"Charged Coupled" crossovers?

[pierce]

I've seen numerous references here to 'charged coupled' crossovers. When I first saw this, I was thinking "huh, CCD based delay lines or something?" but I've since seen a couple of schematics, indicating they are really just DC biased capacitors.

I've read various threads like... http://www.audioheritage.org/vbullet...hread.php?t=43

Frankly, with my somewhat naive understanding of analog electronics and filter networks, I don't get it, and would love to see some discussion of the theory behind why it works. URLs to reading material are fine, too.

[4313B]

Frankly, this is all you need to know:

Bypassed and Biased Capacitors

Read Greg's various explanations about it in his product papers as linked above.

At this point all we have to say is bias or don't bias, do whatever you want, but leave us out of it. It's remarkably simple.
No emails, no phone calls, no PM's. Thank you and have fun!

[John]

Frankly, this is all you need to know:

Bypassed and Biased Capacitors

Read Greg's various explanations about it in his product papers as linked above.

At this point all we have to say is bias or don't bias, do whatever you want, but leave us out of it. It's remarkably simple.
No emails, no phone calls, no PM's. Thank you and have fun!

Who is we and us ???

[4313B]

Who is we and us ???

Whenever this topic comes up someone sees fit to bother Greg or myself. I think we just went through this once again four months ago. I'm not real sure why it keeps coming up. He has graciously offered up everything he has and feels that should be sufficient.

If this is just another thread to yammer on about it and it won't result in emails, PM's and phone calls asking why this topology works then by all means carry on. I'm not trying to be rude, I'm simply trying to put an end to all the behind the scenes discussions before they even start this time around.

My earlier post was made in haste, as they often are, and I've been told that puts people off. I apologize for that. From my perspective, unless someone has actually charge-coupled some networks and given them a thorough listen they very probably have nothing of interest to offer on the subject. Challenging posts and PM's such as those that have arisen in the past are just trolling as far as I'm concerned.

[John]

Whenever this topic comes up someone sees fit to bother Greg or myself. I think we just went through this once again four months ago. I'm not real sure why it keeps coming up. He has graciously offered up everything he has and feels that should be sufficient.

If this is just another thread to yammer on about it and it won't result in emails, PM's and phone calls asking why this topology works then by all means carry on. I'm not trying to be rude, I'm simply trying to put an end to all the behind the scenes discussions before they even start this time around.

My earlier post was made in haste, as they often are, and I've been told that puts people off. I apologize for that. From my perspective, unless someone has actually charge-coupled some networks and given them a thorough listen they very probably have nothing of interest to offer on the subject. Challenging posts and PM's such as those that have arisen in the past are just trolling as far as I'm concerned.

I agree on all the points you have laid out, thanks.

And as far as the CC networks go, the proof is in the pudding.

Thanks Giskard and Greg.

[pierce]

Frankly, this is all you need to know:

Bypassed and Biased Capacitors

Read Greg's various explanations about it in his product papers as linked above.

indeed, that was what I needed to know. dielectric hysteresis..

don't worry, I won't PM you

I am curious how many millivolts and/or microseconds this hysteresis is for the normal sorts of nonpolar caps used in these crossovers, but I'm sure I can find some technical component data on this.... And, as I saw someone else asked on some other thread, it does strike me that the bias voltage of the classic circuits has to be at least as high as 50% of the peak to peak voltage, which might be as high as 50 or 60 volts for high wattage transients from a big amp (assuming the cap is directly across or in series with the load)

[pos]

some interesting info:
http://www.diyaudio.com/forums/showt...hreadid=141929

[4313B]

some interesting info:

Thanks for the link.

*****

I see that it was started 03-31-2009. Interesting that it can go on for 68 posts. I only did a quick scan but it looked like the first few posts were worthwhile and then everything up to post 68 could be whacked as typical Internet noise. It'd be nice to see more posts along the lines of 68. My experience though is that people just do it and then enjoy the results. It's curiously difficult to get them to post something on an Internet forum.

One question jumped out and is exactly the question Greg posed to me several years ago during one of our conversations.

But why is it not more common?

He was rather surprised that competitors hadn't jumped on it. I think Ian has since pointed out that some other manufacturers are doing it.

In any case, I personally bias the entire network including any shunts. In this instance I don't worry about cost or space issues.

Here's one of the latest pair I need to finish wiring up. The boxes are finely crafted by another forum member for his 4355's. Maybe someday he'll post about them. :dont-know

[Loren42]

So, this improves the phase delay for capacitors, I am thinking, but what about the inductors, which are the worst offenders in a passive crossover network? DC bias would not help that.

I guess anything is an improvement.

[Zilch]

I only did a quick scan but it looked like the first few posts were worthwhile and then everything up to post 68 could be whacked as typical Internet noise.

Somehow, I believe you'd leave Rob's post, too, though there may be merit in not inviting more noise to move over here.

[Those guys are sure good at noise generation in lieu of the "Do" part of DIY.... ]

[Ian Mackenzie]

I've seen numerous references here to 'charged coupled' crossovers. When I first saw this, I was thinking "huh, CCD based delay lines or something?" but I've since seen a couple of schematics, indicating they are really just DC biased capacitors.

I've read various threads like... http://www.audioheritage.org/vbullet...hread.php?t=43

Frankly, with my somewhat naive understanding of analog electronics and filter networks, I don't get it, and would love to see some discussion of the theory behind why it works. URLs to reading material are fine, too.

True it is simply dc biasing but many would not have thought of that approach to topology.

As to the rest of the discussion its perhap useful to understand exactly how a polarised and non polarised capacitors works and then related that to the application of a Dc potential. Black Gate used to have a very useful explanation of the facts . Try Google. http://en.wikipedia.org/wiki/Capacitor
http://www.elna-america.com/tech_al_principles.php
http://www.technologystudent.com/elec1/capac1.htmhttp://en.wikipedia.org/wiki/Capacitor_(component)


A lot of research as been done recently on voltage (AC signal) induced vibrations within capacitors used in audio crossover applications.

According to the reseach its the voltage not the current that induces the vibrations within the structure and this directly effects sound quality.(Vibrations caused by sound within the enclosure have no effect what so ever according to the research)

Depending on the manner of the windings within the structure a DC voltage potential may help control these vibrations

[Russellc]

I agree with charge coupling, but have a implimentation question: Does one need to CC the cap in the woofer zobel? I didnt do that on the one I built and was wondering. CC the zobel cap or not?

russellc

[jblsound]

I agree with charge coupling, but have a implimentation question: Does one need to CC the cap in the woofer zobel? I didnt do that on the one I built and was wondering. CC the zobel cap or not?

russellc

I C-C all the caps. If a current is flowing through a cap w/o C-C then it is producing a phase shift.

[Allanvh5150]

I C-C all the caps. If a current is flowing through a cap w/o C-C then it is producing a phase shift.

A current flowing through a capacitor or inductor will always produce phase shift. Charge coupling will actually double the phase shift up to somewhere near 180 degrees.

Allan.

[jblsound]

A current flowing through a capacitor or inductor will always produce phase shift. Charge coupling will actually double the phase shift up to somewhere near 180 degrees.

Allan.

Wrong, I suggest you go back and do some searches for what Greg Timbers has to say on the matter, and look at the pics of an audio sinewave in a cap w/wo C-C.

When the sinewave crosses the zero dielectric point in a non C-C cap the wave shifts. When C-C the sinewave is above the zero dielectric and continues w/o the shift.

http://www.lansingheritage.org/html/...3-k2-s5500.htm