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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
6,436 posts
 
To my ear and based on years of testing and rolling caps, Mundorf caps with silver, silver & gold and the Evo line are all tilted up in the presence area. For that reason they are just not my cup of tea for mids and highs. This is especially true in the upper end Evo line. A speaker that is on the dull and dark side is a good place for these, but not as good as film and foil caps. The best sounding caps are film and foil from the likes of Jupiter and Duelund. The Jupiter copper foils are in a completely different league sonically being more natural in tone and less electronic sounding. Their more affordable VT line is also wonderful. I would also consider the wonderful Jantzen Alumen Z as they are very smooth and natural.

For the largest values (bass) I would look to Clarity CSA before Mundorf.

I would also stay away from Mundorf resistors or sand cast resistors as they sound rough compared to Path Audio or the more affordable Mills MRA.

For the most part I agree with George about the pitfalls of bypassing and I avoid doing this most of the time in crossovers. There are some proven combos, but in general they can sound phasey and strange.
georgehifi's avatar
georgehifi
10,312 posts
 
I avoid doing this most of the time in crossovers. There are some proven combos, but in general they can sound phasey and strange.
"Phasey" An even better description than my "smearing", an overlap of two different cap sounds and time constants doing the same job.

Never bypass caps in the signal path.!! Use the best quality single or two or three if you need them that big identical paralleled ones you can find.
Leave the by-passing only to power supply and V rail de-coupling caps.

Cheers George
dhl93449 OP
455 posts
 
"Sorry no you confused the discussion, you said amp (see below) and I said amp and then you bought preamps into it. Most of us with the knowledge know that many sources and pre’s have much smaller coupling caps than what would be on the output of an amplifier. "

Last time I checked, "preamps", line amps, and power amps are all species of the genus "amps". You are the one assigning the term "amp" to Power amps. 

The point being that there are numerous amplifiers using electrolytic coupling caps in the output, not just tube power amps. Substituting a film cap for these electrolytics may the best sonic solution, but not considered practical by the manufacturer.

Phasey??? WTF is that? Are you implying putting two polypro caps in parallel create abnormal phase response in a speaker? Can you point to where this has ever been measured or shown mathematically? If these high end audio caps are supposed to be closer to ideal caps (the purpose of their manufacturers), then there should be no such behavior in their performance, singly or in parallel.
georgehifi's avatar
georgehifi
10,312 posts
 
Phasey??? WTF is that?
You have no idea, if you don't know what we're talking about, then continue to bypass your signal caps and you'll never know because you obviously can't hear it.

Cheers George
erik_squires
15,643 posts
 
The issue of Mundorf vs. Copper film:
Mundorf Supreme caps have their very own house sound. To me it is like a disney / Fuji film sheen with hypersaturated colors. Scintillation is also a good way to describe it.

This is what Magico and B&W like to use in their top end.

If you bought your speakers for that, stick with the capacitor and speaker brand.
If you are getting into swapping to copper film caps, which are my choice, you maybe need different speakers altogether, because they are not going to sound the same and you are going to end up in a lot of expensive upgrades before you realize that.
A good cost effective compromise IMHO is to use Clarity's top end with copper film bypass caps for anything over 5uF
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