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B&W Matrix 801 need help

thymanst

thymanst

Minnesota morning
I picked up a pair of Matrix 801's and they have some problems (I got them super cheap) one tweeter is blown (I took it apart and no ohm reading - the wires look ok) and the mid dosent play in one also (the driver works fine - If I pass signal to the mid from just after the crossover it plays fine) the diaphram on the other one is dented also - Couple questions - Does any know what a diaphram and a tweeter cost from B&W and does anyone have a technical schematic of the crossover?could anyone repair the blown tweeter? thanks for any help -
 
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which version of the 801?

There are probably six different versions of this speaker. Which one do you have?I worked for a B&W dealer years ago and am frankly pretty puzzled that this much damage has been done to these. Have you checked the connector under the head?
Have you tried interchanging the heads?There is a large bolt that comes up thru the top of the head that makes them removable .
These were very robust speakers - not very efficient and sounded best when driven by high powered high current SS amps. Some versions incorporated a protection circuit and I suppose it's possible that the relay(s) for that have gone bad.Replacement drivers for this are not cheap ( think pistons on a Ferrari ) - but you don't want to lash these together - get the original parts even though you may spend as much on these as you paid for the entire pair.
 
they are version 1 - the tweeter I took apart looks fine, but I get no reading with my ohm meter so there must be a break in the voice coil it - the mid on the other speaker is another thing - It plays but very softly, I would guess it is something on the board that is causing the problem with the mid - the tweeter plays normal and if I try the wiring right after the board the mid plays fine....I paid an very low amount for them so if it cost a couple of bucks to fix I'll have a pair of speakers I've always lusted after.....
 
ferrofluid?

I think these might have the ferrofluid voice coil treatment.Not just for B&W - this has turned out to be a long term bad idea - as tweeters have aged this dries up or simply collects on the bottom of the voice coil gap - result is displacing the VC and the tweeter failing. Apparently B&W no longer has replacements?
Am really curious about how your restoration effort is coming?
 
Dear thymanst, any B&W at a good price is worth fixing and keeping. To fix a dented diaphragm , suspend a vacuum spout 1/2" above it to suck out the dent. Be careful when lowering spout as close as necessary to avoid spout ramming dome. The only failure I see in the mid crossover is an electrolytic cap that's dried up (10 yr. life span or less) or thee most common electronic problem, cold solder or bad contact. Run your multimeter point to point along the mid crossover path to detect a break in continuity. I saw 4 generations of 801's on B&W website. The original is 1980 (distinguished by no vent below woofer). Series 2 is 1986? I'm guessing. Check B&W site I pasted below. The "APOC" stands for "Audio-Powered Overload Circuit". There are two: one on woofer and one on mid/tweeter. This is a glorified curcuit breaker that doesn't belong in any speaker of B&W quality. You have not triggered either one of these "APOC"s as the woofer would be silenced, or both the mid & tweeter would be silenced. I'd rip these two pieces of sound path-degradation-crap out and replace them with a jumper of 10 AWG military-spec. silver-coated copper, teflon-jacketed wire. You'll find this at most electronic surplus stores. Call B&W to buy a replacement tweeter diaphragm kit. Sincerely, John Marta

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Wow, I was surfing around and came across my old post that I didn't follow up on- I brought the crossovers to a local tech and ordered two new tweeters from b& w - the crossovers had a couple bad parts - I'm listening to them right now and andd they are amazing speakers - the crossovers in them are from 1999 so they are replacements the crossover also doesn't have the apoc circuit in it- I have the stands for them and also the bass align filter which both improve the sound-
 
I used to work at a b&w dealer and the owner had some series 2 801's, she was running them with a sumo andromeda amp and we brought them in to demo a sunfire sig pre and stereo amp. Ive never been so dissapointed in a speaker, they sounded terrible.

Even the owner didnt like them!

could the protection circuit be the cause?
 
Mine dont have the protection circuit - I'm pretty sure I have a series 3 crossover in them from production date on crossover - the tweeters are also not the stock series 2 (They didnt have the series 2 part number) they fit perfectly and sound right - I've had a couple hundred pairs of speakers go through my house and the m801s are the best of them all - best over all, they more things right and enjoy all music on them - (this is with Altec model 19's, ML Monolith III's and Apogee Duetta II's in the house right now) I have them running off 4 Marantz ma 6100's and a Lexicon MC8 pre - he bass alignment filter also tightens the bass up. they are really 3d when set up well...
 
Thats cool, its coincidential that you mention the ML Monolith. Thats the speaker i brought the sunfire combo in to drive.

A customer was having issues with his bryston 4b driving his monoliths, the Sunfire rig sure lit those speakers up!

the dealer who sold him the amp set him up with dollar store interconnects, i was astounded! He ended up with all Tara Labs ic and speaker cable.

He was Very happy, then he moved to the UAE, boo hoo, no tuning sessions.
 
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