Originally Posted by Silversam
You need connect the 401 card to a WMT-1 (or similar) matching transformer. The 401 card is designed to connect to a 600 ohm telephone line. An auxiliary input on an amp is 15,000 ohms and a mic input is 150 ohms.

They don't play well together without a matching transformer.


Sam

The WMT-1 is going to kill the battery on the T/R that you need to supply the phones that you need to page from. There needs to be an isolation cap to block the DC. If you look at the Melco KA-390 schematic, it's basically a transformer and it has a cap in series with one side of the T/R input.

I suspect that the 600 ohm amp input will have the same problem.

-Hal

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