Hi,
the lytics caps // to the woofer in a passive filter are :
often lytics
always x00 uF capacitance
looks like more and more a mini-zobel as the ESR of the NPEs is increasing with years.
Should we bypass the lytics caps // to the woofer with film caps ?
I always seen 100 nF film // to 200 uF npe in commercial speakers for instance. Is it a real good idea to see such ESR mismatch for current flowing towards ground ? I mean the curent always flows toward the most easy path, aka less resistive... so is there a problem here like oscillation because of the ESR and capacitance mismatch with the // caps // to the voice coil Z of the bass - or mid- driver ?
Any rule like : bypass with 1% capacitance film a npe lytic the filter npe caps being between the plus and minus ?
Many thanks, not sure I can modelize that with Xsim like softs, would know more from members experience what happening at ears when designers choose it or used to. 😕
the lytics caps // to the woofer in a passive filter are :
often lytics
always x00 uF capacitance
looks like more and more a mini-zobel as the ESR of the NPEs is increasing with years.
Should we bypass the lytics caps // to the woofer with film caps ?
I always seen 100 nF film // to 200 uF npe in commercial speakers for instance. Is it a real good idea to see such ESR mismatch for current flowing towards ground ? I mean the curent always flows toward the most easy path, aka less resistive... so is there a problem here like oscillation because of the ESR and capacitance mismatch with the // caps // to the voice coil Z of the bass - or mid- driver ?
Any rule like : bypass with 1% capacitance film a npe lytic the filter npe caps being between the plus and minus ?
Many thanks, not sure I can modelize that with Xsim like softs, would know more from members experience what happening at ears when designers choose it or used to. 😕
Measurement is your friend to gain understanding of this. Use Limp or REW to do an impedance sweep measurement of the x00 uF cap you are looking at. Does the impedance rise at high frequency? Probably not in the audio range, but a measurement is the way to know. Bypass caps are used on physically large capacitors because they have equivalent series inductance that causes the impedance to rise at high frequency. Usually in the MHz range. So physically smaller caps are used by bypass them to keep the impedance down at those very high frequencies. Again measure that film cap in and out of the circuit. Yes you can model it in Xsim or LTSpice very easily as caps with ESR and series inductance no problem. No mysteries here.
A small film capacitor across the electrolytic definitely can cause ringing. You have to do an analysis
with the exact characteristics of the parts to predict the behavior.
with the exact characteristics of the parts to predict the behavior.
thank you olsond3 and Rayma
Mhz range! Indeed, not usefull.
So small 100 nF or bigger -few uF- bypassing is not suitable for a x00 uF speaker driver plus & minus decoupling if we talk about MHz results. It would not bother the amp.
I have seen people wanting to bypass the woofer // caps of second order mid filter by smooth foils NPE that have less ESR than rough foil caps. And also with 0.1 uF we can see sometimes I asked myself why less ESR seemed to be more important here than with the serie high pass caps...
Mhz range! Indeed, not usefull.
So small 100 nF or bigger -few uF- bypassing is not suitable for a x00 uF speaker driver plus & minus decoupling if we talk about MHz results. It would not bother the amp.
I have seen people wanting to bypass the woofer // caps of second order mid filter by smooth foils NPE that have less ESR than rough foil caps. And also with 0.1 uF we can see sometimes I asked myself why less ESR seemed to be more important here than with the serie high pass caps...
Hello AllenB,
Not sure I understand the last part of your answer.
You mean small uF despite of its low esr will brake the curent to the ground if parralel to a big uF cap ( not talking about frequency for the moment because not sure I undetstand the consrquence of it at high frequencies when those caps are in parralel with the woofer.
Have to say I always add pain with curent & voltage relation in complex circuitry like a filter for instance...So the naive questions
Not sure I understand the last part of your answer.
You mean small uF despite of its low esr will brake the curent to the ground if parralel to a big uF cap ( not talking about frequency for the moment because not sure I undetstand the consrquence of it at high frequencies when those caps are in parralel with the woofer.
Have to say I always add pain with curent & voltage relation in complex circuitry like a filter for instance...So the naive questions
I was talking about the ESR
if I understand you properly. A 100nF capacitor at 2kHz has a reactance of around 800ohms. This makes the ESR quite insignificant.
😀... indeed !
that means some famous brand used it for porno hifi reviews I surmise... enthusiasts liked to see expensive bypass caps everywhere in a filter when the speaker was a little expensive ! You have some like the HumbleHomemadeHifi who still advice 10 nF in serie... but not in the shunt position as per my original question to stay totally honest. But in serie maybe the impulse AC behavior of the signal harm less, dunno, but I remember it's the same from a topic I asked and you had answered already.
So ok, let us live the big lytic caps their own life without bypass. 😎 less expensive hey ! To say you the truth when I see a capacitor of 10 uf with allien copper more expensive than a ScanSpeak speaker I ask myself if I live in a real world 😱
that means some famous brand used it for porno hifi reviews I surmise... enthusiasts liked to see expensive bypass caps everywhere in a filter when the speaker was a little expensive ! You have some like the HumbleHomemadeHifi who still advice 10 nF in serie... but not in the shunt position as per my original question to stay totally honest. But in serie maybe the impulse AC behavior of the signal harm less, dunno, but I remember it's the same from a topic I asked and you had answered already.
So ok, let us live the big lytic caps their own life without bypass. 😎 less expensive hey ! To say you the truth when I see a capacitor of 10 uf with allien copper more expensive than a ScanSpeak speaker I ask myself if I live in a real world 😱