Eschenborn, did you find you needed to replace the ferrofluid in the tweeters? (I think they have ferrofluid, don't they?).
OP will draw their own conclusions on b200 reliability after 40 years. I haven't looked but I'd be surprised if a KEF reference speaker from 2025 measures worse than a KEF reference from 1980. I'm not saying they are bad speakers, far from it, as stated above i think they sound(ed) great.
The T33 SP1074 in the 103.2 does not contain ferrofluid.
If you have the feeling that the tweeters are not up to snuff, it's probably worn out caps in the crossover.
If you have the feeling that the tweeters are not up to snuff, it's probably worn out caps in the crossover.
Ahh, OK thanks. Yes, mine are lacking a bit of sparkle. The crossovers are untouched from new. Is Falcon Acoustics the best source for capacitors? I place some value on the fact that I can just order them without thinking about making up a BOM (as there are so many!).
Falcon is ok, but they sometimes can't supply the exact specifications anymore. even in their complete recapping kits there was often some wrong cap (e.g. a 50V cap where in the schematics was called for a low loss (LL, or in Mundorf terms "plain foil") cap with a different voltage rating) or something similar.
Here is what I have used a couple of times (did a lot of experiments... although with my ears only, no data). for the tweeter part, the 4.2uF cap can be a high quality film type, the others can be film but can also be a good quality electrolytic. All tweeter caps as film works. If treble becomes too prominent, there is a jumper for a resistor to pad down the tweeter section already on the crossover PCB. But it will probably work.
Re the woofer part: The 600uF in total series caps can be any quality electrolytics, no LL. The series cap with the inductor should be a 50V normal ("raw foil") cap, can be of general quality (yes, it's strange). The shunt cap can be a LL electro.
Restoring such a crossover needs some tuning by ear, my experience. I've also done, among others, an upgrade to the KEF Concerto original crossovers, adding the aB section. The thread is somewhere on this site.
Other people's mileage may vary 🙂
Here is what I have used a couple of times (did a lot of experiments... although with my ears only, no data). for the tweeter part, the 4.2uF cap can be a high quality film type, the others can be film but can also be a good quality electrolytic. All tweeter caps as film works. If treble becomes too prominent, there is a jumper for a resistor to pad down the tweeter section already on the crossover PCB. But it will probably work.
Re the woofer part: The 600uF in total series caps can be any quality electrolytics, no LL. The series cap with the inductor should be a 50V normal ("raw foil") cap, can be of general quality (yes, it's strange). The shunt cap can be a LL electro.
Restoring such a crossover needs some tuning by ear, my experience. I've also done, among others, an upgrade to the KEF Concerto original crossovers, adding the aB section. The thread is somewhere on this site.
Other people's mileage may vary 🙂
You've done an Acoustic Butterworth version of the KEF Concerto xover??!! 😲 Where? WHERE??
I recommend the Falcon "KEF 103.2 Replacement Capacitor Set". Sound is not quite original but good. So replace both speaker in your pair. Will give you at least another 2 decades of good sound.
I see many regretting that certain drivers have become unavailable. KEF 103.2, KEF B200, etc. This question is longer on my mind. WHY do speaker manufacturers keep developing new drivers over and over and take the old ones out of production. Is any new type better than the previous one?
I mean the B139 was phased out in favor of the B200. And the B200 was replaced by what?
Do they do this ONLY if you have a defective driver you cannot replace it? The successor invariable has different dimensions of course if the parameters are comparable. Or other parameters in case the dimensions match. Why oh why?
Somewhat off-topic. As for my pair of B139s, I recently wanted to re-use them for a new project. Unfortunately the Fs had increased from the nominal 25Hz to 43Hz. Now, if better materials had been used, this might not have happened. But then again, the climate here is extremely adverse to any material and ageing might not have happened in a moderate climate. Still I can not imagine that any manufacturer produces its goods to last longer than 40 years ago. That would be totally against any economic development.
I mean the B139 was phased out in favor of the B200. And the B200 was replaced by what?
Do they do this ONLY if you have a defective driver you cannot replace it? The successor invariable has different dimensions of course if the parameters are comparable. Or other parameters in case the dimensions match. Why oh why?
Somewhat off-topic. As for my pair of B139s, I recently wanted to re-use them for a new project. Unfortunately the Fs had increased from the nominal 25Hz to 43Hz. Now, if better materials had been used, this might not have happened. But then again, the climate here is extremely adverse to any material and ageing might not have happened in a moderate climate. Still I can not imagine that any manufacturer produces its goods to last longer than 40 years ago. That would be totally against any economic development.
In the case of B139, I know of at least 5 different versions with quite 'different' performance sold to DIYs as the same model. Of course KEF thought the later versions were 'better' than the previous one. Later versions had at least 2x the power handling of the early ones.
But to the DIYer, they fit in the same hole so must be the same 😊
The differences in B200s is MUCH greater than differences in B139s
IIRC, KEF policy on spares was to estimate & make enough to last 20 yrs after production stopped. The estimate might be wrong but it's always worth asking the official agent if they have any.
I won't go into the EVIL subject of pricing for spares 😲
BTW, fs change from 25Hz to 43Hz hides the REALLY IMPORTANT parameters. This change might have trivial effect if the IMPORTANT parameters are the 'same'
Too bad, you were right. Yesterday evening I was playing some soft acoustic music and the slight rattle came back.
I think I'm gonna give up. I really think these are one the best sounding speakers I've ever had, but I can't live with returning defects once a week. I could have the woofer repaired. But then I'd also need to do the recap. When that's done, the other woofer would probably go bad. Sad about this.
On the bright side.....I do have budget. Are there any new or recent speakers that might give me the same enjoyment as the 103.2?
I could spend about 1000 euro's
Thanks for this eschenborn.
I'm not sure just copying the KEF 104ab treble circuit is appropriate for all T27 applications. System 7's is the 'correct' model but the mounting is rather different. IMHO, it is wrong for the original, which was in a shallow 'waveguide'.
The 'ab' stands for Acoustic Butterworth, so you really need to measure the T27 + new xover in the intended mounting to see if you have an Acoustic Butterworth response.
Just going over to the 104ab circuit WILL change the sound but whether it is 'better' depends on loadsa stuff, especially the midrange, its mounting and its xover too. But if it sounds good to you ... 😊
If you look at the schematics of the „new“ Concerto crossover, you will see that mid and treble circuits have changed. As you see from the discussion, the layout seems to sound good for more than two ears. Falcon supplied crossovers with an added (different) aB section for the Concerto, too, which don‘t sound right — to my ears. But of course, as said above, ymmv. And as this here is a thread about the 103.2, not the Concerto, I‘ll respond to additional comments over there.
After all these years, you might be better to turn the entire cab. Putting the bass above the tweeter. This ensures it sags back in the right direction. Which can't be achieved turning the bass. If they are just in storage, then that's an even stronger case for just turning the cabs over. Though if in constant use, a calendar turning of the bass units may be preferable.
Hey, that's a really good idea! Why didn't I think of that! 🙄
They are on rotation and are currently sitting in a spare room unused, so I'm going to do it asap. Thanks.
They are on rotation and are currently sitting in a spare room unused, so I'm going to do it asap. Thanks.
Hey, no problem. I appreciate your comments. Yes, I was referring to their kit and was just being lazy, hoping Falcon's offering was up to scratch.
Just one question though; are you referring to using 'ordinary' polarised electrolytics, or have I misunderstood you?
Hi Stuey, thank you.
I was referring to two types of bipolar electrolytics – the usual ones (with "raw" foil) inside, and the low loss (LL) ones, with "plain foil" inside. Both are bipolar, not polarized. Then I was also mentioning polyester or polypropylene film caps. They are bipolar by default.
I was referring to two types of bipolar electrolytics – the usual ones (with "raw" foil) inside, and the low loss (LL) ones, with "plain foil" inside. Both are bipolar, not polarized. Then I was also mentioning polyester or polypropylene film caps. They are bipolar by default.