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Spectra 3, Identification needed

Read more on the Acoustat Spectra 3 in our home audio section

John2004-02-23 22:21

Hi, I live in Singapore, a small island just below Malayisa. I have owned a pair of acoustat speaker with following info...

1. Interface ... Mk 2123
2. Panel size / color ... Approx 3\' x 5\' ( color blk )
3. Internal ..... 3 way system

Following questions need your kind advise....

1. What is this model ? Not able to identify the actual model
2. Faulty right speaker is very soft.
3. Any replacememt for the transformer ?
4. Improvement needed. Sound is great but lacking in mid bass.

Using Kinergetics kcd20, Denon dcd 3520 to drive Jeff Rowland model 7 , no pre-amp used. Thank you, John.


Andy Szabo2004-02-23 22:21

I believe you have an Acoustat Spectra 3. You didn\'t specifically mention a built-in woofer, but I am assuming that\'s what you meant by ”internal three-way system”. The Spectra 3 has the woofer housed in a curved cabinet at the bottom of the speaker. The interface electronics are mounted to a plate on the bottom of the cabinet.

If I have misinterpreted your description, and there is no built-in woofer, then you have a Spectra 33 or 3300. A schematic for that model is available from this site.

Please see my recent response to Francois Bronic in the Spectra 3 section. It seems you may have the same problem as he does!

Does your speaker use a wall transformer, or does it plug directly into the wall? The Ultrasonic Bias Power Supply, which uses the wall transformer, was introduced shortly after the start of the Spectra series. Some of the early Ultrasonics suffered from a design problem, and would not always work properly. If you have one of these, this could be your problem. Also check for the proper output from the wall transformer. Try swapping the wall transformer from one speaker to the other to see if the problem follows it. Replacement wall transformers are easy to find.

See my Technical Bulletin, ”Ultrasonic Power Supply”, which includes a procedure for measuring and adjusting the bias power supply. A failed bias power supply is often the cause of a speaker not playing loud enough.

If you suspect that you have one of the early Ultrasonic Power Supplies, I can provide instructions to modify it to the later design. The modification uses commonly available parts, and is easy to do.

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