Any thoughts on the Boozhound active crossover?
JFET Crossover Kit – Boozhound Laboratories
https://cdn.shopify.com/s/files/1/0289/4153/files/Boozhound_Laboratories_JFET_Crossover.pdf
Looks ideal for us novices.
JFET Crossover Kit – Boozhound Laboratories
https://cdn.shopify.com/s/files/1/0289/4153/files/Boozhound_Laboratories_JFET_Crossover.pdf
Looks ideal for us novices.
Hi erez1012,
You've probably moved on to other interesting things already, now that I'm this late sticking my big nose in, but just in case this is still useful:
> > > Your crossover is massively over-damped -- even more than Bessel.(*1)
This is an unavoidable consequence of the clash of two Sallen-Key design methodologies: Equal component value and unity gain. They are mutually exclusive - can't have 'em both at the same time.
To achieve a Butterworth response, the frequency-setting element in the feedback path needs 2.2 times(*2) the influence on the signal, as the path to signal ground. If its the capacitor, it needs 2.2 times the value; if the resistor, divide its value by 2.2.
> > In a Low Pass, that's the capacitor from the FET Source back toward the input, to the node between the two frequency-setting resistors.
> > High Pass it'll be the resistor from the Source to the node between the frequency-setting capacitors; lower value = 'more influence'.
The frequency-setting parts directly in the signal path remain unchanged -- only one of the two adjacent parts, the one from the FET Source, gets changed. The other one to signal ground remains as is.
'AndrewT' tried to set us straight in post #83, but it seems like everybody was more concerned with other aspects of the design to see the importance.
Plenty of good-sounding crossovers have been built with a 2:1 ratio, but I wouldn't take a chance on 1:1. The attenuation 2 and 3 octaves out of the passband will not be adequate -- I have a whole shoe box full of shredded LE85 diaphrams (JBL, 1970's) to prove how hard the lesson was on me!
Regards,
Rick
*1) I happen to prefer the sound of 'tighter' damping, but hardly anybody else seems to. And I'd be surprised if it is really what you're after.
*2) That is, 2.2 times, if I remember right; I wanted to read all 292 posts before giving somebody's toe a stomp from a 5-yr-old thread -- and am out of patience to look it up right now. Sorry.
You've probably moved on to other interesting things already, now that I'm this late sticking my big nose in, but just in case this is still useful:
> > > Your crossover is massively over-damped -- even more than Bessel.(*1)
This is an unavoidable consequence of the clash of two Sallen-Key design methodologies: Equal component value and unity gain. They are mutually exclusive - can't have 'em both at the same time.
To achieve a Butterworth response, the frequency-setting element in the feedback path needs 2.2 times(*2) the influence on the signal, as the path to signal ground. If its the capacitor, it needs 2.2 times the value; if the resistor, divide its value by 2.2.
> > In a Low Pass, that's the capacitor from the FET Source back toward the input, to the node between the two frequency-setting resistors.
> > High Pass it'll be the resistor from the Source to the node between the frequency-setting capacitors; lower value = 'more influence'.
The frequency-setting parts directly in the signal path remain unchanged -- only one of the two adjacent parts, the one from the FET Source, gets changed. The other one to signal ground remains as is.
'AndrewT' tried to set us straight in post #83, but it seems like everybody was more concerned with other aspects of the design to see the importance.
Plenty of good-sounding crossovers have been built with a 2:1 ratio, but I wouldn't take a chance on 1:1. The attenuation 2 and 3 octaves out of the passband will not be adequate -- I have a whole shoe box full of shredded LE85 diaphrams (JBL, 1970's) to prove how hard the lesson was on me!
Regards,
Rick
*1) I happen to prefer the sound of 'tighter' damping, but hardly anybody else seems to. And I'd be surprised if it is really what you're after.
*2) That is, 2.2 times, if I remember right; I wanted to read all 292 posts before giving somebody's toe a stomp from a 5-yr-old thread -- and am out of patience to look it up right now. Sorry.
Hi,
I will happily admit that I have a lotta catchin' up to do, after many years away from the field. But .., doesn't the magic of Linkwitz stem from 4th-order slopes and 180 degree phase shift at the crossover frequency ..?
Glad your Vifa tweeters don't mind, but I've known a lot of HF drivers that wouldn't tolerate a stopband that's only ~13 dB down, THREE OCTAVES below the crossover frequency -- at least for very long.
The speakers you described in post #9 sure sound interesting. Got any pictures? Glad to hear I'm not the only guy still lighting up favorite 40-year-old gear. (Or at least WAS when this thread started 7 years ago ..)
Cheers,
Rick
I will happily admit that I have a lotta catchin' up to do, after many years away from the field. But .., doesn't the magic of Linkwitz stem from 4th-order slopes and 180 degree phase shift at the crossover frequency ..?
Glad your Vifa tweeters don't mind, but I've known a lot of HF drivers that wouldn't tolerate a stopband that's only ~13 dB down, THREE OCTAVES below the crossover frequency -- at least for very long.
The speakers you described in post #9 sure sound interesting. Got any pictures? Glad to hear I'm not the only guy still lighting up favorite 40-year-old gear. (Or at least WAS when this thread started 7 years ago ..)
Cheers,
Rick
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