Parasound A51 - Different Temp Heatsinks?

I would first try to determine if you even have a problem. Its possible that the different heatsinks on your amp are colling different components that operate at different temperatures. I would just call Parasound and ask them. Also, I don't see why your Kef speakers should be too much for your amp. It's probably a very good match.

Hello All!

Thanks for all of your input; just spoke to Tony at Parasound and he stated it was within normal operating procedure. Parasound has outstanding customer service and I am very happy to own one of their pieces in my system.

Also, Al, thank you for your incredible detail in your response. This site has become an exceptional resource for me while I delve into this new hobby. Thanks again!

Richard

I too have a Parasound A51 which I originally was running with a new pair of tower speakers which after a couple of hours were causing one of the left side channels of the amp to shut down from overheating protection.  I am using two channels to the left and two to the right for bi-amping the speakers.  These speakers were 8 ohm and this amp went into overheat protection several times over the past few months.  I switched the speakers around to see if the over-temperature protection would remain on the left channels or if it would follow the speaker.  It followed the speaker, so I knew that I had a speaker problem.  The speaker was replaced by the manufacture under warranty for a new one.  

I sold those speakers at a deep discount and recently purchased some nearly new Bryston Model T's which are 4 ohm speakers and hence the amp is generating 400 watts per channel vs. 250 watts with the 8 ohm previous speakers.  Putting out 400 watts should cause the heat sinks to run much warmer as it's delivering a lot more current to the speakers now.  I find that the amp is running on average, quite a bit cooler after reading the temperature with a heat reading infrared gun.  With the 8 ohm speakers, it would run up around 135 to 140 degrees with moderately loud volume.  With the Model T Brystons and 4 ohms, it averages around 115 degrees under similarly loud playing.  However I did notice that the right side of the amp runs about 5 to 10 degrees warmer than the left after prolonged playing.  And last night the temperature did hit 145 degree on the right with the left at 130 degrees after 6 hours of heavy loading.   It did not go into over temp protection at any time, but I don't know what the threshold is for that to happen.  I also don't know if the output devices are on one side more so than the other with other devices such as in the power supply or input sections laid out on certain sections of the heat sinks, so I cannot tell if the temperature readings are due to variation in the output devices or from other influences.

I plan on switching the Bryston's from one side to the other just to see what the readings show.  If there is no change, then I'll suspect that either there are variances in the amplifier such as biasing adjustments, not exact component matching or placement of devices on the heat sinks.  If there is a change in readings, then there is a difference in the speaker loads presented to the amp.  It should prove to be interesting to see what it shows.