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AudioDon

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    K-400 differences

    in Technical/Restorations

    Posted

    1 minute ago, KT88 said:

    I would like to come back to Don's question. Are there any differences in the sound? At some point I read that the older K400's are a little heavier and some say they have a better sound? Or are these fairy tales?
    If I understand Don's question correctly it's not only about better vs. worse, but also the potential hope if there are no differences and he could use both different horns together in a stereo system?

     

    Thanks,

    What I noticed is that the newer seemed a little more open and livelier, while the older less so, perhaps heavier is a good way to describe it.  In the end I got a little confused about what I was hearing because I was trying different amps and swapping K-55V drivers.  Also one of the speaker positions is next to an opening to a another room and that effects the sound 

    K-400 differences

    in Technical/Restorations

    Posted

    As I mentioned in another post, my pair of La Scala's were made in different years. 1 is from 1975, and the other from 1978.  The 2 K-400's have slightly different castings.  The later one has a smooth  outside of the throat, and the other has small square bumps about midway on the throat.  I've also noticed that the flanges that mount to the cabinet are different as well as the opening of the plywood.

     

    Can someone explain the reason for the differences between the two and if they can be used together?  The sound the same to me but I am curious what the wisdom of the group has to say.

     

    Thanks

    AA network question

    in Technical/Restorations

    Posted

    10 hours ago, mboxler said:

    Hey Don

     

    Can you post the schematic you have (I believe it's 820928, not 82092B???).

     

    The latest schematic I have is revision 900102, which appears to be what you have installed?  I'm also assuming the rheostats are variable L-Pads.

     

    Mike

     

     

    TypeAA.jpg

    Hi Mike,

    Here's the one I downloaded the other day. The last 8 in the date isn't very clear to me and I thought it was 8/20/92B instead of what's written with the year first. Now that I've seen the schematic you posted, I can see where the Zener has been edited out of mine. Don

    CCI06102021.thumb.jpg.eb66f9a653a8f89800a2d27d81b3f63f.jpg

    La Scala distortion help needed

    in Technical/Restorations

    Posted

    Thanks for everybody's help.  I think I've found the problem. 

     

    My La Scalas with the AA crossovers have L-pads for the tweeter and squawker.  Mine were originally sold along with a Rodgers electronic church organ.  Both of the L-pads are really dirty. At one point I touched one to adjust it and heard the distortion or crackle. 

    I'm in the process of cleaning them now, perhaps even removing them

    AA network question

    in Technical/Restorations

    Posted

    3 hours ago, KT88 said:

    AudioDon, that alone could explain why one of your squakers sounds distorted. The above shown circuit is right and everything else is added by someone later on and it is not original. Normally you do not need to adjust the SPL of any of the drivers if you have the original ones and the genuine AA network.

     

    If you still have this zener diodes in just try to listen without them, just unscrew one of them. Be careful not to damage the tweeter by switch on or off noise of your amp, but the gain of sound quality is significant.

    KT88,

    Thanks for bringing this up.  I'll check it out.  I think I found the source of the noise. I'll update the other posting.

    AA network question

    in Technical/Restorations

    Posted

    4 hours ago, mboxler said:

    Hey Don

     

    Can you post the schematic you have (I believe it's 820928, not 82092B???).

     

    The latest schematic I have is revision 900102, which appears to be what you have installed?  I'm also assuming the rheostats are variable L-Pads.

     

    Mike

     

     

    TypeAA.jpg

    Hi Mike,

    It's funny, the copy I downloaded the other day looks identical except for the Zener.  Thanks for providing this.

    AA network question

    in Technical/Restorations

    Posted · Edited by AudioDon
    addition

    4 hours ago, jimjimbo said:

    Definitely NO rheostats in an original AA.  Two different cap types and wired differently is not optimal, to say the least.  The schematic above hasn't changed in a long time.

     

    Certainly recommend the Crites folks for network rebuilds or for parts.  Outstanding customer service for many years.

     

    https://critesspeakers.com/

     

    Thanks,  The La Scals's I've seen like mine, which were sold along with a Rodgers Electronic church organ,  have the variable L-pads which I previously called rheostats. They're 2-wire tapped off the positive leg.  I called Crites a few days ago, and they just got back to me a moment ago.  I guess their answering machine was down for a day or two. Nice folks 

    La Scala distortion help needed

    in Technical/Restorations

    Posted

    20 hours ago, RandyH001 said:

     

    .........new klipsch OEM  Capacitors are only sold through  @JEM Performance -  these Parts  reproduce the klipsch signature sound , and  you are simply no longer hearing  that unique sound -

     

    as far as whether your tweeters or Midrange drivers need repairs ,  take an Ohmmeter and report back with the DCR readings of the woofers-midrange drivers and tweeters for both speakers , if anything is out of line , I will hauler back --

     

    https://jemperformanceaudio.com/

     

     

    Thanks.  Just focusing on the mids, One is 10.4R, the other 10.5R

    La Scala distortion help needed

    in Technical/Restorations

    Posted · Edited by AudioDon

    On 6/8/2021 at 4:44 PM, KT88 said:

    Welcome, Don.

    Just as info to classify it. What year are your Lascala? What is the name of the crossover? E.g. AA or a similar letter (number) combination? Does the tweeter have a square or a round magnet? What is the name of your midrange driver? Is it a K55V? or some other designation?

    I have 1977 Lascalas and I bought new diaphragms last week from Michael Crites, Bobs son, Bob passed away this January, RIP. Also new sealing rings between driver and horn. I don't hear distortion but I aim for original condition. And after 44 years I would like to replace the diaphragms. I'm sure that makes sense in your case. Bob Crites said here on the forum years ago that too old diaphragms degrade the energy of the lower frequencies.

    Since you carefully listened to the driver without freq.crossover, and it still distorts, I would think the driver is the cause. Probably the voice coil could be scraping at the air gap.
    You say that only one driver/horn distorts. You also say that both horns sound bright. Do you mean that positively or negatively? Have you heard only the one speaker whose squaker does not distort? Does it sound round and pleasant? If too bright it could also be caused by worn out caps so that the energy for the bass is reduced? But this is only my guess and others may habe a better explanation.

    Maybe you can also swap the crossovers once to see if the distortion goes along or stays.

    Another trivial but effective thing. Clean all cables and connections. Are the cables attached to the Squaker driver with compression springs or soldered? If with compression springs, clean this connection as well.

     

    I can only say that if everything is ok then the Lascala is one of the most beautiful sounding speakers on this planet, and I have met and heard quite some speakers.

    In summary no matter if a driver distorts, I would start by buying new diaphragms and the sealing rings.
    BTW is the distorting driver properly torqued to the horn?

    A word about the capacitors. This is a hot potato and there are a thousand opinions and tastes. And everyone should use what makes him happy. Gut this is just my personal opinion. I have made the experience that with the Lascala polyester capacitors sound very good. They are the ones that Klipsch also recommends because they have very similar characteristics to the original polyester in oil Aerovox in the sheet metal cases. Really, it's not a strict must, but I've taken these polyester types and replaced polypropylene types no matter how well the polypropylene caps measure, etc. The horns are happy to see some "softer" Q of the caps and the impedance of the overall balancing network keeps like intentioned, that is what Roy Delgado, the chief engineer of Klipsch pointed out here. You can buy a fitting set with the right values of your xover type of Klipsch approved polyester caps from JEM, have a look at the pinned thread of this modification section. It's just my personal opinion but confirmed by some of the people.

    I also know Clarity Caps. These are very good caps, but maybe in electrical values "too good" for the horns, not that the horns don't deserve the best, but it should be the best that suits them best.
    More on that here:

     

     

    Thanks KT88.  I enjoyed reading your other post about the polyester caps. What you experienced is what I'm looking for.

    Don

    AA network question

    in Technical/Restorations

    Posted

    I'm confused about what I see in my pair of AA La Scala networks.  One appears to be original with the big cans, the other was changed at some point and the wire routing appears to be a little different but effectively similar. They both have rheostats for the Tweeter and mid drivers. The confusing part to me is that in the CAD schematic I got here dated 82092B, I see that the positive input leg splits before it gets to the 13uF cap, feeding the squawker  with the 13uF cap, and the tweeter with the 2-2uF caps.  In both of the networks, the 2-2uf caps are taken after the 13uF cap.  There are the other components but I'm just trying to separate out how the caps are fed.

     

    What am I missing?

     

    Thanks, Don

    La Scala distortion help needed

    in Technical/Restorations

    Posted

    KT88- Thanks for your response.

     

    As for specs, The Crossovers are AA. Horns are K-55V and the tweeters are the K-77.  I've seen pictures of the K-77x tweeters and they have a gold-ish tone to the metal with a small Klipsch logo on them. Mine don't have the logo, only have K-77 stamped in ink.  Based on some decoding of the serial numbers mine are also from the 70's but I don't remember what year. Because I got 2 singles they don't have sequential serial numbers.   When I buy caps for my stereo projects, I try and find Polyester or polystyrene. I also try and take a step up from Panasonics without going to the expensive boutique models. The Clarity were priced below the Sonicaps recommended here.  I just got some Multicaps from Reliable for my Conrad Johnson amp.  I also bought a set of Cornell Dupilier from Mouser that are Polypropylene. I thought they were film and foil but they're film and Metallized.

     

    I also saw the info on Crites website about the diaphragms and the gasket washer and thought I would start with the gaskets to see if they weren't sealing properly. I just went to one of the speakers and was able to tighten the driver onto the horn by 20* or so.  I'll see if that makes a difference. 

    La Scala distortion help needed

    in Technical/Restorations

    Posted

    Hi,

    Newby here, although I've been a lurker for a while now. 

     

    I recently bought a pair of La Scala's from an organ dealer that are identified as LS-BB.  I'm in the process of re-capping the crossovers with Clarity Caps of the original values. 

    The woofers sound great.  I'm not hearing much resolution out of the tweeters, but my old ears don't hear much at that frequency anyway.  My question today is about the horns. 

    They both sound bright to me. and one of them sounds grainy or distorted. I was listening to Diana Krall, and while she can be breathy, this was more edgy or grainy. I played Steely Day which sounded much better but I could still hear the distortion. This was at low volume levels.  I tried hooking up the leads directly to the horn by bypassing the X-over and it's still there. Is there any servicing I can do to improve the sound? I was looking at Bob Crites site and see new diaphragms or the gasket between the driver and horn.

     

    I tried them connected to a yamaha receiver as well as my main Conrad Johnson system and it doesn't really change. It's also not a room reflection issue either.

     

    Thanks,

    Don 

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