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Pass 250.5 shuts down driving Magnepan 3.7

This is my first post so please bear with me.

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.

Has anyone experienced this issue ?

Any suggestions ?
gcoxsom
hasse
230 posts
 
Yes, I´m using the Cardas tweeter and midrange jumpers on my 3.7´s.
podeschi's avatar
podeschi
303 posts
 
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.
honeymonster
4 posts
 
I think the impedance of the Maggies is too low to be safely handled by your power amp - the protection circuits see them as a fault (short) circuit load.
tmsorosk
1,013 posts
 
If you want to get loud, Maggies may not be the best choice.
hasse
230 posts
 
"I think the impedance of the Maggies is too low to be safely handled by your power amp - the protection circuits see them as a fault (short) circuit load."

Nothing wrong with his amp;
"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"
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