, Acoustat Electrostatic loudspeakers

Read more on Acoustat in our home audio section

David May2005-09-06 20:37

Is Acoustat still in business? address? Is service/repair available for Acoustat electostatics. Is the model 4 still available? If so, what is the retail price.(per pair) Thank you very much David May


James Wong2005-09-08 21:10

Acoustat went out of business in 1992 and the brand was acquired by Audio Physics. In 1993 Acoustat was relocated to Italy. The Acoustat spekaers were then only sold in Italy. In 2004 Acoustat moved to China. In 2005 Acoustat launched new models.

Andy Szabo2009-06-21 17:30

Acoustat USA is no longer in business. There is no official repair service available, but if you write again with a specific problem I can possibly help you or direct you to a source of parts and/or service.

The Model Four was one of the earlier models produced by Acoustat, and was discontinued probably mid-80\'s or earlier.

Susan2011-03-22 19:03

Is the Acoustat Spectra 22 a common ground loudspeaker? I want to purchase an amp
that can not be connected to a loudspeaker system with a common ground and need
to be sure I can use it with my Spectra 22's.

Andy Szabo2011-03-22 19:38

There is no connection between left and right speakers, so there should be no reason why you shouldn't be able to use an amplifier that is non-common ground. Even if you are using an Acoustat SPW-1 woofer with your Spectra 22's, the left and right grounds are kept separate inside the woofer.

Joseph Fabricatore2012-02-13 23:15

My Spectra 33 (right speaker) no longer puts out sound. I checked the connections, fuse, changed out amps, but can't find a solution. Can anyone suggest a fix, or know where I might get it checked out. I am in Los Angeles.

Thank you

Andy Szabo - Acoustatanswerman2012-02-14 18:52

Check the operation of the wall transformer. There should be a small red pilot light on the rear of the interface box when the wall transformer is properly energized and connected.(it's not a very bright light). If it's not lit, then try the wall transformer from the other speaker to see if that makes the speaker work. Replacement Acoustat wall transformers are frequently available on eBay, or any 15-volt AC wall transformer will work (you may have to change the plug).

If that does not yield any results, write again. We'll get you back in operation!

Joseph Fabricatore2012-02-15 16:23

Hi Andy,

Thank you so much for your response.

I am not aware of nor have I ever seen a "small red pilot light on the rear of the interface box." Only see two sets of terminals, a woofer switch, a 5 amp fuse, and a power cord.

And I am not sure what a "wall transformer" is. These speakers have a grey power cord coming out of the interface and plug directly into a wall socket. I don't know what a 15-volt AC wall transformer is.

If it might be more efficient for us to communicate via phone, please let me know.


Andy Szabo - Acoustatanswerman2012-02-15 19:15

Ok, evidently you have one of the earliest Spectra 33's, which had a line-powered bias power supply (hence the gray line cord on your speaker). There is no pilot light on those versions. Most of the Spectra models used the low-voltage 'ultrasonic' bias power supply, which is powered by a wall transformer.

There are two more fuses inside the interface box, which protect the line-voltage supply. You should check these first, preferably with an ohmmeter or continuity checker. Being very small-value slow-blow fuses, it is sometimes hard to see with the naked eye that one of them is blown. If you find one of them blown, it may be just a matter of an old fuse giving up on life, or it could have blown for good reason. If necessary, replace the blown fuse with a 1/4-amp (or 250 mA) fuse. If it doesn't blow again, you're back in business. If it blows again, you probably have a problem with the bias transformer (smallest of the three transformers). Replacements are sometimes available from eBay or from other sellers.

While you are inside the interface chassis, also check to make sure all of the colored pin-plugs are firmly seated in their sockets. These are the wires that connect the panels to the interface electronics. Also look for any obvious burnt parts, or discoloration on the printed circuit boards (not to be confused with the black dust that collects on high voltage parts). You may also want to loosen the high voltage board (4 screws) and look at the smaller crossover board beneath it. I have run into cases where the soldered connections to the fuse holder may have come loose.

You may also want to swap interfaces between speakers (only the panels are left/right) to see if the problem moves with the interface.

If all of this fails to reveal the problem, do write again! The good news is that it is almost 100% certain that the problem lies in the interface, and not the panels themselves.

Joseph Fabricatore2012-02-15 22:40

I don't have an ohmmeter and on the internet they are price from the low hundreds to thousands.

any other options?

I will carry out your suggestions in the next few days as best I can.

Assuming I can get an ohmmeter, how do I actually check the measurements you suggest? Where do I place the leads? Is the device powered? etc.

(I recognize these are very rudimentary questions and I appreciate you patience - my stereo engineering experience is limited to recognizing that pre-amps and amps are superior to receivers).

Thanks again,


Mat2012-02-16 20:27


Andy is talking about using an ohm meter to test your fuses. You can buy an ohm meter at RadioShack $20 or so. Good luck, I hope you get your speaker going again soon!

Andy, I asked a question about my 2 plus 2 earlier, but am not getting a response. Can you help me with that please?

Thanks for a great and informative site,


I have the Sprectra 22, 44 and 2 plus 2 speakers……

Joseph Fabricatore2012-02-16 20:53

Thank you, Mat.

Will do.


Mat2012-02-16 22:32

Glad to help, Joseph. Post your findings, if you would, I'd be interested.


Joseph Fabricatore2012-02-17 22:51

got the ohmmeter-set scale at 200 - both fuses in both interfaces checked out at 4.5-5.0. Reversed interfaces: no problems found.

So it looks like the culprit is the amp (a Music Reference MR-9) with no signal right channel. Interim amp powers both channels and both speakers sound fine.

Many thanks to Mat and Andy for their help and advice. I learned a lot more about the Spectra 33s and am curious to know if anyone suggests any mods or updates.


Andy Szabo - Acoustatanswerman2012-02-18 12:03

Joseph- Glad to hear you've found the problem!

Mat - I looked for your post but couldn't find it. I did receive an email a few weeks ago that a question had been posted, but was never able to get the link to work. Please post your question again and I will try to give you an answer.

Mat2012-02-18 14:06

Will do, Andy, thanks.

Glad you solved your problem there, Joseph. Enjoy!

Joseph 2012-02-18 15:44

Thanks, guys.

Any suggestions for updates or modifications?

Mat2012-02-18 16:36


You might look into getting your interfaces upgraded by Roy Esposito. His contact info is listed here:

I have a Acoustat TNT 200 that was refurbished and upgraded by Roy, and am very pleased with it.


Mat2012-02-18 16:43


I tried to post a new question in the forum index here, like before, but I keep getting the message that "the page you are looking for is not available."

I'm just trying to figure out why this pair of 2 plus 2 speakers I recently acquired start breaking up/crackling/popping at anything more than low volume. All panels equally.

Should I suspect the panels, or the interfaces?



Andy Szabo - Acoustatanswerman2012-02-19 14:33

The accuracy of my diagnosis depends much on the exact words you use to decribe it, so here goes:

'Breaking-up' suggests to me a problem with the interface. The transformers may be arcing above a certain voltage,which would cause all panels of a speaker to misbehave identically. If the transformers are pre-Medallion, the chance of old-age arcing is greater.

On the other hand, words like 'crackling' and 'popping' suggest to me a panel problem. If the speakers have been in storage for some time, it may take a while for the panels to reach their full potential. Or they may be very dirty, in which case a good vacuuming of the bare, un-energized panels will be necessary. Be sure to do both sides, and you may need to repeat the process a few times for it to be fully effective.

If it's a panel problem, usually some panels will be worse than others, but it can be hard to tell which ones are misbehaving. Sometimes a disturbance in one panel can cause a 'pop' or 'crack' in the other panels.

With the power off, try looking (and smelling) in the interface boxes for any tell-tale signs of arcing, especially on the largest of the three transformers. Then if possible, look (don't touch!)at the inside of the interface while the speaker is operating, in a darkened room, and look for flashes of light. Neither test is definitive - the transformers can arc with no outward signs.

You might also try looking at the panels while operating in a darkened room, to see if you can detect any arcing. Again, arcing can occur even if you can't see it.

So do some poking around and let me know what you find. Panel problems can usually be home-remedied, as long as the diaphragm is intact. Interface problems will require a trip to SoundsLikeNew.


Mat2012-02-20 17:49


Thanks for your detailed response.

I'm assuming these utilize pre-Medallion transformers, as there are no "Medallion" stickers on the interface enclosures.

I'll follow your instructions, check them out, and report back as soon as possible.

Till then, thanks again,


Joseph Fabricatore2015-08-03 18:06

I have a question, and don't know to whom I should pose it, so I'll take a =
chance and ask you.
For LPs/CDs, the 33s are driven by a tube preamp/amp combination. But most =
of the time, I run the audio from my TV into a solid state amp which drives=
the 33s.
Would there be an harm in hooking both the preamp/amp and the solid state a=
mp to the 33s, but only power them when I am using either the LP/CD setup a=
nd turn off the solid state amp to the TV, and vice versa?
It is possible to purchase a device that I could switch the power sources, =
but since I am only going to have one power source driving the speakers at =
a time, that seems to be an unnecessary solution. Currently I disconnect th=
e speaker cables from the solid state amp to the TV, and then connect the c=
ables from the preamp/amp combo when I wan't to listen to music. Obviously =
an inconvenient solution, but don't want to take a chance on blowing fuses,=
etc. What do you think?

Acoustatanswerman2015-08-04 23:49

NEVER connect the outputs of two amplifiers simultaneously to one speaker, even if one of the amplifiers is off. Damage will likely be the result, or at least very poor performance.

Instead, you should connect only one at a time, either by swapping wires or using a switchbox. The switchbox should switch both (+) and (-)leads of the amplifiers and speakers. Otherwise, if it has a common ground (as do most speaker-selector boxes)a ground loop could develop and cause hum.

Hope that answers your question.

Joseph Fabricatore2015-08-05 07:37

Thank you. That definitely answers my question and confirms my hunch.

Roy A. Esposito2017-04-25 15:23

Dear Clients, Friends and devotees of Acoustat --
Please make sure to change the Audio Fuse in the outside post of
your Acoustat Spectra or MK Series interfaces to a 3 ampere
slow-blow type. The original factory spec 5 amp fuse is not adequate protection
against costly audio transformer damage using modern fast and powerful
amplifier designs. This is especially urgent if you use a tube preamp
paired with a solid-state amplifier.
Mouser.com part number 313003 is a good source. Or perhaps Home Depot or Lowes.
Note : The two internal 1/4 ampere AC line fuses on Acoustat models that have them
never require replacement. As always, I am available for service/upgrades/improvements
of your Acoustat Interfaces and Acoustat power amplifiers and preamplifiers.
Enjoy the Music ! ----Roy

Post a reply

Your name will appear on the website next to your contribution. Your email address will only be used to contact you if something is wrong with your contribution. It will not be shared with others.