I shouldn't think there'll be any aluminium in there. Those braids are usually either copper or silver and I can't imagine KEF using silver. 😂😂 I think flux is in too short supply to use CCAW in a bass unit but it's interesting that you mention Scan Speak because they pioneered making that joint in their tweeters which, because of the two metals, needed a particularly aggressive rosin - I presume to knock away the AlO3 that would reappear instantly.
But that really is a weak point which at some time gets nearly all manufacturers, especially if spider/coil former/cone and the wires all meet in the same place. You can sometimes find old B139s with burn holes round there, where someone has either been making a hash of things or has corrected a previously made hash (very hard to disguise if you have expanded polystyrene near your soldering iron).
But that really is a weak point which at some time gets nearly all manufacturers, especially if spider/coil former/cone and the wires all meet in the same place. You can sometimes find old B139s with burn holes round there, where someone has either been making a hash of things or has corrected a previously made hash (very hard to disguise if you have expanded polystyrene near your soldering iron).
In bass units? I'm surprised. You can probably get back some of the turns if you've flattened the wire but I'm still quite surprised. You are saving some mass but it's nothing like as important as it is on a tweeter or even mid and you need a given amount of mass for your bass resonance anyway. And I'd have thought you'd be sacrificing some power handling too - so that might mean you have to go up in coil diameter, which could mean an increase in magnet size too. I'm sure you can get something out of it but you'd need to do a proper study to see if things can turn out better with CCAW and though I can't do those calcs in my head I still think it's going to be a step back in most applications.
I HATE Pb-Free and all the Brussels idiots who brought in the law. One thing's absolutely for certain, it's doing nothing for the environment!
I HATE Pb-Free and all the Brussels idiots who brought in the law. One thing's absolutely for certain, it's doing nothing for the environment!
The key thing is the leachability of lead from tin/lead solder in landfills. Historically this was not a major problem, because domestic and industrial, usually valved/tubed gear, rarely found itself simply thrown away and ending in landfill.
However in recent times, with our use, throw away and then buy the latest gizmo society it has become much more of an issue. Hence lead-free solders. These are much better now than they used to be in joint wettability, and joint appearance. The old lead-free solders produced grey-looking joints that all looked as if they were dry joints, or one that had moved before the solder solidified.
For hobby use I want none of that nonsense. So I use tin/lead with 2% silver, and have stocked up with different gauges, and enough to see me in my box.
One of the reasons for aluminium voice coils is cheapness. Aluminium is a whole lot cheaper than copper. But voice coils with aluminium wire are really difficult to solder to, and needs a really aggressive flux.
Thinking back to lead leachability, our friends in Europe passed a law regarding disposal of old-style colour picture tubes from old TV's. The front assembly, with the shadow mask and phosphors was temperature sensitive, but it had to be bonded onto the envelope that contained the electron gun - and manufacturers used a very high lead content frit, which because of the lead had a very low softening temperature, and did not damage the shadow mask assembly,
That law had good intentions at it core, because the lead frit was exceptionally leachable in landfills. But in the law of unexpected consequences this also included in the catchall legislation all CRTs - including black and white CRTs (no frit at all, and used by collectors and restorers of old TV's) and test equipment CRT's such as those that were used in oscilloscopes. So many thousands of repair parts got disposed of unnecessarily.
I'll shut up now....
However in recent times, with our use, throw away and then buy the latest gizmo society it has become much more of an issue. Hence lead-free solders. These are much better now than they used to be in joint wettability, and joint appearance. The old lead-free solders produced grey-looking joints that all looked as if they were dry joints, or one that had moved before the solder solidified.
For hobby use I want none of that nonsense. So I use tin/lead with 2% silver, and have stocked up with different gauges, and enough to see me in my box.
One of the reasons for aluminium voice coils is cheapness. Aluminium is a whole lot cheaper than copper. But voice coils with aluminium wire are really difficult to solder to, and needs a really aggressive flux.
Thinking back to lead leachability, our friends in Europe passed a law regarding disposal of old-style colour picture tubes from old TV's. The front assembly, with the shadow mask and phosphors was temperature sensitive, but it had to be bonded onto the envelope that contained the electron gun - and manufacturers used a very high lead content frit, which because of the lead had a very low softening temperature, and did not damage the shadow mask assembly,
That law had good intentions at it core, because the lead frit was exceptionally leachable in landfills. But in the law of unexpected consequences this also included in the catchall legislation all CRTs - including black and white CRTs (no frit at all, and used by collectors and restorers of old TV's) and test equipment CRT's such as those that were used in oscilloscopes. So many thousands of repair parts got disposed of unnecessarily.
I'll shut up now....
this is new for me and good news.
I think, you mean this manufacturer in U.K. for speaker drivers in the top-quality range:
https://voltloudspeakers.co.uk/contact/
Unfortunately on their website isn't mentioned this.
Maybe It is possible, that this supplier under
https://www.falconacoustics.co.uk
also has the remakes of various old KEF driver models manufactured there.
Wilmslow Audio might be worth contacting https://wilmslowaudio.co.uk/ . They carry out drive unit repair.
Also they say "B200 bass - use Monacor SPH-210"
Also they say "B200 bass - use Monacor SPH-210"
The B200 was not a very good driver back in it's haydays. It comes from an era when amplifiers became more powerfull and loudspeaker manufactureres began to manufacture drivers with highly damped cones to avoid breakup behaviour at the expense of sensitivity and unfortunatly also at the expense of live sound or exitement. Loudspeakers became over polite and the B200 and other KEF drivers where the perfect example of it. The KEF speakers did sound well balanced but they lacked dynamics, lacked detail and simply lacked live.
Certainly a good description of KEFs of the day. But i heard some really good DIY speakers. with KEF drivers.
dave
I have also heard very good diy loudspeakers with KEF drivers in the past so I thought but that was untill I knew better. It was untill I started working as a sound engineer and hearing live music on a daily basis I knew something was just not right with these kind of drivers/systems and after a while I just could not stand the sound of it anymore, it was too far of what I heard from real instruments, like a over romantisized picture of reality.
But the best system is the system that brings the owner the most enjoyment.
But the best system is the system that brings the owner the most enjoyment.
@Sjef. Very interesting. I think the SARAs are a pretty good implementation of the B200. They don't do anything like KEF did back then and put them against the wall so they didn't have to compensate for the 4pi to 2pi transition. That allowed them to stay more sensitive and be much more dynamic because you didn't have the bass swamping the sound (by putting only one unit of bass into the room rather than two). Sadly they aren't a patch on the Isobariks and if I were pushed, I think I'd have to say the Kans were better - and that's with a driver I definitely wouldn't use these days, the SP1003. (I would use the SP1228 at a pinch but there are better drivers out there and I anyway prefer either plasticised paper or carbon fibre nowadays.) But I wouldn't go as far as saying it was never a very good driver. It was cutting edge in its time and I bet the sales figures don't bear out your perspective. What is surprising is that they didn't make a polypropylene version (I think), especially as they would go on to produce about half a dozen models after the SP1014. Had they done so, it would still be giving almost everything equivalent in the market a decent run for the money. But at £10-£15 each - which is almost exactly what we paid trade in the early and mid '80s - they offer good value and would be very tempting for someone starting out. And you can get more out of them than the SARAs do.