High Efficiency Speaker Asylum

Need speakers that can rock with just one watt? You found da place.

Return to High Efficiency Speaker Asylum

Message Sort: Post Order or Asylum Reverse Threaded

JBL charge coupled capacitor network in crossover??

76.112.135.123
Posted on March 4, 2009 at 19:56:15
limono
 Anybody heard or experimented with this?? My friend asked me about it and seems like JBL is using this crossover topology in their top line of speakers.

 

Hide full thread outline!
    ...
RE: JBL charge coupled capacitor network in crossover??, posted on March 5, 2009 at 03:49:58
Robert Hamel
Audiophile

Posts: 1905
Location: New York
Joined: October 24, 2002
 I have built several networks using it and it works. Better lower level detail. Can get expensize with twice the capacitor coumnt at twice the value.

 

RE: JBL charge coupled capacitor network in crossover??, posted on March 5, 2009 at 20:02:39
rjd
Manufacturer

Posts: 387
Location: So. Cal.
Joined: June 16, 2002
 I've been using it with our Cogent horn system for a couple of months now, it works just like Robert says. Well worth the effort.

 

Shhhhhh*, posted on March 5, 2009 at 20:38:24
eso
Manufacturer

Posts: 7843
Location: Long Beach, CA, USA
Joined: March 15, 2001
 .
They were a carnival of American decay on parade, and they had no idea of the atrocity they had inflicted upon themselves–Henry Chinaski

 

Can anyone point me to a schematic??, posted on March 5, 2009 at 23:00:37
SLM
Audiophile

Posts: 321
Joined: March 2, 2002
 I am not grasping what charge coupled means

S

 

RE: Can anyone point me to a schematic??, posted on March 6, 2009 at 02:07:10
djk
Manufacturer

Posts: 6135
Joined: June 17, 2000
 http://audioheritage.org/vbulletin/showthread.php?t=43&highlight=battery+bias

http://www.lansingheritage.org/images/jbl/specs/home-speakers/1993-k2-s5500/page11.jpg

 

RE: JBL charge coupled capacitor network in crossover??, posted on March 6, 2009 at 08:12:40
dave slagle
Manufacturer

Posts: 5430
Location: NYC
Joined: April 27, 2001
 Hey Rich!

Very cool, If applying a charge to cables to improve (stabilize?) dielectric properties has a following it only seems logical that parts that require a dielectric to operate would also benefit. For years people have been saying capacitors sound better with DC on them and it great to see people experimenting with this idea in the speaker world. I wonder where on earth you are going to find 12V or so to bias your caps tho' :-)

dave

 

RE: Can anyone point me to a schematic??, posted on March 6, 2009 at 08:23:25
JoshK
Audiophile

Posts: 820
Location: NJ/NYC
Joined: August 3, 2001
 Very interesting!

 

RE: JBL charge coupled capacitor network in crossover??, posted on March 6, 2009 at 09:34:32
PakProtector
Audiophile

Posts: 12365
Joined: May 14, 2002
 lemmme see, where would he have a source of 12V in that design?...yer obviously kidding I think.
cheers,
Douglas

Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.

 

RE: Can anyone point me to a schematic??, posted on March 6, 2009 at 10:33:08
gfederys
Audiophile

Posts: 367
Location: S. E. Michigan
Joined: June 22, 2004
 I got a charge out of it........

 

RE: JBL charge coupled capacitor network in crossover??, posted on March 6, 2009 at 13:55:14
gymwear5@hotmail.com
Manufacturer

Posts: 3475
Joined: April 10, 2002
 In this arrangement can you replace non-polarized electrolytics with standard polarized electrolytics? looks like so from the JBL cross over pic.

 

Charge Coupled Capacitor Network, posted on March 6, 2009 at 18:50:55
JoMoCo
Audiophile

Posts: 78
Location: Cascadia
Joined: July 17, 2007
 Here is a link to check that shows a schematic if you have not already...

 

RE: Charge Coupled Capacitor Network, posted on March 6, 2009 at 21:38:59
JoMoCo
Audiophile

Posts: 78
Location: Cascadia
Joined: July 17, 2007
 more...

 

JBL K2, posted on March 7, 2009 at 21:23:22
djk
Manufacturer

Posts: 6135
Joined: June 17, 2000
 .

 

RE: JBL K2, posted on March 8, 2009 at 11:08:05
freddyi
Audiophile

Posts: 3852
Joined: December 6, 2001
 what kind of caps does this circuit like best? - electrolytic?

 

RE: JBL K2, posted on March 8, 2009 at 12:35:52
Robert Hamel
Audiophile

Posts: 1905
Location: New York
Joined: October 24, 2002
 JBL uses Solens in this system for the Mids and UHF. Use Electrolytics for the LF section. They tend to split it up that way. In the Everest 2 they use a combination of Electrolytics and Solens on the woofers and all Solens on the Horn and UHF.

 

RE: JBL charge coupled capacitor network in crossover??, posted on March 8, 2009 at 13:36:53
Steve Schell
Manufacturer

Posts: 1440
Location: So. California
Joined: December 16, 2001
 I have been fortunate to meet Greg Timbers of JBL on several occasions. He has mentioned the battery biasing of capacitors more than once, but just as with RCAfan mentioning conical horns it took a while for the importance of the information to make it through my thick skull. As with the conicals, when I finally experimented I was delighted with the results of this "charge coupling" technique.

Greg describes the technique creating a class A situation. I think this is correct. I have long thought that the remarkable retrieval of fine detail possible with single ended tube circuits is due to the avoidance of a zero crossing point with zero signal, i.e. the transformer(s) are biased up to some point between cutoff and saturation by plate current. Instead of tiny microvolt signals (reverberant tails, etc.) being distorted by nonlinearities in the crossover region where magnetic fields are collapsing and reforming in opposite polarity with every audio half cycle, these tiny signals sail on through the most linear operating region of a biased transformer as just a tiny modulation of the quiescent bias point.

So now it seems we have the same situation with capacitors. In the usual passive crossover, to pass the audio signal the electrostatic fields have to collapse and reform with every half cycle, and the smallest signals live in the most "dirty" nonlinear region of the device. Biasing the capacitors involves extra cost and expense, as one needs to two capacitors of double the value of the unbiased circuit (four times total capacitance) to achieve the same filtering. Rich and I have found that with the high pass crossover to our midrange / high frequency driver the improvement in sound is not subtle, more of a "Wow" experience.

Greg Timbers discusses the technique in the third post of the Lansing Heritage thread linked to below.

 

RE: JBL charge coupled capacitor network in crossover??, posted on March 8, 2009 at 13:44:00
Steve Schell
Manufacturer

Posts: 1440
Location: So. California
Joined: December 16, 2001
 Here is the link to a profile of Greg Timbers. BTW, he is about the farthest thing possible from the wild eyed audiophile who obsesses over every questionable nuance, so I should have picked up on his enthusiasm for charge coupling sooner.

 

RE: JBL charge coupled capacitor network in crossover??, posted on March 8, 2009 at 13:57:20
Steve Schell
Manufacturer

Posts: 1440
Location: So. California
Joined: December 16, 2001
 Hi Dave, we got yer 12 volts right here! We're using 9 volt batteries for the crossovers though. As with the battery biasing of tubes, there is no load on them and the batteries last their shelf life. Best, Steve

 

RE: "charge coupled capacitor network in crossover"..., posted on March 8, 2009 at 17:57:32
Ivan303
Audiophile

Posts: 48887
Location: Cadiere d'azur FRANCE - Santa Fe, NM
Joined: February 26, 2001
 It would seem at first thought, that what you describe might be far more critical with high efficiency drivers, as the signal levels we are seeing are quite small, relative to a "traditional" speaker.

With 106db horn speakers, we're not talking watts, those "fine details" you speak of may represent only a few milliwatts of power, very small signals, which could easily get distorted in a complex crossover.

Well worth a try!

OK Rabbits, happy now?

 

RE: JBL charge coupled capacitor network in crossover??, posted on March 8, 2009 at 18:17:44
dave slagle
Manufacturer

Posts: 5430
Location: NYC
Joined: April 27, 2001



Rather than use two identical caps and the large value resistor, it would be interesting to try the proper valued cap and a series battery (which could then be bypassed with a small cap. This would actually be really easy to try in any existing crossover design.

dave

 

RE: "charge coupled capacitor network in crossover"..., posted on March 8, 2009 at 22:37:12
Steve Schell
Manufacturer

Posts: 1440
Location: So. California
Joined: December 16, 2001
 Hello Ivan (and rabbits),

I think you make a good point about this technique perhaps being particularly useful with high efficiency speakers. We live in millivolts and below nearly all the time. With the efficiency of most compression drivers, hall ambience, audience coughs etc. are down in the microvolts region. Combining this with the superior IMO resolving power of these devices it is not surprising that crossover improvements loom large.

 

RE: JBL charge coupled capacitor network in crossover??, posted on March 8, 2009 at 22:48:32
Steve Schell
Manufacturer

Posts: 1440
Location: So. California
Joined: December 16, 2001
 Dave I like your out of the box thinking, though I don't think this would work due to the equation for total capacitance of two capacitors in series, C1 X C2 divided by C1 + C2. Whaddya think?

 

Can I ask an "is it kind of like" question about the sound?, posted on March 9, 2009 at 06:29:36
Dan_ed
 I read that using the charged caps helps the low level details. I also read that using PLLXO also increases low lever details.

For those who have experience with both, can you offer further comments on how things sound between these two approaches?

 

Have you tried with cheaper caps?, posted on March 9, 2009 at 07:21:03
Ivan303
Audiophile

Posts: 48887
Location: Cadiere d'azur FRANCE - Santa Fe, NM
Joined: February 26, 2001
 Could it be that you could might be able to get away with using cheaper caps? Could this be the reason JBL/Harmon is doing it?

IIRC, JBL uses electrolytics in their crossovers.


OK Rabbits, happy now?

 

RE: "charge coupled capacitor network in crossover"..., posted on March 9, 2009 at 08:28:23
Ivan303
Audiophile

Posts: 48887
Location: Cadiere d'azur FRANCE - Santa Fe, NM
Joined: February 26, 2001
 Wonder what all of this means when it comes to selecting capacitor brands and types for use in X-over designs?

Did the capacitors we thought were the "best sounding" sound good because the resisted the very problems with biasing now eliminates?

Do we get to start a whole new era of "cap rolling" in out x-overs?

Inquiring minds what to know!



OK Rabbits, happy now?

 

RE: Have you tried with cheaper caps?, posted on March 9, 2009 at 09:26:21
Robert Hamel
Audiophile

Posts: 1905
Location: New York
Joined: October 24, 2002
 I have always used Poly caps, so I have not tried it with the electrolytics. Should work there as well. Many of the JBL CC networks are Electroltics or combinations of them with Polypropylene and Mylar caps mixed in.

 

RE: JBL K2, posted on March 9, 2009 at 10:06:49
freddyi
Audiophile

Posts: 3852
Joined: December 6, 2001
 thanks!

 

RE: "charge coupled capacitor network in crossover"..., posted on March 9, 2009 at 10:21:38
Steve Schell
Manufacturer

Posts: 1440
Location: So. California
Joined: December 16, 2001
 I've wondered the same thing, but haven't yet experimented. What if some charge coupled doggy-doo electrolytics would outperform non-biased living legend pixie dust caps?

 

Could be...., posted on March 9, 2009 at 10:29:40
Ivan303
Audiophile

Posts: 48887
Location: Cadiere d'azur FRANCE - Santa Fe, NM
Joined: February 26, 2001

JBL seems to like a combo of Solens and electrolytics in speakers using this technique.

Not exactly Duelunds!

OK Rabbits, happy now?

 

RE: JBL charge coupled capacitor network in crossover??, posted on March 9, 2009 at 11:45:55
dave slagle
Manufacturer

Posts: 5430
Location: NYC
Joined: April 27, 2001
 the battery has a very low AC impedance so in theory it behaves like an infinite cap. The .1u cap is there as a local bypass

dave


 

RE: JBL charge coupled capacitor network in crossover??, posted on September 17, 2016 at 03:27:09
thraxAn
Audiophile

Posts: 13
Location: Mumbai
Joined: January 9, 2009



Hello Dave:

I'm willing to try your implementation so can you please let me how I go about implementing this in the capacitors of the attached x-over schematic?
---thrax

 

RE: JBL charge coupled capacitor network in crossover??, posted on October 1, 2016 at 02:41:58
mah
Audiophile

Posts: 87
Joined: May 26, 2008
 Old thread.

This took me 2 minutes to find. JBL idea?

 

RE: JBL charge coupled capacitor network in crossover??, posted on October 1, 2016 at 02:52:12
mah
Audiophile

Posts: 87
Joined: May 26, 2008
 Edit - add:

 

Page processed in 0.044 seconds.

[ Top Top of Page ] [ Contact Us ] [ Support/Wish List ] [ Copyright © 2024, Audio Asylum, all rights reserved ]
[ General ] [ Speakers ] [ Tubes ] [ Vinyl ] [ Digital ] [ Hi-Rez ] [ Video Asylum ] [ Cables ] [ Tweaks/DIY ] [ Music ] [ Films ]