The Hub: Acoustat X: 'stats with tubes!

While some companies ease their way into the public eye, others leap out with a big, bold statement product. Think of the Wilson WAMM, the Avantgarde Trio. In their less extroverted way, the Acoustat X (seen here) was no less audacious. The level of technological density rivals a late-model S-class Benz, only less prone to failure.

Last time out, I mentioned a visit to Frank Van Alstine's basement showroom, 'way back in 1978. Along with the Connoisseur turntable directly connected to earth ("earth", as in DIRT: the 'table was on a column Frank had constructed, anchored right through the floor to the cold, cold Minnesota soil), there were Acoustat Xs. I think Frank had tweaked the amps, just as he had tweaked everything else. I don't recall any details other than Frank's comment, "they (the Acoustats) make everything else sound like they're broken."

And so they did. Even at that point in my young life I was no stranger to 'stats, having heard QUADs, KLH 9s, the boxy, almost-forgotten Koss, hybrids from Infinity, ESS, JansZen and RTR, and an oldie which resembles our subject, even in name: the Acoustech X. As the audio village is a very small one indeed, it's not surprising how much inbreeding there was in that group: the KLH 9, Acoustech X and the Koss Model One were the work of Arthur Janszen, and the RTR elements were a descendant of the Janszen add-ons. More detailed history of the ESL can be read here, courtesy of MartinLogan.

But I digress, as always. Those Acoustats in Frank's basement were punchier and less-fragile-sounding than any of those other 'stats I'd heard. Their drive and dynamism were reminiscent of big Altecs or JBLs, with greater resolution and less coloration. How'd they DO that?

Electrostatic speakers are by nature high-impedance devices. There are basically two ways to drive them: either have a step-down transformer so that conventional amplifiers can drive them (assuming said amps can handle a capacitive load of widely-varying impedance), or directly-drive the elements with a high-voltage amp. QUADs, KLH 9s, the Koss, and most modern electrostats follow the former path, while both the Acoustech and the Acoustat followed the latter (as did Harold Beveridge's speakers, with amps designed by Roger Modjeski).

Jim Strickland, President of Acoustat, worked for "Jeep" Harned, the founder of MCI, the well-known producer of recording and mixing consoles and pro tape transports. Strickland handled the design of the tape-tension and logic systems, developed the first autolocator system for pro consoles, and wrote a few papers on tape-transport issues, which were published by the AES. Strickland and Harned developed an electrostatic speaker (named after Harned), which was reviewed in the Summer, 1966, Stereophile. Oddly, the speaker was a two-way which included a built-in amp for the treble panels, but had a matching transformer for the bass, so separate amps had to be used.

The Harned electrostat foreshadowed the ski-slope design of the Acoustat X, but the X refined the earlier design and improved it in every parameter. In the Stereophile review of the Harned, JGH had noted a phasey, unreal quality to the sound, and a rolled-off high end. Neither criticism was ever made of the Acoustat X.

Strickland brought elements of his tape-handling experience to the X, and subsequent Acoustats: the diaphragm was formed of a special Mylar utilized by Ampex in the production of recording tape, and the method used for applying conductive graphite was derived from methods of oxide-application. Each electrostatic-element panel was constructed of a plastic grid (which looked suspiciously like the diffuser element of a commercial fluorescent light fixture), rather than the perforated metal commonly used; this, coupled with a glued-wire element, produced a panel claimed to be indestructible. You can see the production process at this link.

The X used three full-range panels arrayed in an arc to minimize the beaming characteristic of most 'stats. The panels were driven by a hybrid solid-state/tube amps, designated "Servo-Charge", and if the 300 or 400 volts commonly found in tube amps makes you nervous, you probably don't want to hear about the 5000 volts found in sections of the X's amps.

A few minutes spent Googling the X (sounds like a SoCal NoWave band from 1987, no?) will show that a cottage industry has been built around maintaining, restoring and tweaking them. You can find ex-Acoustat guys who can do pretty much whatever you want with Acoustat Xs; the panels do indeed tend to be indestructible, but the amps will probably require maintenance, as any 30-year-old amp probably will. Ironically, later transformer-coupled models of Acoustats can be fried: not the panels, but the transformers!

Acoustat went on to build a wide range of 'stats, and some excellent and innovative amps. As most know, the company was bought by Hafler, and merged into the Hafler/Rockford-Fosgate family. In the US the brand disappeared in the early '90's, and was moved to Italy. More recently the brand reappeared in China, complete with vintage logo, and still appears to build electrostatic speakers. We may not have seen the end of this brand yet.
Remember those very well indeed and the moment they took the audio world by storm. Never owned those but had the Model 2. Living in South Florida as I have for some 37 years, met many of the principals of Accoustat and was at the factory once. Brilliant design from a truly gifted designer. They continue to impress to this day and a close friend of mine have a pair of the X's, that he has restored and they are still magical.

I cringe at the thought of Chinese made Accoustat. Lets hope that if they do, it will be better than the vast majority of audio products coming out of there.

Thanks for the comments.

The webpages I found for the Chinese Acoustat company are not of recent origin, and I can't ascertain if the company still exists. I'm going to keep looking into it, though.
Thanks for the update on Acoustat. I sold Acoustats from 1978 until they went out of business, I still wish I had my pair of X's. I got those in on a trade and what a difference. The transformer driven Acoustats were not even close. I had Jim Strickland update the amps for $300 and WOW. I still believe those were the best electrostatics ever built, much better than the Quads abd I had several pairs if those.
My first Planars(1981) were Acoustats. We may not have seen the end of the name, BUT- we CERTAINLY have seen the end of the QUALITY. China? PU-LEEZE!!!!
I bought the Xs years ago and had only few troubles with the amps (after 30 years I can concede them to feel old ..) Panels are still ok, I would like to compare all the other elettro-brands (apogee, MLogan, Quad, Sound Lab ...) ...
One week ago I heard MLogan Spire with a super Mac Intosh equipment (7k Euros for Mac Power amp): very similar sound indeed.
And Spire cost 8k Euros. Guys, 15k Euros are not peanuts to obtain a similar sound ...
Back in 1986 I had the Medallian Acoustat 3, and powered them with Conrad Johnson MV75-A1,and Conrad Johnson Premier Two pre amp.One of my all time favourite systems. know how it goes,just a fond memory.

A couple of my friends still have their X versions in 2+2 and 3 and 4 panel versions.
One fellow re-purchased his original pair and uses them to this day with a nice Atmasphere MP3 pre.

Still impressive sound,and if you have a knowledgeable tech,a good speaker/amp system.
Not as detailed or adept at inner detail as some newer stats(CLX is best I've heard)but for music lovers only, as good as it gets.
I've never heard the servo-charge amps, but I have Spectra 66s driven by CAT JL-3 monoblocks, and they SING!
I bought the model 4's back around 1977, because I wanted to be able to drive them with my Marantz 9's. This was a mistake. The 4's absolutely required subs (the X's didn't) and were beamy as heck; definitely a one person sweet spot, and only if you didn't move your head!! The X's had a very good dispersion pattern and really solid punch - wish I had a pair now.I sold the 4's and bought 2+2's, which have seriously better imaging than the 4's, but still need a good sub. In the last few years the problem I've found is that if I leave the speakers plugged in, one of them starts to exhibit low level hum; I assume the HV filter caps are failing. I unplug them after every use now, but would prefer to fix the problem; has anyone a source for said caps and or schematic? Thanks!!
I went through most of the Acoustat models and my favorites are the Monitor 3's and the 2+2's. I had a friend that did outrageous modifications to the Acoustat Servo-Charge amps back in the mid-80's. He changed the original tubes to higher-output 6LF6 tubes, replaced the solid-state input stage with a good tube stage, beefed up the power supply capacitance significantly and upgraded the stock resistors and caps (especially the output coupling caps which he had custom made in polystyrene).

This was the only way to fly for many years, and sometimes I still yearn for that sound.
I have a beautiful pair in my attic and new tubes ready to use but my hearing is gone thanks to the 60's.

How much are these babies worth in Walnut?
Well I got lucky and purchased a very nicely refurbished pair of three panel X monitors, yesterday, two days before my birthday.
Happy birthday to me.
The amps were tweaked by Dan the Man of DTS, and the results are very good.The cabinets were refinished to a pristine condition by Mark.
My hat's off to both of you gentleman.
And Matt, I'll treat these with the care and respect that you would have given them.
I hope you can be re-united with a pair in the near future.

I can hear one of my long time audio buds now when he sees them the next time he visits.It will go something like this -"well, it's about time,I told you to buy a pair of these 35 years ago, think of all the money you could have saved".

Well that's what I'm telling myself, but seriously,in my large room they are a perfect fit,most speakers just can't fill the room with sound and need to be played at loud volumes and that's not how I like it.

But they will play loud, make no mistake.

How can I describe the sound?

In a word effortless.

I have a friend who has a system composed of all AA listed heavey hitters, and a sound(effortless) that I have always tried to emulate but have never duplicated it on my budget.

But, taking a step back in time with these old relics has narrowed the gap considerably.

I realize most younger audiophiles haven't a clue about what I'm raving about, but I was a hold out for many years and passed on the Acoustats of old, just because I felt that newer is better.So a lot of X monitors slipped thru my fingers.But not this time.I knew how good they can sound when set up properly,and given upscale power cords and conditioning and using front ends that are better today than back in the 1970's.Like my two friends who never parted ways with their Servo amped Aoustats.

In fact I doubt people who parted with these ever knew how good the design really was/is because of the inferior quality of a lot of front ends back then compared to what's available now.

Really,these dinosaurs retrofitted for today,are worthy of mention as "end of the line" in the search for an amp and speakers.

To better them with what is available new today, you would have to spend a great deal of money,and perhaps not be as pleased with the outcome.

For the folks with the non servo amped Acoustat's , even the ones with tweaked Medalian mods,you have never really heard how good these speakers are.

I know, because I used to own the Model 3 Medalian, and the magic is in the servo amped models.

Am I happy?
Oh yeah.
To the initial poster, I beleive I have the cottage pair from the pictures.

They sure do clean up well.
Had a pair modded by Ian Fung. Loved everything about them except for the "auto on/off feature"
Yes Ian used to mod them and he modded the CJ pre-amps at the time to match up with the X's.
I've wanted a pair of these ever since way back when my friends went to Ian's for the mods in the 80's.

Dan Santoni,DTS Audio does a fantastic mod to the servos.
Very fast and clean sounding, and eliminates the auto on feature.The tubes are still left in warm up mode,you just flip a toggle switch to power up or down.
Also he upgrades the brilliance control with a stepped resistor array and upgrades caps and resistors.

He isn't far from where Ian lived, just outside Hamilton.
Update, the Acoustats are sounding even better with my new naim cd player.

I have found a source for tubes for the amps ,enough to keep me running for a number of years, or until I run out of time.

Very happy I made the move to this set up, not that there was anything really wrong with my previous system.

This set up just sounds more real,dynamic and less strained,which makes for some very easy litening.

Detail retrieval is better than I remember when I had a pair of the 3 panels with medallian mods.

Compared to my other friends who have the servo Acoustats,I believe they may have a bit more bass, but with a heavey overhang that tends to blur some detail.

The sound from my speakers is very fast and detailed, with bottom end authority when it's there on the recording.

Some may think that they are bass shy, but that would imply that there's never any low bass.

There is low bass when it's on the recording,and only then do you realize how low these speakers can go.

My friends speakers seem to pump out mid bass all the time at the expense of detail,which some may find pleasing, but not to me.

So after about a month, the honeymoon isn't over yet.
Nice thread.... But not my experience.

I owned the first and probably last new pair of Acoustats in Alaska when they first came out. Shimiks Audio in Ancorage was a great place for audiophiles to meet and listen to the current crop of Hi End. We considered the X to be somewhat of a love/hate speaker. The main issue was the listening window. They were just fine if you had a head the size of a grapefruit and duck taped yourself into position. Nirvana was reached. I bought them for a song, took them home and ripped the cabinets off of them and screwed a set of nicely finished handrails on each side of each speaker. Problem cured, to a point. They still had some nagging high freq. problems that made me let them go bye-bye. It was back to the LS3/5a again for a while... Can't remember what came next. One thing that I am sure of, the X isn't worthy of all the hype and placating that I have been reading. The cheap cabinet was the the real Achilles Heel. Rip it off and throw it away and the speaker wasn't too bad... Leave it on and all you have is "half" a Stat. IMHO no other speaker has been more deserving of a hammer and some home brew mods.
Everyone has speaker preferences,that's why so many are for sale.Nobody buys a speaker they hate.
They buy it, live with it long enough to either appreciate it's strengths and ignore the weaknesses or move on to the next speaker and start the love/hate relationship all over again.

Understandable, I and my friend have gone thru 40 years and hundreds of speakers,mostly cones for my friend, mostly stats for me.

Neither of us has found the perfect speaker in either a stat or a cone.

But for me I would rather live with all the good things that the X does,which for me ,far exceede any of it's weaknesses, which in the old days was mostly the fault of poor quality of the gear driving it.We have advanced a lot.

Every improvement that I've made in front end electronics,either vinyl or digital is very easy to hear.The X is very resolving,not a euphonic smeared rendition of how someone wants their music to sound.The X tells it like it is.Most stats do, that's why I like them.
But I did have to sweat the details that a lot of audiophile/music lovers fail to think are worth the effort, to get them to this state of sound.

Dedicated lines,20 amps to each speaker direct from the panel,upgraded HiFI supreme fuses,upgraded top of the heap IEC, plugs and RCA's from Furutech and some mods to old cheap original Acoustat parts have transformed this speaker.

It is no where close to what they would have sounded back in the day they were made, and especially with most of the gear that people put in front of them back in the mid 70's.

I have compared my sound to a couple of systems that just the pre amp alone,costs more than the sum of all my components, and that pre isn't the most expensive piece of that system.

Yet, the way the Acoustats mesh with their own power amps, and no crossover(which is a big plus) and the large open window(yes there is an ideal sweet spot, but I do most of my listening in it)energizes the whole room with music.
I had the LS3/5A back in the day, they cost me $400.00 new,and we used to compare them to the X's back in the day.
For a fifth of the price they were a very nice speaker back then.

Now used Rogers sell for $2000.00 and upwards, plus you need to spend money for a good power amp, and speaker wires.So the tables have turned.

Even if both share a similar sound, you now have to spend more money to better the sound of an Acoustst X in top shape.

Personally, I like the style of the X but I did beef up the cabinet's walls and made them more inert and weighed them down.

I get sound out and beyond the sides of those walls, if it's on the recording,so I don't think I'm suffering much by using the old/modded enclosure.

And as I said, my speakers are for personal(me) listening, so that sweet spot is just for me.

If I have to I can share the sweet spot on occassion, and yes,off to either side of the sweet spot it is less of an experience, but if you increase the distance by moving the sofa back a few feet, it also widens the sweet spot for a couple more listeners,but still in the centre is the best seat in the house.

I had the 3 panel non X models back in the mid 80's and used the Premier series from Conrad Johnson to drive them.
The sound was decent, but not as coherent as with the captive servo amps.Again, the non powered panels were the same, but they were highly coloured by the transformer interface, amp and speaker wire of the day.

My friend still listens happily to this day to his AcoustatX speakers(modded and with an AtmaSphere MP3 tube pre/phono(his X amps have XLR connectors but aren't really balanced)that he bought new in 1976.
He paid around $1500.00 for them, about what I paid for my Acoustats used a couple of years ago.I did invest in some new upgraded parts, but I'm happy I did.
Compared to how much old Rogers 5A have appreciated,used working X's are now the bargain.

As stated I would have to spend at least 5 to 6 grand to get a nice pair of Ls3/5A with a nice tube amp and speaker wires, so I think I am ahead of the game.

If I would have followed my friend's advice back in 86, and bought a pair of used X's then, I would be way ahead of the game.

I wouldn't have gone round the merry go round of one love/hate releationship after the other.
I still have mine. I did have some updates like the fuses were replaced with magnetic hydraulic circuit breakers and the sleep circuit was replaced switches. Oh and I added tube risers as the pc board was showing signs of heat and replaced the rca inputs with nice new ones!

Still enjoying them in 2021!

I had a pair of Acoustat IIIs, then sold them and bought a pair of Acoustat IVs. Great sounding speakers. I was driving them with an ARC Classic 60, which was nowhere near the power required by the Acoustats.

One night, a friend brought over two of Van Alstine’s most powerful solid-state amps, along with a Van Alstine bridging device. We must have had 800-1000 wpc going through those speakers. I had a big listening room at the time ... and I have to say, those Acostats played BIG !!! They filled up the entire room. It was like having a giant pair of electrostatic headphones on. That was one of the most fun listening sessions I’ve ever had in the hobby. I’d love to have those speakers back. But the ones I have now move a lot more air, have better bass and better highs. The midrange is about on par.

It just occurred to me ... I wonder what the Acoustats would sound like with the house and system all tricked out with the PPT products?? Awesome, I bet.
I have Acoustat Spectra 33's and when in use, I use VTL 450MKII tube amps to power them. I purchased them new in 1988.  My daily use speakers are B&W 801S3.


does anybody knows where I can buy spare Resistors, Transformers etc for my beloved Acoustat X?