New to Martin Logan, but not to Electrostatic speakers

[ESLFan]

Has anyone replaced the spring loaded binding posts on the Electromotion ESL model? I can't find a thread on that. The ones I found were replacing already nice banana binding posts.

 

[Jazzman53]

I plan to create a new thread, adding some pictures and explaining why certain design decisions were taken. Mike Wright was a physicist and so he designed his speaker sort of like NASA would, not trying to be practical. This is probably the reason why financially the company never made any money. Anyway I read a few books on the subject, the Sanders book to name a few. From what I am seeing, there are certain design decision made by others that seem less than ideal.I will post the link here after i get started.
Hoping that the third set of bracket will arrive next week, but since going by post office and the July 4th weekend coming up,, I am not going to hold my breath.

You obviously have a passion for ESLs and I'm looking forward to your planned thread about the Dayton Wright design decisions.

I've read about the Dayton Wright ESLs but there aren't many around anymore so it's unlikely I would ever hear an original pair, but I might get lucky and someday hear a pair of the new the Hommage Dayton Wright speakers shown here: https://hommage.lemayaudio.com/en/hommage/

I'm not sure I could contribute much to a discussion thread, but I've devoted a lot of thought to ESL design and it's nice to know there are others who share the psychosis

 

[ESLFan]

I grew up in a suburb of Toronto. That city probably had many of the best audio shops in all of Canada. As a teenager, I had a nice University sound speaker system I put together from the plans published by that company. It had a 12 inch woofer with Alnico magnet (seems those were amazing magnets because the field is unaffected by the magnetic flux in the voice coil.) The system was a threeway and I had purchased their super-tweeter, that claimed a response to 40,000kHz. I used that using a calibrated signal generator to test my hearing which extended to 22kHz at that age. Since I had amazing hearing when I was young, I focused a lot on how badly all HiFi sounded in the upper octaves compared to live music. The first time I heard electrostatic speaker was at an audio show in 1968. I still remember they were playing the Dayton Wrights using a direct drive tube amplifier playing Abraxis. When I heard how accurate the sound of drums and how clear the other instruments were I decided after I graduate from college I am going to buy one of these speaker. Well I did, never realizing how much effort it was to maintain them. Anyways, thought the 70's and 80's it was the blossoming of HiFi. I heard Heil air-motion transformers, the Ohm speaker, the original Quads, the amazing Crown 2x10 hybrid electrostatic system. They were 10 Jantzen electrostatic panels with a acoustic suspension double 10 inch woofer cabinet, driven by the crown DC150. very clear sound but somewhat un-musical, because the transition between bass and treble panels was not so good. The panels also seemed too bright. The thing I remember about the Quads was they did not play that loud and when driven by the crown they had to be repaired a few times because people in the showroom played them too loud because they really sounded good. A few of the staff used to sit in front of them, play some Beatle albums and smoke weed. There was a turntable, I don't remember which one, but they were using a Goldring cartridge, which at the time was probably the best sounding out there. Another store demonstrated the Hill plasma air tweeter. The treble was amazing, but the practicality was not. There was tank of helium in the cabinet and it would have to be replenished. But for me the subtle hiss of the gas escaping the jet made them uninteresting.
At that time, the driving the Dayton Wrights were presented as a challenge to several famous amplifier designers in the US. The PhaseLinear 700 amp is one. After a few modifications it stopped blowing up. The transformers in the speakers were 1000VA 100:1 step-up and insulation rated at 20kV. the speaker terminals were those ceramic things you see on high voltage power lines, lol. The reason I mention it is that that transformer, no matter what amp you threw at would be unaffected by any amplifier destruction. Worst case it would blow the 7A slow blow fuse. The ideal amplifier at that time and I think even today, a good match is any of the Nelson Pass designs. The effective speaker impedance is a 4.7uF capacitance in series with 3 Ohms. One of the ML impedance graphs I had seen was similar, 2 Ohms in series with a 2uF capacitance.

 

[ESLFan]

Ok the brackets arrived and finally put them together. It got late so i have not hooked them up. I need to make up some other speaker cables since I cant use my Kimber Kable speaker wires yet. The speakers look great.

 

[ESLFan]

Ok here is the thread on the Anatomy of a high output high efficiency electrostatic loudspeaker.
https://www.martinloganowners.com/t...-high-output-electrostatic-loadspeaker.20052/

 

[ESLFan]

I can well imagine. The space between the outer diaphragms would form a distributed acoustic resonator, particularly as the half wavelength approaches the spacing. Not insurmountable, just complicated. At low frequencies, though, the three diaphragms would move approximately in unison, and the wide spacing would allow for large excursions, ideal for a separate bass panel, if one wanted to go that route. If you create the thread I'd be interested in following it.

I started the thread on it already. One thing to remember all the design criteria depends entirely on the use of SF6. The bias voltages were between 12 and 16kV. There was a reostat on the bias supply to lower the voltage on humid days and increase it on dry days. Even within the the mylar enclosed speaker, there was still enough ingress of humidity. The best thing it provided was preventing dust settling on the cells.