KEF 105.3 crossover

[Cwess]

I have a schematic One of the inductors has a value of .07mh. Is that a typo. Or are there inductors of the low value?

 

[Sonce]

If you want a reliable answer, you have to post the whole schematic, or at least the whole filter for that driver.
It looks to me that it is not a typo.

 

[Galu]

Full schematic attached.

 

[Galu]

To spice up the discussion, post #17 in the thread below has the KEF maintenance document attached.

S

Thread 'Kef 105/3 crossover'

2010-01-06 10:22 am

Hello I have a pair of these speakers and have been reading about people replacing the capacitors due to ageing. I have had a quick look inside my cabinets and the caps look fine i.e not swollen, but I have read that they dry out. If it is advisable to replace them, what caps would any one recommend? I have a schematic of the crossovers and there a total of 23 caps per speaker 😱 The values on my schematic are as follows;(value times total)
240 x 2
100 x 7
80 x 4
60 x 1
50 x 3
20 x 3
15 x 1
7 x 2

Any advise would be greatly appreciated, I think these are fantastic speakers and about 18...

• sbx
• Replies: 16
• Forum: Multi-Way

The schematic in the document shows the inductor in question (L34) as having an inductance of 0.007 mH!

Which is also the value annotated in the diagram of the physical crossover board.

 

[Galu]

Is that a typo. Or are there inductors of the low value?

We can say with confidence that an inductor of low value (whether it be 0.07 mH or 0.007 mH) is indeed incorporated in the crossover.

 

[Sonce]

Full schematic attached.

Thank you, now it is clear - that RLC trap is in the tweeter filter branch and it levels a peak in the tweeter frequency response.
If the inductor is 0.07mH, than the maximum attenuation is at 4.254 Hz.
If the inductor is 0.007mH, than the maximum attenuation is at 13.451 Hz.
Based on this numbers, it is inconclusive - both frequencies are logical for a tweeter. But I think 13.451 Hz is the most probable, so the inductor value should be 0.007mH.