transparent that Music Reference/Direct-Drive ESL pairing must sound.