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La Scala AL crossover


Masca72
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3 hours ago, henry4841 said:

Believe me I am smart enough not to lock horns with Dean.

 

Oh sure you are. I'm not that smart, seriously. I just made a lot of mistakes along the way and accidently learned some things.

 

"Rough bunch". I would say less so now than before. These days it's mostly because of pain.

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4 hours ago, henry4841 said:

Someone please show me on the schematic where the AL crossover has a fault electronically that makes it a bad crossover. That is all that I am saying. 

 

Looking through old threads last night, there were two issues. The first was blown tweeters, which Dennis blamed on poor soldering. The second issue relates to a peak in the response that drives some people nuts. One of those people is John Albright, who hears a howling sound. 

 

"I have run into this same exact problem with the AL network and it is the ground connection for the tweeter inductor (which is on the 2µF cap for the elliptical filter). With this connection open the network goes to 6dB and breaks tweeter leadout wires in no time." -- DJK

 

@CECAA850 had an AL problem, and involved Bob. This ended up being a failed autoformer. When Bob replaced the autoformer, the problem went away. Attached are the before and after plots.

 

AL_fixed.jpg

Type AL.jpg

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6 hours ago, henry4841 said:

I can agree with this statement

I cannot agree with that statement -

 

the AL Networks  AL-AL2-AL3 are used in several thousands, if not tens of thousands  of Lascala speakers  with 0 issues  , however as usual ,  some people just like to complain -

 

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7 hours ago, henry4841 said:

I read about Dean's experiment with batteries in a crossover and have wanted to experiment with that design.

 

Dean sent the parts for free just so I would give my impressions.

Not much of motive for profit on his part with that regard...

 

Battery bias Cornwall networks

 

post-4542-0-01340000-1395795330_thumb.jpg

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3 hours ago, Deang said:

 

Looking through old threads last night, there were two issues. The first was blown tweeters, which Dennis blamed on poor soldering. The second issue relates to a peak in the response that drives some people nuts. One of those people is John Albright, who hears a howling sound. 

 

"I have run into this same exact problem with the AL network and it is the ground connection for the tweeter inductor (which is on the 2µF cap for the elliptical filter). With this connection open the network goes to 6dB and breaks tweeter leadout wires in no time." -- DJK

 

@CECAA850 had an AL problem, and involved Bob. This ended up being a failed autoformer. When Bob replaced the autoformer, the problem went away. Attached are the before and after plots.

 

AL_fixed.jpg

Type AL.jpg

Not my plots.  The bad autoformer I had showed a big spike right before it rolled off.  Not sure where my graphs are but I've posted them somewhere. 

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1 hour ago, Deang said:

That would have been around 2015 I think. I did a Roadshow with some battery biased AA's. There's a handful of those floating around.

There's a set of battery B's in my old cornscalas somewhere around College Station.  They were some great crossovers. 

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I thought it made inexpensive metalized caps sound more like film and foils. It's a difficult thing to describe without sounding like a lunatic. I was convinced it was placebo, so I built some regular AA's using the same capacitors (Dayton Audio), and compared. Metalized (polypropylene and polyester) have a tizziness in the top end and it's one of those things you don't really notice until it's gone.

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29 minutes ago, henry4841 said:

I started participating for enjoyment and when it is not that I will just leave and let you guys have it. I am not here for conflict or arguing.

I sure hope you don't run off I enjoy your posts and participation in these discussions. I pretty much came here to learn and a lot of times these debates are exactly what's needed to flesh out the facts, wade through the Bullshit.

 

If topics get too heated or certain someones decide to start throwing insults then its easy to just move on to another topic or thread no hard feelings. You learn pretty quickly who's worth engaging with and who's not-- really this forum has tamed down quite a bit its seems to me recently but then again I haven't been on here as much either. 

 

As far as the AL topic goes here's a snip from the La Scala history page:

 

History of the LaScala by Klipsch employee Mark Kauffman.

 

LS Time Line MK 060411.pdf

 

1983 The Type AL crossover network was introduced incorporating steeper filter slopes for enhanced tweeter protection and smoother response in the crossover regions.

 

1983 The Type AL-2 network was introduced to accommodate the new K-55-M mid-range driver. This Electrovoice sourced driver was essentially the same as the previous K-55-V with a smoother response

 

1987 The Aluminum K-400 horn was replaced with the K-401 structural foam horn resulting in slightly improved distortion figures.

 

1989 The AL-3 network was introduced to correct for a shift in the output of the K-55-M midrange driver.

 

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2 hours ago, jjptkd said:

1983 The Type AL crossover network was introduced incorporating steeper filter slopes for enhanced tweeter protection and smoother response in the crossover regions.

 

1983 The Type AL-2 network was introduced to accommodate the new K-55-M mid-range driver. This Electrovoice sourced driver was essentially the same as the previous K-55-V with a smoother response

 

Ah here is a lot of things explained, AL has been updated in AL-2 because the K55-V driver has been replaced too, not because it was not good. So it makes no sense to plug in an AL-3 if my speakers have the original K55-V driver and aluminium castle K400 horn, my ears didn't lie to me then ... Tweeter burnt, connections jumping I don't get any of this my AL's have been checked and they respond perfectly. I think it depends on the condition the speaker was stored in, if the digetted AL crossovers came from some barn then understandably they weren't right..

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