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
I've done some work on my 800D2 crossover, which makes the mid-treble response smoother and more "seamless".

The FST driver exhibits a slight peak at 3.5 kHz, which can be fixed with a RLC (2mH + 6R+ 1uF) network in shunt with the driver, and by soldering a 0.67mH inductor in parallel with the tweeter, the tweeter's response conforms more closely to ideal, and the improved phase relationship reduces the dip around 2kHz.

Ideally, the tweeter series cap should be 4.3uF. 

I've confirmed before / after with comprehensive measurements. 
hi guys,

hope to open this archeologic thread back up 😁.
for the last 2 years i've been working on a couple of n803's.
guys have i been upgrading these speakers.
i rebuilded the crossovers from scrap.
hard wired on wooden multiplex boards.
the following brands have been used:

duelund vsf, cast cu, silver bypass for tweeter.

jupiter cu wax, mundorf  , jantzen foil inductors, path audio resistors for midrange.

mundorf bl 180 for bass and mkp for parallel.

matrix skeleton has been removed in the midrange compartment and a tube shaped room with a difuser has been installed.

a labyrinth has been installed between the matrix bass compartment to reduce standing waves.

original tweeter housing has been modified to accept diamond domes and therfore uses the 1st order crossover as seen in the "D" series.

the speaker cabinet was completely stripped, stained in red and sprayed in hi gloss with the polishing and stuff.

the tweeter housing as well the bass port are veneered in dark lambs leather.

as final all units have been finalized with chrome trim rings and bars as seen in the signature 30.

too bad i can't upload pictures but they are beautiful and sound awesome...

cheers,

werner
Hi folks. I'm new to the Forum but I've joined to explore the 803d crossover mods. I've owned these speakers since new and I am getting older which brings its own set of issues regarding hearing loss. As a consequence I'm having to play my music at quieter levels. I love the speaker but my purpose for doing the mods would be the help them come alive at lower volumes and of course an improvement across the board at all volumes would be wonderful. I too hear a little harshness on the top end of the tweeter at times, but for me the biggest fault with the speaker is that the mid-range is a little recessed and lacking detail. I'm not really looking for improvements in bass which is good because it seems like those that have modded the capacitors in the base crossover did not realize many gains. I have good knowledge in electronics and have built and molded many audio devices especially vacuum tube devices for both music and guitar amps. Too many mods over the years to describe - I've been at this for about 35 years now. Having said all that I spaced out the parts and this project could cost around 1500 Canadian dollars so I'm on the fence at the moment and this is where I'm hoping you guys will help me. Funny enough I heard Totem metal V2 speakers and this is something of a target for me to get that kind of resolution at lower levels. So my choices are really to mod the 803d which I still love for the scale they bring to the musical presentation or bite the bullet and sell them and try to wait for a used pair of Totems (or other contenders) to come for sale which doesn't happen very often. I'm retired now and finances are more of a consideration than they once were. Thanks in advance for any advice you guys can offer. Thanks, Dale