Acoustat Spectra 1100 Speakers

Complete speaker system, modified for a much better sound, and in great condition. Includes both right and left speakers, two bias transformers and the original manual.

I do not have boxes for them and they weigh about 65 pounds each, so they are available for local pickup only.

my audio system

The Spectra 1100's shown setup in my living room, with the ARC amps peeking out behind them.

My modifications:

The Solen Polyproprolene capacitor, wiring, and vibration control upgrades resulted in an amazing improvement in these fine speakers sound quality Detail, imaging, and transparency are in a whole different class now.

Isolated interface circuit board, box, and panel assembly with sorbothane strips and rubber grommets. Built an MDF amp stand to fit on top of Interface and woofer box.


Acoustat 1100 woofer Box
Rear view of Spectra 1100 woofer enclosure with electrostatic Interface box on top
Acoustat 1100 woofer Box
Spectra 1100 woofer box
Woofer Xover mods
Replaced woofer crossover inductors with Alpha Core devices and bypassed aluminum spacers in the signal path with heavy gauge copper wiring. Disconnected poor internal connection to electrostatic interface.
Acoustat 1100 Panel
Spectra 1100 electrostatic panel. Note good condition of grill cloth.
Acoustat 1100 Interface Detail
Spectra 1100 upgraded Interface electronics
Interface mods
Replaced electrolytic interface caps with Solen PP types. Added new input connectors and wiring. Cleaned up the boards and dressed wiring.
amp/speaker connections
From bottom: Modified Acoustat woofer box with crossover panel, electrostatic interface box, homemade amp platform. D-52d Amp, steel cube to sink stray flux. Wire to woofer is Tributaries 12 gauge stranded, electrostatic interface is connected with a short section of Goertz MI 1 copper ribbons. Unused amp input is protected with a Cardas cap.