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I copied my round up post over from this thread, please list any other LaScala mods, threads and parts sources.







My LaScalas are circa 1980 Stock AA crossovers


If I want to make improvements or changes in incremental steps, this is what I understand:


Based on the above posts, and a conversation (2-3 years ago) with B Crites and the Klipsch factory support guy, the drivers in the LaScala don't wear out under normal circumstances. The capacitors, on the other hand do have an end of life, the transformer and inductor rarely fail (it would probably require an amp incinerating failure to fry the inductor or transformer).




Update the 3 caps on the AA crossover, from the schematic in the pinned section.


Stock: Sonicaps from Crites or others inc Parts Express brand.

To me, stock always sounded very good


2x  2uF capacitors

1x 13uF


Alternative Crossover update to lower the volume mids by 3db aka 50% decrease in power to Squawker.

This is done to flatten the output across the bass and mids?

I currently use an EQ to add output at the 400Hz point and rolling off into the up and down freqs from this point.


2x 2uF caps

1x 6.8 uF cap


Both of these updates-mods are stand-alone and can be listened to and evaluated without further mods or repairs.





This step could be either replace the K-77 (matched ?) phenolic tweeters with the Crites CT-125 EV driver with custom Crites Lens and titanium diaphragm. OR Replace the woofer with the Crites stamped Woofer $$, or Eminence Kappa 15C $, also mentioned above is the K-44 Factory $$$ woofer.




Both the tweeter and the woofer "upgrades" are standalone changes and require no mods to the crossover or anything else.




If the K-77 is replaced with the Crites CT 125, as an option after moving to the CT-125.....the crossover point between the Squawker and the CT-125 can be lowered to take advantage of the increased range of the CT-125.


Thread on CT-125  topic, one of many?



Thread on Crossovers



Volti take on LaScala



More horns + ALK



Alethia's take on custom crossovers





Crossover Options with CT-125: Do nothing leave at 400 and 6,000Hz, replace crossover 400 and 4,500 Hz, somehow modify existing crossover to 400 and 4,500. Forgot to mention the ALK Universal, I'm sure there are others....


The existing crossover may be modified, I don't know how.




The AA crossover can be replaced with a new A 4500 from Crites




"Problem with this is that the K-55 mid-range driver is pressed really hard to reach 6000hz.  It would be much more linear in it's operation if the highest frequencies it has to reproduce were in the 4500hz area."


Note: I'm guessing that PK the Designer was aware of this, and perhaps no better option was available than the EV K-77 tweeter, AND OR  the mid-range K-55 is so sweet with the voice that it is better to leave as much of the voice as possible on the K-55 up to 400- 6KHz. Maybe if we had the engineer's notes we could know how the decision was made, I'm sure lots of trial and "does this sound better than"........



My opinion the LaScala:


PK was a very good audio engineer, everything was done for a reason. Speakers that sound good, sell better.


Was the mid range 400-6,000 intentionally boosted to put the human (Female) voice more forward aka Hear the Angels Singing? The K-55 really makes the angels sing.


The low end could be better, a design trade off

Edited by Bubo
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the transformer and inductor rarely fail (it would probably require an amp incinerating failure to fry the inductor or transformer).


While these parts may appear not to "wear"    -    in the AA type crossovers I have  -- they were the lowest production quality to pass  #s.   Q  is very important in design/balance.


I have inductors purchaced from Mr Crites,  and they are simply made to better standards.  The bass is louder/clearer.

Perhaps due to the overall resistance  being closer to spec,  larger wire...


The Belle Klipsch  AB Type crossover used no inductor for series bass connection.


Other similar crossovers use  2.5, 3,or 4mH   straight up or w/caps.   


They all sound differently.  IMHO      YOU get to pick   :)    have a good journey/upgrade. 



  RU suggesting an inductor swap on the existing AA crossover, or the entire crossover for one of BCs?


I'm probably going to order the stock replacement caps from BC, so once the iron is hot, a few more joints is easy.

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1. Crossbraces doghouse to sidewalls would be the first I would do.

2. Getting a flare in the cutout for the tweeter

The do other things


Crossbraces lots of examples, and volti sells them.


Tweeter flares, haven't seen this one. Any pics and sources or are we talking router work?

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I finished Round 1 of updating my LaScalas circa 1980 AA

They should now be approximately in the same condition they where when new.


  • Watco Danish Natural oil all the way around, they soaked it up. Brush on, wipe off.
  • Recapped the AA crossovers with the Sonicap that Bob Crites sells
  • Replaced steel screw that secures inductor with a stainless one per Crites recommendation.
  • Replaced the gaskets between the Squaker and the Horns with the ones Crites sells, perfect fit.
  • Added IKEA locking Casters rated 125-150lbs ea to the bottoms of the cabinets, exact fit between screws. Pilot holes.
  • Cleaned smoked glass tops and reinstalled with new felt pads

Total parts cost is approximately $150


Wood looks nice natural and oiled, crossovers sound approx the same, the casters I should have added 30 years ago.

When I purchased them I did use Minwax natural stain 2 coats just to bring out a little bit of grain.


When I have time, and some unallocated $$, I may order two baby cheeks Beyma CP-25 tweeters and mount them on top of the glass on a sled just to see if there is any difference.









Edited by Bubo
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Post some pic's, lol.  How would you describe the sound with the changes.  They already sounded great in your system before the change.


I recapped one speaker, then ran it in stereo and mono for four hours with the other speaker still original.


No real differences that I could tell, the old caps were in surprisingly good shape for 35.....wish I could say the same.


If something dramatic happens, I'll post it..... but the consensus is that for the films there is no such thing as break in.... the electrolytic may be a different story.


This is very very good on the system.....




Update: Though not dramatic, the system does sound a tiny bit 2-3% better, slightly clearer and slightly more well defined bass. Not sure if the casters effected the bass, and the recap simply brought the unit back into spec.

Edited by Bubo
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Nice article on Horns on Wikipedia.


I'm no expert, but it seems like a very good round up article, doesn't mention Klipsch which seems odd.




The notes look like a good educational source


Nice article on Compression drivers and phase plugs







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We have very similar systems.  Thanks for gathering all of this in one place.


I must get some glass, that looks fantastic.  Brings the glass from the Macs to the speakers.  Do you have felt or rubber feet?


I went with felt for  the second time in 25 years, the clear and rubber ones will bleed into your wood and stain it.


The felt just dry rots after 20 years and peels off the glass with a window razor tool in seconds, no stains at all.


I used about 12 felt pads per glass, 1/4 inch smoked several colors to choose from, these are more in the bronze color.


Don't forget to have the edges of the glass rounded off completely by the glass company, a few dollars well spent. No sharp edges or corners.

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Sounding: a tiny bit more focused especially on the low end, which could be decoupling from the floor and less bounce off of the floor.


The rest is a little bit clearer sounding.


Next step, install some used ATLAS squaker drivers that I purchased last week that are a tiny bit more linear than the excellent EV ? K-55s that are in there now.


It's really a game of 1-2% improvements, as of now I would say that I am back to spec with decoupling from the floor.


If I like the new-older ATLAS K-55s, I may send them out to Crites to be measured and replace the diaphragms, at 30 years life for many of the parts that should take me pretty far.


Rolling them in and out should make life much easier where tweaks are concerned, I love my racks on wheels, the TV stand is next if I can find some wheels.

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