Tweeter for Sonus Faber Electa

68Spider

Member
2011-11-15 9:28 am
UK
Sad day - one of the tweeters in my venerable Sonus Faber Electas has just died. It is identified on the back as "tw.28.SF" MADE IN DANMARK. Odd misspelling of Denmark, possibly a rebadged Dynaudio D-28? I'm guessing that original units are unlikely to be available, anyone know of a viable replacement?
 

Attachments

  • IMG_20191007_102437.jpg
    IMG_20191007_102437.jpg
    429.9 KB · Views: 323
  • IMG_20191007_102416.jpg
    IMG_20191007_102416.jpg
    986.7 KB · Views: 332

Lojzek

Member
2012-02-10 12:12 pm
Croatia
Yes, a wise suggestion to first be confident it's the unit itself that is defective. Otherwise this Dynaudio look-alike tweeter should be reasonably close relative to Morel units, such as CAT 308, or Scan Speak D2905-930000; D2905-950000. I am not saying these are exact replacements, rather likely to perform well without major modifications needed, so I figure. Personally I don't do anything without consulting measurements.
 

68Spider

Member
2011-11-15 9:28 am
UK
As you can see from the pictures, I have the unit out of the cabinet, and I have tested it with a meter - unfortunately it is open circuit. Since there is nothing to loose I may try some investigative surgery.

It was a while ago when I bought them, but I think my Electas would be late 1980s or maybe very early 1990s - serial number 1087A/B. They are the original type, not the later Amators. I have contacted the UK distributer to see if there is any chance of spare parts - not holding my breath.
 
Last edited:

Lojzek

Member
2012-02-10 12:12 pm
Croatia
Try contacting Dynaudio as well, might be more affordable than through SF. While investigating faults, see if you can get a dc reading from the wire visible just next to the dome or somewhere near. Lightly scraping the enamel off would be necessary. I had once repaired a SS midrange cone like that, broken connection being right at the point of voice coil wire meeting flexible braid. These older SF production loudspeakers are a treasure aesthetically and I would get these repaired one way or the other.


Can you spare a couple of photos of this speaker, perhaps a crossover board too? I am curious. Thank you!
 
Last edited:

68Spider

Member
2011-11-15 9:28 am
UK
Thanks @Lojzek - Something like the Scan Speak units look like a likely replacement, although they are slightly undersized at 104mm, compared to the Sonus Faber's 110mm. I'm sure I can be creative to make that work.

But will I be happy with that compromise? They will not be the same speaker, and it is not a cheap experiment to try. I may well end up buying new speakers instead, and have wasted a couple of hundred quid.
 

68Spider

Member
2011-11-15 9:28 am
UK
@Galu - Great! That's just the information I've been trying to find. The current Dynaudio website is very "corporate", and it was almost impossible to contact them for historic information. From that archive site, the D-28 AF, with 4 inner screw fixings, and three outer ones looks like a dead ringer for my SF unit. Getting closer...
 

Lojzek

Member
2012-02-10 12:12 pm
Croatia
The safest bet is to send the drive units to Dynaudio factory and have them replace the voice coil assemblies. It is their unit, so they would know how to repair. They used to do that service for DIYers. Morel offers separate assemblies to repair their units, costing from 17-21 gbp at wilmslow audio. I wonder if it would somehow be doable to fit the Morel spare voice coil to a Dynaudio unit. I'd risk buying one to test, were it me.
 

68Spider

Member
2011-11-15 9:28 am
UK
Well that would be a relatively cheap diversion for a rainy afternoon. Is there any shared DNA for Morel and Dynaudio units, or are we just guessing that a 28mm voice coil will be much the same? If it works as a replacement then I guess I would have to do the same surgery on the other, working unit.
 

68Spider

Member
2011-11-15 9:28 am
UK
Disappointment on arrival of the replacement unit, not much like mine at all. From the historical docs I would guess they have sent a D28/2. Further research shows that my Sonus Faber unit is more than likely based on a D28AF. Mine has a different rear acoustic chamber - I guess that was one of the Sonus Faber mods.

On eBay I see that Queensland Speaker Repairs has a D28 dome rebuild kit which will fit the D28AF, I think I may go that way. Get two kits and refurbish both tweeters.
 

68Spider

Member
2011-11-15 9:28 am
UK
TL;DR - I have my speakers working again

The (much) longer version:

My contacts with Sonus Faber, through dealer and distributor, came up with nothing; except being told that the list price of the no longer available tweeter was £450. A moot point if no such thing exists any more. Another sobering thought was the discovery that there was a modern MkIII version of the Electa - a snip at 9 grand, hmm no thanks. Strike 1.

As discussed earlier, Dynaudio claimed to have a replacement but it turned out to be an off the shelf D28/2, not the modified D28AF. I'd really need two and then have to figure out what the modifications were, and then probably have to fix the crossover. Strike 2.

In my efforts to find someone local to repair my tweeter I came across Wembley Loudspeakers, and by extraordinary chance they had an old pair of Sonus Fabers with blown bass drivers and the correct tweeter. Unfortunately, despite numerous call to get a deal done with them, they were hung up on the Sonus Faber list price - they do repair work for Absolute Sounds, the Sonus Faber distributor in the UK, and had some odd notion that the distributor would have some say over the price of a 30 year old, S/H tweeter. Like going to a Ford main dealer and asking what's the price of a 1982 Cortina. Strike 3.

I contacted Ernst in the Netherlands and he was very helpful but could not repair a tweeter with a fault within the coil itself. My diagnosis, after dissection of the tweeter, was that the coil was broken internally. Strike 4.

After pulling apart the tweeter to check the coil, I figured out that the Sonus Faber modification to the D28AF was just a larger, acoustically padded, rear chamber. Something easily transferable from my tweeters to another pair of D28-AFs, but they are also NLA new. A S/H pair on eBay for €140 hmm... Go back to Dynaudio for a pair of those D28/2s and hope they are similar enough to the D28-AF at £175? The accepted replacement seemed to be the Morel MDT32S/CAT 328-110. In the UK about £140 a pair, sighs, reaches for wallet... and yet...

...looking again, through a 7x loupe, at that busted tweeter coil and prodding with my finest meter probes. It was just one side of the coil, at the junction between the coil and the fine feeder wire, that was open circuit. Barely 0.5mm of coil wire to try and attach to. But just enough to grab with fine tweezers, unwind a turn, steady nerves for the fiddliest of soldering jobs, attach coil end to feeder wire, meter out, measures within spec at 5.6 ohm, faceplate screwed to magnet, tweeter installed --- happiness ensues. Sorry, Celestion DL6s, a solid replacement in times of trouble, but back to the garage with you.

Thanks for reading this far, you now know as much about early Sonus Faber tweeters as I do.