B&W 803D crossover caps

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

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

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. 

You can paralell caps of the same brand at near the same value with no problem at all. In fact, this method is used my some very high end builders for the best sound.

Yes this is the only time to do that with caps in the signal path as I said previously.
And yes it "can" even be beneficial as  2 3 or 4 paralleled caps will have a lower esr than one cap of the same make and value. BUT!! the lower esr means that driver will have a slightly louder presentation due to the lowering of series resistance. So the voicing of that driver will change to what the manufacturer designed it to be and this should be taken into account.

Cheers George

Jantzen Alumen Z. Just combine/paralell for needed total by using as close to equal values as possible. I think the Clarity CSA is a better sounding cap on the mids then the Evo line and should fit using good DIY skills.

You can paralell caps of the same brand at near the same value with no problem at all. In fact, this method is used my some very high end builders for the best sound.

I don’t doubt that your upgraded B&W sound wonderful and better than stock. More than one way to audio bliss! 

Erik S:

Last time I checked, a few years ago, Jupiter did not make a copper film cap in 47 uFd to replace that critical midrange coupling cap. Clarity cap makes one in their CSA line, but that is metallized poly pro. It is 62 mm diameter (much larger than the 50 mm diam EVO and the 42 mm MKP), so it may not fit on the MR CO board. Plus, I doubt if those CSA versions are any better than an OIL or SGO Mundorf. In general copper film caps are too large to fit or are not available in high enough capacitance. And of course, we dare not parallel smaller values for fear of the dreaded "phasey" smearing effect.

I also need to say that in general, with 90% of the music I listen to, the modded B&W 803D I have sound wonderful. There is some material, mainly compressed rock (like in my case Genesis Trick of the Tail/CD ,not vinyl), that sounds harsh. I do not ascribe to your description of these speakers whatsoever, and I have had numerous friends and strangers listen and they find the results impressive (some are musicians). So I am happy with them for the most part, but continue to look for ways to improve them if I can.  

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

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

"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.

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

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.

George:

You miss the point.

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.

"For example, when an Al electrolytic is used as a coupling cap at the output of an amplifier driving low impedance loads."

As I responded to this statement of yours. Nothing to do with preamps.



Cheers George

biggy:

I am currently using all Silver Gold Oil Mundorfs; either Supreme versions (TW coupling, MR bypassing) or EVO (not Supreme) versions (MR coupling), except for the bass LF crossovers, which are bone stock. As mentioned, the harshness I believe is from the FST MIDRANGE, not the tweeter. If you want to de-emphasize the tweeter, you can increase the resistor in series with it. Replacing that MKP 47 uFd with EVO oil or EVO SGO will make a major difference, so I would start there and then listen to the results. I would not go in and wholesale replace multiple caps and resistors. Adding the anti vibration weight from the 800/802 can make another significant difference. You can see this in the midrange driver replacement video on the B&W parts website.

I put little importance into those cap reviews that rate plain "oil" with Al metallization with silver or silver/gold. Too many variables that may or may not apply to my personal system. When I have compared oil vs SGO in preamp outputs and DAC outputs, I have always like the SGO. 


As I said, try the "oil" versions first and see if you like them. They are the cheapest version and if they are better for you than SGO, then you are ahead of the game. But be aware that swapping these caps is not easy, and pulling and re-installing the crossovers is time consuming.

George:

You miss the point. I just explained that film caps are often not an option when the manufacturer is using surface mount technology for the components. Plus, the proper size poly pro film cap will physically not fit in a 1U chassis and is extremely expensive to boot. Polyester (mylar) caps are smaller, but are not as good as polypropylene.

Not as rare as you think. Did you know the Bryston BDA-1/2/3 all have Al electrolytic (surface mount) coupling caps in their outputs?

I said amps, they are preamps, and yes many preamps and sources are cap coupled, but they don't need anywhere near the size cap an amp does so one only good quality film cap will do them, again never by-pass them.

Cheers George

" This kind of amp cap coupled output is very rare to have. I take it it’s tube with no output transformer, but with capacitor coupling instead, I would just get an OTL myself but??"

Not as rare as you think. Did you know the Bryston BDA-1/2/3 all have Al electrolytic (surface mount) coupling caps in their outputs? Along with I think their preamps, even current production. Their engineers are concerned with the small amount of DC offset their class A discrete amps produce (10 - 20 mV), ergo the caps. Using a 10-30 uFd film coupling cap is out of the question for them, as it's size and cost would be prohibitive.

Bryston does not parallel a film cap with these Al Elct caps in the output stages, due to the lack of compact surface mount film versions (poly pro are very rare in surface mount), and NPO ceramics are outrageously expensive. 

In my new BDA-3, I removed the Elect caps and put in a surface mount shorting bar. The small DC offset is easily handled by my Parasound JC2 preamp and its DC offset servo controllers. Made a significant difference in sound quality. I have been in contact with Bryston Eningineering and urged them to put in DIP switches so that users have the option of shorting out those caps if they have downstream circuitry that can handle the offsets. 

B&W itself did "downgrade" from Supreme Silver Gold to an "inedited" Supreme Oil, without silver, and the general consensus is the 803 D2 sounds much better in the treble range than the D, much smoother (and still not enough...maybe the problem is Mundorf?).

I don’t know if replacing a silver cap with another silver cap, but with oil, is worth the money an the work; @dhl93449 please, I ask you to tell me the changes you had in hf so I can have some elements to make my decision easier (better to say less hard).

@stoni chaged the B&W custom 51uF Supreme Oil in his 803D2 with SGO, then he had to make another work to change tw cap again (with a Jensen Duelund if I remember well), it is clear he was not satisfied from the upgrade (iscit a real upgrade, with these diamond tweeters?) from an (aluminium?) oil cap to a silver gold oil cap, since the latter highlights high frequencies and may mask the other parts of the spectrum.

In a well tuned and high quality system (in mine, electricity and source are near to state-of-the-art, with a power regenerator followed by isolation trasformers for each machine and a divine Accuphase DP700 SACD player, cables are near to the best Cardas ever made, Luxman 509u integrated is not the best amp in the world but if you read Uday Reddy’s Soundstage! 2009 review maybe you may hurry to find an used one, or to buy the new 509x) a SGO capacitor could sound without harshness afterall.

Don’t misunderstand me: I don’t listen now with harshness in the highs (only some selected albums make me struggle, for example Genesis’ "Selling England by the pound" or Joe Satriani’s "The Extremist", and I know even these albums could sound better, and all the music with them), I have simply reached speakers limits and I want to go on in my audiophile journey of (personal and equipment’s) improvement.

Another idea could be to use the Supreme EVO Oil in all positions: 4.7uF tw coupling, 47uF mr coupling and 10uF mr bypassing, and EVO Oil on the woofers.

Or 4.7uF Supreme Evo Oil in tw coupling and 10uF in mr bypassing, Evo Oil both in mr coupling (47uF) and in woofer caps (2x100), to make something similar to the original project of both D and D2.

The only truth is one should have to try, not reasoning "on the paper" ... !

I had a change in my system I did not tell you until now...
A (deplorable in my opinion) technician repaired my Purepower putting inside it Claritycap SA caps instead of the original taiwanese Fu-Jack caps (they seem Panasonic or Vishay clones) without telling me before, maybe because he had that caps in stock, without need for ordering a 10uF 500V (for the power stage, right after power inlet) Panasonic and a 2uF 600V (for battery recharge system) Vishay caps.
Now I have the impression of a tonal shift towards mid-highs.

The Humble Honemade Hifi comparison tells the Claritycap make sound shift towards clarity, since Panasonic is the most neutral cap in its range, it does not highlight anything.

Do you think I have to make another technician replace the Claritycap SA in my regenerator with Panasonic and Vishay (since there is no Panasonic cap under 10uF), and only after that to think at speakers recapping?

Many thanks

@dhl93449

I found here http://www.audiokit.it/it/30951-condensatori-mundorf (I am from Italy) there is a 47uF Supreme EVO Oil, which measures 76x67 mm.

The 47uF standard M-Cap EVO Oil measures 50x50 mm, the same as your EVO Silver Gold Oil.

Do you think the extra 26mm thickness of the Supreme Evo can make it not fit in?

Maybe if Stoni (see the 12-09-2015 10:27pm post) could use the Supreme EVO Oil into his 803D2 the same could happen in our 803D ...

The M-Cap Evo Oil is available at 100uF, so if I use the EVO Oil in series with the midrange maybe I could put woofer and midrange (coupling) caps of the same type (like in the original project!) even if you told me woofer caps don’t make significant difference in sound, but there would be a theorical coherency between bass and mids, both with EVO Oil instead of MKP, and the same thing would happen between mid (bypassing) cap and tweeter (coupling) cap, both with Supreme SGO instead of Supreme SG.

I am also thinking of removing all silver from my speakers, and "downgrade" from the Supreme SG to the standard Supreme for coupling tw cap and bypassing mid cap: warmer, richer and more natural sound, with absolutely no emphasys on the treble and upper midrange.

Maybe If I do, I would transform the B&Ws in other speakers and I don’t want to, but I would be happier.

Hard choice

For example, when an Al electrolytic is used as a coupling cap at the output of an amplifier driving low impedance loads.

This kind of amp cap coupled output is very rare to have. I take it it’s tube with no output transformer, but with capacitor coupling instead, I would just get an OTL myself but??

For and 8 ohm speaker you would need at least 2000uF for the coupling cap to see low fr limit of -3db at 10hz.
One or a couple paralleled depending what polarizing output voltage this amp has of these would fine great with NO! bypass cap.

https://hfc-fs.s3-eu-west-1.amazonaws.com/s3fs-public/audio-note-electrolytic-update-051217_0.pdf
or you could get cheaper Black gates instead.
https://www.hificollective.co.uk/components/black_gate_n_type.html

Cheers George

George:

Regarding parallel caps. I agree in general, except when there is no or limited choice. For example, when an Al electrolytic is used as a coupling cap at the output of an amplifier driving low impedance loads. A polypro or film cap may not be available or practical to use in that application if DC offset from the amp is an issue. Adding a parallel poly pro film cap will definitely improve the sound over just an electrolytic alone. 
I believe one reason that parallel caps are not a panacea is that certain properties (like poor dielectric adsorption) cannot be compensated for by placing caps in parallel. 
One practitioner of massively paralleling film caps (John Curl of Parasound) has recently commented that that practice (seen in many early Parasound power amps) may not be best. He cites resonance effects between these parallel stacks at extremely high frequencies (100's of Megahertz) as the issue. Those early power amps still sound pretty good though.

biggy:

Regarding sizes. Check a website like parts connextion. Not all "EVO" sizes are the same, and the "Supreme" (black) versions are larger I think. I used the " 47 uFd EVO silver gold oil", in the white cases with gold printing. The "Supreme" versions have special, non-inductive windings and are therefor actually two caps in the same package, therefor much larger. I don't think a EVO Supreme SGO is available at 47 uFdf. 

biggy

That is what I did. Silver gold Oil 4.7 uFd for the coupling tweeter; 47 uFd EVO SGO for the mid coupling cap; SGO 10 uFd for the mid bypassing cap.  
Whether you use SGO or just "oil" (those are aluminum metallized instead of gold/silver) is a matter of personal taste (and budget). I never found SGO "harsh" or "bright". Maybe you can try the "oil" version first, since they are much lower cost. I just think the silver/gold metallization is lower impedance since gold and silver are much better conductors, but the aluminum may be applied by Mundorf in a thicker layer, which compensates for lower conductivity of the metal itself. Specs wise I don't think there are major differences, but longevity wise I think the gold/silver are better.
As far as the resistors go, you will have to see exactly what B&W put in your crossovers. As I said, they vary by production year and model. I substituted Caddok MP9100 series for the versions used by B&W; they are a pin/pin exact replacement, and fit in the pc board holes (and on the heatsink) precisely. I would avoid the exotic resistors that will not fit on the pc board. Running long wires to mount these can undo the benefits of them in the first place. Plus, you need to replace the OEM parts with versions that have the same or better power rating.

Wait a minute, maybe I have misunderstood some things:

- does the Supreme EVO Oil not fit in the MR crossover?
Can I use only the standard EVO Oil?

- in the D2, the 10uF bypassing cap is  "Supreme Oil" ... is it a custom model only for B&W speakers, not on the market?

Anyway, my 803D uses Supreme Silver Gold (without oil) both in series with the tweeter (4.7uF) and in parallel with the midrange (10uF).

Replacing both caps with Supreme Silver Gold Oil should give more smoothness and refinement  without changing too much the original project, I guess.

Replacing the MKP 47uF coupling cap in the MR crossover  with the EVO Oil (not the Supreme EVO Oil ?) should give a GREAT improvement in mid frequencies.

@dhl93449  tell me if now I am right

Sorry, I used "nF" instead of "uF".

@dhl93449

Do you like my project (to "add oil" to the 4.7uF TW coupling cap and to the 10uF MR bypassing cap -since I have 803D, not 803D2- and to replace the 47uF MR coupling cap with the Supreme EVO Oil) ?

What differences could I expect using Supreme EVO Silver Gold Oil instead of Supreme EVO (Aluminium) Oil in the MR?

What values for TW and MR resistors do you suggest?

Ok, I will keep the MKP caps on the bass section.

Many thanks

(there are two MKP 100 uFd in PARALLEL with the four drivers)

Two cap of the same paralleled in series in the signal path is fine, as both are identical as both have the same time constants.

It only becomes a problem when the two are different values or makes, as both are behaving differently at a certain frequency.

EG:
A series cap 20uf seeing an 8ohm load will roll off -3db at 1khz and go out to beyond many mhz.
A series cap 2uf seeing an 8ohm load will roll off -3db at 10khz and go out to beyond many mhz
If the 2uf was use to by-pass the 20uf both will be letting through the frequencies higher than 10khz at the same time creating smearing effect because each have different sound characteristics.

I have proved this to myself many times, with caps in series with the music signal.
  
The only time a bypass cap should be use is in power supply decoupling.

Cheers George

biggy79

I don't think george reads your posts carefully. You are correct, there is a 'bypassing" cap (ie one parallel to the FST driver) in the crossover network. It is a Mundorf silver gold or silver gold oil, depending on what product you have or version of crossover. It is an upgrade (at least according to Mundorf, who makes these capacitors) over the any MKP version, which is in series with the FST driver.

The EVO versions are the only ones that will fit (47 uFd) as a substitute for that MKP 47 uFd. They will improve the sound considerably, although at very high cost. I do not understand, from a sound quality perspective, why B&W would use an MKP version instead of an EVO (either oil or SGO). From a COST perspective, perfectly understandable.

Don't forget the series coupling resistors in the MR CR network. The service manual shows a couple of values being used (and mine had even different values). Plus or minus 0.5 ohms in this coupling resistor can make a significant difference in the 800-1.2 KHz region.

The changes from 47 to 51 uFd in the D2 may not have anything to do with "smoothness", but a shift in crossover frequencies due to driver changes from previous versions. 

With respect to the "woofer" caps (there are two MKP 100 uFd in PARALLEL with the four drivers), remember these are there to roll off the bass drivers at higher frequencies. I don't think Mundorf makes 100 uFd SGO caps, and as these are there to attenuate signals across the woofers, their impact on sound quality is minimized (unless you have an lower midrange peaking problem). My tests with pink noise do not show any such peaking (nor do I hear one), so I leave these alone. I have heard of people "bypassing" these with lower value (like 1-10 uFd) SGO type caps, but I doubt if you gain much, because the frequencies (and impedance) needed to impact bass drivers. For example, a 10 uFd cap will be lower than 4 ohms at frequencies above about 4 KHz. That is quite a bit higher than the 200 Hz cross over frequency for the bass drivers, so these bypass caps will have little to no impact on the bass drivers at or below the crossover frequencies. 

george- download a version of the service manual from B&W and check out the crossover schematics before you comment.

There are various differences in the tweeters in the 800/802/803 series products. Whether some sound "better" than others may be a matter of personal taste or sensitivity.

georgehifi:

I don't think I suggested there is a quality issue with the parts in the crossover, but a cheaper MKP version will not sound the same as a Silver/Gold/Oil. That is why they make the SGO in the first place. Do you even have 803Ds or have listened to them?

Replacing that MKP 47 uFd with a SGO did make a significant difference in sound quality. Neither capacitor sounds "bad", but the SGO sounds better, and isn't that what we all strive for? If every manufacturer had the tuning of their product perfect out of the box, then there would be no upgrade market then, would there?

Since my original post I have added a few more mods. I now believe the upper midrange harshness that sometimes is present is sourced from the FST midrange driver. There is a mod that the 800/802 series had (a heavy cast iron weight attached to the back of the FST driver) that is absent from the 803 series. When I asked B&W tech support why the 800s have this but the 803D does not, they told me the weight will not fit in the 803 cabinet, but it will fit in the marlan cabinet on the 800/802. So not entirely believing their story, I ordered two to see if I could fit them. I had to remove a small pc of 1" of foam at the back of the cabinet (so tech support was correct) and the drivers and weights fit fine. You have to make another threaded tension rod (I used 6mm stainless threaded rod) and obtain a couple of 6mm SS nylok nuts; one set to attached the rod to the FST driver, and another set to hold the weight snugly against the back of the driver. Don't forget there is a rubber gasket placed between the weight and driver. You may also need loktite between the threaded rod and the FST driver to keep things tight and to prevent loosening. This mod also worked quite well in smoothing the upper midrange even further.

What I would really like to get a hold of next is the latest version D3 midrange driver. They are completely different from the older FST and from what I understand, have addressed many of the problems of the earlier version. But, they are not available on the B&W parts website yet (maybe the never will be).  

There's no cheap caps on the mid xover I just linked to, Mundorf and M-Cap!!! and no 47nF there is a very good quality 47uF.
 
One good cap of the correct value that B&W worked out that's it, if you look at the 802D MkII photo I linked to of the mid, they have already used very good caps, I have no doubt the tweeter would be just as good if not better. 

Cheers George

I don't want to bypass caps ;) , I read the cheap 47nF MKP is in series (a "coupling cap") with the midrange driver, while the 10nF Supreme Silver Gold Oil (in the D2, without oil in the D series) is in parallel (a "bypassing cap") with the driver.

My project is to put a 47nF Supreme EVO Oil instead of the MKP and a 10nF Supreme Silver Gold Oil instead of the same model but without oil in mounted in the 803D, and to replace the 4.7nF Supreme Silver Gold in series with the tweeter with a 4.7nF Supreme Silver Gold Oil.

I read above 803D2 have a 51nF (instead of 47nF) Supreme Silver Gold Oil on the tweeter, maybe that's why D2 series is smoother than the D (which tweeter cap is without oil), but even more forward in the treble range.

dhl93449

There is nothing wrong with this xover in the quality of it’s parts, look elsewhere for your upper midrange brightness.

As for the suggestion of by-pass caps, don’t! The only time to use by-pass caps is with power supply caps (decoupling), never with a cap in series with the signal or in xovers (coupling), as the two different time constants of the caps will have a smearing effect in that region that they are working in and actually degrade the sound, always use one good quality cap, and that is what B&W have done here.

https://img.usaudiomart.com/uploads/large/934237-bowers-amp-wilkins-bampw-803-diamond-803d-mf-crosso...

Cheers George

@dhl93449 
@stoni 

I have 803D first series since 2009, I won't change them with D2 or D3 series since (expecially the D3 with only 2 woofers) I find them leaner than the original D series.

The 803D are the best speakers (in my very well tuned system, with Purepower 3000 and two isolation trasformers added in series, one for Luxman 509u integrated amplifier, one for Accuphase DP 700 SACD player, Cardas Clear series cables - Beyond XL for isolation trasformers, Beyond and standard Clear power for amp and source, Beyond XLR interconnects-, except for speakers -where I have still the old Golden Reference, 2 pairs biwiring-) I have ever heard in their price range, they are complete speakers and can play all kind of music, with satisfying bass response (no other speaker have that punch) and great clarity and imaging.

803D obiouvsly have faults:

- in the highs, sometimes harsh/hard/highlighted  (I could never make Genesis' "Selling England By The Pound" sound without harsh metallic highs, since lots of albums sound great and smooth, maybe it's a matter of recordings)
 - in the midrange, lacking of warmht and richness, sometimes hard in jazz music (horns dynamic peaks sometimes are strident)
- in the bass, sometimes fat in the mid-bass (covering the lower midrange) and not so well articulated and "vibrant"

After reading your experiences, "merging" both, I am considering to replace caps, sticking with Mundorf, trying to respect as much as possible the original project:

- the Supreme SG on the tweeter, with a Supreme SGO; I hate silver sound signature, but I want to respect the project only adding "warmht" and refinement an oil cap can bring to the table

- the MKP coupling cap on the midrange (the bigger weak point!) with a Supreme EVO Oil; I started thinking about a Supreme Classic, but it seems it does not fit :/ ; Stoni said his 803D2 now sound better than the Sonus Faber in the midrange using Supreme Evo Oil !
I don't want to add silver at this point, where the original project had no silver caps, and I don't want to highlight upper midrange giving an unwanted "silver signature"

- the Supreme SG bypassing cap on the midrange with a Supreme SGO (same as tweeter thoughts : I hate silver, but I don't want a revolution, only a step up in warmht and refinement)

- the woofers MKP caps, with ... ???
Maybe every other cap I will put will be better than the MKP, so I would not have to worry about!
As I told before, keeping punch and richness, I would like to improve bass articulation making it more "vibrant".
I am thinking about Supreme Silver Gold, without oil (maybe could I "recycle" caps I put out of tweeter and midrange?) ...
There was no silver in the original project here, but I think it could be useful making bass faster. On the other hand, I don't want it to become lean.

Any comment or suggestion (keeping in mind I want to use only Mundorf capacitors and I don't want to change too much the speakers, but only to improve where they have weak points) is welcome, many thanks if you do

Love reading this stuff as I am a big BW fan.  Good job gents. 

Hi guys,

I just took my midrange crossover out and replaced it with the midrange crossover of the 800D.
The bass and treble crossover are the same  in the 803D as in the 800D.
I owned the 800D years ago and always liked the sound of its midrange.
The sound wasn’t coming from the midrange but was like hanging around the speaker. (Maybe reversed polarity? )
I owned and tweaked lots of B&W speakers. The silver signature is one of my reference speakers and are recaped with mundorf silver gold in hi frequency and mundorf silver gold oil in midrange.
The sound is really transparent, lots of resolution, silky and no harshness. (Tweeter is also operating in reversed polarity here!)


There is some place in the bottem of the 803D cabinet.
Remove the bass crossover and install the 800D midrange crossover in theen same compartment, but upside down on the matrix internal structure.
Afterwards the 803D sounded
BEAUTIFUL.
The emphasis of the tweeter disappeared.
I wouldn’t put the silver oil, silvergold in oil in the tweeter or midrange because personal I found them to be a bit too detailed.
The 800D was the most natural sounding speaker of the whole 800D series. (800D, 800 Diamond )
The crossover cares 2× mundorf supreme and 1 silver gold (no oil).

Cheers Werner.

Mark:

You're welcome. They are sounding exceptional right now. That 47 mFd EVO SGO midrange coupling cap is really making a difference.

Thank you for sharing your crossover upgrade experiences - I previously owned the 803D and 803 Diamond speakers - great value high tech speakers with timeless industrial design.

edwyun

Because that route is fraught with just as many variables and complexities. I was going to do that with another previous set of speakers and ended up buying the B&Ws instead.

To do what you suggest  first you need 3 to six power amps, depending on if you use stereo or mono amps. You need to adjust the output levels of each amp with each driver, so you need an RTA/pink noise setup to do it right. Then you need a decent XO setup. Anyone know of discrete component class A XOs that have three XO points? And a choice of first, second, or third order slopes? No? Me neither.  There are XOs out there, but most are op-amp based which is unacceptable to me. Finally, if you are using B&W drivers, you have to have impedance and parameter data for the drivers which is unobtanium unless you measure it yourself.

As I stated I considered building my own speakers prior to buying the B&Ws, and was going to go the full active route. But I could never get over the compromises and costs, plus I cannot design a cabinet like B&W does. 

Um, why not go to active crossovers and get the most control of the drivers and how they sound?  A lot easier than the "black arts" of trial and error using different caps.

Over the last few days I have had a chance to complete the mods to my crossovers. Thanks to all for their suggestions.

I had to remove the upper bass driver and the mid range FTF driver to get at the crossovers and the wiring. I also removed the tweeter but I will get to that challenge below.

The XOs are mounted on plastic standoffs that are a bear to release the PC boards from. B&W slops glue on top of the barbs that hold the boards to the standoffs, and getting all the glue from the barbs usually means destroying the barbs. I contacted B&W and their CS was kind enough to send me back ups (they are not listed in their parts lists). I ended up pulling the two front standoffs and replacing them with a threaded insert designed for wood. My local hardware store had some that fit the .280" holes perfectly (use 5/16", for #8 screws). With .25" tall spacers, these mounted the boards perfectly.

The HF XO board is mounted on the roof of the midrange chamber, the MID XO is mounted on the floor. To remove the HF XO you have to release the board from the standoffs, then cut a number of tie wraps to release all the wiring. The HF XO is fed with two 12 ga wires (red/black) terminated in gold plated tab connectors (nice). Another pair of 12 ga black/red are soldered to this board and are terminated in a Molex connector that feeds the tweeter. I did find many of the tab connectors to be very loose, so I had to correct that before re-connecting.

I ended up swapping out the Supreme SG 4.7 mFd for an identically sized Supreme SGO. I also pulled the 0.5 OHM tab power resistor (no name on it) and replaced it with a 0.75 OHM 1% 100W MP9100 Caddock thick film resistor that mounted to the OEM heatsink perfectly. I used 0.75 OHM instead of the 0.5 OHM to reduce the tweeter output slightly. B&W originally spec'd a 1.0 OHM which they changed mid production to 0.5 OHM.

For the MID XO, I also swapped out the 2 OHM resistor with a 2.0 OHM 1% Caddock MP9100. I pulled the MKP 47 mFd Mundorf film cap and replaced it with an EVO SGO 47 mFd. This cap also fit quite nicely. I had PartsConnex match a couple to under 1%.

After re-mounting the XOs, I soldered all the gold plated tab connectors to the wire they were crimped to. Unusually, some were soldered by B&W and some were not. B&W also used some sort of grease on the connectors (not necessary for gold connectors IMHO) so I removed that as well. I pulled all three bass drivers to tighten and solder connections.

Now the tweeters. I strongly suggest most users leave these guys alone. They are extremely fragile and you must not touch that diamond diaphragm if at all possible. In mine, I felt a little too much front to back play, so I thought something might be loose. The motor unit/diaphragm is coupled to a bar that runs rearward through the end of the casing tube. At the end of this bar, a soft, gooey gasket material (looks like Sorbothane with the consistency of a gummy bear that has been on a hot sidewalk) surrounds the bar and isolates it from the casing. When you pull the motor and bar forward, you inevitably destroy this gasket as it sticks like crazy to the bar, and turns itself inside out as you pull forward. So order a backup from B&W before you disassemble the guts of the tweeter.

In my tweeter, the plastic coupling nut that holds the bar to the motor was loose. And you cannot tighten this nut unless you pull the guts of the tweeter out.

After all was put back together, I had a chance for some preliminary listening. I have to say the total end result was more pleasing than I anticipated. If I have to use a single word, it would be "smooth". Edginess on horns and vocal sibilants was gone. Bells and symbols are now slightly recessed in volume, but still very clear in position, with more 3d space between them. The overall sound fill left to right is vastly improved, with sound spilling outside the boundary of the left and right speakers (something I have been struggling to get with these 803d's for some time). The midrange seems to be separated better from the bottom end in clarity (this is hard to describe), so the bass transients no longer "mask" some of the midrange, as they had done before.

All in all, I am very happy with the changes.

I use the Jupiter copper caps and have never had an issue. You will never have an issue in a speaker crossover as there is no heat. Heat is the only factor of concern with these caps. I use them in tube amps with heat and still no problems. 

I have had them in my speakers and gear since they were introduced perhaps two years ago. So much better than any Mundorf caps based on my considerable cap rolling experience.  They are far more quiet, they remove noise better than the Duelund CAST. They are SOTA for micro details and exhibit a nice airy, natural tone. I prefer them to Duelund as they are more neutral through the upper mids. Very special cap. 

Stoni:

Interesting post. I have been looking at what B&W has been doing with these cross overs in the last few product iterations. Particularly with the capacitors, they have been all over the map, except with that 47 mFd MKP, which is consistently used from the 804S through the 803D2/3.

In my 803d (first diamond in the series), the tweeter coupling cap is 4.7 mFd Mundorf Silver/Gold Supreme (not oil). In the 803D2, they went to Supreme Oil (Al metallization?), not Supreme Silver/Oil or Silver/Gold/Oil. Looks like in the D3 they are using Supreme SGO at 5.1 mFd, not 4.7 mFd?

I have decided to try the EVO SGO 47mFd in the midrange. The Al/Oil is cheaper but I prefer silver metallization. I have also decided to replace my Supreme 4.7 mFd S/G with a Supreme 4.7 mFd SGO. If that is too strident, I will consider a Jupiter copper paper/oil, but I am nervous about the longevity of these paper/oil caps (along with the cost).

I also have a pair of 804S, with the Al tweeter. That product uses almost the same values as the 803d. The tweeter coupling cap is Mundorf 4.7 mFd Supreme, and the midrange (which is the same unit as in the 803) is coupled with that MKP 47 mFd, and bypassed with a Mundorf Supreme 10 mFd. Like the 805, the bass drivers are bypassed with an electrolytic parallel with a film (150 mFd electrolytic parallel with a 47 mFd MKP film). In the 803D, the bass drivers are bypassed with two 100 mFd MKP films.

I agree with you that bypassing an electrolytic with a film in a cross over is not a good idea. I think that is because in a XO, the caps see significant AC voltages. Any dielectric adsorption effects in an electrolytic cannot be reduced by a film in parallel, and may therefor may be audible.

Hi, my experience might be of some help if you want to upgrade the 803D2, which is what I've done. I did buy a new set of Sonus Faber Olympica III, and wanted so much to replace my 803 (or to be honest, my wife wanted to replace my 803...) The SF midrange was to die for, but the same cannot be said about the tweeter and bass. To make a long story short, I sold the SF after upgrading the X-over in the 803.

The 803 suffers from; some light upper frequency enhancement with the tweeter, and some nasality and "in the box" sound from the Kevlar midrange.

When going through the x-over (B&W had kindly posted the schematic on their homepage), it was obvious that the 47uF MKP Mundorf and the industrial resistor in series with the midrange was a week point. I knew also that the 5,1uF Mundorf Supreme SGO combined with tweeters easily can highlight the upper frequencies, too much in a not optimal set up.

I first replaced the 47uF with the new EVO MCap Alu oil and put in a Duelund Silver CAST resistor. I also replaced the 10uF Supreme Oil in parallel with Supreme SGO.

It took some hundred hours to burn in the new setup, but the result was very satisfying. In brief, a much larger soundstage, the in the box sound was 75% reduced, the bass(!) was indeed punchier, 3D stage in all direction had grown. At the same time, there were some highlighting of the upper midrange that was not to my likings. I therefore decided to replace the EVO MCap with the new Supreme EVO Oil.

At the same time I decided to replace the 5,1uF with a Duelund Copper CAST to see if I could get more from the tweeter.

It now needed some 500 hours to sound OK, and after around 700hours, it was confirmed, not only was the midrange free from any kind of boxiness, it was also the best sounding midrange I've experienced so far in my home. The tweeter together with the midrange now sounds like a Stradivarius with all I can wish for regarding holography and texture.

I have listened to the new 805D3 in two different setups. The first did impress me deeply. They had the speed and holography like never before. In the second set up they did not impress me at all, just telling me that the surrounding is just as important as the speaker themselves. I did like the speed and holography, but they did not have the texture as the 803 now has.

With the speed from the 805 in mind, I decided to replace the MKP for the bass drivers as well, this time with the fantastic resistors from Pathaudio and Mundorf EVO Alu in oil.

This time the upgrade gave me some more macro dynamic, but not as much as I had hoped for. It seems like the driver themselves are the bottleneck here.

There is space for the upgrade behind the Kevlar driver, but you have to reorganize X-over a bit. For those how want to see how it can be done, just send me a mail, s-b-o@frisurf.no.

I'm very happy I sold the Sonus, the sound from the 803 betters them in every aspect, and this with a great margin. I've of course considered the new 804D3, but I'm not sure they will better the fantastic texture, bass and resolution from the 803. Be aware, they use MKP, electrolyte and not the top of the line Mundorf capacitors. They have also started to bypass the capacitors with smaller values. I've never succeeded with this little trick in my x-overs, for power supplies, yes, but not in loudspeakers.

The 803D3 are too expensive, and since I've now started to upgrade of the 803, I've ordered the new Continuum drivers to replace the Kevlar. Still waiting for the drivers to arrive.

My experience tells me, there is lot more to get from the 803 with better components, and it is a shame that B&W has not offered a signature model with these upgrades incorporated already!

(To bad I cannot show any photoes here in the Forum)

Ptss:

I can see the potential benefit to moving the XOs outside the box. My early JBL L212 had the crossovers outside of the enclosed driver housings.

Vibration from the drivers will definitely influence the inductors and capacitors in the network, simply "gluing" them to the pc board with lumps of RTV or caulk may not be that effective.

But practically speaking (no pun intended) moving them outboard of the 803D also has it's pitfalls, as you end up with longer speaker wiring between the drivers and the XO, with the accompanying increase in inductance and resistance. Not to mention the ugly appearance. The bass XO is huge, with monster 100 mFd Mundorf polypropylene bypass caps. Placing that outside would look butt ugly IMHO.

Bypassing caps...not sure what they buy you in a crossover. I know folks use them to "tweak" the sound but I have never played with them for that. I would rather buy a single cap with the right dielectric and low ESR in the first place if at all possible. Plus, from a technical viewpoint, things like dielectric adsorption cannot be remedied with parallel caps; only ESR or maybe ESL. The frequency range in a speaker crossover (maxing at maybe 30 KHz) is just not high enough to see a resonant frequency shift by using a 0.1 mFd cap in parallel with a 5 or 10 mFd coupling cap in a tweeter XO, for example.

So for example, the B&W diamond tweeter is crossed at 3500 -4000 Hz. The reactive impedance of the 4.7 mFd coupling cap at 4KHz is about 8 ohms. It would only be 0.8 ohms at 40 KHz! The 4.7 Mundorf has an ESR that is about 10 milli ohms or .01 ohms, still 10 times lower than the capacitive reactance at 40 KHz. Now what good is placing a 0.1 mFd cap in parallel with the 4.7? It would have a capacitive reactance of 50X the 4.7 (at 40 ohms) and who cares what its ESR is, because that would be swamped with the capacitive reactance.

If you are parallel connecting a series of lower value caps that may make sense if you cannot get the total value in a single cap (like a teflon or polystyrene, for example).

The best sounding resistors by far are Path Audio folks. Tried them all and these are special. Not cheap, but very special! Look into them and be impressed.

Dhl I did move the huge crossover in my 1985 JBL 250Ti's outboard to great effect. Perhaps you can consider ways of isolating your XO within the boxes, although I feel B&W are respectful of this benefit as previously they advertized the benefit of having the XO in the bases of top speakers. By the way what are your feelings re: bypass caps?

Dover:

In a word, no.

I had only planned to replace a few caps, not rebuild the entire cross over. I don't think that a rebuild is sonically warranted at this point.

I am hesitant to replace 100W rated components with 20W versions, no matter what the sonic results MIGHT be. Perhaps with a 0.5 ohm resistor a 20W might work, but I have not done the power dissipation analysis to confirm.

I have also used the Mundorph M-Resist (20w) with good results.
Have you considered redoing the crossovers on new boards with point to point wiring and better component layout to reduce interaction ?

Dover:

I would like to maintain the stock look if at all possible. Relocating the XO to the outside, well, you might just as well build the XOs from scratch then. No for me at this time. I agree that relocating them outside the cabinet would remove a lot of component vibration issues that XOs face while mounted inside.

The Dueland resistors will not fit the stock layout, as B&W uses radial lead (not axial lead) power tab type resistors with heat sinks. Their power rating of 100W is also way above any Dueland power rating.

Only an EVO 47 mFd SGO will fit. But I agree that one should be replaced first.

From my experience with both Clarity and Mundorph caps the Mundorph S/G/O to Clarity is not a big jump and not worth the cost.

My recommendation, based on many crossover updates, would be to change the resistors to Duelund Silver Graphite first. This will improve transparency and more importantly in the context of your comments result in a much smoother sound. Steen Duelund is on record as saying that when upgrading crossovers with Duelund components you should start with his resistors.

Of the caps in the standard crossover I would only do the 47mF in the mid - probably a Silver/oil Mundorph which is a little smoother than the S/G/O.

Another option if you are keeping the speakers long term is to remove the crossovers and place them externally. Again I have found significant improvements in lower noise floor and less grain by simply removing the crossovers from the box.

Regards

Oh, and one other point. B&W went with a Supreme SGO (10 mFd) as a bypass/parallel cap across the mid driver, but an MKP in series with it. I always wondered why they did this, but now realize that the series cap is in series with a very large outboard inductor (1.25 mH). So why spend a lot for a low inductance cap like the Supreme if you are going to put a large inductance in series with it? The parallel bypass cap, however, is directly across the driver so low inductance will pay off there.

Rtilden:

I am kind of where you were at. I would like to make a change, but not really mess around with a lot of trial and error swapping stuff in and out. If I could have gotten a general consensus that a particular option was a no brainer improvement, I would have gone that route.

But now it looks like that is not the case so I will probably stick with two mods, the 47 and the 4.7. For the 4.7, I will try the Clarity MR in comparison to the stock Supreme SG. I would like to also try a Jupiter copper/wax/paper but the cost of entry is quite high.

Regarding the 47 I hear what you say but a stack of three parallel caps just will not fit. So practically I am left with the EVO or EVO/Al-Oil or EVO SGO. The EVO Al-oil was suggested by Tony Gee's review but I am actually leaning toward the SGO. Since the EVO Al-Oil is not that expensive, perhaps the reasonable thing to do is to try that first, then maybe the SGO. Then once the mid range choice is selected, try the Clarity MR in the tweeter 4.7 position.

Supremes have a real advantage technically over the EVO in that they are two series capacitors interwoven, which reduces the series inductance of the overall capacitor. The EVO is a conventionally wound single cap, but is more compact because it is not really 4 caps in one like the Supreme.

What I cannot rationalize from a fundamental POV is what difference the materials combos make. Aluminum metallization with and without oil vs silver metallization with oil vs silver/1% gold with and without oil. Clearly silver and silver gold are much better conductors than Aluminum, but the metallization thickness matters too. The silver/gold should have a better (lower) DF if the metal was a better conductor, but Mundorf's DF data do not support this. So maybe the Al films are much thicker than the Ag/Au, offsetting any advantage in bulk conductivity.

I suspect the gold is added to the silver to reduce any tendency for corrosion of silver. Silver is not really that "noble" in that it easily forms chlorides and sulfides (tarnish), and these may be formed by chloride or sulfide impurities in the oil (or in outside air contamination if it gets into the cap). Gold, even in small percentages, may reduce the tendency to form these compounds. That is why I prefer the silver gold alloys from a basic longevity perspective, although people's impressions of sonic performance are another matter.