Dead KEF X300A - what to do with them?

[sorryimfrench]

Thanks! a few questions to make sure I'm picking the right parts:

1. Capacitor: Solen 3.9uF 400V <https://www.solen.ca/en/products/so...b390-3_9uf-400v-metallized-polypropylene-film> or Mundorf ECap AC 3.9uf 70V Bipolar Electrolytic Capacitor - PLAIN. <https://willys-hifi.com/products/mu...ar-electrolytic-capacitor?variant=51749035539>
2. Resistor: Mundorf 0.68ohm <https://www.partsconnexion.com/MUNDORF-82484.html#40898> or or Mundorf M-Resist 10W 6.8 Ohm 2% MOX Resistor <https://willys-hifi.com/products/mundorf-m-resist-10w-6-8-ohm-2-mox-resistor?variant=51026545875>
3. Inductor: Solen 0.68mH 20AWG <https://www.solen.ca/en/products/solen-perfect-lay-air-core-inductors-s20_68-0_68mh-20awg-inductor> or Audyn Crossover Inductors <https://willys-hifi.com/products/cr...e-core-litz-wire-large?variant=31065146392635> (there's a bunch of inductors here https://willys-hifi.com/pages/rapid-search-results?variant=31050177511483&q=0.68+inductor but not sure which one to choose).

PCB: Not sure which one is the one I need, this one Intertechnik Crossover Development Circuit Board 1342756 <https://willys-hifi.com/products/crossover-development-circuit-board?variant=21298937626683> and this one Intertechnik Grid Board RA140 <https://willys-hifi.com/products/intertechnik-grid-board-1342765-small?variant=21299474333755> look like the right size, but not sure what the benfit of the first one is over the second.

Last, do I need specific wires to connect the components on the PCB? I was thinking that an amp'ed signal may have different requirements than basic electronics?

 

[Galu]

There's no need to overthink this simple crossover.

Choose a polypropylene capacitor, a 10W resistor and a Monacor 0.68mH air core inductor from Willys HiFi.

https://willys-hifi.com/products/monacor-audio-inductors-air-core-1mm-ofc?variant=33569754742843

You can glue the components to a piece of hardboard and use ordinary loudspeaker flex for the wiring.

 

[Galu]

P.S. You can get every component from Willys HiFi, just add this capacitor:

https://willys-hifi.com/products/mk...sover-capacitor-3-9uf-250v?variant=1165239957

 

[Galu]

Willys Hifi says "Royal Mail international services suspended until further notice", but these services now appear to be reinstated according to today's Royal Mail update: https://personal.help.royalmail.com/app/answers/detail/a_id/5317/~/international-incident-bulletin

 

[b0p]

Hi there, I'm another owner of a set of non-working X300A speakers. I tried to create the crossover filter based on the information in this thread and I'm having some issues after completing the first speaker. At first, only the tweeter was working on a really low volume. I was pretty sure I connected everything correct, but after some basic troubleshooting (different amp, different cables, checking the crossover filter again etc.) I tried switching the woofer and tweeter connections on the filter. Volume is better now, but the speaker is really lacking bass.

Components I used for the crossover filter:

Inductor: https://www.conrad.nl/nl/p/monacor-lsip-68-1-luidsprekerluchtspoel-1331929.html
Capacitor: https://www.conrad.nl/nl/p/monacor-mkpa-39-luidsprekercondensator-1332094.html
Resistor: https://www.ruttenelektroshop.nl/product/rf0e68-weerstand-10w-068-ohm/

I'm not really sure how to proceed with troubleshooting at this point. I hope someone is able to point me in the right direction..

 

[Galu]

Test the woofer on its own without the crossover in place, i.e., apply the music signal directly to the woofer terminals. Report back on the result.

 

[b0p]

I just tried that and the woofer is producing sound at an expected level. Just sounds a bit muffled, probably because of the filter + tweeter missing?

 

[Galu]

Check your crossover carefully to ensure that the inductor is in series with the woofer and that the capacitor and resistor combination is in series with the tweeter.

You may have to post images of your crossover construction, making it clear which pairs of wires go to the amplifier, to the woofer and to the tweeter.

Please verify the values of the inductor and capacitor you have bought, as I can't read their links.

In case further troubleshooting is required, do you have a multimeter?

 

[b0p]

See attached photos. I rarely use a soldering iron, so it might look a little rough. But all the joints seem to make contact. I do have a multimeter if needed.

 

[Galu]

Do some tracing of the signal pathways for me, as I'm easily confused. 😉

Here are the pathways you should have:

Woofer section
Signal Out: amplifier positive to inductor to woofer positive
Signal Return: woofer negative to amplifier negative

Tweeter section
Signal Out: amplifier positive to capacitor to resistor to tweeter negative
Signal Return: tweeter positive to amplifier negative

 

[b0p]

Oh my, now I feel bad. I did not notice the reverse polarity for the tweeter in the crossover schematic you posted. I basically used the '2 way 1st order XO.gif' image posted somewhere in the thread while soldering (which has amp positive going to tweeter positive if I understand it correctly).

Just did a test by reversing the tweeter wire ends on the HF side of the terminal and I now have a fully functional speaker 😀

I am really really happy with the result. I recently brought the speakers to the shop where I bought them a long time ago. They were deemed irrepairable (at least for a reasonable price) and the alternative they had on sale was significantly higher priced (I think it was the LS50 Wireless II?). Now I will be able to enjoy this set for some more time.

Thanks a lot for helping out Galu!

 

[Galu]

Thank you! I'm glad to have been of assistance.

I believe you are now the 5th happy customer in regard to this active to passive speaker conversion. 😎

 

[Ianradtan]

Hello,
I also want to convert my X300A. Will this crossover works with X300A? Any suggestions?

 

[Galu]

I cannot vouch for the suitability of the above crossover.

Please build the correct and simple crossover shown in post #116 which has now resulted in five happy customers!

 

[Galu]

P.S. A written description of how to wire up the three crossover components is given in post #130.

 

[stephhhen]

hi galu thanks for the breif explaination.

finally I'm done installing q100 crossover into x300a and its sounds amazing, even better from the build inpower amp dac of x300a itself.

I even tried other crossover which I bought from amazon but I think it was lacking the right frequency range (just based on what im hearing when I compared it side by side with the q100 crossover).

Well this settles it, Im very thankful I found this thread and learn a lot more from you guys. Thanks a lot.

Hey Vrachie, any logical reason that you kept the bell looking coil in the speaker compartment? Does that thing still serve any purposes?

 

[stephhhen]

Hi @vrachie @Galu, thanks a lot for the input. I am another owner of a dead X300AW pair. 🙂

 

[Galu]

You are welcome!

The passive crossover couldn't be much simpler, consisting of just three components.

It has been fully described above and there should be no need to look for further explanation.

No components from the active setup require to be kept other than the loudspeaker drivers.

 

[Galu]

To be perfectly clear, @stephhhen, please refer to my posts #134 and #135 directly above.

If you require any further help with the conversion, do not hesitate to ask me.

 

[stephhhen]

Thank you again @Galu! I am currently scouting for the components. Surprisingly EU has WAY more audio related suppliers than US/CA.