Sacrilege/what problems have I caused myself/what next?

[planet10]

These two SP1039 units were purchased new from KEF and have been kept as spares - hence the high asking price of £250

Sounds like a good price. You do perhaps need to worry a bit about sag if they have been in the same storage orientation for that long.

But i have 16 SP1014 of simialr age and they are fine.

dave

 

[Southdowns]

My computer seems to be acting up and earlier posts are appearing after I have posted. Hence I missed your post #20, Southdowns.

Obviously a matched pair of B200 would be nice, but needs must!

It’s not your computer - because I’m a new member posts had to be approved. No longer though 🙂

 

[Galu]

a mess to change if ported and needs to adapt the port

There's no port, iggy - there is a passive radiator.

 

[diyiggy]

Rigth but I really believed by innocence it was not lythics !

ah Ihave all bad on that thread, lol, shame on the french ! So a bigger Ab I assume than the 104s, I didn't know it! Ok, not so easy to refurbish, certainly needs the coils to be changed if veiled (and on two units for consitency)... and as said it is complcated, not always guaranted good job. Yes better to look for a second hand equivalent from Kef. Maybe a list of compatible Kef uniits with kef sp1039 drivers should help ?

 

[planet10]

black and red ELCAPS

And they were available and fairly cheap.

dave

 

[AllenB]

No longer though 🙂

Welcome to the forum 🙂

 

[Southdowns]

Yes, when the replacement driver is sorted out, we should perhaps talk about replacing the old electrolytic capacitors in the crossover.

If they are the black and red ELCAPS as shown in the attachments, they will have suffered badly from ageing and changed their capacitance value to the detriment of the performance of the loudspeaker system.

I think the caps might have been replaced when my Dad had the speakers serviced about 10 years ago. From memory they’re not black and red, but I’ll check.

I was wondering about changing the crossovers for the 104ab ones once I’ve replaced the drivers. Apparently the crossover was the only difference between the 104 and the 104ab.

 

[Southdowns]

Welcome to the forum 🙂

Thanks 🙂

 

[Galu]

Rigth

Sorry, iggy, I think you were referring to your DM14s while I was referring to the 104s.

 

[planet10]

a passive radiator.

dave

 

[planet10]

Yes, the ab upgrade is worthwhile. There is a thread on the subject.

dave

 

[Galu]

I was wondering about changing the crossovers for the 104ab ones once I’ve replaced the drivers. Apparently the crossover was the only difference between the 104 and the 104ab.

Yes, there's thread on that, but the crossover for the ab version is more complicated.

https://www.diyaudio.com/community/threads/kef-104-to-kef-104ab-mkii-with-spice.189530/

 

[Galu]

Here's the simple 104 crossover schematic (a 2.7 mH inductor is used in the bass filter).

 

[diyiggy]

Sorry, iggy, I think you were referring to your DM14s while I was referring to the 104s.

sames : https://www.diyaudio.com/community/threads/b-w-dm14-from-1980-hot-pics.370134/post-6592805

However the red lythic PYE were quite good I found after replacing them (think the exact capacitance was important here...)

 

[Galu]

I see one red and black ELCAP on your crossover board. They are known to go high value.

 

[planet10]

Looks like this one came from the same place.



dave

 

[Galu]

I've just twigged to the fact that the 'aB' in 'KEF 104aB' stands for 'acoustic Butterworth'!

 

[planet10]

:^)

dave

 

[Galu]

Good stuff! The three functions of the acoustic Butterworth (aB) filter are fully explained in the above pdf.

 

[Boden]

Strictly speaking there is only one function: to create a textbook BUT 3 acoustic transfer function including a near perfect stopband.