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Type AL Crossover (La Scala) Capacitor replacement?


innerwestsoul

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Hi and thanks for reading,

 

I have a pair of La Scalas with the Type AL crossover, as pictured. It seems to be pretty hard to find a circuit diagram for this network, including from the thread between Bob Crites and ALK. There are no pictures I can find online and from the few discussions I have read, the general advice is that rather than re-cap it, this network should be replaced with something else - Both Crites and ALK have solutions, but both run into several hundred $AUD with postage and I don't have that sort of budget atm.

 

  • La Scala LSBR S/N 8504510
  • K55-M squawker
  • K-77M tweeter

 

In terms of capacitors on the crossover, these are the markings on each part:

 

  • 3x 2uF [+- 5%] 180 VAC - black rectangular block type
  • 2x 8uF [+- 5%] 250 VAC - black rectangular block type
  • 1x 30uF 250 VAC "CDE Soggy Foil Protected" 60 Hz - large canister type

 

There is also a resistor marked "5 [Ohm] 10%" - white packaged type.

 

My questions:

 

  1. Is it indeed not worth (in terms of financial outlay) replacing these parts with new components of the same values?
  2. What capacitor types are these and what would be suitable replacements (as I am not familiar with the respective uses of the various capacitor package / build types)?
  3. What would be the best bang for buck, if I had to choose between parts to replace - treble, mid or bass? I assume top end?
  4. My understanding is that there would be no benefit updating any of the inductors or transformers. Is this correct?
  5. Are there any other alternatives apart from Crites / ALK ? I would also consider DIY if I had a solid schematic and wiring guide to follow.

 

I am spurred on to try the re-cap after some significant success replacing the caps on some 1975 Mordaunt Short speakers this week, dramatically uplifting performance!

 

Any advice, experiences or general comments would be most appreciated. Anyone locally (in Australia anyway) done this before?

 

Thanks!

 

IWS

 

IMG_5774_small.jpg

IMG_5773_small.jpg

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I agree, it's not worth recapping/rebuilding them.  Look into the AA network, and use your boards and whatever other parts are appropriate for the AAs.  Here's the AA schematic.  If you want to tame the midrange a bit, change the tap on T2A from 4 to 3, and replace the 13uf cap with a 6.8uf.

 

 

AA crossover schematic.jpg

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Use the AA as is (same auto former attenuation and same capacitor values).

 

One change would be to take the two diodes out of the circuit (go easy on the volume knob however). 

 

You don't need to spend a ton of money on capacitors, however you may want to bypass the caps with some small  film / foil caps, perhaps Daytons from Parts Express (search the threads on "bypass"). Madison or Parts Express will have the caps (although you may need to parallel a pair to get the 13uF - Solen is fine). 

Good Luck,

-Tom

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6 hours ago, Dave A said:A simple search would have found your answers right away.

 

Really? Wow I wish I had known that. 

 

Thanks however to the other responders who took the time to inform me that I should look into the AA network. That was the great community-sourced response I was looking for. Hopefully my pictures, descriptions and those helpful responses will add to the fantastic canon that is the Klipsch Forums, and help someone else out in the future. 

 

IWS

 

 

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1 hour ago, innerwestsoul said:

 

Really? Wow I wish I had known that. 

 

Thanks however to the other responders who took the time to inform me that I should look into the AA network. That was the great community-sourced response I was looking for. Hopefully my pictures, descriptions and those helpful responses will add to the fantastic canon that is the Klipsch Forums, and help someone else out in the future. 

 

IWS

 

 

Well you did say you could not find any info on schematics and I demonstrated how. Sorry it excited you so much and welcome to the forum.

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I hate that thread. It's convoluted. I don't think there is a single part on the AL that I would reuse. I've never seen an AL that wasn't a dirty rust bucket with some of the worst soldering I've ever seen.

 

Get some clean boards and start over. The AA only has seven parts. Just take your time while you build them and they will turn out nice. As for capacitors, spend as much or as little as you want. AudioCap PPT Thetas are the best value film and tin foil and will produce better sound than any metallized type. Contact Bob Crites at bobcrites@gmail.com and he can supply you with the coils and autotransformers.

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I think what many here may have missed is that this bloke, like a few of us others, doesn’t share the luxury of the US domestic market... sigh

 

The sensibly priced options available in the CONUS become cost prohibitive crossing borders and currencies.

 

That being said, mate, if you are patient and diligent there is a pretty fair chance you will snag a bargain on here or eBay in the not so distant future.

 

Were they my LaScalas I would have my sights set on a pair of AA or Crites A/4500 crossovers AND a pair of DE-120 tweeters.                                                                                                                                                  

 

...if I didn’t already have them...!

 

And welcome to THE definitive forum for all things Klipsch.

 

 

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2 hours ago, Deang said:

Surely you guys can get decent caps and coils down there, right? That would mean the only troublesome part would be the autotransformers. Do I have that right?

We can, albeit with less suppliers. Mainstream is fine - we have element14 and RS and then a chain-store called Jaycar with a small range of stuff for hobbyists. Audio-specific, the market is a lot smaller. International postage is the main issue - I think due to all of the old postal treaties "expiring" of late, costs are going through the roof. I buy a lot of records and CDs, but never from the US. Vendors are often looking for up to $25 USD to ship a single LP these days *sigh*

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18 hours ago, geoff. said:

Were they my LaScalas I would have my sights set on a pair of AA or Crites A/4500 crossovers AND a pair of DE-120 tweeters.                                                                                                                                                 

...if I didn’t already have them...!

 

And welcome to THE definitive forum for all things Klipsch.

 

Thanks Geoff - I'm a classic long-time lurker. Bought these things off a guy in Seattle on CraigsList about 10 years ago - got them crated and shipped to Botany, dicked around with Mainfreight for weeks ("Special Company, Special People") and ended up with a Toyota HiAce engine being loaded into the back of my van... Took another week before they found and released my actual consigment (in perfect condition thankfully).

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4 minutes ago, innerwestsoul said:

We can, albeit with less suppliers. Mainstream is fine - we have element14 and RS and then a chain-store called Jaycar with a small range of stuff for hobbyists. Audio-specific, the market is a lot smaller. International postage is the main issue - I think due to all of the old postal treaties "expiring" of late, costs are going through the roof. I buy a lot of records and CDs, but never from the US. Vendors are often looking for up to $25 USD to ship a single LP these days *sigh*


Plus the Aussie Grote is today running at .68 USD

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On 11/16/2019 at 10:41 AM, Dave A said:

Google is not your friend but for things like this it works.

 

Amen to the first part.  They've gotten worse than Microsoft ever was when they were marginally relevant.  The latest is the push for every site to go HTTPS as if it were for we the surfers' protection when in reality it's to maintain ad / profiling revenue by disabling filtering proxy usage.  Of that I'm certain.

 

Use duckduckgo instead of google.

 

On 11/16/2019 at 2:29 PM, PrestonTom said:

You don't need to spend a ton of money on capacitors, however you may want to bypass the caps with some small  film / foil caps, perhaps Daytons from Parts Express (search the threads on "bypass").

 

On that recommendation I just spent the weekend reading the results of searching "bypass caps" here ("bypass" by itself was much too vague).  What a rush.  It seems not much has changed in 15 years beyond capacitor flavor of the day.  I found nothing backed up either way, re bypassing, with anything factual.  Same goes for the tangent of biasing in the few places that notion also cropped up.  I'll stick with them both being likely not harmful though totally unnecessary.  My favorite bit was one BEC offering as reward a bag of dog biscuits for objective proof that bypassing (proper) does anything for a crossover!  Near as I can tell he still has it available.

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"...there should be no audible difference." Now of course we are comparing a Marantz Model 9 and a Crown D-60, and while he might think there shouldn't be, there most definitely is.

 

"...the same philosophy applies to capacitors." Right, there shouldn't be, but there is. 

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2 hours ago, glens said:

" ........

On that recommendation I just spent the weekend reading the results of searching "bypass caps" here ("bypass" by itself was much too vague).  What a rush.  It seems not much has changed in 15 years beyond capacitor flavor of the day.  I found nothing backed up either way, re bypassing, with anything factual.  Same goes for the tangent of biasing in the few places that notion also cropped up.  I'll stick with them both being likely not harmful though totally unnecessary.  My favorite bit was one BEC offering as reward a bag of dog biscuits for objective proof that bypassing (proper) does anything for a crossover!  Near as I can tell he still has it available

......."

 

 The Dayton caps cost all of a dollar. I don't think my suggestion was outrageous. I do agree however that any improvement might be small. There are some very capable guys (including Nelson Pass etc) that recommend a simple bypass cap. For the cost, I am comfortable relaying that information.

 

Regarding the issue of biasing, JBL has a long history of this. These are no-nonsense engineers that probably do not engage in fluff. 

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