I picked up a pair of B&W DM110 Loudspeakers some time ago and have had them apart for a restoration until just recently.
I replaced the electrolytic caps with poly, fitted banana terminals and have tidied up the vinyl wrap and grill connectors.
They're about to be re clothed.
Given B&W's reputation for quality HiFi I was very disappointed after an A B test with my Interdyn Model 212 Loudspeakers.
The B&W's sound dull and flat.
Not having the skill nor equipment to test and diagnose possible improvements I'm not sure how to go about improving the sound.
Given my experience of adding a resistor to the Interdyns I thought maybe I could experiment by removing the resistors in the crossovers.
Is it possible removing the resistors could improve the high notes?
They're Bennic 2.2 Ω sandcast resistors.
Also the larger of the 2 Inductors is a iron core type.
Don't know if this has a bearing.
Thanks Cliff
I replaced the electrolytic caps with poly, fitted banana terminals and have tidied up the vinyl wrap and grill connectors.
They're about to be re clothed.
Given B&W's reputation for quality HiFi I was very disappointed after an A B test with my Interdyn Model 212 Loudspeakers.
The B&W's sound dull and flat.
Not having the skill nor equipment to test and diagnose possible improvements I'm not sure how to go about improving the sound.
Given my experience of adding a resistor to the Interdyns I thought maybe I could experiment by removing the resistors in the crossovers.
Is it possible removing the resistors could improve the high notes?
They're Bennic 2.2 Ω sandcast resistors.
Also the larger of the 2 Inductors is a iron core type.
Don't know if this has a bearing.
Thanks Cliff
I have recently listened to a pair of B&W DM110 and they sound far from "dull and flat".
It is the Interdyn 212 speakers that are untypical as the main driver runs full range and the only filter is a capacitor in series with the tweeter. This can result in a 'bright' sound.
Do you have the B&W DM110 service manual? It includes the crossover schematic.
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwiNoY2Eg5rzAhUDsaQKHQK9Bq4QFnoECAoQAQ&url=https%3A%2F%2Fwww.vintageshifi.com%2Frepertoire-pdf%2Fpdf%2Ftelecharge.php%3Fpdf%3DBowers-and-Wilkins-DM-110-Service-Manual.pdf&usg=AOvVaw1xxs6jwj2FRALvuKrDYv97
It is the Interdyn 212 speakers that are untypical as the main driver runs full range and the only filter is a capacitor in series with the tweeter. This can result in a 'bright' sound.
Do you have the B&W DM110 service manual? It includes the crossover schematic.
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwiNoY2Eg5rzAhUDsaQKHQK9Bq4QFnoECAoQAQ&url=https%3A%2F%2Fwww.vintageshifi.com%2Frepertoire-pdf%2Fpdf%2Ftelecharge.php%3Fpdf%3DBowers-and-Wilkins-DM-110-Service-Manual.pdf&usg=AOvVaw1xxs6jwj2FRALvuKrDYv97
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There is one 2.2 ohm resistor in series with the HF filter.
Rather than remove it, simply bypass it by soldering a length of copper wire across it and see if you like the result.
The LF inductor is a 2.5 mH iron core and I don't see any urgent need to replace it.
Rather than remove it, simply bypass it by soldering a length of copper wire across it and see if you like the result.
The LF inductor is a 2.5 mH iron core and I don't see any urgent need to replace it.
In the 80s I worked in a hi-fi store that was a B&W dealer. I actually loved the speakers at the time... but I wouldn't say they would hold the test of time. My favorite pair of speakers I remember from those days were a pair a B&W. But, I don't think B&W hit its stride until later. The 90s had many regular models with kevlar, the early ones in my opinion were quite colored and not in a good way... the later versions got very close to neutral and cemented them as one of the best brands of all time. So, in restoring a pair of speakers of this vintage, I would simply do whatever sounds best and not worry about keeping it original. As was mentioned, just try bypassing it? Also, it is not just electrolytics that are poor... capacitors in general from begone eras are poor (mostly). Maybe even look at new film for the entire crossover, which is usually very underrated as for influence on sound. But don't forget, maybe they are one of the best products of all time, but that doesn't make them amazing today.
Thanks Galu & Cyclone.
The replacement poly caps I used were tested first and all close or spot on their rated values.
I'll fit a jumper on the resistor for the experiment.
If it ends up sounding worse, this can be removed.
Also, thanks for the manual.
The replacement poly caps I used were tested first and all close or spot on their rated values.
I'll fit a jumper on the resistor for the experiment.
If it ends up sounding worse, this can be removed.
Also, thanks for the manual.
Hi Cyclone.
There were 2 electrolytic caps in each crossover which I replaced with poly.
The parts remaining include a 2.2 resistor, and 2 almost floss thin inductors, 1 being iron core.
Are there other parts which should be replaced to film?
cheers Cliff
Thanks Galu.
I ran a jumper to by pass the resistor in one of the Loudspeakers.
Surprisingly I couldn't hear a difference.
I used a copper multi strand wire, sheathed at each end and wrapped on either side of the resistor.
Is it possible it wasn't conducting properly?
It twisted the knots to get as close a connection as possible.
The schematic shows three capacitors in each crossover, so what have you to say about the third one?
I'm beginning to think that you may have made a mistake when renovating the crossovers.
Did the speakers sound "dull and flat" before you changed the capacitors?
And, what about the third capacitor shown in the schematic?
Sorry Galu.
I've been involving myself with so many projects, I confused what I had done to the B&W's with a pair of Yamaha Bookshelf Speakers I also recently recapped.
I can confirm that I did replace 3 capacitors and their values match the schematic, that is 7uF , 8uF , & 10uF.
As they were larger than the electrolytics each set were fitted to an outboard piece of masonite with jumpers leading back to the original crossover board.
Before the old caps were removed, their values were marked on the circuit board to ensure replacement aligned correctly by value.
As it's low hanging fruit I'll repeat bypassing the resistor and put a multi meter between the wires either side of the resistor, beyond the points where the jumper has been fitted. If the wire connects correctly it should reveal no resistance?
I should have performed the recapping on one of the speakers to A & B test any improvement, but was impatient and replaced both to get on with it.
The electrolytic caps I removed were off their rated values by about 15% on my meter (they displayed greater uF values).
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If the resistor is bypassed by the wire the reading will be zero, and not 2.2 ohm.
I asked an important question: did the speakers sound "dull and flat" before you decided to renovate them?
Hi Galu.
Having atleast a dozen pairs of speakers as well as other projects to juggle I hadn't found the time to listen to them before the alterations.
My mindset over the period that I owned the B&W's was that I was convinced recapping would improve them.
I know, not very scientific.
On prior recaps I found, often some of the electrolytic caps would end with broken terminals too short to reuse easily, so also felt committed once I started on one of a pair.
Having atleast a dozen pairs of speakers as well as other projects to juggle I hadn't found the time to listen to them before the alterations.
My mindset over the period that I owned the B&W's was that I was convinced recapping would improve them.
I know, not very scientific.
On prior recaps I found, often some of the electrolytic caps would end with broken terminals too short to reuse easily, so also felt committed once I started on one of a pair.
It is debatable whether a budget speaker such as the current example will benefit greatly from a crossover component upgrade.
I think I've explained to you before that changing components willy-nilly can actually lead to a downgrade in sound. My advice is to always listen to the speaker in its original condition and carefully retain the original crossover components if deciding to 'upgrade' them.
There's nothing wrong with the sound of my 110 examples and I'd happily pass them to another owner in stock condition.
I think I've explained to you before that changing components willy-nilly can actually lead to a downgrade in sound. My advice is to always listen to the speaker in its original condition and carefully retain the original crossover components if deciding to 'upgrade' them.
There's nothing wrong with the sound of my 110 examples and I'd happily pass them to another owner in stock condition.
Don't see the point in renovating an old mediocre speaker. To be blunt, they're not worth it. They won't ever achieve anything impressive compared to modern speakers, manufacturing has moved on leaps and bounds since then.
FWIW, when you replaced the caps, you likely put in lower values. Poly caps typically measure lower, whilst electrolytics measure highers. So for instance your 7uf was probably 7.5 whilst the replacement was likely closer to 6.8
But really, don't waste your time on them. you'll just wish you hadn't.
FWIW, when you replaced the caps, you likely put in lower values. Poly caps typically measure lower, whilst electrolytics measure highers. So for instance your 7uf was probably 7.5 whilst the replacement was likely closer to 6.8
But really, don't waste your time on them. you'll just wish you hadn't.
Thanks Galu.
I've just replayed the 110's and thought there's something seriously wrong.
They sound far too flat.
I removed the wire terminals from the Woofer to test the sound coming out of the tweeter.
Just as I suspected, no sound at all.
There's no sound coming out of the tweeter at all.
It's occurring on both enclosures.
Atleast I have a diagnosis on why they sound flat. 🙂
Just need to test why?
I've just replayed the 110's and thought there's something seriously wrong.
They sound far too flat.
I removed the wire terminals from the Woofer to test the sound coming out of the tweeter.
Just as I suspected, no sound at all.
There's no sound coming out of the tweeter at all.
It's occurring on both enclosures.
Atleast I have a diagnosis on why they sound flat. 🙂
Just need to test why?
Well, since you didn't listen to the speakers before you worked on them, the tweeters may have been blown all along.
Measure their DC resistance while disconnected from the crossover.
Measure their DC resistance while disconnected from the crossover.
Hi nannoo, appreciate your input.
It totally depends on the circumstances.
From what I've been learning from a variety of sources, is that the current crop of modern Loudspeakers are built to a price, rather than performance.
Also many highly respected brands are now being used as vehicles to sell junk.
Pricing for sub par products has also gone through the roof.
One particular audio guy who makes a living from improving mass produced speakers has reviewed some Speaker models costing higher than US$5,000 performing no better than $500 speakers.
There's a lot of over priced rubbish out there.
Some vintage reviewers are reporting better sound from $50 vintage speakers compared to $500 to $1,000 contemporary products.
In my opinion the best value for money sound available today would be a DIY build using a well engineered design and quality parts.
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