Cornwall III Schematic?

[ClaudeJ1]

Anyone have one sketched out or a picture of the Xover?

[dtel]

Never opened them up to look, [A] would you like a pic, or did you get one already ?

[ClaudeJ1]

Never opened them up to look, [A] would you like a pic, or did you get one already ?

Sure I would love a photo of the cornwall III schematic, you are the first to respond. Are you curious enough to do it? If it's like the Chorus, is should be attached to the plastic cup that holds the speaker connectors.

thanks in advance.

[whamo]

I think we all would like to see the insides of a Cornwall III. That'd be sweet. I'd be hesitant to do it if they were mine though. I'd only open 'em up when it's necessary, Mark

[dtel]

Sorry, was out, I will take some pics and put them here. probably not tonight.

[dtel]

#1

[dtel]

Other side, I have no idea what I am looking at ?

[dtel]

?

[dtel]

Not being on a single board (spread out) it looks much more complicated, to me at least.

Is that what you wanted to see? I doubt it could be figured out unless each level were seperated to see what goes where, or you could see it in person ?

I havent a clue whats going on there ! [:|]......... It works though !........

I tried to take a pic of the inside of the cabinet with 18mm lense, pointing up through the hole but all you could see was the back of a magnet with the word Klipsch. The back is sealed, so that makes it much harder.

If someone can change the size of the pics, please do.

I set the camera to the smallest size I could, and this is the first pic's"I" have ever posted.

[Erik Mandaville]

"Other side, I have no idea what I am looking at ?"

The things with exposed, wound magnet wire are the inductors; the yellow plastic things are capacitors; and the white things (such as the one that indicates a value of 50 ohm/25 watt) are power resistors used for both the L-pad to balance the output between the drivers and/or part of a simple circuit that's used for impedance equalization (as one example).

The L-pad shown is called a 'fixed' L-pad. Some speakers have knobs on the back of the cabinet that control variable resistor L-pads, where the user can adjust the midrange and/or tweeter outputs to his or her liking. Klipsch did a good job with those! The glue you see is probably silicone rubber adhesive.

Erik

[boom3]

Gasp! Iron core inductors! Non-trendy film capacitors! Shudder! Cement resistors! Oh, the horror! []

and, as noted on the new Klipschorn...no autoformers in sight. Love to hear from Roy why Klipsch has moved away from autoformers.

[Deang]

I asked Roy about that a while back and he said that resistors don't introduce phase shift. Phase and polar patterns come up often when discussing things with Roy -- so when I came across the following, where both are mentioned together in the context of desireable attributes for a crossover design, I thought it might be what he was alluding to:

"Zero phase difference between drivers at crossover. (Lobing error equals zero, i.e., no tilt to the polar radiation pattern.) In addition, the phase difference of zero degrees through crossover places the lobe of the summed acoustic output on axis at all frequencies."

"The low pass and high pass outputs are everywhere in phase. (This guarantees symmetry of the polar response about the crossover point.)"

Roy likes higher order filters and he designs using LEAP. I'm only guessing here, but maybe there is trouble meeting those design goals with an autoformer in the mix.

As for the schematic, Klipsch doesn't release or provide them on current production models. The caps and resistors probably have the values marked on them, but the coils would need to be removed from the boards and measured. You're done when you trace out the PCB. I personally don't see much point in it, the filter wouldn't be much use unless you built the same box using the same drivers. And yes, the speakers would sound cleaner and more open with better caps, sorry Klipsch.

[Erik Mandaville]

They work well for adjusting driver outputs, and have been used by many major speaker companies for a long time. I also prefer the way it sounds without one, but that's subjective -- although Klipsh may have found something similar. Some use the autoformer in higher order networks, too.

Erik

[DrWho]

Have you ever experimented with DC Biasing of caps Dean?

[ClaudeJ1]

Not being on a single board (spread out) it looks much more complicated, to me at least.

Is that what you wanted to see? I doubt it could be figured out unless each level were seperated to see what goes where, or you could see it in person ?

I havent a clue whats going on there ! [:|]......... It works though !........

I tried to take a pic of the inside of the cabinet with 18mm lense, pointing up through the hole but all you could see was the back of a magnet with the word Klipsch. The back is sealed, so that makes it much harder.

If someone can change the size of the pics, please do.

I set the camera to the smallest size I could, and this is the first pic's"I" have ever posted.

Well you did a good job AFAI can tell. Thank you.

The main reason I even asked is because I wanted to find out if there is any attenuation going on with the tweeter horn. If so, how much, because I may be interested in using a Cornwall III tweeter (tractrix) with my newly acquired LaScala cab for the 6th channel on my 6.1 receiver, I have a K5J from 1956 with a JBL LE 85 driver, which is 16 ohms, so if the Cornwall III tweeter is effcicient enough, I could run it straight into the 2 uF capacitor of my "A: Xover and maybe bypass the autoformer if I needed less attenuation. I know the Cornwall III specs out at 102 db efficiency, which is only 2 db away from a LaScala/Khorn, so that tweeter may be useful. If it's being attenuated on a Cornwall III, then I know it would work with a La Scala.

Mostly I want to know if there is an Lpad or autoformer being used on that tweeter.

tweeter

K-107-TI 1" (2.54cm) Titanium diaphragm compression driver

high frequency hornK-79-T Tractrix

[boom3]

I'd suggest using Bob's CT-125 tweeter. It's a drop-in replacement for the K-77. I use one in my center channel and it's good match for the K-79 tweeters in my Corns.