Please help identify these Acoustat Panels

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Hello,
Could anybody please help me identify these panels?
The owner claims that they are for the MK-2123 Acoustat speaker and are full range electrostatic panels. They seem to be new but there is no way of testing them. The owners are a reputable repair centre in Portugal, but they do not have the schematics to connect the panels to the electronics.
My google searches show the MK-2123 is an interface and not a model of the Acoustat speakers.
I wish to put the panels on sale on ebay or to anyone interested, but I am at a loss as to which model the panels belong to.
As all electrostatic speakers present a difficult load, would it be wise to run them using the Quad II or Quad 303 amplifiers ( I have both)?
Thanks for your help!
 

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These appear to be Spectra panels, as indicated by the split stator wires. Therefore, they can be used as exact replacement parts for ANY Spectra model, be it Spectra 11, 1100, 2, 22, 2200, 3, 33, 3300, 44, 4400, 66 and 6600. Any sales listing for these panels should include a clear photograph of the split stator wires so that potential buyers know these are Spectra panels.

Furthermore, they can also be used as replacement parts for any Acoustat model that uses a 9" wide panel (some models also have 8" wide panels).

For operation, these panels require a high voltage bias power supply AND a transformer step-up system, such as the MK-2123 interface that is used with most of the Spectra models. They cannot be driven directly from a conventional audio amplifier.
 
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It occurred to me that, if you get an MK2123 interface to test the panels, you'll need some help with the electrical connections. Since you are testing only a single panel at a time, you'll want to run the whole panel full range.

With power and amplifier disconnected, connect the panel's yellow/red wire to the red socket on the edge of the interfaces printed circuit board. Note the four stator wires exiting the bottom edge of the panel, and how two of them are closer to the rear edge (rear being the felt block side), and two are closer to the front edge. Connect both rear stator wires to the blue socket. Finally, connect both front stator wires to the white socket.

Plug in the interface and allow the panel to charge for a few minutes. Then carefully apply music. Don't expect the single panel to play very loudly or have much bass. Efficiency and sound quality will improve over the first few hours, if you test them that long.

There's not much than can go wrong with these panels, so unless there is physical damage or they are dirty, they will likely work okay. Spectra panels are less common so should sell easily.
 
Hello,
I truly appreciate your help in how to connect up the panels for tests! I shall also find the schematics so as to better understand these panels: a split stator you say: does that mean there are effectively 2 independent panels in each panel for different frequencies?
The interface hasn´t arrived yet, but it should be an interesting exercise testing these panels. I am familiar with the Quad ESL57 as I repaired my pair!
Thanks and regards,
Alnasir.
 
Hello,
I truly appreciate your help in how to connect up the panels for tests! I shall also find the schematics so as to better understand these panels: a split stator you say: does that mean there are effectively 2 independent panels in each panel for different frequencies?
The interface hasn´t arrived yet, but it should be an interesting exercise testing these panels. I am familiar with the Quad ESL57 as I repaired my pair!
Thanks and regards,
Alnasir.

Yes, the Spectra panels are effectively two independent but equal panels with a common diaphragm. All Spectra panels are the same, but depending on their position within the speaker, a panel-half may be assigned to full range, mids and lows only, or lows only. Quad uses a similar arrangement, but done as concentric rings. Acoustat uses vertical strips.

A Spectra 2200/3300 Schematic is attached. Note the schematic labels for the red and orange transformer taps are reversed. The notes are correct.
 

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