Plinius sa250 overheating

my sa250 mkiv is overheating when run in class a for about two hours at which time it shuts down. runs great in ab mode. the amp has been serviced by a plinius authorized tech with some improvement. has anyone else had similar problems or have any suggestions?
The SA250 does run very hot in class A. A scorching 160 degrees which is HOT HOT HOT!!! By comparison, even the Class A Krells run at a "tepid" 140 degrees.(That indeed HOT! to touch) I never ran my SA 250 ( MkI original version) in class A for more than a few hours at a time. But, I never experienced any problem with the amp shutting down. My room size is fairly large and opens into the rest of the house, so I think it had good ventilation. I dont know if your amps location and in what room size, ventilation ability, causing it to run hotter than would be expected, but you are apparently tripping the thermal safety devices designed to protect the amp( a good thing)... and keep it from baking in its case.

It may be that you could set a small quiet running fan behind the amp to help. FWIW, I rarley ran mine in class A, as I found most casual listening extremely good in AB.

Good luck.
Sounds like your amp is either under-designed for Class A operation ( not enough heat sink area ) and / or your installation lacks enough airflow to allow the natural convection of heat to flow away from the amp. If the amp hasn't got at least 12" of open space above it with nothing surrounding it on the sides, you are bound to have problems. You either need to address that situation and / or install some type of forced air system to help keep the amp cool enough to keep operating. Sean
I've seen/heard the SA102 amp at a demo. It did indeed run hotter than any other "Class A" amp I've ever seen. I can hold my hand on a Pass Aleph amp for a few seconds. I'd never do that with the Plinius.
I'm going to guess they could use more heatsink area on those amps..........
I have a Plinius Sa250mkIV which I have been running for awhile. I had my first shut down this weekend. I normally run the amp for 4 to 10 hours in class A, decent volume with no problem. This is with Martin Logan CLS IIz speakers which are a difficult load. I changed to a Shunyata Sidewinder power cord based on a recommendation from an audio dealer in Chicago. This is the first time I ran it with this cord. After a 6 hour run time with no problems, left it running as I normally do (goes to AB after 30 minutes) and went to sleep. Next day, hit the button to go to class a and it shut down immediately. I found I had blown 2 fuses when I started it back up.. Changed the fuses, put the regular cord back on and no problem. Dont know if this is chance or what, but that cord will not go on again. If you are using an accessory power cord, you may want to check this. It cant hurt anyways. I emailed technical service in NZ when I thought I had a problem and they responded promptly. You might want to email them, I was very impressed with the quick response time. I am very happy with this amp and company, one of the best solid state I have ever heard. It is one of my 2 keeper amps, the other being Cary SLM-200 monos, the best tube amps I have ever heard or owned. Good luck with your quest, try contacting New Zealand. I beleive they will try to help you out based on my experience.
Linnlp12: It's possible that the Shunyata was able to deliver a higher level of current to your amp on a faster basis than your original cord was capable of. Due to the huge demands that in-rush current places on the AC system, blowing the fuses might have been a sign that you've actually got a power cord that can more than keep up with the demands of your amp. This is one of the advantages of going to a low inductance design. Sean
this amp does run very hot in "a", no doubt about that. the amp sits on its own stand with complete open ventilation on all sides. i may have to try a supplemental fan, but the thought of that noise interfering with my listening pleasure may be intolerable. thanks for all your input.
Sean, interesting reply. I had not thought of that. I appreciate the response, gave me something to think about. The CLS IIZ are a brutal load but the ams sounds so good on them. Ditto for my Cary's but the bass is a bit better with the Plinius. Now I am not sure what I am going to do about the cord. Maybe I will give it a try on less demanding speakers. For the original poster with the overheat problem, maybe the cord solution will work in "reverse". Thanks again.