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Old 6th November 2015
Gear Maniac
A little off-topic: we have two slots open in our M1 frame... can those take other than M1s (M2, Twins, options)?
The M-2 cards will plug into an M-1 frame with no issues, but the gain markings are already on the front panel at all four channel locations for the M-1 gain ranges.

The Jensen Twin Servo cards will fit in the M-1 (or M-2) frame, but there are modifications required, as well as the gain control markings already being there for all four channels of the M-1 frame. The grounding scheme is different, requiring addition and/or removal of jumpers. There are series diodes for the +/-24.7V power supplies of the Twin Servo, resulting in +/-24VDC at the 990 op-amps, whereas the M-1/M-2 frame starts with +/-24VDC and has no series diodes. So, you would have to add or jumper across those diodes, depending on which direction you were going. So far, nobody has put any Twin Servo cards in an M-1 (or M-2) frame. I would have to put on the "cone of knowledge" to remember the details of the modifications. Beyond that, Deane Jensen did not want the cards mixed anyway.

Thank you.

John Hardy
The John Hardy Co.
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