Are these speakers worth refurbing?

[AlfaGTV]

Please excuse me if i haven't read the thread properly, but what did you do about the tweeters? Did you buy new ones?

Reason for askin' is that i had the very same tweeters in my Dali 40 speakers, and these had a reputation for getting sticky with age and consequently blowing the voice coil easily.
Anyways, i bought a repair kit for mine, consisting of an assembly with both the dome and voicecoil, easily replaceable. The did sound a little harsh and grainy though, after repair... Seemed also to add quite few decibels of efficiency which meant i had to tune them down a bit with a series resistor of about 1,5Ohms.

In the end i converted my Dali's to 40SE spec. instead, using ScanSpeak 2905/970000 tweeters and adjusted x-overs. Result was a thouroughly more enjoyable loudspeaker!

Beautiful job by the way, the speakers sure look good!
BrMike

[DSJR]

Tweeters can lose efficiency after a few decades of thrashing and I don't know if this is physical age of the moving parts, or any ferro-fluid drying out (more likely), Changing the tweeter module may have removed what's left of any sticky ferro-fluid in there??????

If the Scan tweeter is the 28mm dome I think it is, it's an utterly civilised unit with smooth and wide response out to over 30kHz.

[Mothman]

Please excuse me if i haven't read the thread properly, but what did you do about the tweeters? Did you buy new ones?

No the tweeters are the original Audax units. The crossovers were re-capped with Alcap electroytics of the same values as the originals, my tech also beefed up the internal wiring using some silver plated copper stuff he had.

[Wakefield Turntables]

Eventualy got around to getting the refurb of my Audiomasters finished. Crossovers have been re-capped, internal wiring upgraded, cabinets rubbed down followed by 3 coats of Danish oil and then polished with beeswax. Grilles have also been recovered, though I would probably make a better job of these if I had to do them again. I'm pretty happy with the overall result though I'm still adjusting to the new sound.

I think you've done a great job here, well done!

[Canetoad]

Rich, they look lovely!

[Alex_UK]

Top job there fella!

[Barry]

+1

[Mothman]

Thanks for the kind comments guys. Cosmetically the speakers have come out better than I could I have hoped for as I did not think it would be possible to remove marks such as the water stains and flower pot rings from the tops. Can highly recommend Danish Oil if you are not looking fo a high gloss finish on your veneered speakers as it's cheap, easy to apply and doesn't need rubbing down between coats. A

Sonicaly I need to get some miles on the new crossovers and maybe experiment with a couple of different amps and cables. My Sansui AU-505 will hopefully have some new life breathed into it soon and so I'm looking forward to seeing how that stacks up against the A&R A60.

[Kaiman]

Such an awesome job, Mothman, they look lovely.

I am finding the occasional touch of harshness

I think it's just the speakers' own sonic signature, a dip in the presence region coupled to a peak in the top octave, as seen in the frequency response charts:

I recall the exact same flaw in my own pair when I was actually using them. Back then I sorta solved the problem with some lateral thinking. I experimented with cartridge (an Ortofon MM) loading. With moving magnet cartridges, increasing capacitive loading causes a presence hump and a corresponding treble droop. I tried various values and ended up adding an extra 220 or 330 pF, IIRC. This brought the presence region up to par and flattened the whole response out, at the expense of some high treble loss. It was not a perfect solution, but it sounded much more pleasing to my ears compared to the status quo ante. I was an intrepid young man back then; right now I don't think I could have detected the high treble loss anyway.
I can report zero progress WRT my own MLS4s as I am a notorious procastrinator, but if I am to do anything with them, it seems that I'll have to settle on new drivers, most probably the Volts I referred to earlier on, and maybe a pair of Scanspeak tweeters.

[spendorman]

I seem to remember that these speakers used the Audax soft dome tweeter, yes could be a tiny bit harsh at the very top end, seemed better with a good valve amplifier though.