aleph output fuse

MikeZ · 9th November 2003, 04:49 PM

I was wondering if anyone has suggestions and comments on fusing the output on an aleph 2 to protect the speakers. I was wanting some sort of protection for the speakers in case something happens to the amplifier so I dont ruin my speakers. Thanks

Mark A. Gulbrandsen · 9th November 2003, 05:58 PM

I have always felt that fusing the output is a personal choice. It will screw up the damping factor quite a bit. I would say to listen with and without and make a sound decision. Also if you have some sort of high value collectible speakers then by all means fuse them!!
Mark

jleaman · 9th November 2003, 07:43 PM

Wonder what pass labs does when there amplifiers blow up at customers houses and they take out speakers. Do they replace them or repair the amp for free if the amp is at fault..?

That would suck to have a class a amplifier go full tilt into your nice b&w or ect ect other brands of speakers and kill them .

Nelson Pass · 9th November 2003, 07:49 PM

Our policy is that we do not warranty against consequential
damage. We have had people blow up their speakers by
playing too loud, and we have seen cases where they passed
DC or transients from the source to the detriment of the
speakers, but the actual cases of failure damaging the
loudspeaker is very rare. I can recall only one case, although
my memory is not the best.

The failure we would expect to damage speakers would be that
of full DC offset, and that is very rare. Far more likely to simply
not work or blow the fuse.

jleaman · 9th November 2003, 08:01 PM

Well im 99% done my aleph 2's just got to add 2 parts to the FEB's and then assemble and test

here are a few pic's

jleaman · 9th November 2003, 08:04 PM

And me sitting on the floor at 2 am soldering board's : O )

Brian Donaldson · 9th November 2003, 08:16 PM

I considered putting a relay that would short the outputs in the event of heavy dc offset. The Aleph owners manual says somthing about driving a short shouldn't hurt the amp, and It wouldn't degrade sonics.

Mark A. Gulbrandsen · 9th November 2003, 09:05 PM

Even the fastest relays are way too slow to guarantee protection to voice coils. BGW used a crowbar curcuit that sensed any DC on the output terminals. An SCR then turned on and shorted the power supply out so a breaker would trip. I've seen it work in the case of a ground loop where there was a high level oscillation...it worked flawlessly and no damage to the speakers resulted. No reason a crowbar circuit couldn't blow a line fuse instead of a breaker. It would actually shut down the amp faster.

Good work on that amplifier! I used Brians boards in my 2's..... But you do need a work bench..... Thats how DIY'ers start homes on fire!!
Mark

9th November 2003, 04:49 PM	#1
MikeZ diyAudio Member Join Date: Apr 2002 Location: missouri	aleph output fuse I was wondering if anyone has suggestions and comments on fusing the output on an aleph 2 to protect the speakers. I was wanting some sort of protection for the speakers in case something happens to the amplifier so I dont ruin my speakers. Thanks

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9th November 2003, 05:58 PM	#2
Mark A. Gulbrandsen diyAudio Member Join Date: Sep 2001 Location: Salt Lake City	I have always felt that fusing the output is a personal choice. It will screw up the damping factor quite a bit. I would say to listen with and without and make a sound decision. Also if you have some sort of high value collectible speakers then by all means fuse them!! Mark

9th November 2003, 07:43 PM	#3
jleaman Banned Join Date: Apr 2002	Wonder what pass labs does when there amplifiers blow up at customers houses and they take out speakers. Do they replace them or repair the amp for free if the amp is at fault..? That would suck to have a class a amplifier go full tilt into your nice b&w or ect ect other brands of speakers and kill them .

9th November 2003, 07:49 PM	#4
Nelson Pass The one and only Join Date: Mar 2001	Our policy is that we do not warranty against consequential damage. We have had people blow up their speakers by playing too loud, and we have seen cases where they passed DC or transients from the source to the detriment of the speakers, but the actual cases of failure damaging the loudspeaker is very rare. I can recall only one case, although my memory is not the best. The failure we would expect to damage speakers would be that of full DC offset, and that is very rare. Far more likely to simply not work or blow the fuse.

9th November 2003, 08:16 PM	#7
Brian Donaldson diyAudio Member Join Date: Jan 2003 Location: Texas, Love it or leave it	I considered putting a relay that would short the outputs in the event of heavy dc offset. The Aleph owners manual says somthing about driving a short shouldn't hurt the amp, and It wouldn't degrade sonics.

9th November 2003, 09:05 PM	#8
Mark A. Gulbrandsen diyAudio Member Join Date: Sep 2001 Location: Salt Lake City	Even the fastest relays are way too slow to guarantee protection to voice coils. BGW used a crowbar curcuit that sensed any DC on the output terminals. An SCR then turned on and shorted the power supply out so a breaker would trip. I've seen it work in the case of a ground loop where there was a high level oscillation...it worked flawlessly and no damage to the speakers resulted. No reason a crowbar circuit couldn't blow a line fuse instead of a breaker. It would actually shut down the amp faster. Good work on that amplifier! I used Brians boards in my 2's..... But you do need a work bench..... Thats how DIY'ers start homes on fire!! Mark

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