Belles Ocm 200

David Belles still answers emails for power modules usa, although, My experience with him has been terrible... I sent an email asking easy, general questions for amps that he designed.  I made sure that I was cordial and brief..... To my surprise,  he answered me fairly quickly,  it was a simple answer... 
"I do not have any current affiliation with these products"   I made an appeal and he never responded again..... 
Hopefully,  You may get a better response than I did. 
Good Luck,  Tim

 OCM was not under Dave's control
 It was a Magnum product almost 30 years a go try calling them.
 He has backed every amp under the Power Modules brand and Belles for
 me like clockwork
 Best,
  JohnnyR

Dave personally answered questions of mine and provided excellent service for my amp. I think he is a one man operation, which is very impressive to me considering all it takes to run a business. To me his the two amps I have had are very high value amps.

I used to own 2 OCM 200's in monoblock configuration with XLR interconnects. They sounded great and doubled their power output this way. Speaker outputs only on positive terminal on each amp(I think, it's been > 15 years). Good luck