B&W dm610i worth fixing up?

Discussion in 'Speakers' started by Xlot, May 4, 2011.

  1. Xlot

    Xlot New Member

    I picked up a pair of Bowers and Wilkins dm610i's as part of an ebay purchase last week that I got mainly for the amp (Audiolab 8000A mk3) and CD player (rotel rcd-965bx LE). I already have some nice Monitor Audio Silver RS speakers which do the CD and amp justice, so the speakers are redundant at the moment.

    Is it worth fixing these speakers up (they both have issues - see below)?

    The dm610i's both have a snapped off binding post, on one of them it prevents the bridge between high/low drivers making contact, but when I cheated and used a crocodile clip to attach to the slightly raised nub, it sounded alright. On the other speaker, it sounds like the tweeter and mid are doing nothing, although I haven't investigated yet to see whether its to do with the broken post, crossover issue, or just a loose wire.

    I'll post pics in a while - need to clear some space on the garage bench so I can get good pics, and start to look inside the cabinets.
  2. pete_mac

    pete_mac Super Member

    Aha!! I was chasing that lot of gear quite feverishly (I made the first offer on it, along with many subsequent offers) but all communication ceased at the last minute. Given the speaker issues, perhaps I was lucky!

    Congrats on the purchase anyway. Nice CD player and amp. The rack also seemed decent enough.

    From many accounts, these are reasonable-sounding speakers. Your MAs will certainly be better though - if I were in your shoes, I'd do my best to rectify the issues, take decent pics, and onsell them to recoup some of your initial outlay.
  3. jeremyjustic

    jeremyjustic Analog

  4. Xlot

    Xlot New Member

    Small world eh? Judging by the history my "winning" offer was $50 higher than anyone else offered. Seller's communication was abyssmal.. I'd pretty much given up on it when he phoned, and I already had bids in on other stuff.

    The amp works well, but 3 inputs RCA's are broken (a common Audiolab problem - the plastic goes brittle and cracks) so I've ordered a full set of replacements from Audiolab's support in the UK which I'll solder in.

    Anyway.. back to the speakers..

    Here's some pics of the issues:

    1. One of the tweeters is pushed in, but both woofers look good and the roll surrounds are pliable and in good condition.

    2. Binding posts are snapped on each speaker

    3. Here's the binding posts disassembled - I'll check my local electronics store for a suitable replacement or upgrade. Otherwise, new ones from the link jeremy posted look like a good option.

    4. The crossover is simple - I also found a shorted capacitor on the one I opened, so will grab replacements for all capacitors when I'm checking out binding posts.

    A re-cap of both crossovers and 2 binding posts will be cheap, and should make the speakers sound good.. hopefully the tweeter will still do acceptably well, as I don't fancy $57 for a replacement one just yet, until I know whether I'm going to keep them, or the damaged tweeter sounds poorly.


    Attached Files:

    Last edited: May 5, 2011
  5. Xlot

    Xlot New Member

    Thanks for the link.. hopefully I can find local replacements for the posts, but I may yet end up getting a replacement tweeter
  6. JonVH

    JonVH Active Member

    Those are nice speakers, Xlot. The later version had a poly woofer. The tweeter will whistle at a certain note with some music and there is cabinet resonance but these speakers go deep for their size and are depressed in the most sensitive area of the hearing range to make then un-shrill and calm. They are not NS-1000Ms or Apogee scintillas but B&W sound easy to listen to with any material. My opinion is they are worth it, but a diy speaker could go far beyond. It'll be a matter of taste. Best of luck!
  7. Xlot

    Xlot New Member

    Thanks for the feedbback Jon - it'll be interesting to hear them compared to my Monitor Audio's which are fairly bright with metal cones.

    DIY tempts me, but small kids and a car hobby chew up most of my time, so for now DIY speakers are just something to read about :)

    From a post elsewhere, I gather its possible to take the dome off the tweeter carefully without damaging the coil, and push it out. Once I've verified the tweeter actually works I'll give that a try.
  8. Xlot

    Xlot New Member

    Sound great!

    Turns out there were more issues than I thought :D

    The good news is the dm610i actually sound pretty good.. well, the one that's perfect at present.

    They're not as good as my Monitor Audio Silver RS LCR's (I run a pair of LCR's on my PC - they've got 3 drivers and I prefer them to the RS1's).

    The dm610i's sound fairly relaxed - good separation, and fairly full low end, but slightly muddy highs compared to the Monitor Audio's. The B&W's are very pleasant to listen to.

    So... I mentioned more issues.. here's what I did last night and a coupleof hours this afternoon.

    First I took the tweeters out, and tested them for continuity on the multimeter. And found the one with the good dome had a break somewhere (open circuit).

    While I had them out, I removed the pushed-in diaphragm (the inner 3 screws hold it to the magnet), and carefully pushed it out again. Here it is fixed (this tweeter tested ok).


    Then I took the diaphragm off the broken tweeter and had a look.. someone had been in there before and attempted a repair, which either didn't work at all, or failed some time later.


    So I cut a couple of strands from some oxygen-free stranded speaker cable and twisted a loop on the end of each pair. Then I made a little hook-shape on the coil tails and set the loops over the hooks to carefully solder the strands on.


    A quick solder on the other side to attach the new strands to the connector pins, and the tweeter works again. :D I was lucky the coil itself was intact (I did inspect it before doing the very fiddly repair with thin copper strands). You can also see what the other dome above should look like.


    Then, it was time to re-cap the crossovers.. so I unplugged the leads from the woofer, and put the crossovers on the bench.


    I couldn't find a 5.3uF 70V replacement, so I used a couple of smaller ones in parallel to make a 5.5uF 100V which with +/- 10% tolerance should make an excellent replacement. The 10uF was the easy one :)


    And here's a crossover re-capped:


    So, after reassembling.. I found one of them was still suffering in the tweeter department - the tweeter works, but barely. Sigh.

    A quick disassemble later, and a check of the crossover, and it seems one of the ceramic resistors has failed - they're both supposed to be 5R4 (5.4ohm), and one is consistently reading 1.1ohm.

    So, I'm almost there I hope.. just have to find a suitable replacement resistor and undo more hot-melt glue.. and then the pair should sing well.

    All in all pretty a enjoyable odyssey as my first speaker repair ever.. assuming I've found the last issue to fix.
  9. pete_mac

    pete_mac Super Member

    In light of the above, I'm glad I didn't buy this batch of gear. The seller never mentioned ANY of this in their description to me when I questioned him regarding the condition! I would have been FUMING after driving up from Sydney, only to see these faults.

    However, good work in resurrecting the speakers. Hopefully you can get the resistor sorted and have these speakers making sweet music in the very near future!
  10. 59Vampire

    59Vampire New Member

    I really like my b&w dm610s. If you decide to scrap them i would be interested in buying the grilles from you if you ever want to move them. One of mine is broken. Enjoy them though., They are nice speaks
  11. DON73

    DON73 MSGT USAF 1955-1976

    FYI I've repaired a few pushed in dust covers with a small vacuum cleaner. Haven't had a failure yet. I have an Advent that has a crushed dust cover and when I get the woofers back in I'll try to "vacuum it back into pretty much what it was new. My B&Ws are 801s, 803s and 805 matrix. I also have a pair of 805 nautilus. I find the matrix series much easier to listen to than the Nautilus. Just slightly softer high end. They're old and maybe they're tired like their owner but we go well together and :music::music::music:they're the only speakers I'll never sell.
  12. rfincher

    rfincher New Member

    XLOT: I too need a replacement for the 5.3uF 70WV capacitor on my B&W crossover - how did the 2.2uF 100V and the 3.3uF 100V in parallel work out for you? Or did you ever find a supplier for the 5.3uF 70WV?

    Also what kind of solder did you use?
  13. Xlot

    Xlot New Member

    Well apologies for the really late response :) for some reason I didn't get a notification email..

    I ended up buying a complete new crossover from bwgroup linked above. It was only about $US15. When it turned up, it was different to the original ones - the plastic tray had two tiers of angled binding posts, and it had no circuit board - just components directly soldered to each other.

    So I ended up taking apart the new one for parts (they had the same binding posts and electrical components). I used binding posts to fix each speaker and the caps into the one which I'd re-capped before. The one I alluded to with a problem turned out to be poor connection on one of the solder pads (I tested each component individually first).

    So the dm610's are completely stock using stock B&W parts (interestingly, the parts measured very close to their spec - I suspect B&W measure each part before using, as they were all within 0.05 mfd - I have a good old Tenma LCR meter). They sound really good - warmer than my Monitor Audio Silver RS1's.

    For solder on audio gear, I prefer to use a lead-free solder from Goot.. its Tin-based, with 0.5% Copper and 3% Silver. Its less prone to vibration cracking than lead/tin stuff.

    I also bought the replacement rca jacks from audiolab for the amp and replaced all of them.

    The bits have been serving me well as a combination computer-speakers and cd hifi for a couple of years now.

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