Crossover upgrade recommendations

0 Members and 1 Guest are viewing this topic. Read 2678 times.

Fritz

  • Jr. Member
  • Posts: 14
Crossover upgrade recommendations
« on: 28 Jan 2017, 03:41 pm »
I purchased a pair of B&W CDM 9NT's from Craigslist that are in excellent condition. I'm not looking to turn a chicken into an Eagle but I would like to upgrade the crossover components. Can I get advise as to what brand of caps and resistors along with any suggestions as to the upgrades? Attached are pics of the crossover components.












poseidonsvoice

  • Full Member
  • Posts: 3144
  • Vector - I've got Direction & Magnitude! Oh Yeah!
    • 2 channel/7 channel setup
Re: Crossover upgrade recommendations
« Reply #1 on: 28 Jan 2017, 04:52 pm »
Fritz,

What you posted were PCB layout diagrams, which is nice but not as constructive as the actual schematic. B&W Service manuals are available for download on a number of their previous products. See page 17,18,19 here:

http://bwgroupsupport.com/downloads/techmanuals/bw/CDM9NT-TM.pdf

Best,
Anand.

Fritz

  • Jr. Member
  • Posts: 14
Re: Crossover upgrade recommendations
« Reply #2 on: 28 Jan 2017, 08:16 pm »
Anand,
You are correct my mistake,thank you. I have the PDF download already.
Does anyone have recommendations as to which components (Brands) I should use to yield best results for caps, resistors, and coils if needed. Here are the correct diagrams.








Jeff

  • Facilitator
  • Posts: 168
  • Test...
    • Sonic Craft, Inc.
Re: Crossover upgrade recommendations
« Reply #3 on: 28 Jan 2017, 09:58 pm »
I purchased a pair of B&W CDM 9NT's from Craigslist. I'm not looking to turn a chicken into an Eagle but I would like to upgrade the crossover components.

This part of your query makes it hard for me to interpret your goal.  Yes, I could make a bunch of broad generalizations...  However, I don't think you will find that helpful, and that sort of thing is already generously available throughout the net.  In the interest of time, I'll take a poke.  If my recommendation comes in above, or below your budget LMK.

Almost always, better caps are bigger.  The better, the bigger (besides more expensive).  I'm assuming that your comment above also pertains to the difficulty, not just the budget :dunno:  In any event, this mod will require some work, but will not attempt to reinvent the wheel.  You will not replace any inductors, or the resistor in the lowpass shunt.

HF Board:

R1: Mills MRA-12...we are out.
R2: http://www.soniccraft.com/product_info.php/47-ohm-vishay-mills-mra-12-p-4687
C1: http://www.soniccraft.com/product_info.php/mundorf-supreme-47uf-600vdc-p-4202
C2: http://www.soniccraft.com/product_info.php/mundorf-mcap-evo-oil-10uf-450vdc-p-4172

MF Board:

R1: 3Xhttp://www.soniccraft.com/product_info.php/ohm-mills-mra-12-p-663
R2: http://www.soniccraft.com/product_info.php/056-ohm-mills-mra-12-p-661
R3: Mills MRA-12...we are out.
C1: http://www.soniccraft.com/product_info.php/gen-sonicap-13-uf-200vdc-p-453
C2: http://www.soniccraft.com/product_info.php/mundorf-mcap-evo-oil-47uf-350vdc-p-4167

LF Board:

C1: http://www.soniccraft.com/product_info.php/mundorf-mcap-150uf-250vdc-p-3559

Everything above times two.

Fritz

  • Jr. Member
  • Posts: 14
Re: Crossover upgrade recommendations
« Reply #4 on: 29 Jan 2017, 01:34 am »
Jeff,
Thank you for your time. I've already regestered on your site to place my order.
Couple questions.

B&W has in the HF crossover  C1 = 6uf film cap, You suggest a 4.7uf for it. Is there a reason?
Also
B&W has in the MF crossover a 40uf electrolytic in parallel with a 6uf film cap for a total 46uf
you suggest a 47uf mondurf supreme. Will the 1uf not make a difference?

Please forgive my ignorance. I'm just trying to understand the variance from original to the upgrade. Best pics I could get without removing for now.





 

Thank you
Fred

Jeff

  • Facilitator
  • Posts: 168
  • Test...
    • Sonic Craft, Inc.
Re: Crossover upgrade recommendations
« Reply #5 on: 30 Jan 2017, 02:10 am »
HF crossover  C1 = 6uf film cap, You suggest a 4.7uf for it.  MF crossover a 40uf electrolytic in parallel with a 6uf film cap for a total 46uf you suggest a 47uf mondurf supreme.  Will the 1uf not make a difference?

Fred,

You are correct, I was mistaken.  The HF C1 is 6uF.  And this does change things.  My selections were based on my memory of the sonic characteristics of you speaker.  My desire to improve them.  Biased by assumed budget, and known space limitations.  I would have selected Mundorf Supreme S/O for the HF C1/C2 if we were swinging for the fences on this speaker.  Besides considerable cost, they are very large.  Those two considerations also kept the Mundorf Supreme out of the C2 location.  While the available real estate is reasonable for a 2.7+3.3uF Supreme combo, the price breaks the rest of our scheme.  Since HF C1 has a strong influence from 2K-8k, it is still important.  More important than say 2.7+3.3uF EVO Oil.  My new recommendation for HF C1 is: http://www.soniccraft.com/product_info.php/dynamicap-6uf-210vdc-p-155

I assure you that not one single one of these speakers left the factory with a 46.00uF result for the pairing at MF C2.  Why?  Because both the electrolytic, and the film cap have a tolerance likely no better than 3-5%.  47uF is within about 2% of target.  Further, we offer custom matching.  You could buy your 47uF caps, and request Level 3 matching for a 46uF target with better than 1% results.  IMO, the 1uF does not matter regarding target, but I'd want better than 1% matching Left to Right.

Fritz

  • Jr. Member
  • Posts: 14
Re: Crossover upgrade recommendations
« Reply #6 on: 5 Feb 2017, 01:27 am »
So to sum it up these are your recommendations?
Just want to make sure I'm purchasing the correct components.
Also will you be getting more of the resistors?
Sorry I haven't gotten back with you. Work work work!
Thanks Jeff

Fred

HF Board:

R1: Mills MRA-12...we are out.
R2: http://www.soniccraft.com/product_info.php/47-ohm-vishay-mills-mra-12-p-4687
C1: http://www.soniccraft.com/product_info.php/dynamicap-6uf-210vdc-p-155
C2: http://www.soniccraft.com/product_info.php/mundorf-mcap-evo-oil-10uf-450vdc-p-4172

MF Board:

R1: 3Xhttp://www.soniccraft.com/product_info.php/ohm-mills-mra-12-p-663
R2: http://www.soniccraft.com/product_info.php/056-ohm-mills-mra-12-p-661
R3: Mills MRA-12...we are out.
C1: http://www.soniccraft.com/product_info.php/gen-sonicap-13-uf-200vdc-p-453
C2: http://www.soniccraft.com/product_info.php/mundorf-mcap-evo-oil-47uf-350vdc-p-4167

LF Board:

C1: http://www.soniccraft.com/product_info.php/mundorf-mcap-150uf-250vdc-p-3559

timind

Re: Crossover upgrade recommendations
« Reply #7 on: 5 Feb 2017, 02:23 am »
The real question is, what are you hoping to achieve with upgraded caps? What don't you like about the speakers in stock form?

I ask this because a while back I had a pair of speakers which, although I was happy with the sound, I thought getting better (more expensive) caps would naturally improve the sound. The result was a different sounding speaker, but not better to my ear. I had owned, and loved, these speakers for a lot of years. After my "upgrade," they lost their magic, so I sold them.

If the speakers are new to you, maybe this won't apply. Just my 2 cents.

Jeff

  • Facilitator
  • Posts: 168
  • Test...
    • Sonic Craft, Inc.
Re: Crossover upgrade recommendations
« Reply #8 on: 5 Feb 2017, 02:57 am »
So to sum it up these are your recommendations?
Just want to make sure I'm purchasing the correct components.
Also will you be getting more of the resistors?
Sorry I haven't gotten back with you. Work work work!
Thanks Jeff

Fred

Correct, that is my recommendation.

Not in time to help you.  We do not know what we will receive until it arrives.  Those "Mexico" resistors are hit and miss.  Your looking for 4 pieces of 1.5 Ohm, and at least four other outfits in North America handle them.  I would think Michael Percy or PCX would be your best bet for buying a NOS part.  If all else fails, Digikey and PE will have the crap shot Mexico part.

I'm glad to hear you are working!  It is a good problem to have  :wink:

Fritz

  • Jr. Member
  • Posts: 14
Re: Crossover upgrade recommendations
« Reply #9 on: 5 Feb 2017, 03:25 am »
Yes Jeff, work is a purpose and we all need that in our lives.

Timid, the answer to that question is because I want to mess with them. If they turn out sounding different
(better definition, hear finer sounds that I didn't before, better imaging, more dimension with the closer tolerances) If it doesn't please me Ill just go back to the original XO. Why didn't you just change yours back if you loved them?  :roll:


Thanks Jeff. Ill put in my order.

Jeff

  • Facilitator
  • Posts: 168
  • Test...
    • Sonic Craft, Inc.
Re: Crossover upgrade recommendations
« Reply #10 on: 5 Feb 2017, 03:27 am »
The real question is, what are you hoping to achieve with upgraded caps? What don't you like about the speakers in stock form?

True true...  For many years, my first reply to such a query would be:  What do you listen to?  Tell me about your system, and your room.  What do you like about your system now?  What would you want more of if you could have it all?  Budget?  If we got this far, I would need a schematic if I did not have one.  And, some pics of the caps that currently resided in the XO.

The problem is that we would only get that far about 25% of the time.  The most common reply to specific improvements was, "I'm just looking for general improvement".  It often headed downhill from there... :?

In this situation, Fred told us everything from the beginning.  Given his new acquisition, he could not have given an in depth account of the current performance.  He did not want to reinvent the wheel via installation or budget.  He was willing to pay up if someone could sell him on something with actual experience (reading between the lines).  He knew that caps and resistors were a viable source of improvement if chosen correctly.  He was looking for advice, because his selection would have been from an uninformed position.  And, most importantly, I gave advice because I know these parts, and his speakers.

Quote
I thought getting better (more expensive) caps would naturally improve the sound.

More expensive=better....BIG mistake.  Caps "can" improve the sound, but they are application specific.

Quote
The result was a different sounding speaker, but not better to my ear.

Roll the dice, and you will likely buy an education.

Quote
I had owned, and loved, these speakers for a lot of years. After my "upgrade," they lost their magic, so I sold them.

That is truly unfortunate :(  Fortunately, I have helped many before they moved to sell, and hundreds more before they made that mistake :D
« Last Edit: 5 Feb 2017, 05:50 am by Jeff »

Jeff

  • Facilitator
  • Posts: 168
  • Test...
    • Sonic Craft, Inc.
Re: Crossover upgrade recommendations
« Reply #11 on: 5 Feb 2017, 03:30 am »
work is a purpose and we all need that in our lives.

I have plenty of purpose :lol:

Quote
If it doesn't please me Ill just go back to the original XO.

Ah...  I hope you contact me, because something is wrong :wink:

Fritz

  • Jr. Member
  • Posts: 14
Re: Crossover upgrade recommendations
« Reply #12 on: 5 Feb 2017, 01:25 pm »
Thanks Jeff
Order placed!  :thumb:

Fritz

  • Jr. Member
  • Posts: 14
Re: Crossover upgrade recommendations
« Reply #13 on: 10 Feb 2017, 01:09 am »
Jeff,
I would like to say thank you for my order. So thank you! :thumb:
I received them today. Everything is as ordered. Question... can you recommend
a reliable capacitance meter that is reasonably priced?

Thanks again.
Fred Stenzel

Jeff

  • Facilitator
  • Posts: 168
  • Test...
    • Sonic Craft, Inc.
Re: Crossover upgrade recommendations
« Reply #14 on: 11 Feb 2017, 12:08 am »
Fred,

Thank you for the good word, and your business.

I do not know...  I have not kept up with this kind of thing in 25 years.  30 years ago, a good handheld LCR was over $800.  Today, I have seen them as low as $20.  Off brand higher accuracy starts around $100....brand name $180 up.  It comes down to budget and desired accuracy.  I doubt any would yield the accuracy of our bench tester.  For instance, the 10uF caps you received measured 9.9300/9.9345uF.  Even with atmospheric differences, a handheld will not reliably yield that kind of resolution.

What will you be using it for?

Fritz

  • Jr. Member
  • Posts: 14
Re: Crossover upgrade recommendations
« Reply #15 on: 11 Feb 2017, 01:08 am »
Jeff,

I appreciate your knowledge and time.
I've been thinking about getting a Fluke multi-meter for a while now. Use it for things around the house and  trouble shooting Cup machines at work. (Dam things are always breaking down :duh:). Also I wanted to see what tolerances the B&W crossovers were at.

Jeff

  • Facilitator
  • Posts: 168
  • Test...
    • Sonic Craft, Inc.
Re: Crossover upgrade recommendations
« Reply #16 on: 11 Feb 2017, 07:18 am »
Fluke is good stuff.  But, I tend to use a cheap handheld.  That was after busting one Fluke, and having two more walk off :x  The worst thing about the cheaper meters is the probes.  They tend to make poor connections sooner.  Then you can buy an upscale set of probes :wink:

BTW, we do offer our customers free testing.  Of course, this requires shipping...  Our accuracy is +0.02%.  I can measure 0.0000000001uF (0.0001pF).  Atmospheric conditions would account for much more delta.

borism

Re: Crossover upgrade recommendations
« Reply #17 on: 11 Feb 2017, 01:46 pm »
Fritz,

I have been using a Fluke 87-V in assembling a few Bottlehead kits. It is of high quality and I can highly recommend it. However, there are many cheaper alternatives.

Fritz

  • Jr. Member
  • Posts: 14
Re: Crossover upgrade recommendations
« Reply #18 on: 11 Feb 2017, 04:43 pm »
Borism,
Thanks for the input. I ended up getting a Klein. Seams to be fitting the bill.


Jeff,
Please confirm. The Mills resistor I need for the HF XO should be a .47 ohm and not a 47 ohm.
I think I got the wrong size. Heres a pic of the HF board.

I finally found time to work on them.

Fritz

  • Jr. Member
  • Posts: 14
Re: Crossover upgrade recommendations
« Reply #19 on: 11 Feb 2017, 06:42 pm »
Slow progress. Not a lot of room for these caps.