2 plus 2, Output, output problem

Read more on the Acoustat 2 plus 2 in our home audio section

Robert2004-02-23 22:21

Hi Andy, I have a pair of 2+2\'s that I got used about 10 years ago. They have preformed incredibly up until just a few weeks ago. One of them doesnt seem to provide the full range of sound anymore. I get mostly the mid to low end of the spectrum, and Im getting alot of static as highs go in and out. I\'ve always have had problems with fuses blowing on this speaker, and I do tend to run them at high volumes. I looked over the Q&A section but didnt seem to find anyone with my problem. Could the wiring be a problem (oxidizing)?

I run them using Adcom aplification (GFA585). I have tried both channels on the amp, and I tried a different cable, and I still get the same results. Any help you could provide would be most appreciated. Thank you, Robert.

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Andy Szabo2004-02-23 22:21

Your problem almost certainly lies in the interface, and not the panels. However, just to make sure, swap the interface from one panel to the other. If the problem moves to the other panel, then the problem is in the interface.

From the description of the sound, you likely have one or more faulty components in the high frequency transformer section. See the schematic in your owner\'s manual, or on this site under ”Manuals”. The schematic shown in the manual section is the ”B” version. If you have a red Medallion Transformer label on your interface, then use the schematic shown under ”Modifications, MK-121-2(A) Medallion \'C\' Modification”.

The most likely cause of the problem is T2, the high frequency transformer, or C4/C5, 0.01 uF 6000V capacitors. Unfortunately, neither of these parts is commonly available. You might try some of the firms mentioned elsewhere on this site, or seek out an extra interface to use for spare parts.

Another possibility, though less likely, is the high-pass crossover components feeding the high frequency transformer. This involves the variable resistor (High Frequency Balance Control) and associated capacitors. The exact values depend on which interface version you have. These components are much easier to obtain, so, of course, you know the problem won\'t be there!

Unless you find a component with obvious damage (i.e. burnt), carefully swap components from one interface to the other. Be sure to change only one component at a time, to see which one causes the problem to move to the other speaker. I would recommend starting with C4 and C5, and then T2. Hopefully this procedure will isolate your problem.

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