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Gallo Reference III midrange COOKED

They were purchased new from a dealer in 2007. I'm using an all PS Audio system (except for a Denon multi-player for a transport). I Was using a p300 power plant till about a month ago I purchased a Power Plant Premier here at Audiogon. Two weeks later the midrange drivers in both speakers are gone. They have since been to the factory for repair and returned. Repair wasn't covered by warranty. They said if the speaker was defective it would have already blown during the first three months.

My system:

Trio P200 pre amp

Digital Link III D/A converter (with Cullen Circuits level 3 mod)

GCA 250 Power amp

Power Plant Premier

The speakers are rated a 350 watts; but my PS Audio 250 watt amp cooked the midrange drivers in both speakers. Go figure...

Just wondering if anyone else out there may have had the same or similar problem?
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shadorne
7,467 posts
 

The speakers are rated a 350 watts; but my PS Audio 250 watt amp cooked the midrange drivers in both speakers. Go figure...

I don't think these speakers are designed to play loud despite their "rating".

The 4 inch mid range is crossed over at 150 Hz to the bass woofer - that is quite low for such a small driver. Also the voice coil is 4 layers - so it certainly isn't designed for good heat dissipation (voice coils get extremely hot when driven hard and can melt or short). It is very likely you simply cooked them.

I suggest to be careful with the volume settings...
audiokinesis
2,732 posts
 
A 250 watt amp driven into mild clipping could easily heat the voice coil more than 350 watts peak of clean music signal.

What Elevick was told is however an exaggeration. It is heat, not a clipped waveform per se, that is damaging. From a thermal power handing standpoing, a clipped waveform simply means the average wattage (heat) going into the voice coil is much closer to the maximum wattage that the amp can put out. 500 watts peak unclipped might be ballpark 50 watts average (depends on the music of course), which is far higher than 1 watt clipped.
martykl
3,578 posts
 
Duke,

I think Elevick was probably told that a higher power amp is less likely to clip in the first place. This advice is sometimes offered to shoppers who will state their amp's power and try to infer a speaker match from their rated power handling specs - kinda like the OP here. I agree that this point wasn't accurately reflected in his post, but it goes to the real issue here: 'twas probably clipping (not too much power, per se) that killed his beasts.

Marty

Marty
martykl
3,578 posts
 
Actually, as Chaz noted - it may well have been stray DC.

Marty
elevick
2,636 posts
 
I'm always open to advice. I was getting at the fact that many speakers can handle their wattage ratings with ease if the signal in is clean and undistorted. However, as hinted at above, a 20 watt receiver that is pushed way past its limits can do more damage than a 200 watt amp that is not being pushed hard. (ie both are trying to put out 100 wpc?)
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