The Workbench

Re: Misc repairs

Evan — Sun, 19 Dec 2010 15:33:41 GMT

I guess what made me think it was ok was the fact that the instructions said a difference of up to 1/8" is acceptable.

I agree with you Martin, this isn't the right way to do it.

Re: Misc repairs

Søren Mexico — Sun, 19 Dec 2010 14:33:35 GMT

I've ordered some cheap ones and dust caps from the US bay site, for 8" S45 and for 6.5" RL 140, will come back with report, when i get it.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=250740941075&ssPageName=STRK:MEWNX:IT

I have here 4 6.5" to play with, and for the S45s its serius, I will shim and do my very best.

Re: Misc repairs

Dillen — Sun, 19 Dec 2010 13:21:43 GMT

The surrounds will try to shrink back to their cast shape.
One of butyls good properties is exactly that.
Therefore, it's essential that the surround is "relaxed" when mounting.

I'm amazed at the number of B&O speaker owners that report of
woofer surrounds that were sold to be a guaranteed fit but wasn't.
Some were even far off.
And what puzzles me even more is that the same suppliers keep listing
and selling the same junk.
I don't dare to think how many speakers were thrown out because even
skilled DIY'ers didn't manage to get it right.

Seeing that this supplier lists the same surround as suitable for
both the MS150 and the M75 makes me sad.
The sizes stated doesn't match any of them particularly good.

Thanks for sharing your experiences. Surely that will save other
Beoworlders from similar troubles.

Martin

Re: Misc repairs

Evan — Sun, 19 Dec 2010 12:43:03 GMT

I stretched them dry and left them to resize overnight. Once completely on, the fit was snug but not as tight as you think.

When I ordered my things, the web site (simply speakers) even listed my driver model number as applicable, even listed as the very first one.

Re: Misc repairs

Dillen — Sat, 18 Dec 2010 00:18:08 GMT

You stretched the inner lip of the new surrounds to make them fit ?
(How on earth did you do that ?)
Yes, that's the problem, I'm sure.
It's probably just a matter of time before one or more of the other woofers
show the same problem too. The foam material needs to be "at rest" when
done (and not playing), tension will cause problems.
Try to find surrounds that fit the actual woofer.
Like many other B&O woofers they look standard but are not.

Martin

Re: Misc repairs

Evan — Fri, 17 Dec 2010 19:30:54 GMT

Die_Bogener:

Hi,

It is a differnce when you replace a 8uF cap in the crossover by a 10uf type... and it is not necessary to use a different size. 8.2uF Wima are available. Use a good MKP or MKS cap... i prefer WIMA, Intertechnik, Audyn or Mundorf (probably the best stuff ever built...).

Martin

I have not heard these speakers in many years, what would the difference be exactly? I mean they sound decent, but they are connected to a worthless amp (10% THD!) right now. My 3000-2 is on the bench too!

Oh and BTW, they were both 50v but now 100v.

Re: Misc repairs

Evan — Fri, 17 Dec 2010 18:38:56 GMT

EDIT

Re: Misc repairs

Evan — Fri, 17 Dec 2010 18:34:09 GMT

Hello Martin, thank you for your reply.

What is so irritating is the fact that I did align the woofer. (I didn't align the mids, both work great!) The other subwoofer was aligned too. I was very pleased with my work, especially since it was my first time refoaming anything. I even put the inner edge of the rings behind the woofer as they were originally!

When the original foam on the woofer failed it was used for quite a long time in the damaged state. Is the speaker permanently damaged? Doomed?!

BTW the inner edge of the foam rings was quite small and had to be stretched quite a lot for me to get them on, <-- problem?

If it doesn't make a rattle/knock noise at low volume is it safe to use? I would like my father to be able to enjoy his present while I am away or until I can get it fixed.

Thanks again!

Re: Misc repairs

Dillen — Fri, 17 Dec 2010 11:34:56 GMT

There's only one thing to do with the misaligned woofer - cut the
surround and dustcap off, align and refoam again.
Sorry but you cannot correct it any other way.
It is essential to align the spider/center piece/coil etc. properly before glueing in the new surround
as you can read many other places on these forum pages (but not on the suppliers websites, they just
tell you how easy it is without aligning!).
A success rate of 75% is not the worst result, I've heard and hopefully that woofer can still be rescued,
from what you tell it should be possible so long as you don't play it any more before it is refoam'ed.

Martin

Re: Misc repairs

Evan — Fri, 17 Dec 2010 10:48:58 GMT

Thank you both! For some reason I did not notice anyone replied to my thread.

Fortunately I was able to find the parts and pieces. I have MFD and Sprauge/Goodman Atom caps.

3 of the 4 refoam operations were successful. 1 of the 10" woofers is misaligned. Is there any easy way to fix this? It only rattles at a long throw or about half volume. This is kind of an emergency since I am gifting them in a few days!!!

Thanks again guys!

Re: Misc repairs

Søren Mexico — Thu, 09 Dec 2010 22:39:36 GMT

As you are US, look here

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=250740070660&ssPageName=STRK:MEWAX:IT

Re: Misc repairs

Die_Bogener — Wed, 01 Dec 2010 09:50:18 GMT

Hi,

refoaming is not very difficult, it just needs time. You can buy them here... there are many suppliers.

http://cgi.ebay.de/10-zoll-hochwertige-Schaumstoff-Sicke-Speaker-Ring-/270389679719?pt=DE_Lautsprecher_Martin&hash=item3ef47b1667

It is a differnce when you replace a 8uF cap in the crossover by a 10uf type... and it is not necessary to use a different size. 8.2uF Wima are available. Use a good MKP or MKS cap... i prefer WIMA, Intertechnik, Audyn or Mundorf (probably the best stuff ever built...).

http://cgi.ebay.de/2-x-MKTA-8-2-uF-160V-MKT-Folienkondensator-/140478746090?pt=Lautsprecher_Selbstbau&hash=item20b52f8dea

http://cgi.ebay.de/2-x-Audyn-Cap-MKP-8-2uF-250V-radiale-Bauform-/160508194371?pt=Lautsprecher_Selbstbau&hash=item255f08ae43

http://cgi.ebay.de/2xMundorf-Kondensator-MCap-Supreme-8-2uF-Selektiert0-6-/260688573581?pt=Lautsprecher_Selbstbau&hash=item3cb23ff48d

Martin

Misc repairs

Evan — Mon, 29 Nov 2010 19:42:45 GMT

Okay guys this is not a B&O project so be nice
I ask here because I know many of you are helpful regardless, as you probably dabble in other brands as well.

I have a pair of Realistic Optimus T-120 3-way speakers im fixing up for my father as a chrismas present.

Foam:
I am going to undertake the refoaming of the 4 woofers, even though I am completely inexperienced
The drivers are 5" and 10". I need to find a place to get the foam rings from and learn how to measure them out properly, help?

Caps:
The originals are 4uF and 8uF, one for each crossover. This morning I purchased a pair of 4uFs and 10uFs. Will I be abe to notice the difference between a brand new 8 or 10? The man behind the counter told me they are REAL close. What would the difference be?

I also need to recover the frets, but the local fabrics store didn't have anything suitable. Sources?

Thanks for the help!

Oh and I realize that I have a project already running, but this is sort of taking priority -Christmas coming up and all!