Posted by gregc4 on January 28, 2012 at 10:53:54

In Reply to: RE:ISSUE RESOLVED Magnepan 3.7 shuts down amp at high volume posted by gregc74 on January 27, 2012 at 20:38:57

I started to tell you my whole story but not sure that's what you want to hear. Let me just say that the Pass amp is the best I've had in my system. I've had it for over four years and it does get a little warm during normal use but it sounds great compared to the others I had or have. I currently have the Cary 500mb(s) mono blocks, Odyssey Stratos stereo, Odyssey Stratos mono blocks, and Proceed HPA 3 all great amps for their price point and application, but to me not in the class with the Pass.
So, yes I was able to drive the Pass 250.5 to shutdown from overheating while driving the Magnepan 3.7s. I discovered I had several issues at the time. The main issue was the speakers ship with the tweeters disconnected; you have to install the supplied jumpers. After the Pass thermal protection shut the amp down I read the speaker manual and discovered I had been listening with no tweeters. I also went back and found some of my wire connections were not complete, I had loose strands in several connections.
Consider I was driving the speakers and the Pass amp very, very loud for about 20 -30min. before it reached thermal overload. Not sure of the sound SPL but I can tell you I would never listen at that level for very long. I had a non-audiophile friend over and he kept saying turn it up just a little more. I find some people equate volume and how loud a speaker will play with great sound.
I later put the Cary 500mb (s) in my system and I discovered they would shut down. The Cary's are 750watts (4ohm). So after talking to all the manufacturers I started to measure what was going on. I found the Cary's shutdown at about 300 w but the sound level is around 112db. Yesterday I put the Pass amp back in the system and immediately heard the difference in sound quality between the two amps at normal listening levels. I drove the Pass amp up to about 120db for 20 min. or so and had not problem. I'm now convinced I never had a problem with the Pass but I realize there is a limit to what any amp/ speaker or piece of equipment will do. I guess the best in endorsement I can make is I plan to look for another Pass 250.5 . I plan to use separate Pass 250.5 to drive a each channel and I’m done buying equipment for awhile.