B&W 802 Series 80 repair

[luvdunhill]

Dextrous humor you guys have!

[Zonker92]

Did you know that lefties are brain-damaged from birth and live five years shorter lives than righties? At least that's what I told my sinister sister-in-law.

OK, this morning I popped mine open and but for the spider spunk it's the same as the Monkey's. November 82 is the date on the bass driver I pulled. I was pleased to see a lot of internal bracing (making them almost Matrices I guess) and some heavy sound damping boards stapled to the inner walls and inner base.

My crossover (APOC, no battery) looks much like the one I showed on page 3 of this thread, but without the fucked-up capacitor. The colors are a little different too. Are these electrolytics? Should I replace them?

If I wanted to bypass the APOC I would cut the (three?) diodes out and remove the relay?

[spritzer]

Those are electrolytics and I for one would replace them. These are about as old as me so well past their sell by date. If you can't fit polyprop caps in there I'd recommend something like the Nichicon ES series which are non-polar. They are radials though...

[Zonker92]

Thanks! I'm counting seven caps, and I can solder and identify a cap from a diode or resistor or transistor, but that's about the extent of my Mad electrical Skilz. Which is another way of saying I wouldn't know which caps to replace them with. Are the white rectangular units caps, too, along with the blue tubular ones?

I guess I could send a high-res photo and this schematic to one of the Parts Express gurus and ask them to give me a parts list of comparable caps. I just don't want to run into the risks Monkey quoted here about screwing up the crossovers with the wrong replacements.

Still gotta figure out how to bypass the APOC, too, if I so choose. I guess on the schematic posted above, I could just "short circuit" the entire protection circuit at the bottom of the page?

[The Monkey]

Not sure how much, if at all, these will add to the discussion, but 2 shots of one of the crossovers:

[spritzer]

The white sand cast bricks are resistors and you can certainly get better units such as the non-inductive Mills and the Mundorf stuff.

The other white boxes (such as the one in the upper left hand corner above) are film caps. You could replace them as well and it might be worth to do so.

As for choosing parts, we can help you with that. If either of you has a high res picture then that would be a great thing to have and also measure the distance between the mounting holes and how much wider a new cap could be.

[Zonker92]

Thanks! That's a very generous offer and I do have a huge photo of the board. But (dammit) at the urging of some enthusiasts I put my camera into RAW mode so now, predictably, I can't open the files in Photoshop CS2, and the RAW plug-in (3.7) isn't helping. Shit.

Sigh. Maybe I'll tear it open again and go back to shooting JPGs, as I've been doing quite happily for ten years now. It's super-easy to get at the crossovers, but the cabinets are really heavy to tip over and set right again safely.

[Zonker92]

Dinny:

If you can pop the crossover boards out, send them to me. I'll rebuild them for ya.

Monkey, are you going to do this? I'm thinking seriously of pulling my boards out and at least lensing them in high res, with an eye toward replacing the caps with new electrolytics.

Eric

[fabrice]

Hello,

I just bought a pair of b&w802 series 80 and I noticed a problem on one of the speakers. When I turn on my amp at very low level, the midrange driver (and sometimes the tweeter) does not work. As soon as I increase the volume, it starts immediately. I think the problem comes from the crossover with protection circuit apoc (maybe the relay or a cap), but I am not sure.

Does anyone had a idea?

Thanks

Fabrice

[Zonker92]

I noticed a problem on one of the speakers. When I turn on my amp at very low level, the midrange driver (and sometimes the tweeter) does not work. As soon as I increase the volume, it starts immediately. I think the problem comes from the crossover with protection circuit apoc (maybe the relay or a cap), but I am not sure.

Does anyone had a idea?

I would check both the head-to-body connecting cable and the APOC relay. Try switching heads first. If the problem moves with the head, look at the cable and plug. If it stays with the bodies, look at the socket for the connecting cable or the APOC relay.

If you have to replace the cable or its socket, maybe you can find a substitute cable or socket at Parts Express.

To check the APOC relay, remove the head and lay the body on its side or back and remove the bottom panel, which is held on with four Philips screws. The relay, located on the crossover board, has a plastic cover that you can squeeze and pull off. An ohmmeter will show whether you have good continuity across the two sides of the relay.

I removed one of my crossovers yesterday. I think I'm going to bypass the relay just for the heck of it, although I have my doubts about any resulting audible benefits. I may also install new electrolytic capacitors using the OEM spec, and upgrade the binding posts.

I may start a new thread on this project, but in short I believe that to remove the APOC circuit I should unsolder and remove the relay and the three adjacent diodes, then install a jumper across two of the remaining relay connections, i.e., the center connection and the single corner connection, leaving the other two corners (the connections that actuate the relay) open.

[fabrice]

Zonker 92, thank you for your response

I will try the method that you recommend to find out the problem.

I will also follow with interest your thread relating how to bypass the apoc system.

By the way, what is the amp you use with your 802?

[Zonker92]

Yeah, the more I think about it, the more likely it seems that the problem is your head-to-body connection. An APOC problem would be more likely to cut out the entire speaker, not just the mid and/or tweeter.

I am using an NAD C272 stereo amplifier, which is about 150 WPC at 8 ohms. My source / DAC / preamp is a Sonos ZP90 Zoneplayer feeding off a 1 TB RAID NAS drive. For some reason, even though the Sonos will output up to 1.7 volts IIRC, and the NAD is supposed to see at least 1 volt (again, IIRC) I can't get the system to play as loud as I would expect at full volume (not that I normally listen that way). My iPhone dB meter app is reading only 96 dB at full volume from my listening position. I have some hope that maybe the APOC bypass will allow more power to reach the drivers. Eventually I may get another C272 amp and run them each in bridged mode for 300 WPC.

Today I rmeoved one of the binding posts and yes; they're pretty lame. I'm ordering some of these to replace them with these:

Amazon.com: Dayton BPA-38G HD Binding Post Pair Gold: Electronics

[fabrice]

First, I apologize to write very short posts but I'm french and It's not so easy for me. Well, you were right, the problem is my head-to-body connection. I don't know yet if it's the wire or the socket but there's no doubt It's cut somewhere. The previous owner should have known the problem because the head had been previously unscrewed.

Your amp seems to be a nice choice for your b&w. It's the kind of amp I'd like to find (or a rotel rb1070 2x130wpc)

[fabrice]

Yes! It's repared. The common wire (yellow/green) for the midrange and the twetter was cut in the insulation just at the base of the head.

But It's my lucky day! There was enough wire lenght in the head to cut it and it has been easy to open the socket to solder. Thank you for your advice!

[Zonker92]

Wow; glad it was such an easy fix! I was afraid your connector had broken, which would have been a minor pain to replace.

I took apart one of my heads yesterday just for fun. It was interesting to see how the tweeter is attached by a single bolt running into the head. I also oiled my veneer and used some spray-on fabric dye to re-black the grilles. It's really looking great now. And I did the APOC mod on one speaker: I unsoldered one end of each of the six diodes, and put a drop of Goop on the loose ends to keep them from vibrating. And I ran a small wire under the PC board to bypass the relay. I also put some stick-on speaker gasket material on the underside of the edge of the crossover cover board to keep it from rattling when I reinstall it.

Once I install the new binding posts I'm going to play the modified speaker against the other one on a mono signal; maybe a 1 KHz sine wave, and test them with a dB meter to see if the one without the APOC circuit is louder.

[fabrice]

Hi eric,

I've just found the same amp as yours. It's obviously a second hand amp but it seems fine.

I have to go to pick it up next week. I'll tell you how it sounds for me. My previous amp was badly clipping (too low powered 2x45wpc) and I was afraid to damage my drivers.

[Zonker92]

Excellent! I bought mine used, too, but it's in perfect condition. I find that the 802s aren't very efficient and need a lot of power.

I bypassed the APOCs a week ago, re-blacked the grill clothes, put new feet on the cabinets, installed five-way gold binding posts and gave the cabinets fresh oil and wax (they look terrific!) but until we take down our Christmas tree they're sitting in my garage, so I haven't listened to them yet. I'll report in when I do. Happy holidays!

[fabrice]

well, what do you mean by "five way" gold binding post? I can't translate.

Merry christmas to you and your familly.

[Zonker92]

Thanks, Fabrice! You too!

Five way describes the general type of binding posts that everyone uses nowadays: You can attach cables to them five ways: (1) Spade connectors; (2) bare wires; (3) banana plugs; (4) pin connectors; and (5) dual banana plugs.

5-way binding post ? [Archive] - AudioKarma.org Home Audio Stereo Discussion Forums

[fabrice]

Hi eric,

The first seller has changed his mind about the NAD C272. Luckily, one month later I found a store that sold his last two NAD C272 half price. They were used in store but are guaranteed for 2 years.

That makes a big difference using two amps. Mids are very clear, especially the voices. It seems that the singer(s) are behind the loudspeakers.

bass are obviously more powerfull. Only treble seems the same.

The problem now is that bad recordings seem worse than ever.

[mikeymad]

Thanks for this thread guys. I have had my 802-80's back up and running since last June (after about 5 years of storage).

I had not really thought about the Caps until now. I had to replace a driver about 10 years ago, but other than that, it has been super clean sound. But now I might have to do a little inspection tour and order up some parts. Still, overall the speaker design holds up.

Cheers,

Mikey

[Sharpie]

Hello, 

I hope there is still some life left in this thread.  I think you all have the information I need.
I have a pair of B&W Series 80 Model 802.  One of them stopped working today while I was testing a new receiver (new to me, anyway)
I checked all of the speakers individually, and they all work, so I am guessing the fault is somewhere in the crossover board.

 

I'm hoping someone can guide me through picking out the parts for upgrading the board. 

It looks like I have the same crossover board as posted near the top of page 5 (How do I post a picture?)

It looks like you have all been through this before, 
I'd appreciate your help

 

[DefQon]

I'm surprised somebody took the time and went through threads here and revived a 4 year old thread.

[grawk]

I'm sure it was just google

[fp_lue]

Hi guys,

Sorry to revive something this old!

I want to do a complete refresh of the crossover to make sure it will last me an other 30 years.

Do I only need to change the caps?

If so, by looking at the schematics, I just order the same value caps at mouser?

I am very limited in electronics (can identify, can solder) but I have never done any work that requires more than soldering cables.

Thanks to anyone who would like to help! I will post detailed photos of my work once I get the confidence to do it.