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Using Adcom GFA-555s as monoblocks to power magnepan 3.3s in active biamp

Yeah, a long title but it says it all.  Presently I have my rebuilt Magnepan 3.3rs actively biamped through a Marchand active crossover, then using 2 stereo amps to power bass and mid/treble respectively.

I am considering taking two Adcom GFA-555s and bridging them and using one each to power the bass panels of the maggies. 

Since the Magnepans are 4 ohm rated, however it's only the bass panels I'd be powering, what are your thoughts on stability?

Appreciate the help.  Don't need suggestions on "selling all my amps and buying one bigger one" - I have a lot of different amp options but am a tinkerer and want to see if the power of a bridged adcom would be good to control the bass panels. 

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russ69's avatar
russ69
3,360 posts
 

The 555 will power Magies just fine but I would not bridge them. 

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jji666 OP
462 posts
 

Thanks.  Seems to be the consensus that it will "work" but not sound great, with some chance of actual trouble. I may stick with the Nak there for a while - it's not bridged, and it's beefy.

My 16 year old came upstairs and asked me to turn down the volume!

aeriya
8 posts
 

Back in the late 80's I was evaluating a pair of Apogee ribbon panels, stunningly beautiful and wonderful sound. The dealer modified the 555 to drive 2 ohm loads, if I remember the costs was 1/2 the power but I could be wrong. Still using the Adcom today but I returned the speakers.

retiredfarmer's avatar
retiredfarmer
339 posts
 

I did much like you I had a pair of sim audio w3 moons and a bryston  10b active crossover. My room was 16x28x8. There was absolutely  no lack of power there. I really  doubt you are going to need more than you have running them as stereo  amps. 3.3 are power piggies but you should have lots. 

invalid
1,106 posts
 

 the bass panels will still be 4ohm but the amp will see a 2ohm load when bridged.

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