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Ancient AA Crossover


Dave A

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I have read about Paul Klipsch using WW2 surplus components before in speakers because they were cheap and worked. So the story goes and I have no idea if the story is true but these sure would indicate it might be.  Are these worth rebuilding or should they be preserved for posterity by a collector? I had bought these to use in a Cornscala but after further digging I am probably going to use ALK's universal crossover for that.

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I'm not the expert, but I thought the zener diodes to protect the tweeters were a later addition.  Are you sure those caps are original issue?  If that is how Klipsch built them, I wouldn't mess with them, but, would replace them as you're doing.  They might have historical significance, perhaps to the museum.

 

The AA networks I refurbished had zener diodes and motor run caps, but they didn't look like yours.  BTW, I must have gotten one of the last sets of GE motor runs from Bob Crites.

 

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36 minutes ago, Dave A said:

I am sure these are as built. There is an age patina that would be hard to do on purpose for no good reason. Your AA is like the ones I have seen so far. How did yours get so rusty, were they stored outside for a time?

 

All I know is what I was told, which was that they came from a bar in Ohio.  Perhaps the bar was in a car wash.

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11 hours ago, DizRotus said:

BTW, I must have gotten one of the last sets of GE motor runs from Bob Crites.

I've built 3 sets lately with Genteq caps with great results.  I even sent a set to Bob.  He measured them and was impressed with their numbers and consistency.

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My 1972 k-horns had same crossover in them. Says AA with diodes in them before I rebuilt them. I also used Bobs motor run caps like DizRotus .....But used Iron core inductor and modified them to 4500 hz for Bobs tweeter.  No diodes in my rebuilt ones.

So either the diodes were factory or a factory upgrade not sure....someone knows what year they started the diodes I'm sure. 

I still have the parts to the old crossover board and parts it was built on 1/2 inch plywood also. I used the original tranny on my rebuilt ones.

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OK why use those big honking caps? I am going a different route and just ordered some Erse Pulse X caps that claim to have good specs and have good reviews on other sites. WAAY cheaper than Sonicaps and I am going to find out if that matters. I hear both sides with some recommending Dayton caps from Parts Express for instance but they are huge. I like the size of the Sonicaps. It is hard to know sometimes what advice to trust and I tend to lean towards the opinion of people who get their hands dirty doing things over those who seem to like to have bragging rights. 

 

  I am finding out those old caps have collector value and it is possible I could send these off to Crites, have him redo them and then test the old caps. If they are OK they can sell for as much as the crossover rework would cost.

 

  These were also from a K-horn.

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1 hour ago, CECAA850 said:

I took the AL's and made them into AA's.

I turned my ALs into As. I used a Crites auto-former. The Gentecs are pretty close given their tolerance. I found two of the 2uf Gentecs that measured straight up 2uf and used them in the tweeter branches. (I did not measure ESR though)  

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1 hour ago, jwgorman said:

I turned my ALs into As. I used a Crites auto-former. The Gentecs are pretty close given their tolerance. I found two of the 2uf Gentecs that measured straight up 2uf and used them in the tweeter branches. (I did not measure ESR though)  

Bob measured ESR, they were right on the money and identical to each other.

 

The stock transformers were doing some strange things on his spectrum analyzer so I replaced them with a pair of his.  All issues went away.  On the second set, I just replaced them as I don't trust the stock ones anymore.

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