I took the photo of the crossover in the topic Kef 104/2 tweeter replace...
I was asking the crossover experts if changing the values of 13 /14 /15 /16 caps and the resistors regarding the Tweeter power could also affect the performance of the two B200 woofers which are in push-pull mode?
thankyou
I was asking the crossover experts if changing the values of 13 /14 /15 /16 caps and the resistors regarding the Tweeter power could also affect the performance of the two B200 woofers which are in push-pull mode?
thankyou
Yes. But as you see there are few caps that needs precision. But my experience with this loudspeaker is it's hard to recap, because you have to respect the serie resistance of the capacitor. Some caps values are hard to get. You need to refoam the mushrooms, plenty of kits available.
so if I use caps with higher voltage, like - instead of 50 and 100v, I use 250v MKPs with the same uF value, do these change everything?
Yes. The esr of a MKP is much less, so you will need to add a resistor in serie. Anyway you have not the aera room to put such big caps.
To ensure the crossover performs as KEF intended, you would be advised to only change capacitors like for like.
Note that C13 and C14 differ from C15 and C16 in that they are low loss (LL) types.
LL types have low esr (equivalent series resistance) and more closely resemble film capacitors in that respect than ordinary bipolar electrolytics.
Note that replacement capacitors should be matched to within +/- 5% of the values on the schematic.
Note that C13 and C14 differ from C15 and C16 in that they are low loss (LL) types.
LL types have low esr (equivalent series resistance) and more closely resemble film capacitors in that respect than ordinary bipolar electrolytics.
Note that replacement capacitors should be matched to within +/- 5% of the values on the schematic.
I wouldn’t embark on such modification plans without the abilities to proper measure acoustic output of the system. KEF used to match the real (not printed) values of components to the specific driver responses. While the system might be off anyway after years of service, changing to textbook values likely worsens response rather than improves it.
@diyiggy
@Galu
@markbakk
thanks guys, don't worry, everything is ok. I won't do anything strange on my Kefs, but now everything is clear and I also had the doubt that the difference in voltage could compromise the original performance. let's say that now I have more information on the behavior of the caps on the crossover.
thank you all
@Galu
@markbakk
thanks guys, don't worry, everything is ok. I won't do anything strange on my Kefs, but now everything is clear and I also had the doubt that the difference in voltage could compromise the original performance. let's say that now I have more information on the behavior of the caps on the crossover.
thank you all
If you ddon't know this adress already from you readings, it can be handy : https://www.falconacoustics.co.uk/l...laritycap-solen-audio-capacitors.html?cat=231
For reference, Falcon Acoustics does a complete replacement capacitor set for a pair of KEF 104/2:
https://www.falconacoustics.co.uk/l...sets/kef-104-2-replacement-capacitor-set.html
https://www.falconacoustics.co.uk/l...sets/kef-104-2-replacement-capacitor-set.html
@diyiggy
@Galu
Thanks again for your info.
I know the Falcon site very well, I know that they have a lot of things related to the old Kef components. I will create a parallel crossover, external and assembled in a very spartan way so as to be able to do more rapid tests. the large front hole allows the passage of all cables 🙂 I'm curious to see how much difference there is using the MKP caps.
@Galu
Thanks again for your info.
I know the Falcon site very well, I know that they have a lot of things related to the old Kef components. I will create a parallel crossover, external and assembled in a very spartan way so as to be able to do more rapid tests. the large front hole allows the passage of all cables 🙂 I'm curious to see how much difference there is using the MKP caps.
I didn't know Falcon has the recaping kit yet. Imo it is the way to go before it is NLA. First you need a capacitance meter to measure what you remove of the board. If you have one with ESR measurement it is even better. For sure you will se the values certainly moved, some staying in the capacitange range of the sheematic till 10%.
But indeed the capacitors were sorted out to accomodate the reference alpha loudspeaker measurement.
Also maybe with agging and refoaming of the mushrooms and/or (according your model year) the foam surround of bass drivers as well as the loss in magnetic power change things anyway. You don't care MKP for the reason talked before : if you have a closer look at the shematic, resistors in serie are avoided a lot by playing with the Dcr of the caps and coils : brillant !
Maybe MKT is feasible for the LL lythic marking, for instance you can swap the two // for the treble by one MKT. I fear MKP to have too much low ESR, but trying is knowing !
Yes it is a mess to put ount and in the filter, so a very good idea to externalise the filter board for the refurbishment and tests to make a serious job.
Also : do what @markbakk suggested : do an impedance measurement of the two loudspeakers, and a spl gated (7 to 5 ms for the mid/tweets).
Which profits the most of the recaping is old lythic have leaking characteristics when agging too much.
But indeed the capacitors were sorted out to accomodate the reference alpha loudspeaker measurement.
Also maybe with agging and refoaming of the mushrooms and/or (according your model year) the foam surround of bass drivers as well as the loss in magnetic power change things anyway. You don't care MKP for the reason talked before : if you have a closer look at the shematic, resistors in serie are avoided a lot by playing with the Dcr of the caps and coils : brillant !
Maybe MKT is feasible for the LL lythic marking, for instance you can swap the two // for the treble by one MKT. I fear MKP to have too much low ESR, but trying is knowing !
Yes it is a mess to put ount and in the filter, so a very good idea to externalise the filter board for the refurbishment and tests to make a serious job.
Also : do what @markbakk suggested : do an impedance measurement of the two loudspeakers, and a spl gated (7 to 5 ms for the mid/tweets).
Which profits the most of the recaping is old lythic have leaking characteristics when agging too much.
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@diyiggy
mine have the rubber suspension reversed and I've already redone the donut. here you can see it just glued, where I then cut out in the center for the screw of the aluminum bar 🙂
what is missing, as you suggested, is the measurement of the B200 and for this I have to equip myself with the best equipment.
mine have the rubber suspension reversed and I've already redone the donut. here you can see it just glued, where I then cut out in the center for the screw of the aluminum bar 🙂
what is missing, as you suggested, is the measurement of the B200 and for this I have to equip myself with the best equipment.