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La Scala distortion help needed


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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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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:

 

 

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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. 

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12 hours ago, AudioDon said:

Hi,

. Is there any servicing I can do to improve the sound?

 

.........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/

 

 

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14 hours ago, AudioDon said:

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.

 

For sure I would check the gaskets first. If those were K-55M not  K-55V then sometimes on Ms back cap was ungluing  itself, causing distorted sound. Also check if everything is screwed correctly, maybe it's mechanical buzz.

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Probably not gaskets. More likely bad connection somewhere. Reach way back in the cabinet and disconnect and connect the tweeters a few times along with the mids as well. Check for loose connections at amplifier and speakers along with all connections at crossover. Common problem I sometime have being that I swap my more than 30 amps in and out of my system on a regular basis. 99% of the time bad connection is what I find. Other then bad connection problem in amplifier. Drivers rarely ever give this kind of problem. Speakers occasionally but rarely drivers. They have never made a connection that will not fail at some time in the future. Welding or rather soldering is the only positive solution connecting devices. 
 

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Posted (edited)
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

Edited by AudioDon
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16 hours ago, Peter P. said:

When you mean horn, do you mean the midrange driver?

 

Is it both channels or just one?

The driver of the horn. They're both kind of edgy, but one is worse than the other

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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

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On 6/8/2021 at 6:44 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:

 

 

Discussions of capacitors is not welcomed on this forum unless one is talking about the one Klipsch is promoting. When I posted the truth of capacitors most all technicians know my post was deleted and I was scolded by saying only J&M capacitors are the ones recommended by Klipsch. Called censorship which is prevalent in these times. Paper, polyester, polypropylene is only a dielectric used to keep the plates separated. No logical reason why there should be any difference if the dielectric is doing it's job, adequate job keeping electrons from jumping from one plate to the other. Does this make sense to anyone but me? That being said I do hear differences between different brands of capacitors after having used many types over the years. If the engineers at Klipsch recommend J&M they must meet their standards for what they like in sound. This is not to say other types and brands will not sound as good or even better. Most technicians do not get caught up in the hype of capacitors but just use a quality brand at a good price point for equipment they are working on. 

 

 

 

 

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10 hours ago, mustang_flht said:

I would say like @Bacek: check the bottom of your K55M first, then you will look at the rest 

Agreed.  Then loosen and retighten every screw on the crossover terminal strips.

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41 minutes ago, CECAA850 said:

Agreed.  Then loosen and retighten every screw on the crossover terminal strips.

But he says he has K55V in his post.

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4 hours ago, CECAA850 said:

Agreed.  Then loosen and retighten every screw on the crossover terminal strips.

Thanks,

I thought I'd get in there with some DeOxit when tightening.

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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

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