My Pass labs 250.5 protection circuit shuts the amp down when I drive my new Magnepan 3.7s at high volume. I'm talking about a volme higher than I might consistently listen, but not an unbearable level.
I'm using a Cary Slp 05 preamp with long balanced ICs (25 ft,) The amp is close to the speakers with less than 6 feet of speaker wire. The system works fine at normal volumes. I've tried the same thing with a pair of Cary MB500 (750 W @ 4 ohm) and they too shut down at high volume.
I believe the maggies drop below 4 ohms and I wonder if either amp can handle the impedance drop below 4 ohms.
I had a problem with the Cary SP-05 driving my Pass Labs Amp X350.5. The result was Low bass and Highs. With your long interconnects that can't help. I moved to a Pass Labs Preamp XP-10 and all is fine.
Are the amps in a well ventilated place? They very big and heavy with LOTS of heatsink. If in restricted space, they could simply be not getting enough air.
I don't know that Magnepan has ever made a speaker that was a 'bad load'. Low sensitivity? sure. Low impedance? yes again. But I've never seen any data showing bigtime dips or huge phase angles. Is the new 3.7 an exception? It does use a new design series crossover, so MAYBE, but don't bank on it.
If you haven't popped a speaker fuse, I'd look back at the amp......Onemug's bias meter suggestion is good.
I suspect if could be a defective speaker. I`ve heard good tube amps drive maggies to loud levels with no sweat. It`s hard to believe these large and powerful SS amps run out of gas with these speakers, they can`t be 'that' power hungry(given the sucess of the tube amps).
The OPs answer on the planar asylum: I can't figure out what he did except hook it back up after litle success with Cary amps.....?
I finally went back and hooked up my Pass Labs 250.5 and I've had nothing but great music since. The fact that my pass amp overheated was apparently not related to the Cary amps shutdown.
The Cary amps are new because just purchased off of Agon. I wanted mono blocks to place behind the speakers, But after listening to both amps there's no way I could go back to the Cary's. The pass amp just sounds so much better in every way. This is not to discredit the Cary but to my ears there's no comparison. Not to mention that the Cary's don't appear to be a good match for the Magnepan load. I should have known
Now these go back on Audiogon and someone will get a great deal. I now would like to see if I could get a another 250.5 and use one 250.5 to drive each channel. Not sure that would work with these amps but I guess that's for another post.
I'm not sure what the problem was with the OP's set up. Again, my Cary's are having no issues with my 3.7R's. They handle Mahler(front row loud)without complaint. There is not an inherent incompatibility between the Cary's and the Maggies. Something else was not right.
As for the OP's preference for the sound of the Pass 250.5, well, there is a reason Pass amps have such a great reputation. I wouldn't mind having a chance to A/B the Pass and Cary's myself.
bought my first system in about 1987. magneplaner IIc with an onix integrated amp ( 30 watts per channel). didn't know any better. but listened to 'thus spake zarathrustra' many times and never had to ask myself "where's the bass". never shutdown either.
Pass Amps are great and I've heard that the xa100.5s will drive the Maggies no problem so the 250.5s shouldn't break a sweat. I use a VAC 150 wpc tube amp and they play loud without breaking down on the 3.7s.
I tried the Cardas jumpers (have a new set if anyone wants to buy them). It was like using resistors...Cardas smoothed/dampened the sound out a little too much for my likes. The Empirical Designs are the bomb.
"Cardas smoothed/dampened the sound out a little too much for my likes. The Empirical Designs are the bomb." I think I read somewhere that the Empirical Design jumpers are made of silver plated copper? All silver plated cables I´ve been trying have had a "tweeter-in-your-face-sound", is this true for the ED jumpers?