ARC Ref 75's as monoblocks?

@wturkey has it right.  CHECK with ARC and then see if you can bi-amp your speakers, which would be the best solution for amps not specifically made to use as mono-blocks. I THINK ARC will agree, although you should work with them on the precise config. you have in mind.

Cheers!

If the speakers you are using are bi-wire or bi-ampable, perhaps using another arc ref 75 is feasible? Are there 2 sets of preamp outs on the pre-amp in service?

Thanks so much for the input, I had no idea if it would work but now I see it's probably not a good idea. Appreciate it. Joe

@almarg Good info as always. I was planning to run another brand stereo tube amps in parallel but probably best buy mono version. Thanks!

In general, I am not a fan of bridging amplifiers. It's sort of like a parlor trick and, yes, sometimes the result is ok. But if you want a monoblock amplifier, I think the best thing to do is buy one rather than kludge a stereo amp.

If you were to run just one channel of each Ref 75 it would be prudent, IMO, to put load resistors on the output of the unused channel.

Tube amps having output transformers should of course not be operated unloaded when they are processing a signal.  But in this scenario, where one channel is not processing a signal, consider what would happen if a tube developed a short or some other problem that would cause that channel to output a "signal" while unloaded, and with no means for the user to become aware that anything is amiss.

I agree with the comments about bridging.  Paralleling the channels is another possibility, but I certainly wouldn't do that without an ok from ARC, and I can envision ways in which a cloud of smoke might result.  For example, if a small signal tube in one of the paralleled channels were to fail, the other channel would be applying a large signal to the output of that channel, while that channel would be trying to force its output to zero volts.  Not a good situation.

Regards,
-- Al
  

(((ARC Ref 75 amps as monoblocks? )))Joe
 Running one channel of each Ref 75 would allow the power supply to isolate, have less saturation on demanding peaks. A significant advantage with faster recovery.  
 

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These are differential amplifiers. I don’t think they can be run as monoblocks.
Bridging amplifiers isn't usually a good idea even when an amplifier is suited for it.