I'm having trouble sleeping

shrubs

Member
2020-02-15 9:06 am
I got some bone stock original B&W DM4 that sound quite good. Im not 100% about the xover yet.

And well, I've been up throwing all the music at them I can find. After playing around with placement I followed advice in a read that says, placing nearer the wall reinforces bass response. This is true, minus the "boom". To be honest, I expected some boom. They remind me of my Harbeth HM ll, only better. These have a sweeter mid range. Thats a lot to be said, I love the silky mid range of those others.

Being that they were made in 1972 leads me to wonder about caps. I'm in no real rush to hop aboard that bus, and they sound fantastic. Would it be worth having them gone over?

What is more of a concern is wich styles of amplifiers blend well with the DM4?


I have a couple in mind, like a small Sugden or Exposure. Then theres a pure musical fidelity class A. It would take a bit to sway me away from British brands. But, perhaps.

Plan A is to build an analog set up, with a Rega l or ll. Something with phono built in could be nice.


I can see about uploading a couple pictures later tomorrow for site reference purposes.
 
Due to there age some of the capacitors may be out of spec, it depends on types used by B & W for your speakers, possibly a previous owner may have done this already. I am assuming that they have had at least two owners by now.

A picture of the crossover would help us decide possible candidates for checking, if you can measure them, or go for replacement as a precaution.
Black bodied ones with red endcaps (elcaps) or other bipolar type capacitors are the obvious choices to replace.
If they are plastic types then they should be good. Swapping a vintage bipolar with a modern polypropylene type may skew the frequency balance, due to them not having the same equivalent series resistance as older types. If you are enjoying the midrange then this is something that could be very subtly altered by the substitution of a modern plastic type. Don't throw the oldies away!

Amplifiers, hmmm, whatever you like basically, people did use DM4 with valve amplifiers so they must present a sensible load, which wouldn't tax any of the candidates you have in mind.
 

shrubs

Member
2020-02-15 9:06 am
Thanks for the tips. I can pull the board, or at least have a peak at it. I have seen some jobs where people got over zealous with glue or epoxy. To say the least.

They sound pretty spanking good. Since I'm not a pro tech I never assumed anything was changed. BTW 6 drivers look correctly original. They could use a quality sub woofer at times. Not to overwhelm, just add a touch of enforcement providing it does not alter timbre.
 

eriksquires

Member
2013-05-10 4:11 pm
I wouldn't get into a B&W crossover without doing a full analysis and measurement. Lots of them have wonky designs to begin with, and at the end of the day just doing part swapping may be expensive and not do as much as they really need.

I would consider sealing them (even temporarily) and adding a subwoofer. Sealing will increase the dynamic range.
 

shrubs

Member
2020-02-15 9:06 am
Im using them for desk system set up, about 5 feet apart. a foot from wall. I like the flat BBC signature from these types of monitors. I almost bought Spendors that share that super-tweeter. I think they can squeeze a little more out of them with an A or A/B. Currently on a Bell D class. And don't sound bad at all.

Everything seems to be intact. Even the old school looking B&W logos. I haven't cleaned or oiled them yet. Could do with some stands.

Appologies. I tried to flip them back over. Darn phone.
 

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shrubs

Member
2020-02-15 9:06 am
I always appreciated the flatter BBC signature sound. I'm using them for a desk system set up about 5' apart, a foot from back wall. I think a class A or A/B would up the sound. Although a class D Bell doesn't sound bad at all.

I have gotten curious about the Music Fidelity A1. A newer one after they began reproduction. I'd like to make an amp some day. For now Im too afraid I might blow something up.
 

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boswald

Member
Paid Member
2014-06-27 3:32 pm
Don't change a thing.
If you must mess around, keep these as a reference and play with something that's not working right, or that you build from scratch.


This is a fine implementation of some very good, if a bit unusual drivers.
Kind of a smaller Spendor BC1. See Troels Gravesen's study of the Spendor and particularly the 1300 tweeter(the lower one).


I have the 1300s in Celestion Dittons, and they are something special, ColesAcoustics still make a version of them(and that supertweeter) that I plan to try sometime when budgets allow.


If you want to make these sound better, work on your room and placement, add a bass bin or sub for the bottom end.
Leave these as they are until you have made a few speakers better at this size than these. The only thing that will hurt those caps is frying them with a soldering iron.


Enjoy them. And enjoy messing about with other stuff(that doesn't work right).