B&W DM2A refurb's

[Audio Al]

I have removed the speaker front mounting plate to have a look inside



Looks like they have been mounted in several different ways , Red felt , Blue tack and evidence of spike marks
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Tweeter rear
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Super tweeter
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The drive unit with a cloth cover over it ?
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Masses of wadding 3 different types
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This shows a date of 4 Jan 1974, fits in with the age of the speakers

Stephenson Blake and Co
Caslon Letter foundry
Sheffield

A bit of history re the company http://www.stephensonandblake.com/ , not sure why this would be stamped on the chipboard ? maybe early recycling of printing press cases ?



And shows initials GW , maybe the person who built these speakers



The crossover unit , Now I feel stupid don't know what any of it does

Will have a look in the other one , I am assuming it will be the same
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[Rare Bird]

The crossover unit , Now I feel stupid don't know what any of it does

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You may well be suprised how many Audio companies had their woodworking jobs carried out in Sheffield

The switch in the centre is an HF level switch, variable from -2 to +2.. the two fixing underneith are the speaker inputs.. The green jobbies are power resistors, the brown boxes are caps..The others are obviously Inductors.

Leave the inductors, rebuild the rest.

Might be an idea to check see if the Coles super tweeters are working..

btw: I used to have 'DM2a' Mk.II (Not DM2 Mk.II). I replaced the original X Over with an hardwired version, i retained the inductors but used Mills 'MRA-12' power resistors, Ansar 'Supersound' polyprops, bypassed the HF switch..High quality binding posts & wiring.

[synsei]

Super speakers these, the best I have ever owned. Disregarding financial limitations (which I can't sadly) it would take something really special to push my DM2's off their perch. As for them being inefficient, I disagree wholeheartedly. The Mini-T has no problems driving mine to insane levels whilst still keeping things clean and tight. Incidentally, mine are original DM2's without the HF pot

[spendorman]

Super speakers these, the best I have ever owned. Disregarding financial limitations (which I can't sadly) it would take something really special to push my DM2's off their perch. As for them being inefficient, I disagree wholeheartedly. The Mini-T has no problems driving mine to insane levels whilst still keeping things clean and tight. Incidentally, mine are original DM2's without the HF pot

The ones without the treble control have some subtle differences in the crossover and I believe that the HF1300 is connected in opposite electrical phase to the version with treble control. It is possible that the midrange of the ones without the treble control is better that the version with it.

I have several of each type of DM2/ DM2A

[synsei]

That's interesting to hear Alex. I've listened to several pairs of DM2a's and although there is very little difference, I do prefer the midrange on my DM2's by a smidgeon. I also find DM2a's to be a a tad brighter sounding, even harsh on some material.

[spendorman]

If anyone is interested I can dig out the crossover circuit diagrams for the DM2/DM2a.

Would not be tonight though. Probably tomorrow.

[walpurgis]

I distinctly recall seeing DM2s with a soft dome used as the super-tweeter, maybe an early version. I think it was an Audax unit, I believe IMF used the same unit in the TLS50, but in that speaker, used with an STC/ITT/Coles super-tweeter.

[synsei]

It would be good if someone could post up a step by step guide on what to replace on the crossovers as I can't read circuit diagrams.

[Audio Al]

If anyone is interested I can dig out the crossover circuit diagrams for the DM2/DM2a.

Would not be tonight though. Probably tomorrow.

Yes please

[spendorman]

I distinctly recall seeing DM2s with a soft dome used as the super-tweeter, maybe an early version. I think it was an Audax unit, I believe IMF used the same unit in the TLS50, but in that speaker, used with an STC/ITT/Coles super-tweeter.

It was a soft dome, but not Audax, was a Heco (or Heyco, can't remember the spelling), very similar to the Peerless DT10HFC.

http://mxlml.home.xs4all.nl/projects.html