Capacitor replacement B&W DM110

[TomJS]

Hello, I've got a pair of B&W DM110's and I'm looking to replace the capacitors. I found out the values of the capacitor's 10uf 8uf and 7uf. The original cap's are electrolytic's now on of my question's is can I replace the electrolytic's with film cap's or do i need to find non-polarized electrolytic caps in these values? The other question is is it okey to replace the 8uf with a 8.2uf and the 7uf with a 6,8uf? This is the link to the schematics of the speaker.https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0CB8QFjAA&url=http%3A%2F%2Fbwgroupsupport.com%2Fdownloads%2Ftechmanuals%2Fbw%2FDM110-TM.pdf&ei=ATBEVMf1NYHamgXXlYLADg&usg=AFQjCNEodOgGLhtRBJyFGLbJZbfwL_r7Pw

Thanks and regards,

Tom

 

[picowallspeaker]

Hi, I think it might be ok
😕 Tolerances are about 10 % and you could buy some more to do some selection 😱😛
Or you might end with some holes or bumps in the response due to sovrapposition or rarefaction 🙄
Too many emoticons ? I'll work it out

( they'll be ok )

 

[esl 63]

For that speaker yes.
The specifikation of your original electrolytics is around +/-10%
Maybe +/-5 %.
So you are within the margin.
Thats one way to see it.

The other way is that the increase of C2 would lower the cutoff for the tweeter slightly, while it is the opposite for the baypass of the woofer. since increasing C3 will short more midrange slightly... Anyway its close enough. I would not be worried!

Then listen to it!
And if you want you can add a smaller cap in parallell and listen again!

 

[TomJS]

Thanks, guys! So I can use cap's that aren't electrolytic's too? Like film or anything else?

 

[wintermute]

Film vs electrolitic is potentially more problematic. The ESR in an electrolytic is much higher than a film cap, and may well have been factored into the design of the crossover.

Shunt caps can be particularly problematic with resonant peaks occuring when the cap resonates with the coil. In the end it will depend on the crossovers design, but the safest option would be to replace with non-polar electro's. If you know what the ESR of the electros should roughly be you could add in some series resistance with film caps to make up for it, if film caps cause an issue.

Tony.

 

[TomJS]

Thanks, I found a couple of cap's but I couldn't find a 8,2uf in a rating higher than 50 volts is 50 volts enough?

 

[eriksquires]

WM is correct, but!!

In general, replacing caps in series is safer than shunts. If you could measure the caps you are removing you could compensate for it as you go.

Also, you might want to consider Mundorf MKP caps which B&W is quite fond of in their midrange speakers today.

For the values, yes, we kind of assume that the designers were OK with toleranceas as marked (even though we have no evidence whether they were tested or not) but if you want to get really close:

6.8 + .22 = 7.02uF
6.8 + .22 + 1.0 = 8.02uF

which brings you to less than 1% within target value, and proves you are a perfectionist.


Best,

E

 

[TomJS]

Thanks, guys! I ordered the caps after a long long long search for a shop that sold all 3 of the cap values. I'll keep you up to date on how it turns out!

 

[TomJS]

So I installed the new caps. I had a bit of trouble installing them at first since the old ones were glued very very well to the board. After trying to cut the glue away I gave up and just cut all the wires to the old caps and installed my new ones on top of them. I glued the new caps with hot glue so they won't vibrate in the speaker. But to the main topic. The speakers sound more refined and detailed. The low end tightened up a bit and is a bit more punchy. The speakers can go louder before the tweeters becoming scratchy. And the tweeter that crackled sometimes in on of the speakers doesn't crackle one bit I think this was because of the old caps shifting values?. Thanks for all the help guy's I really appreciate it. Btw just to clarify the new cap values we're 10 uf, 8,2uf and 6,8 uf.

 

[TomJS]

I'd also like to mention one of my speaker's had two unknown value caps instead of one 8 UF. I found this kinda weird but I guess B&W just ran out of 8uf values and replaced it with 2 caps in parallel. The caps were all original the same brand and the same ANNOYING GLUE!

 

[eriksquires]

Tom,

Glad you are happy with the results. What brand/type of capacitor did you end up using?

Best,

E

 

[YSDR]

and the same ANNOYING GLUE!

You can break the glue with handforce if you put the board into the freezer for a half hour.

 

[TomJS]

Tom,

Glad you are happy with the results. What brand/type of capacitor did you end up using?

Best,

E

I used Mundorf I don't know how good they are but it's the only ones I could find.

 

[TomJS]

You can break the glue with handforce if you put the board into the freezer for a half hour.

Thanks for the tip i'l try that the next time!

 

[eriksquires]

I used Mundorf I don't know how good they are but it's the only ones I could find.

That's what B&W uses. In at least one model, the only difference between two grades is the caps. 🙂



The mid-range B&W uses Mundorf MKP, and the top end some version of the supremes.



Best,


Erik

 

[TomJS]

That's what B&W uses. In at least one model, the only difference between two grades is the caps. 🙂



The mid-range B&W uses Mundorf MKP, and the top end some version of the supremes.



Best,


Erik

Thanks for the info Erik!
Also thanks to everyone who submitted answers to this thread! 🙂 🙂
I will probably ask alot more question's😕 in the future!😱

Tom,

 

[eriksquires]

Tom,

Did you go with the Mundorf Electrolytics or film??

Best,

E

 

[TomJS]

Tom,

Did you go with the Mundorf Electrolytics or film??

Best,

E

Electrolytics I didn’t want to take the chance with film.

Best,

Tom

 

[TomJS]

Tom,

Did you go with the Mundorf Electrolytics or film??

Best,

E

Electrolytics I didn’t want to take the chance with film.

Best,

Tom