How hot should a McCormack DNA-225 get?

I'm not familiar with MacCormack amps, but maybe someone with a DNA225 will chime in. The behavior you describe isn't at all unusual for power amps though. I had an Ayre V-3 that ran too hot to touch. I was speaking with Ayre tech support once and the guy said that's how they should run . . . "hot is good" were his exact words.
As for the rack position - I prefer to keep amps that run hot out (there are amps that run cool too) in the open (ie on amp stands, not in an enclosure), but as long as your rack is as open as you describe this may not be an issue. I would keep 2 ft above it open.

It's also not unusual for it to trip a breaker - especially if you have other equipment powered by that circuit. I imagine the amp is drawing maybe close to 10 amps on startup. If the amp is the only thing on that breaker - it may be worth checking out the amp again though.

It's worth a call to tech support, but it's possible this is all entirely normal

My 225 never gets hot even after several hours.. I have it plugged into a dedicated 20 amp circuit,and have no problems with breakers tripping either. cOntact Steve Mac., hes very helpful. Good luck

Hi Mike -

How hot your DNA-225 gets will depend on several factors, but I suspect that yours is behaving normally. The 225 runs on the warm side normally, assuming it is out in the open. Cabinets will restrict air flow more than you might think, and I feel that this is responsible for yours getting rather warm at idle - but this is not a problem. On the other hand, your Infinity Kappa speakers are known to be a difficult load, and may drop to below 2 Ohms at some point. This is undoubtedly why your amp becomes very hot with use. Under the circumstances, this is still normal behavior, but you might want to think about adding a small, quiet fan to circulate air in your cabinet. You may be surprised at how much cooler the amp will run if you push air into or out of the cabinet. Finally, the DNA-225 does not have a "soft" turn-on circuit, so its current demand at the instant you flip the power switch is quite high. Again, this is usually no problem - but if the circuit branch the amp is on is already loaded-down a bit (with lights or other appliances) or if the circuit breaker is "weak," or if there is a problem with the wiring, this may be enough to trip the breaker. The DNA-225 will not trip the circuit breaker on a normal 15A service, so if the breaker does trip, it may indicate a problem of some kind on that circuit branch.

Best regards,

Steve McCormack
www.SMcAudio.com

when it's on for a while and not playing I registered 117 at heat sinks and about 95 or so on the faceplate. When I played music for an hours or so, the heatsinks get to about 128-130. Get a digital temperature reader and take measurment. i know the heatsinks are hot to the touch, but in reality, the temperature is not that hot....bit it feels hotter. Don't be alarmed. If it is much hotter than what I mentioned above, then be concerned.

Regarding this breaker; you can usually detect a weak spring in this breaker.---Turn it off and on---Then try and compare a different 15a breaker. You should be able to feel if they are equal or different in resistance.