B&W 803D crossover caps


I am considering an upgrade of the crossover capacitors in by B&W 803Ds, particularly the mid and HF coupling caps.

I took out the top bass driver to find out what caps were installed. It looks like for the diamond tweeter B&W uses a Mundorf Supreme silver/gold, 4.7 mfd 1200V. For the mid driver there are two; a 47 mfd Mundorf MKP 400V series coupling cap (in series with the driver) and a 10 mfd Mundorf Supreme siver/gold bypassing cap (parallel to the driver).

I was thinking about changing out all three, but have a few concerns.

I was going to replace the 10 mfd, 4.7 mfd Supreme silver/gold with Supreme silver/gold/oil. Would there be enough of a difference in these two types to justify the cost? I also do not want to make the upper end any brighter.

I am also concerned about the long term reliability of oil filled caps, as some failures have been reported in warmer environments. I wonder if B&W did not use the silver/gold/oils for that reason.

The biggest impact I suspect will come from the replacement of that series 47 mfd MKP. I would probably use either the Mundorf MCap EVO (Al metalization), MCap EVO oil (Al/oil), or the MCap EVO silver/gold/oil. All three are the same size for 47 mfd, and will fit to replace the MKP. Barring the issues about oil, which might be the best sounding? Again, I want to avoid too much enhancement of the upper midrange.
dhl93449

Showing 3 responses by reynolds853

Dhl93449,

My experience with the Mundorf S/G/O was that they added too much emphasis in the treble. I do not have any experience with the S/G capacitors but I suspect I would like them even less than the S/G/O as I would expect them to be brighter and maybe a bit harsher. Given a choice between those two I'd go with the S/G/O, but as I'll describe below, at this level I'd go with the Clarity MR capacitors.

My crossover journeys have ultimately led me to Duelund CAST-Cu capacitors, however, along the way a capacitor that I liked a lot was the Clarity MR. They are fast, extremely quiet, dynamic, very well balanced from top to bottom, spatial and holographic. To those attributes the Duelund CAST-Cu adds a naturalness of tone, greater harmonic richness, and I think perhaps greater sustain although it's been too long since I made that change to likely recall that attribute accurately. Also, I would say that the Clarity MR beats the Duelund VSF-Cu in everything but tone and harmonic richness. I recommend the VSF or CAST ahead of the MR, but unless going with a Duelund crossover, my experience leads me to recommend the Clarity MR without hesitation. I would add, however, that Bill's experience with the Jupiter copper foil caps should not be ignored either, I just don't have any experience with them. Again, based on my experience, and considering budget, if it were my project I would use the Clarity MR's throughout, connecting 2x10micF + 1x27micF caps in parallel to give me the 47micF equivalent for that big value. I strongly prefer the Clarity MR over the Mundorf S/G/O, and as I said, I'm quite confident I would like the Mundorf S/G even less - but comments such as these should be placed in the context of one's system.

Also, depending on what internal wire is already in the speakers I would also consider rewiring the speakers. On my projects I have had very satisfactory results using Kimber TCX. The effect of doing that should not be underestimated. Kimber's Hyper Pure grade copper has no grain that I can hear. Wherever copper wiring is used in my system (interconnects, speaker cables, crossover wiring, speaker wiring) that is what I use. They system is very, very free of grain.

What resistors are in the speakers? My preferred resistors are Mundorf M-Resist 20W. I think Bill likes Mils? Others will recommend the Duelunds, though in my systems I preferred the Mundorfs. For me the M-Resist give a very nice, solid weight to acoustic strings - I don't like plucked acoustic strings to sound too wispy so have come to like the M-Resist a lot.

I do have a couple of questions though. In your original post you said that you wanted to upgrade your crossovers, and in a subsequent post you said that you wanted to maintain the character of the 803. So my questions are: (1) what are you hearing (or not hearing, as the case may be) that has you motivated to upgrade the crossover - what improvements are you seeking?, and (2) what part of the character of the speakers are you wanting to maintain? In what direction are you wanting to take your speakers and/or your system?

Also, what inductors are in the speakers?

Finally, as an upgrade example, I am currently helping a friend with a crossover upgrade to his Silverline LaFolia speakers. The LaFolia uses well-integrated tour-de-force of drivers including the Dynaudio Esotar T330D tweeter, so I have a pretty good feel for where we are headed. For that project we are using:

- Clarity MR 630 VDC caps
- North Creek 10awg inductors
- Mundorf M-Resist 20W resistors
- Kimber TCX internal speaker wire
- WBT Topline binding posts

Unless my friend were going to spend a lot more money I think this will be a very nice setup.

Cheers,

John
DHL,

I wanted to thank you as well for your thoughtful reply. I will be interested to learn how your project goes and hope that you will post updates to this thread.

I wanted to make one more comment about the capacitors I discussed which were in a bit of disagreement with Tony Gee's observation. For me the Mundorf S/G/O tilted things upward too much whereas I found the Clarity MR to be very well balanced. In my system the latter was the superior performer and based on that experience I would not recommend the former to anyone wanting to avoid adding emphasis to the high frequencies. Face's and/or Undertow's comments on this topic a few years back on the Capacitor Log thread make for good reading as well. I agree with you too that it'll ultimately come down to system synergies and personal preferences, I simply wanted to relate my experience for your consideration.

All the best,

John
DHL,

It's funny how these reviews go. I think at this level of capacitor it must come down to system synergy and personal preference.

I have experience only with the 630VDC version of the MR and that's the one with which I would stay. For my friend's crossover project a few weeks ago I ordered a set of MR's from PartsConnexion. They didn't have the ones we needed in stock but it only took them a couple of days to get them from their distributor. If PartsConnexion is indicating a longer delay for the values you need then you might give MadiSound a call. HifiCollective in the UK might be another source.

You mentioned the various conductive materials in your post. As I know you are aware, the MR is an aluminized polypropylene cap. I prefer the tone of the copper film caps more, but as you also mentioned in your note the cost of admission to those caps is high. To me, short of making the jump into those caps, the MR is the best out there.

I reread your original post and it looks like you need a 4.7mfd for your tweeter? I have a pair of MR 630VDC in that value that I don't use anymore since moving the crossover to Duelund CAST. I'll send you an email offline to discuss further.

Cheers,

John