DYI upgrading B&W N805 to Diamond 805?


I have an older Natilus 805 speakers which are still working great, but I am in the need of some better dynamics, top-end, and bass.  Since the cabinet of 805 hasn't changed at all (from what I gather), is it possible for myself to just change the tweeter, drivers, and cross-over to the 805 diamond series and create the same sound?

Anyone's done such a thing before?
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I agree with Elizabeth.

Your good choices are:

  • Sell what you have
  • Upgrade the caps
  • Build a new kit from scratch (my fave!)
Definitely trying to create a new speaker with a new tweeter from zero is nowhere near an easy ask, nor in the end profitable.

It can be a lot of fun, but this way is a very very expensive learning experience.

If you want to play with speaker parts (and who doesn't?) best you consider building a brand new kit.


I have a pair of N805 in a second system that I recently replaced the caps and resistors only in the crossovers( There are two crossover boards in each speaker, one for the mids and tweeters and one for the woofer). Huge improvement! I didn't touch the inductors. The factory crossover parts are the biggest down side of the N805, cheap ICW polypro caps and sandcast resistors. I replaced the caps with Uptone Musicaps(no longer being made, but I found a couple of sources for them) and the resistors with Mills MRA. The sound now has transformed the speakers from just okay to extremely musical and dynamic. It was a bear, though, shoe-horning the big film and foil caps in there, but I managed. 
Love Mills, sherod!

I highly recommend Clarity if you want sincere musical transmission.

If you want the B&W kind of shine of the top end, go with Mundorf SIO.
The Mills MRA are the best "bang for the buck" resistor for a crossover. The Claritycap MR series are also excellent and will far outperform the ICW polypros that B&W put in there. What's interesting is ICW makes the Claritycap line.
   The current 805 Diamonds have a 1st order crossover in them now and B&W uses Mundorf cap( not sure which model) on the tweeter.

   Here's a link to the B&W service web site where you can download a manual for any of their speakers for a list of cap and resistor values they use:

Mills are just great resistors AND they are great value.

I've not found better. Just more expensive.

High precision, amazing thermal stability and small size for the wattage makes them really kind of incredible resistors. I really really don't understand anyone who uses others, but I have not heard everything.

Thanks guys, won't touch drivers but will look into caps, or just sell and buy something else.

Now how easy/hard it is to change the caps? Which is recommended to do the same roll-off, crossover as factory intended? Any guide, parts you recommend?
You can replace the drivers but not the crossover, because the crossover design is linked to the cabinet design, and the relative position of the woofer and tweeter voice coils. 

In the older Nautilus there's a 90 degree offset at crossover, but in the newer diamond models it's 180 degrees, so if you change everything you will not end up with correct phase alignment on axis.   
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Huge gains can be had upgrading the resistors and caps with the exact same values. As long as you use the exact same values matched within 1% for both speakers you are good to go. Mills MRA are only $5-$7 each and are great. The Path Audio Line is better, but they cost $22-$29 each. Put those on the highs and mids and Mills on the bass if you have the budget.

Erik is right about Clarity caps as they sound nice. The Clarity CSA line is affordable also. You can do better with Jantzen Alumen Z caps. They sound wonderful and are not crazy expensive.

As far as resale goes, if done right and professionally, you will not have a problem selling them down the line. I have upgraded every single set of speakers I have ever owned and sold them all no problem. I always share what I have done and use it as a selling point. Take pictures of the work, before and after, and use them in your listing. I have sold 10 or more set of speakers. No big losses etc....It only takes that one person who understands the sonic gains that can be had with crossover upgrades done right. Many Aphiles both understand and have first hand experience with these types of  upgrades so finding that one buyer is not an issue.

I understand why some think resale is a problem, but many of these folks have not actually upgraded parts and then tried to sell ... no actual experience.... just a reasonable anxiety about it.

When done right this approach to upgrading is one of the most cost effective ways to improve the sound of your system. If you enjoy DIY, then it is double fun and enjoyment. If you have not done this before, then find someone to help you or get it done by someone who won’t charge you an arm and a leg.

Its easy to imagine differences that arent there. You would need to compare both versions and correctly guess which one is which blindfolded. 
My comments are based on well executed experience with careful listening over long periods of time. This is an area of huge potential upside. No, I am not self deluded as you suggest. Rather I am well experienced in this area. Speculate on....remember this is a great big world with so much to learn. Get some experience yourself and you will also learn new things over time. Enjoy the ride! 
Parts quality matter.  This is so true in speaker crossovers and audio electronics. Many well respected manufacturers offer upgraded versions on their gear with Vcaps, silver wire, Duelund caps, fast recovery diodes, Output transformers, shunt stepped attenuators, tubes and on and on ..... They also know parts make a difference.  

Speaker builders selling through distributors have to manage build costs and therefore place $ .20 cent resistors and $5 - $15 caps in their speakers. It is done for cost reasons.  
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It is a lot safer to upgrade the caps for modern speakers than for speakers from the 80's.

You don't run into ESR differences luke you did before, which does funky things to the impedance curve.

I am now debating whether to attempt this at all, to me, just upgrading caps at random without thinking of what the design and measurements at B&W WITH original Caps were meant to achieve, is not wise. I may make things worse.

Now, how do I find EXACT SAME spec caps, which wouldn't really change the design parameters and do an upgrade like that?
By the exact same spec we mean same resistor ohm and wattage values and capacitor uf values. These are printed on the parts and can also be measured with a simple multimeter. You are replacing film caps so no real ESR issues to obsess over.
  I provided a link in my above post to get the manual for the N805 which shows the cap and resistor values. Here is a copy from the page:

    1) LF Crossover

R1 5R6     11W   Ceramic Wirewound    BENNIC Resistor
C1 6u8    250V  Polypropylene             ICW
L1 1.45mH         small air core

   (2) HF Crossover

R1 3R3     11W  Ceramic Wirewound    BENNIC Resistor
C1 4u7    250V Polypropylene             ICW
C2 10uF  250V Polypropylene             ICW
L1 0.15mH        small air core
Great info sherod! I would still take actual part measurements to do this job right. Looks like a simple and fun project OP. 
When I pulled the factory caps and resistors out of my N805 speakers, they matched exactly with the values from the manual.
Upgrading the caps and resistors in my 805N is a fantastic idea!   Relatively inexpensive and a good DIY project.  I do have some questions though...   The caps in the 805N are polypropylene.  When looking online at caps, I see there are also oil caps.  Can oil caps be used in place of the polypropylene?   Is there any advantage?   I also see caps with higher voltage ratings, say 600V, instead of 250V.  Are the higher rating caps a substitute for lower?  Any advantage?

Thanks for sharing your knowledge and ideas!

- Jed
You may also want to consider having someone upgrade the crossover parts for you (someone with experience, measurement equipment, and reputation).

Call Danny Richie @ gr-research.com. Yes, you could DIY it, and yes, you'd have to pay for shipping. However, you'll know they're done correctly, you'll have measurements to prove it, and when you go to sell them you'll be able to say, "Crossovers upgraded by Danny Richie @ GR-Research (work order and receipts included)" rather than "I hacked at the crossovers based on suggestions @ Audiogon to try to make them sound better."

The N805 were my first "high end" speaker and I have a soft-spot for them. I'd hate to see a set butchered. 
Good advice to get an upgrade done professionally. 

I would definitely upgrade the tweeter caps, and there's also a potential there to upgrade the N805 to "Signature" 805, which includes the higher spec aluminium dome tweeter.

So long as you have the right uF and don't go down in voltage ratings, replacing caps is pretty simple and safe and can be beneficial.

As I've mentioned, if you want to go with the B&W sound, stick with Mundorf and Mundorf SIO.  Look around on the Internet and you'll see that's what B&W is putting into their top speakers.

There's at least one pair of B&W speakers that were identical except for the tweeter cap. The high end used Mundorf, low end some generic.  I'm sorry I don't remember the exact models, but bookshelves.
I am re-opening this, as I am stuck at home and I'd like to take this on to upgrade the cross-over.

Could ANYONE recommend WHICH Caps, resistors are suitable for the upgrade that DO FIT on the board, and also improve sound being newer and better components.
Mundorf MKP.

Inexpensive (relatively) and quite compact. It's also B&W's mid-range cap brand.