Can U identify these electrostatic units ?

[Cal Weldon]

I think sreten should get first prize.

[tyu]

Hi,

look like Shackmans to me, they were single ended not push pull.

This was posted a day before Calvin...how the hell Can this be right???A day later...Look like a rig prize.... good luck
And the prize goes to .... (10 second pause) ... Calvin

[sreten]

Hi, yes well, at least I seem to have won the peoples vote, , rgds, sreten.

FWIW I think they'd work best is some sort of open baffle arrangement,
with them as the T in a MTM arrangement, bass - open baffle or boxed.

[Calvin]

Hi,

Didn't knew this was a Quiz. So Sreten wins the price.......

jauu
Calvin

...but I've got the looks

[forr]

Originally Posted by bear

If it has HV, then it is likely a single ended ESL, less linear than P-P types, but they can work. There wre some German units, maybe Grundig or another famous brand I can't recall that made some 2" or so round tweeters like that...

A single ended electrostatic driver was made in Japan by Sunsey and sold for a while in France around 1975-1980.

I just discover this site which may help :

Do It Yourself - Electrostatic Speakers

[john s]

Alex Shackman had a company called Southern Sound services, he made two versions of his electrostatic units a smaller one that crossed over at 1,000k i had a pair of these until quite recently, he advertised them as like a Quad but with better bass,

later on he made the larger version which this appears to be, this crossed over at 400cycles both with a Allen bextrene mid bass unit i think a 10 inch with the larger unit and an 8 with the smaller,
he sold them made up in a sealed box with lots of absorbent wadding behind the unit,
i bought the kit, no instructions except where the wire went i rang him and asked about the enclosure Alex replied about 1 to 2 cubic ft, but could not offer any other information on correct size loading etc,ft when Alex died sudenly his wife sold the rights to manufacture the units to Volt who made high quality bass units but they ceased making and selling them after just a few units,

i built a design called the badger from Hi Fi news (i think) and made the box sides deeper and mounted it in a tunnel above the bass midrange unit clarity was fantastic better than any cone unit on the market also sound stage was much wider as it is a dipole and radiated from the rear as well, i used these for about 15 years before giving them away when i moved abroad,

[awkwardbydesign]

I still have a pair of the smaller Shackman panels, which I bought from the man himself. He demoed them in a cabinet with a cone driver, and didn't like me questioning the obvious change from 'static to cone sound! Mine claim xover at 500Hz, but wouldn't fancy that.
I am making a pair of isobaric bass speakers, with KEF B139s, EJ Jordan JX125 wide range drivers and the Shackmans on top.
It will be interesting to see how that works out. Oh, and they are active too, transistor bass amps, 845 SET mids and EL 84 PP hf amps. Wish me luck.
john s -Did you use the piddly transformers they came with? As far as I recall, the impedance dropped to 1 or 2 ohms at 20kHz. I was thinking of buying a pair of Sowter transformers for mine, but that ups the cost a fair bit.

[Boden]

Seems indeed like Shackmans to me. Bought a pair at his home in New Barnett around 1978, indeed loaded with speakers (and 19forties UK interior).

He sold them in conjunction with 8 inch Dalesford Bextrene woofers and a pair of 2 mH ferrite coils. The woofers still perform their daily duties in a friend's 2 way speakers.

I never managed to have The ESL units sound anything other than outright horrible. Unfortunately I threw them away before I could do proper SPL measurements with IMP from 1993 on.

The transformers were very tiny indeed, the whole high tenson section mounted on a shoddy piece of timber. There was a wirewound pot of questionable qulaity included for woofer level matching.

Ah, brings back some audio memories from the UK audio business as it was in the late seventies.

Eelco

[john s]

Originally Posted by awkwardbydesign

I still have a pair of the smaller Shackman panels, which I bought from the man himself. He demoed them in a cabinet with a cone driver, and didn't like me questioning the obvious change from 'static to cone sound! Mine claim xover at 500Hz, but wouldn't fancy that.
I am making a pair of isobaric bass speakers, with KEF B139s, EJ Jordan JX125 wide range drivers and the Shackmans on top.
It will be interesting to see how that works out. Oh, and they are active too, transistor bass amps, 845 SET mids and EL 84 PP hf amps. Wish me luck.
john s -Did you use the piddly transformers they came with? As far as I recall, the impedance dropped to 1 or 2 ohms at 20kHz. I was thinking of buying a pair of Sowter transformers for mine, but that ups the cost a fair bit.

Yes mine had a small transformer i could never understand the circuit on this it had a slow 6 db roll off to try and integrate the two units, which i mounted as close as possible, it was recommended in the HI/FI press at the time that 12db would have been better, which volt did on the units they sold,
mine sounded great, fantastic detail and clarity, the change in crossover frequency may have been when he was trying to get them lower and eventually had to go to a larger size to get the HZ down to 400,which would mean a different circuit design, there were times depending on the singer mostly i seem to remember female voice when it was noticeable and the sound jumped from the cone to the shackman unit,

as Boden mentions it was mounted on a piece of chipboard, but no pot on mine, from what i understand there appear to be ongoing changes as he tried different things, he had removed the details from the tranny before selling them, and Richard Allan Dalesford cone units, (i had forgotten the actual name)
i don't think the quality of the tranny is that important its just a voltage step up device i would think any small toroid would do as long as it had the same turns ratio, from what i remember it's not in the signal path, it's just bias voltage for the stators,
the diaphragm was stretched by hand and held with pieces of celotape and could lose their tension,

John S

[awkwardbydesign]

Mine use a diode/capacitor voltage multiplier to get the HT for the diaphragm, - and a step-up transformer for the audio signal-
"8986 ESL Transformer 1:100 CT 300Hz
Designed for mid/high band use with a 300 Hz crossover. Rated at 2000 volts maximum output. Fully shrouded style S only. Size F
Price: £121.40"
It's the audio transformer that I would like to replace. If yours didn't use this system, how did they step-up the audio?