SpeakerTalk

brucegseidner · Junior Contributor 10+ Joined: 05 Jul 2009 Posts: 12

I am unpacking gear that has been in storage. This is a 70's and 80's time capsule. I have a bunch of KEF drivers that are in very good shape as well as a set of PCB-9 and PCB-11 Falcon Acoustics crossovers. I was delighted to find the Falcon Acoustics website up and running. But my PCB-11 crossover is not listed. It lists them up to PCB-10 that I could see.

I purchased both the PCB-9 and PCB-11 in 1984. I know the PCB-9 went to my B-139's. I don't know the crossover points or slopes of these puppies.

I don't remember what went on the other side of the PCB-11. I am pretty sure it was a T-52 up top but I don't recall if it was a B-200 or a B-110 or something else.

I would also appreciate knowing the recommended volumes of the spec'd cabinets and the stuffing recommendations (lbs/volume). Actually, I don't recall if it is a vented or a sealed box design. Regardless, I have plenty of room in this new space to build these up again.

Oh, and would anyone change out the blue ALCAP capacitors with something manufactured in this century or change to film? They were used 1984-1990 and have been in a box since then. My sense is they should be fine, but not being an engineer or terribly current, there might be a modification that would be recommended. Now is the time to tinker.

I used to use a very big Hafler to fire these up. Nowadays I have flea-weight tube amps and high efficiency speakers. So I just pulled the trigger on a solid state 100W/channel amp in anticipation of getting these drivers singing again.

Should be fun.

Thank you in advance.

SaSi · Senior Contributor 200+ Joined: 24 Aug 2008 Posts: 256

I think you should contact Falcon Acoustics with the model numbers and a picture of the crossovers. Malcom Jones, the person who started Falcon is still with them so there should be no problem identifying them for you and perhaps be able to send you relevant documentation for them.

brucegseidner · Junior Contributor 10+ Joined: 05 Jul 2009 Posts: 12

That is great news. I recall speaking to him when I purchased these 30 years ago. I just sent an email.

There is also a lot of depth on the bench here and I would be surprised if others had not used this crossover. Thanks.

Gossy · Introductory Contributor Joined: 07 Jan 2015 Posts: 8

Hi - not being an engineer either, but having a nephew who is those caps might still be in good working order, or not - only way to know is to test em out ^^ There are ways to gently get a cap back up to spec I've read- some device that lets you feed them current slowly and more and more upto their spec.. I forget the name. If they áre in good order, then they are very good caps indeed - no need to try and improve.

keffan · Posted: Wed Jun 23, 2021 4:08 am Post subject: 104/2 recap question

I am considering recapping the crossovers of the 104/2. Can I replace those electrolytic capacitors with other types of capacitor? I wonder other types of capacitors could improve the sound quality of 104/2.

audiolabtower · VIP Contributor 500+ Joined: 06 Jan 2009 Posts: 686

Polyester and polypropylene caps will have less internal resistance than the original electrolytics, even the low loss ones Kef used in critical positions. This may lead to more output in some regions, usually brighter, which people then interpret as "improvements" even though the balance may be worse than the original design. Complicating the issue electrolytics can degrade over time, and drift from original value, and Kef will have selected them from the tolerance range to suit the overall computer calculated response. However compounding any tolerance mismatch from replacing with new random electrolytics will be worse by changing the type of cap too without adding some resistors to the crossover.

keffan · Posted: Wed Jun 23, 2021 9:38 pm Post subject: 104/2 recap question

Thank you for your reply. There seems no good answer to this question.

audiolabtower · VIP Contributor 500+ Joined: 06 Jan 2009 Posts: 686

If the speaker sounds wrong, and the drivers are fine (foam surrounds etc) it is possible the caps may have drifted. In that case, without measuring equipment, your best bet is a Falcon set.

https://www.falconacoustics.co.uk/replacement-capacitor-sets/kef-104-2-replacement-capacitor-set.html

keffan · Posted: Thu Jun 24, 2021 4:44 pm Post subject: 104/2 recap

Thank you for your advice. Why is Falcon set is better than the caps I can buy from the other source?

audiolabtower · VIP Contributor 500+ Joined: 06 Jan 2009 Posts: 686

They say they supply low loss types for the circuit positions Kef originally had them.