B&W DM-6 Pregnant Penguins - restoration

[gajraaj]

Dear all,

I am embarking on my first vintage audio restoration project.

I bought a pair of DM6's 2 days ago. I did not listen to them but the guy said they work fine and he will take them back if I don't want to keep them. I like their unique shape so I decided to keep and restore.

I found that one of them has a dead twitter. I checked the fuse but its not that. The twitter (TW20) is really dead. Checked also on multimeter. In general the speakers are not sounding very clear and not loud enough.

I opened up one of them (damaged twitter) and found that the caps are leaking.

I have several question and if you guys can help in this project, I would we very thankful

1. What should I do about the twitter? Try to look for an old TW-20 or replace both twitters with another set? Ot try to get it repaired?

2. There is a black lining staples to the the inside walls of the speaker. This is something had and dense. Like a hardened rubber sheet. Anyone know what this is for and should I replace this with something. Was it some to just add weight or had some other purpose? [Picture ]

3. The edges where plastic front face which houses the drivers sits on the wooden cabinet, there is white clay type material. Seems like some kind of sealant. Its still flexible and feels wet. Something like playdough. What is this and what can I use here to seal the boxes when I finally close them.

4. The caps are leaking so I am going to replace them. Which caps should I use? Brand / type? I read somewhere the B&W is now using mundorf. But there are so many types.

5. Should I replace the resistors? I think I should because at least one of them is showing signs of heating up.

6. I am not planning to replace the coils. Just because they look fine. Should I do that and rebuild the whole crossover board?

7. Last one for today, what should I use to renew the exterior of the wooden boxes? They are not in a bad shape but I would like to get them to look a bit better. (but not absolutely new to keep the used touch)


A million thanks in advance for reading so far.

 

[onwardjames]

Hello, welcome to AK !!

The black stuff lining the cabinet is deadening material to reduce resonance of the side panels. That should stay.

When you checked the dead tweeter, did you ohm it out, and it was dead?

These are worth the work. Good luck, ask lots of questions. The experts here will walk you through it.

Best of luck!

 

[onwardjames]

Oh, a few more things -

Yes, replace those resistors. One looks cooked. As for caps, that is a very deep hole, but I'd use Dayton poly caps from Parts Express. Audyn if you wanna spend more cash.

You can use rope caulk to reseal the drivers. BE WARNED - it will lift flaky MDF particles, should you need to get back in there. Might put a thin sheet of something under it, maybe reynolds wrap or something?? I dunno, I just know with my damaged Dynacos, it lifted hunks of the old mdf out.

And I'm a huge fan of Restore-A-Finish, wipe on, then wipe off, with a follow up of Feed N Wax. Easy, and tends to leave wood looking like wood, not plastic.

 

[gajraaj]

Hello, welcome to AK !!

The black stuff lining the cabinet is deadening material to reduce resonance of the side panels. That should stay.

Ok. Will keep it. Just that one piece had buckled and I took it out. What can I replace that part with. Is this thing easy to buy?
Thanks for your answer.

 

[gajraaj]

When you checked the dead tweeter, did you ohm it out, and it was dead?

Yes it is dead.

 

[gajraaj]

Yes, replace those resistors. One looks cooked. As for caps, that is a very deep hole, but I'd use Dayton poly caps from Parts Express. Audyn if you wanna spend more cash.

Thanks a lot. I will look where I can find these in Europe. I live in the tiny kingdom of Belgium.

 

[gajraaj]

You can use rope caulk to reseal the drivers. BE WARNED - it will lift flaky MDF particles, should you need to get back in there. Might put a thin sheet of something under it, maybe reynolds wrap or something?? I dunno, I just know with my damaged Dynacos, it lifted hunks of the old mdf out.

And I'm a huge fan of Restore-A-Finish, wipe on, then wipe off, with a follow up of Feed N Wax. Easy, and tends to leave wood looking like wood, not plastic.

I think it is actually Rope Caulk. Thanks.

Will look for Rope Caulk, Restore-A-Finish and Feed N Wax on this side of the pond.

Thanks again. Will keep you guys posted.

 

[jcamero]

Only can speak to the dead tweeter. Good luck finding one. I needed one for my DM5's, and took nearly 2 years to find one. The one I found was actually from a DM6. You can go up to a TW26. The dome is larger, but a direct fit, (no modifications needed to cabinet or tweeter). Since the "Penguins" have pots, you can dial out the highs.

 

[sax6]

Some very nice speakers there... good luck !

 

[onwardjames]

Ok. Will keep it. Just that one piece had buckled and I took it out. What can I replace that part with. Is this thing easy to buy?
Thanks for your answer.

You're quite welcome. If you still have that piece, I'd use spray adhesive or hot glue, and reinstall it.

As for the tweeter, and you being in Belgium, all I can add is good luck.

 

[gajraaj]

You're quite welcome. If you still have that piece, I'd use spray adhesive or hot glue, and reinstall it.

As for the tweeter, and you being in Belgium, all I can add is good luck.

Lost that piece to the trash truck yesterday .
Thanks a lot. I continue!

 

[gajraaj]

I am looking at Audyn CAPs. But there are so many types. (For that matter... every cap manufacturer has so many types).

which ones are the right replacements?
On the crossover, I see two shapes - red cylindrical and the light brown “book” type.

Please advise !

 

[RossW]

Those light brown caps are film caps and are probably fine. I would focus on the red electrolytic caps. Any cap which meets the capacitance and voltage requirements is ok, beyond that is a matter of opinion and budget. Try to get the capacitance pretty close, but the voltage rating can be much higher (i.e. it's fine to use a 400V cap to replace a 50V cap).

One thing to keep in mind is that film caps will be much bigger than the electrolytic capacitors so you might have to get creative with fitment.

Soft foam weatherstripping is a good alternative to rope caulk, it's a bit easier to work with and less messy.

 

[gajraaj]

Those light brown caps are film caps and are probably fine. I would focus on the red electrolytic caps. Any cap which meets the capacitance and voltage requirements is ok, beyond that is a matter of opinion and budget. Try to get the capacitance pretty close, but the voltage rating can be much higher (i.e. it's fine to use a 400V cap to replace a 50V cap).

One thing to keep in mind is that film caps will be much bigger than the electrolytic capacitors so you might have to get creative with fitment.

Soft foam weatherstripping is a good alternative to rope caulk, it's a bit easier to work with and less messy.

Thanks a lot.
Parts are ordered.

 

[Pete B]

Nice work! You've probably seen this: https://www.stereophile.com/content/bw-dm-6-loudspeaker

Does anyone have specs on the tweeter?

 

[gajraaj]

Nice work! You've probably seen this: https://www.stereophile.com/content/bw-dm-6-loudspeaker

Does anyone have specs on the tweeter?

Just read it. Interesting. Thanks

 

[gajraaj]

So finally I replaced the caps and resistors on one of the crossovers. It all went fine. I could hear a great difference between the right speaker ( recapped) and the left.

However, after playing for about 30 mins, the fuse on this speaker blew off. ( I played max 50% of my BA-F1 output ).

as far as I know. I have done correct replacement. I did not replace the fuses.

any thoughts ?