4, Interfaces, Monitor 4 and Model 1+1

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Fred Verloop2004-02-23 22:21

I have the Acoustat speakers model Monitor 4 and the model One+One. The Monitor 4 model did have the OTL Amplifiers. The One+One models did have the MK121c interfaces. I wil put the MK121c interfaces on the model monitor 4, so that I can listen them to a set Radfort MA75 tube amplifiers.

The colours of the outputs on the OTL Amplifiers are BLUE,RED,and Yellow. The colours of the output from the MK121c interfaces are BLUE,RED and WHITE. Could you tell me which colours are corresponding with the OTL amplifiers and the MK121c interfaces. Greeting from Fred Verloop

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Andy Szabo2004-02-23 22:21

The color codes are as follows: connect red-to-red; blue-to-blue; and white-to-yellow.

You may also want to alter the low frequency transformer tap. This is a small terminal strip inside each interface, with a push-on spade clip. For two panel speakers (such as the Model Two and 1+1), this tap is normally set on the terminal with the small red wire, for maximum bass boost. For four panel speakers (such as the Model Four or 2+2), the tap would be set on the yellow tap, for minimum bass boost. The orange tap is a medium bass boost (for three panel speakers). This is a matter of personal taste, and you can set the tap wherever you choose. No harm will result in setting it for the ”wrong” position.

By the way, it is my personal opinion that this is the best way to repair, upgrade, or otherwise maintain a pair of Acoustats that originally used the OTL servocharge amplifiers. That is, replace the amps with transformer interfaces. No matter how highly regarded the amplifiers may have been when new, they are now virtually impossible (and dangerous!) to repair.

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