Are these speakers worth refurbing?

[spikeanded]

Hi, I think I may stop short of changing drive units as I'm not sure if these Audiomaster speakers are keepers. I bought them to see if I could improve on a pair of Monitor Audio MA4 Mk1's and I must say these are proving hard to beat as they have a lovely warm sound and very smooth top end (which I highly value). I may well try to find a new home for the Audiomasters, nice though they are. Strange though that the mid 70's MA designs seem largely overlooked these days, whereas the likes of Spendor BC1 and Rogers Studio Ones are venerated and worth approximately nearly 10 times what I paid for my MA4's. Would be interesting to do a direct comparison, but I suspect the MA4 would not be too far behind. Must be the kudos of the BBC affiliation of Spendor and Rogers. Apparently theMA4 Mk2's use the same Audax tweeter as these Audiomasters and sound worse for it. Not the best looking speaker in the world though, the old MA4's, it must be said!

[system7]

Well, frankly, Tony, you're a bit of a dead loss as a DIY person then.

The whole bextrene driver/BBC crossover thing was a a child of it's time.

KEF B139 subwoofer, 8" KEF B200 bass/mid, 5" B110 bass mid and T27 tweeter spawned myriad variations.

My own Chartwell speakers were Dalesford drivers plus an Isophon KK10/8 mylar dome.



I'd be interested to see the MA4 schematic. It would be fairly simple, I'd guess. It used a low Qts KEF B200 driver in a reflex box IIRC. Have a dig.

FWIW, the SEAS Curv 29TFF/W treble conversion is very easy to do on the existing crossover board. I'd use 3.9R, 6uF + 0.2mH, 4.7R/10R l-pad for starters:



You'd just need to run the 10R shunt of the l-pad from the removed 0.33uF capacitor to ground. Everything else just slots in. Adjust the l-pad for level if necessary.

[spikeanded]

Hi, I think I will stop short of swapping out drive units. I would like to keep them pretty much as original designed and built as I am not sure if they are keepers. I bought them thinking they might be a step up from a pair of mid 70's MA4 Mk1's, but I'm not so sure they are a step up, especially in terms of treble smoothness. The MA4's sound lovely and warm with no hint of roughness or fatigue at all. So I may well move the Audiomasters on in due course. I find it strange that these old MA4's seem more or less forgotten when their contemporaries like the Spendor BC1 and Rogers Studio One are venerated and cost an absolute fortune these days. Must be the BBC association I guess. I would love to be able to do a comparison but I reckon the MA4 would not be far behind. They are very well built, although not too hot in the looks department! Again, thanks for all your help.

[spikeanded]

Hi, yes, not much of a DIY'er really!
I did fix a nasty treble spike in a pair of old Ruark Sabres by swapping out the Vifa domes for Scanspeak, but it was a drop in replacement with no crossover mods necessary.
I notice your Chartwells have the same Isophon tweeter as my Monitor Audios (although MA claimed to have modified them heavily). Compared with contemporary models like Kef and Celestion, I reckon that Isophon is the sweetest sounding of them all!

[Rare Bird]

I always thought those Chartwell 400's were loverly speakers..

[spikeanded]

I always thought those Chartwell 400's were loverly speakers..

Just to add a postscript, around three years ago I sold that pair of Audiomaster MLS-4's as they were simply too bright for me and a bit harsh with it.
Earlier this year out of curiousity and because of the low price, I picked up another pair.
To my ears, and with no modifications they sound better right away.
They are still a little on the bright side, but without that sting in the top end.
So I don't know whether the original pair had bad tweeters or crossover components that had drifted out of tolerance, or whether there were big variations in the original production run, but these are very nice!
Also these are not even really a matched pair. Certainly the veneers don't match, and one speaker has four grille fixings, whereas the other one has six.

[dantheman91]

Just got a pair of MK1 MA4's being delivered in the next hour or 2...

I'm in too deep - HELP....

[dantheman91]

AH problems - both KEF B200's are distorting and have coil rub - is their a way to fix this tried 180D but still the same - at a guess ate the drivers fried or can they be fixed - i'm not sure im up to this - they were £10 so worth investing in i think.

Any help - will geoff's fix in the other thread solve the issue.

if not they will be for sale very shortly... at a bargain

[Martyn Miles]

I have just been given a pair of Audiomaster MLS4s, so this is interesting stuff. I intend to restore the cabinets, but leave the rest as it is.
As for value, has anyone ever seen a pair for sale ?

[57charles]

Those Audax tweeters could well have reduced output due to ferro fluid evaporation and subsequent residue gunge hinderung movement of voicecoil. Get somenew tweeters from Falcon and change the caps in the crossover. You'll have a very competent speaker even today although personally I could never get along with that Audax tweeter whatever speaker it appeared in.