Most likely for bridged mode... OCM was / is good stuff.....
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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 |
@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 |
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 |
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 |
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 |
A further indication that what I said in my last three posts is correct, that using the amp’s XLR connector with a suitably designed XLR-to-two RCA adapter cable would allow the amp to operate in stereo mode: The OCM 500 has the same input connector configuration as the OCM 200, and like the OCM 200 it can be operated in mono mode via the XLR connector. And like the OCM 200 it has a rated power capability that is four times as high in mono mode as in stereo mode, for an 8 ohm load. I found this photo of the interior of the OCM 500. If you look carefully you can see that there is a purple wire coming from one of the RCA connectors and a purple wire coming from the XLR connector, both of which are connected to the same pin on an internal plug. And likewise for a red wire coming from the other RCA connector and a red wire coming from the XLR connector. In other words pin 2 of the XLR connector is undoubtedly connected to the center pin of one of the RCA connectors, and pin 3 of the XLR connector is undoubtedly connected to the center pin of the other RCA connector. And the ground pin (pin 1) of the XLR connector as well as the ground shells of the RCA connectors are undoubtedly connected to the amp’s circuit ground, via the black wires that are visible. So while the XLR connector is intended to be utilized in mono mode, it seems pretty certain that it could also be used in conjunction with a suitable adapter cable for stereo mode. Also, the fact that there apparently is no stereo/mono switch on the amp further reinforces that conclusion. Once again, though, since the amp provides RCA input connectors for two channels there would seem to be no point in utilizing the XLR connector in that manner. Regards, -- Al |
