Have a OCM 200 power amp

So I can use a Y cable with a XLR on one end and two RCA on the other into the preamp.....????

No.

While I’m not familiar with the OCM 200, after looking at a rear panel photo on the web, and given the info provided by Jperry, it appears that what Oddiofyl said is correct. And therefore the XLR input is only for use when operating the amp in bridged mono mode, in which it would only process a single channel.

In that mode the XLR connector would be connected to an XLR output of a preamp, that would provide the amp with a balanced pair of signals for a single channel. And in that mode a single speaker would presumably be connected to the two + (red) output terminals of the amp, with the - (white or black) output terminals left unconnected.

Regards,
-- Al

Ok thanks I was thinking it would be a single mono signal output and I would need another Ocm amp for the channel . 

Thanks agin!! Wayne 

@Wayne3720

After thinking about it a little further, and if I’m envisioning the design correctly, I believe the amp actually would work ok (in normal stereo mode) if you were to use a y-cable with an XLR connector on one end and two RCAs on the other end.

But every rear panel photo I’ve been able to find via Google Images shows the amp as having left and right channel RCA input connectors in addition to the single XLR connector. So assuming your amp is similar in that respect there would seem to be no point in using a y-cable.

Regards,
-- Al

XLR is for mono. You would need a second amp. I guess you could split it with a Y cable,but,wouldn't you only be getting duplicate mono channels?

Rocray, what I was envisioning in my previous post is that the signal on pin 2 of the XLR connector goes to one channel of the amp; the signal on pin 3 of the XLR connector goes to the other channel; and the ground pin (pin 1 of the XLR connector) goes to the ground of both channels.

If the XLR connector is then provided with a balanced pair of signals for one channel that configuration would be a means by which the amp could provide bridged mono operation without the need for an internal inverter stage. A single speaker would be connected to the + output terminals of the amp, and the - output terminals would be left unconnected, as I indicated in my first post in the thread.

However if a y-adapter were used to connect left and right RCA outputs of a preamp to that XLR connector the result would be that the signal from the preamp for one channel would be routed to pin 2 of the XLR connector and from there into the signal path of one channel of the amp, and the signal from the preamp for the other channel would be routed to pin 3 of the XLR connector, and from there into the signal path of the other channel of the amp. And the circuit ground of the preamp would be routed to both channels of the amp.

In that situation connecting one speaker to the + and - output terminals of the amp for one channel, and another speaker to the + and - output terminals of the amp for the other channel, would result in normal stereo operation.

Regards,
-- Al