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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
grannyring's avatar
grannyring
6,500 posts
 
No it would not be worth it to stay in the Mundorf family. If you want a much better sounding cap top to bottom, then go with the Jupiter copper foil in bees wax cap. Nice step up for sure! I know as I did it. Unless to go with Jupiter or Duelund, stay put.

Yes the Evo is your best bet on the 47uf.
dhl93449 OP
455 posts
 
Grannyring

Thanks for your input. Reinforced what I was thinking. The cost to do the swap to the silver/gold/oils would be about $1000 for both channels. Serious money.

I think I will stick with Mundorf at this point, as I want to maintain the character of the 803. The Dueland are stupid money and there is no place to put them without adding a lot of wiring inductance to the network. The Jupiter are about $500 more than the Mundorf for a complete swap sans the 47 mfd, and the 10 mfd 100V part is just a bit too long to fit on the crossover pc board. But looks like a serious contender for the 4.7 mfd feeding the diamond tweeter if I want to do that alone.

I also discovered that all the bass driver mounting screws were barely tight. Torquing those up made a large difference in the bass response. I also torqued the tension bar on the mid-range driver and that also improved sonics quite a bit as well. Freebes that didn't cost me a dime.
ptss
1,964 posts
 
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
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