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B&K Type AA "refreshed"....


scalawag

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I've always appreciated the engineering and audio/sonic wizardry as put out by the Klipsch and B&K Type AA x-overs in my La Scalas, if not so much the aesthetics.  As the boards are normally mounted inside the cabs, appearance is not really an issue.  But I recently got the urge to bring them up topside just for my own personal viewing enjoyment and decided a "makeover" was in order to give the x-over boards a bit more visual appeal.  I acquired a pair of hand-made "cutting" boards, mounted the x-over elements in their most suitable locations, drilled the appropriate holes, and finally made the wire connections mostly underneath to tidy up the looks.  While I can't claim to be a craftsman compared to others of you on this Forum, I thought the project turned out pretty decent.  Here are pics for your judgement - thanks for reading.  Happy listening!

 

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You, sir, are exactly right !!  Hard to believe, but the original Klipsch AA-s in my LS-s came with standard metal screws, ie magnetic, holding down that inductor, which I have since changed over to brass screws (hard to notice in the pic).  The B&K (B Crites) x-overs, however, were received with the proper non-mag screws in place.

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7 hours ago, scalawag said:

Hard to believe, but the original Klipsch AA-s in my LS-s came with standard metal screws, ie magnetic, holding down that inductor

 

So did the AAs in my '78 LSIs and I don't think it's uncommon. Always a good thing to check.

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16 hours ago, scalawag said:

I've always appreciated the engineering and audio/sonic wizardry as put out by the Klipsch and B&K Type AA x-overs in my La Scalas, if not so much the aesthetics.  As the boards are normally mounted inside the cabs, appearance is not really an issue.  But I recently got the urge to bring them up topside just for my own personal viewing enjoyment and decided a "makeover" was in order to give the x-over boards a bit more visual appeal.  I acquired a pair of hand-made "cutting" boards, mounted the x-over elements in their most suitable locations, drilled the appropriate holes, and finally made the wire connections mostly underneath to tidy up the looks.  While I can't claim to be a craftsman compared to others of you on this Forum, I thought the project turned out pretty decent.  Here are pics for your judgement - thanks for reading.  Happy listening!

 

IMG_0556.JPG

IMG_0564.JPG

IMG_0554.JPG

 

 

If you are going to go to so much loving effort, try to hear what it sounds like when you unscrew one of the two diodes and thus interrupt the diodes connected in parallel. In my case, I hear more pleasant silky highs that sound less brittle. Unless you have SPL of a discotheque.

 

 

 

 

 

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Hmm.  I have the CT-120 tweeters mounted to Dave's wood MAHLs and to my ears they already sound smoother compared to the K77s.  Would I realize any additional audio "enhancement" by performing the mod you suggest?  Searching this Forum the consensus is that there would be no harm in bypassing the diodes with the BC tweeters I am using, but I suppose I could confirm this by emailing B Crites....

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5 minutes ago, scalawag said:

Hmm.  I have the CT-120 tweeters mounted to Dave's wood MAHLs and to my ears they already sound smoother compared to the K77s.  Would I realize any additional audio "enhancement" by performing the mod you suggest?  Searching this Forum the consensus is that there would be no harm in bypassing the diodes with the BC tweeters I am using, but I suppose I could confirm this by emailing B Crites....

There might be a very slight "enhancement" as a result of taking the zener's out of the circuit, but they certainly aren't needed considering the drivers you are now using.

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It is absolutely beautiful.

There is no need to change IMO, but an idea 😈 would be to give every wire its own hole (except the diodes if you decide keep them after the remarks above) that way all the wires exit perpendicular from their source like the capacitors

But again, it is absolutely beautiful.

 

Best regards ... jef

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18 hours ago, scalawag said:

Hmm.  I have the CT-120 tweeters mounted to Dave's wood MAHLs and to my ears they already sound smoother compared to the K77s.  Would I realize any additional audio "enhancement" by performing the mod you suggest?  Searching this Forum the consensus is that there would be no harm in bypassing the diodes with the BC tweeters I am using, but I suppose I could confirm this by emailing B Crites....

Just give it a try with a record you know very well.

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18 hours ago, scalawag said:

Hmm.  I have the CT-120 tweeters mounted to Dave's wood MAHLs and to my ears they already sound smoother compared to the K77s.  Would I realize any additional audio "enhancement" by performing the mod you suggest?  Searching this Forum the consensus is that there would be no harm in bypassing the diodes with the BC tweeters I am using, but I suppose I could confirm this by emailing B Crites....

I noticed a not insignificant difference when I disconnected the diodes. Much smoother to my ears.

 

FWIW when I got new crossovers from Crites for my '77 LS's, I ordered the A's  without the speaker protection diodes based on their recommendation. I let the crossovers break in with the Sonicaps, and I like them well enough, but the other day I swapped back in the originals with the oil caps, and I still like them better.

 

To each their own.

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Interesting that you say that.  After completing the first B&K board, I connected it to one LS and took an original 46-year old board out of storage and connected it to the other LS just for comparison.  Took a good listen to each side separately, and to my mild surprise, the KWP board still sounded pretty decent.  'Course, my ears aren't nearly what they used to be, which might explain what I heard or didn't hear.  Which is reason enough for me to deliberate whether taking out the diodes will result in any noticeable differences to my ears.  Thanks for your comment, and to other posters as well.  Happy listening !

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On 3/30/2022 at 3:21 PM, scalawag said:

Interesting that you say that.  After completing the first B&K board, I connected it to one LS and took an original 46-year old board out of storage and connected it to the other LS just for comparison.  Took a good listen to each side separately, and to my mild surprise, the KWP board still sounded pretty decent.  'Course, my ears aren't nearly what they used to be, which might explain what I heard or didn't hear.  Which is reason enough for me to deliberate whether taking out the diodes will result in any noticeable differences to my ears.  Thanks for your comment, and to other posters as well.  Happy listening !

You will not hear a difference taking the Zeners out unless you drive your speakers at higher levels where the Zeners would normally start to shunt the drive signal. 

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