B&W 803D crossover caps

I don't wish to sound to basic here but I believe more bypass caps may be the only sensible thing. Have you asked B&W-- or an authorized repair center? Are you up on any crossover design changes for the newest series? ?Have you spoken to Mundorf? And lastly,seriously, have you had a lot of success modifying crossover in other comparably high quality intelligently deigned speakers

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

ptss

Do not worry. I have plenty of experience modding equipment. If you doubt it, see my post on mods for the Spectral DMC-10 in the WhatsBest forum.

BTW, my version is just the "803D". I have it on good authority that the later version "803 Diamond" uses only the Supreme Oil, not the SG or the SGO. This info was provided by looking at a replacement crossover for the Diamond version. Seems like that is a big step back, according to the only review I have found to rank all three Mundorf Supremes (humblehomemadehifi).

Call B&W regarding crossover caps? Are you kidding?

A simple swap out of a crossover caps is not rocket science. It will not damage the speaker or destroy my amplifiers. At this level of performance, the results will probably be very subtle, but that does not mean they are not worth doing.

Manufacturers often make design decisions based on cost as well as performance. We have an opportunity to re-evaluate that decision and remove cost from the equation, up to certain limits.

John:

Thank you for your thoughtful comments.

My goal is to remove a bit of upper midrange brightness without effecting resolution in bells, symbols, vocal microphonics. The speakers are not at all bad as they are, but could stand a bit of improvement in these areas. I well know from my experience modding amplifiers that improvements in certain components can improve the sound in seemingly small but still significant fashions. I have no hard and fast goal for the end result, but will probably know an improvement when I hear it.

A few other parameters. The replacements need to fit on the existing pc board without kluges or modifications. No running feet of extra wire from a remotely mounted component to the board. They cannot reduce the reliability of the speaker by leakage of oil or wax. And finally there is cost. Given the value of the 803Ds I don't feel like spending $5000 on caps.

I was using the extensive review of humblehomemadehifi for initial evaluations. That review does not place the Clarity MR above the Supreme SG, but I realize there is probably a degree of subjectivity (to each his own). The Jupiter caps are highly regarded, perhaps above the Mundorf line.

As I posted above, it looks like B&W may have stepped back in SQ for the later Diamond series. They may have had a reason for using Supreme Oils (Al metallization) instead of the more expensive SG as in my D version, but I suspect it may have been more cost driven than SQ driven.

Regarding the other components, from my BOM documents on the 803D, the resistors are part number RNP50s, which are 100W, 5% power film resistors (TO247 package) that are clipped in to heatsinks on the CO board. They are made by MB Electronics in Germany. The resistor in series with the diamond tweeter is either 0.5 or 1.0 ohm (there is a contradiction between the value on the BOM and the schematic). The resistor in series with the midrange FTF is 100W 2.0 ohm RNP50s. My suggested replacement would be a Caddock MP900 power film resistor, which has a tighter tolerance and better tc, same TO247 package.

The inductors look like nothing special. Air core, conventional wire wound, wire gauge 1.2 mm (not flat ribbon).

It seems to me the most important cap is the 47 mFd midrange FTF coupling cap. But here we are limited severely by that capacitance. Mundorf has a Supreme EVO SGO that is 47 mFd, but it costs $700-800 and is too large to fit. The next closest are the EVOs I cited above. Bypassing is possible, but probably not that effective as this driver is crossed over at 4KHz, and a bypass would be kluge at best.

The next is probably the diamond tweeter coupling cap at 4.7 mFd. The Jupiter will fit as well as perhaps the Clarity

And yes, I considered re-wiring as well. But not for now, as that requires a complete strip down of all the drivers, and I want to avoid removing that FTF midrange if at all possible.

Hello again DH. I simply asked questions-that I thought may be helpful to you or others thinking of such mods. Re B&W; JBL Engineering was very (in fact surprisingly so) helpful re my 1985 250Ti's many years ago; even to provide me new ideas that they had come up with and would be implementing! I respect the investment B&W has in it's business and goodwill so anticipate good PR; why shouldn't you approach them? Are you perhaps doing a bit of 'assuming'? I believe Mundorf are technically expert. I could not find your post re the Spectral DMC 10 in the WhatsBestForum but am interested as I enjoy a DMC 20 with phono in my system. Might authorized repair centers have knowledgeable techs-perhaps with real interest in what they do?