Have a OCM 200 power amp

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

Balanced mode is Mono operation only in Stereo mode it is SE.  

P.S. to my previous post: In the paragraph beginning with "However if a y-adapter were used ..." to be sure it’s clear I meant an XLR to two-RCA y-adapter cable designed in the manner I described in the rest of that paragraph. A y-adapter cable that shorted the left and right signals from the preamp together while routing them to the XLR connector (or for that matter a two RCA-to-one RCA y-adapter followed by an RCA to XLR adapter), would of course not work properly, as Rocray indicated.

Regards,
-- Al

Wow guys that is a lot of info considering I can't put my hands on a owner 's manuals!!! Brought this amp used back in 95 and never try to use the XLR jack!!?? 

Will jump the deep in when I get new cables!!!

Great info from all of you!!!! Thanks 

Wayne

Wayne
 FYI you can only run it XLR if you have 2 of these same amps
 one for left
 one for the right.
 In case you missed it that equals stereo with the advantage of separate mono power supplies for each channel.
 
 When running 2 you also need a preamp with Balanced XLR outputs
 If an XLR pre is not obtainable and cant source another identical 200
 Just run it normally as a conventional stereo AMP in RCA with a normal Preamp.

Belles makes an Aria preamp with Remote control and Phono for 1200 bucks that play great music and together would be a great companion.
 Best,
 JohnnyR