Hi Everyone,
I bought a pair of B&W DM2ii speakers, which look great to my eyes. Really nice condition in Teak & generally they sound pretty good, but the sound is a bit hollow on some music, and the treble could do with being a bit brighter, although the actual situation isn't too bad TBH. All drivers are working well, but I feel a recap or refresh of the crossovers is required after 43 years.
These speakers have 9 caps on each crossover, so 6 pye electrolytics for the LF & MF, and 3 film (metallised?) caps for the HF. As mentioned it would be good if a little bit more sparkle was restored to the tweeters.
I have been looking at various on-line shops in Europe & UK, and I must admit it's pretty confusing between the different makes & types, with some big price differences for polyproplyene caps depending on the make & model. Basically this is a pocket money hobby for me, and I don't want to spend too much on restoring them, so I am looking for the best sweet spot between cost & quality. This is my plan :
LF & MF :
Use good quality electrolytics. My considered options are ALCAP low loss, ALCAP 100V, or Mundorf E caps
The advantage of the ALCAP range is that they have the exact same capacitance capacitors as the original caps (ex 80uf, 30uf, 20uf etc) whereas all other makes including MKT types, tend to have a nearby equivalent but not the same capacitance (ex 82uf, 33uf, 22uf)
Can anyone advise what would be best, or any alternative ideas ?
HF :
The orignal capacitors are 3 square rectangular film type caps (5uf in series, 2.2uf & 0.47uf in parallel), in close proximity to other components, and maybe it would be a squeeze to use some large Polyproplyene caps.
My options here are Mundorf Mcap, Jantzen standard Z cap, SCR MKP or Solen MKP, or even WIMA MKP type film caps which would fit the board.
Again, can anyone advise what would be the best compromise ? I want to brighten up the tweeter a bit, but dont want to go overboard or regret it afterwards. I guess trying to be as close as possible to original sound is the target.
Many thanks
I bought a pair of B&W DM2ii speakers, which look great to my eyes. Really nice condition in Teak & generally they sound pretty good, but the sound is a bit hollow on some music, and the treble could do with being a bit brighter, although the actual situation isn't too bad TBH. All drivers are working well, but I feel a recap or refresh of the crossovers is required after 43 years.
These speakers have 9 caps on each crossover, so 6 pye electrolytics for the LF & MF, and 3 film (metallised?) caps for the HF. As mentioned it would be good if a little bit more sparkle was restored to the tweeters.
I have been looking at various on-line shops in Europe & UK, and I must admit it's pretty confusing between the different makes & types, with some big price differences for polyproplyene caps depending on the make & model. Basically this is a pocket money hobby for me, and I don't want to spend too much on restoring them, so I am looking for the best sweet spot between cost & quality. This is my plan :
LF & MF :
Use good quality electrolytics. My considered options are ALCAP low loss, ALCAP 100V, or Mundorf E caps
The advantage of the ALCAP range is that they have the exact same capacitance capacitors as the original caps (ex 80uf, 30uf, 20uf etc) whereas all other makes including MKT types, tend to have a nearby equivalent but not the same capacitance (ex 82uf, 33uf, 22uf)
Can anyone advise what would be best, or any alternative ideas ?
HF :
The orignal capacitors are 3 square rectangular film type caps (5uf in series, 2.2uf & 0.47uf in parallel), in close proximity to other components, and maybe it would be a squeeze to use some large Polyproplyene caps.
My options here are Mundorf Mcap, Jantzen standard Z cap, SCR MKP or Solen MKP, or even WIMA MKP type film caps which would fit the board.
Again, can anyone advise what would be the best compromise ? I want to brighten up the tweeter a bit, but dont want to go overboard or regret it afterwards. I guess trying to be as close as possible to original sound is the target.
Many thanks
Frankly ANY brand Capacitors of the Film And Foil variety. Will far surpass the quality of the original.. Factory fitted Caps.
Noting that audible differences between the Highest Price Audio Weenie Caps and simple Solen type Film and foils is ...Small ...by ANY yardstick. Unnoticeably small...in Real Life.
More to do with audio Religion than reality.
Buy inexpensive decent quality caps and listen.
Then decide IF you want to fiddle about even more.
Noting that audible differences between the Highest Price Audio Weenie Caps and simple Solen type Film and foils is ...Small ...by ANY yardstick. Unnoticeably small...in Real Life.
More to do with audio Religion than reality.
Buy inexpensive decent quality caps and listen.
Then decide IF you want to fiddle about even more.
Those red PYE caps were not bad at all.
Best is to use LL or smooth foil lythics which is the same for small values below 100 uF and normal rough foil for bigger capacitance. Of course best is to find the exact value, so if Alcap has it, take it.
The squared caps can be kept as they do not drift if film.
Best is to use LL or smooth foil lythics which is the same for small values below 100 uF and normal rough foil for bigger capacitance. Of course best is to find the exact value, so if Alcap has it, take it.
The squared caps can be kept as they do not drift if film.
I've recently seen a YouTube vid showing that some safety ( yellow film caps ) aren't sealed properly and let in moisture, causing damage to the alloyminium, this is annoying for me as I made a DAC with LOADS of them. I've used motor run caps a few times without issues.
Thanks for all the advice. Must admit the more I read forums, the more I am confused. People seem to attribute magical properties to some caps
I think replacing the 43 year old électrolytics with Alcap LL from Falcon is a no brainer, just wondered how they would compare to Mundorf E caps. Since Brexit buying from the UK (Falcon Acoustics) has become more complicated & expensive for us europeans. I used Alcap LL in some Celef speakers I have and the results were very satisfying indeed.
Concerning the square film caps, the issue is that the treble does seem a little bit too "civilised" and I thought this may be consequence of degradation of these film caps. Would be nice to have a little bit more brightness, unless of course this is a characteristic of DM2ii of the TW-26 tweeter.......
The highest value cap is 80uf. Alcap don't have a 75uf (everthing else is available) , so either I use a 72uf or 80uf, or I use a 50uf & 25uf in parallel :
There is no coating, just the visible weave of the material, although it is black & a little skicky to the touch
Sticky means it is still there i would expect.
dave
dave
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You must respect the capacitance value as you do not know the precision of the filter. You can assume the lowest capacitance are within 5 to 10 % (and 2% to 5% if they sorted out...which they only do for the flagship loudspeakers only I believe). And the biggest within 10%. You can // two caps rough foils if needed. Yes better to cope to the shematic value. Even C1 can bring you too much bass or not enough, not tigth if not the designer chosen value.
Try Banzai music store as they have F&T caps that are more precise than the said 5% Mundorf...for whom they make caps too (as probably for Jantzen lythics too). Just say to Banzai yo are hurry not to wait 1 month but 1 week instead.
There are better caps than others but with a DM2 due to the tired drivers it will not bring you a Ferrari by just purchase better wheels.
This little tweeter is nice. At least if the one of the B&W DM14...
Try Banzai music store as they have F&T caps that are more precise than the said 5% Mundorf...for whom they make caps too (as probably for Jantzen lythics too). Just say to Banzai yo are hurry not to wait 1 month but 1 week instead.
There are better caps than others but with a DM2 due to the tired drivers it will not bring you a Ferrari by just purchase better wheels.
This little tweeter is nice. At least if the one of the B&W DM14...
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Honestly, you can't go wrong with WIMA MKP10.
Solens should be used across woofers only as they insert some grit on tweeters and mids used in Series, but they do well on woofers.
Standard Zcaps are small for their value, and that can come in handy.
Best budget cap? Gotta be Audyn Q4.
Solens should be used across woofers only as they insert some grit on tweeters and mids used in Series, but they do well on woofers.
Standard Zcaps are small for their value, and that can come in handy.
Best budget cap? Gotta be Audyn Q4.
Thanks for the tip - I looked, but again there are virtually no capacitors having the same nominal capacitance values used in the DM2ii . The ALCAP's are a perfect match in nominal capacitor values and seem to cater for these old British speakers..
True, but the speakers already sound pretty good - big sound & with careful positioning they produce a good centre field 3D stereo image. I am under no illusions, but if a recap brings further improvements, these are really nice vintage speakers.
I really like this option as they are cheap & easily available, even available with different lead spacings. Would be good to use them for the 2 smaller capacitors in the HF secttion (0.47uf & 2.2uf). I wonder why they don't seem to be popular for loudspeaker crossovers ? I always use Wima film whens I recap amplifiers.
Effectively they seem to be very reasonably priced. Could be an option. Thanks for the tip. Available capactitance values are the issue though
I would just replace the electrolytics with closest available values erring on the side of slightly lower than hgiher value, as these tend to run on the plus side of value tolerances. As for the tweeter HP and other series filter caps, the Solen SCRs served me the best for retaining the B&W flavor and tonal character.
Be advised that substituting a film cap for an electrolytic will require adding a small series resistor depending on where the cap is located. You may need to increase the tweeter pad resistor by 1 Ohm or so to make up for higher losses of the original electrolytic if thats what was used in that location. Same goes for the parallel caps in LP filters. You can really screw up the filter slope shapes if you dont take this into consideration, changing the character and tonal balance.
Be advised that substituting a film cap for an electrolytic will require adding a small series resistor depending on where the cap is located. You may need to increase the tweeter pad resistor by 1 Ohm or so to make up for higher losses of the original electrolytic if thats what was used in that location. Same goes for the parallel caps in LP filters. You can really screw up the filter slope shapes if you dont take this into consideration, changing the character and tonal balance.
Thanks for all the replies. Time to stop all the procrastination & orders the caps !
Despite all the good advice, I think I will go with low loss electrolytics of indentical value for the LF & MF.
The more I run the speakers, the more the sound is improving (if this makes sense) & I don't want to take the risk of running into issues.
Concerning the HF caps, these are already some type of yellow brownish film cap as used by B&W back in 1979.
The logic is that these films caps should still be OK, but I think I am going to replace then with Solene Polyproplyene ones. Falcon acoustics have custom sizes made especially by Solene for Falcon so no problem to find the exact sizes.
Despite all the good advice, I think I will go with low loss electrolytics of indentical value for the LF & MF.
The more I run the speakers, the more the sound is improving (if this makes sense) & I don't want to take the risk of running into issues.
Concerning the HF caps, these are already some type of yellow brownish film cap as used by B&W back in 1979.
The logic is that these films caps should still be OK, but I think I am going to replace then with Solene Polyproplyene ones. Falcon acoustics have custom sizes made especially by Solene for Falcon so no problem to find the exact sizes.
Tlhp.com have also the SCR (Solen manufacter) in many values at cheap price if you do not find all at Falcon and they have some other brands too if you want radials.
Not if they're mylar and it also depends on their level of parasitic inductance, winding tension and the type of lead wiring termination, which can certainly deteriorate over the years when the epoxy dipped coating gasses out.
I have replaced alot of crossover caps in B&Ws. Those brown little devils from that era don't compare well to modern PP caps. The top end sounds rolled off with the stock caps. The Solens sound just right with the older soft domes and with some of their metal domes they used later.
Clarity caps are also good but sound a little softer to my ears. The Solens can sound edgy with Ti and Mg alloy HF domes. Usually they're just right with B&W Alu and soft domes.