One of KEF's goals in design was to have their speakers present a very flat, resistive impedance to an amplifier. Hence all the filters. On their 107 they even nulled out the bass reflex (bandpass) impedance peaks, IIRC.
It's certainly a good idea to have a flat impedance curve, btw I had a look to Joe Rasmusen design just because of that, but at the end many said than these old ref Kef speakers, especially the 104/2 needed a very powerfull amp; able of huge current peaks; a guy at HifiChoice said it works flawlessy with 40/50 ampers amps ! At the end even if a little amp can drive them, they sing only with strong amps à la Bryston, Krell, etc.
mine is monowired, I know the filter Evolved in the bi amp and last special edition but never saw the shematics of the two last. Mine has a single pcb filter with all these dim sum coils everywhere on it !
mine is monowired, I know the filter Evolved in the bi amp and last special edition but never saw the shematics of the two last. Mine has a single pcb filter with all these dim sum coils everywhere on it !
This is questionable, and JR is an obvious crank. Good luck with your efforts, though
ah, so converseley as the curve ! Well... duno.
Anyway, thank you ! Because the difficulty to find some capacitance values without // I should stay on elec from Alcap, trying to find the same voltage matching too. I have not the knowledge for mixing the caps and understand the issues on the filter. Sure I will measure first the original caps.
Anyway, thank you ! Because the difficulty to find some capacitance values without // I should stay on elec from Alcap, trying to find the same voltage matching too. I have not the knowledge for mixing the caps and understand the issues on the filter. Sure I will measure first the original caps.
Making the impedance flat for the amp to see ordinarily is just a matter of crossing the 't's and dotting the 'i's. There are some rare cases, and there are some specific cases (such as high Zo) where you will notice a difference but most people won't do it on the premise that their amplifier has a virtually shorted output.
Where to put the good caps and where to save your dollar. Capacitors can resonate at high frequencies but usually this is much higher than the audio band and in a crossover this interaction is unlikely to amount to much. Moving on to the abovementioned filter, there is resistance and inductance in series with the capacitor so those parasitic elements are not unwanted. Further, this circuit goes high impedance at higher frequencies. Combine that with the almost non-existant interaction with the speaker and this should be one case where you shouldn't need anything special as your capacitor.
Where to put the good caps and where to save your dollar. Capacitors can resonate at high frequencies but usually this is much higher than the audio band and in a crossover this interaction is unlikely to amount to much. Moving on to the abovementioned filter, there is resistance and inductance in series with the capacitor so those parasitic elements are not unwanted. Further, this circuit goes high impedance at higher frequencies. Combine that with the almost non-existant interaction with the speaker and this should be one case where you shouldn't need anything special as your capacitor.
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