The continuing saga of the charge coupled network

[Ian Mackenzie]

And all the while they're still stuck with listening to recorded media.

http://www.duelundaudio.com/About_Steen_Duelund.asp

Fondly known as the mad loudspeaker professor, Steen Aa Dueland's influence on the the Gryphon Cantata, Poseidon and Trident resulted in many ideas such as biasing crossover capacitors and Linqwitz Grainer Q circuit. In his diy articles Dueland refers to biasing capacitors.

http://www.gryphon-audio.dk/default.asp

http://www.gryphon-audio.dk/default2.asp

The electrolytic capacitors in the impedance correction circuit are pre-biased to maintain a constant charge in order to eliminate crossover distortion at zero electric potential, resulting in audibly enhanced stability and substantial gains in body, timbral color and image coherence. Operating the battery-biased crossover in “Class A” mode ensures a smoother, more richly detailed three-dimensional presentation.

The Trident crossover network, based on wax-impregnated air-core inductors wound from copper foil and stacked foil capacitors potted in epoxy to resist mechanical interference, ensures undetectable, smooth transitions across the audible range.

28 V DC bias is applied to the capacitors, eliminating crossover distortion at zero electric potential for audibly enhanced stability and substantial gains in body, timbral color and image coherence.

[4313B]

Nice links Ian, what a world that looks like to live in!

[4313B]

Biasing protection caps is just a suggestion. If you don't use protection caps on your compression drivers, for whatever reason, then you don't have anything to bias.

[Earl K]

Scott,

- While you're at it ( dc-biasing your horn circuit ) give a thought to dc-biasing the front end of your horn amps , assuming they have balanced inputs . The pittance invested in the necessary small value caps makes this a no-brainer .

- I did this with my Bryston 2BLP ( pros ) and the result was quite spectacular ( this was done @ 4 years ago ). It makes sense to combine this with any dc-biasing that is implemented after the amp. In my view, it imposes on the whole circuit a sort of "feed-forward" super-symmetry ( a la Nelson Pass ).
- As mentioned, the sonic results are way beyond what one expects .


- The 2BLP has no dc blocking caps in the front end / so adding a pair a battery-biased caps in front of the servo-balanced inputs was quite simplistic . I used .048 mfd ( I think ), 2% polystyrene caps . I didn't use any load resistors in this circuit .

- What amps are you using ?
- Any idea on their stated input impedance ( look for balanced & unbalanced specs. )
- I'd recommend a filter that has a turn-over frequency between 100 to 200 hz ( given your 750 hz crossover point ) .
- If interested, I'll run you through the design process .

<> cheers

[scott fitlin]

Hi Earl, sounds interesting, and I have NO experience with these types of mods, and enhancements, so, I am ALL ears, open to learning.

I went back to Crown, DC-300A on my six JBL 2395/2441 horns, D-150A on six 2404, and D-150A on 16 2402,s!

I used PSA-2,s on the TAD 1603,s, but, this year, am upgrading to Crowns newer amplification, on 18,s used a combination of Macro Tech 3600,s, an I Tech, and QSC 6.0II, again, this year, Macro Tech i series replaces older amps, New Music & computers + New amps and modern drivers = HAPPY SCOTTY!

I must say this, though, IT has been a learning experience, and now that the new music, and download revolution is here to stay, there really IS somethin to be gotten out of it, BUT, I had to be open minded to it, and willing to work at it, and accept that I must do some things a bit differently than we did years ago when setting up and voicing for vinyl playback!

However, once I did, there AIN'T no going back!

First thing I am going to do, regarding inline caps, is take a pair of 400v caps, put em on a pair of 2441,s, and LISTEN to what happens. This is not biased cap networks or such, just a starting point to see what happens, etc!

Of course, I have amps with balanced inputs, etc, and I would love to hear your suggestions.

[Earl K]

First thing I am going to do, regarding inline caps, is take a pair of 400v caps, put em on a pair of 2441,s, and LISTEN to what happens. This is not biased cap networks or such, just a starting point to see what happens, etc!

- Okay, that makes sense to me ( take one step at a time )

- Reactiavte this thread after you've dc-biased ( the after amp ) circuit and then listened for some time ( that implies January ).

<> cheers

[scott fitlin]

- Okay, that makes sense to me ( take one step at a time )

- Reactiavte this thread after you've dc-biased ( the after amp ) circuit and then listened for some time ( that implies January ).

<> cheers

Agree!