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Turning an AL into an AA or an AL-3 or..


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https://community.klipsch.com/index.php?/topic/113804-klipsch-crossovers/

 

# 4 John Albright graciously supplied the AL schematic. If you compare the AL schematic to the AA you can easily see the differences and where the series notch filters are. The are parallel to the speakers. For instance on the woofer you will see an extra 2.5uh inductor and 30uf capacitor parallel to the woofer. Remove these components. On the squawker you will see an 8uf cap, 2.5uf inductor along with 8 ohm resistor parallel to the squawker. Remove these components. On the tweeter you have a 0.5uf inductor and 2uh cap parallel to the tweeter. Remove these components. 

 

After removing these parts you basically have an AA but with a 8uf cap before the T3A autotransformer instead of a 13uf cap. You need the 8uf cap for the T3A transformer instead of a 13UF. If my memory is correct the T3A attenuates the mids 6db whereas the AA attenuates 3db which is a good thing in my room. In fact I even like a touch more attenuation. 

 

Bob Crites has also given excellent advice. A prince of a guy in my book who can be relied on for good advice and prices. I have a pair of his 3636 autotransformers and have tried many combinations of crossover networks, probably close to 30 before settling on what I like best. The crossover is the brains of a speaker. 

 

What did you do about the 245uH choke on the AA? Did you leave that as a 125uH? 

 

Yes leave the 125uh alone. It forms a 3rd order crossover with the two 2uf caps which is needed for the sensitive tweeter. All that needs doing is removing the notch filters. You can then recap what's left and have a decent sounding crossover. I first read about doing this on the forum from someone else years ago. Someone at Klipsch went notch filter crazy around the time of the AL crossover. I am sure they make a flatter response curve but a flatter response curve does not guarantee a better sound. Many say it just sucks the life out of the music. 

 

OK, I have added your mod to the first post.

 

One more question to you or anybody who might know the answer.

 

The schematic shows what looks to be a 2.7Ω resistor across the T3A positive output and the negative of the main speaker input. I am trying to figure out what this is actually doing. Is this to increase the output of the squawker by 2db to offset the fact that the T3A has a higher attenuation than the T2A on it's default tap?

Edited by mustang guy
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The one I have finished? Sounds good and if there weren't all of these options i might be happy with it. I like it better than my kg 5.5 with the titainium diphrams and xovers.

 

Once all the drivers are working, just enjoy the Klipsch goodness and music. You don't have to drink the kool-aid and go down the continuous upgrade path.

 

Bruce

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That is not a resistor. I am not absolutely sure what is refers to but my guess is it has something to do with the autotransformer. It is not a separate component on the crossover. It appears to be maybe Z1 then 7mh. Forget about it, it is not something you replace. 

Thanks again. It looks like we have several options for folks with AL's now. 

 

Costs for different mods and levels of restoration, not including shipping to wherever you live. (per pair)

 

  1. AL wdecho mod - $19
  2. AL wdecho mod with Crites recap kit - $99
  3. AL to AA - $97
  4. AL to AA with Crites recap kit - $177
  5. AL to AL-3 - $224
  6. AL to AL-3 with Crites recap kit - $291

If there are any other mods or ideas of what to do to improve the AL, just post here. 

Edited by mustang guy
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a pair of AL's going in the burn pile  -  Who wants em'?

XH5R9Wi.jpg

Matt ♪ ♫ ♪

 

Those actually look like you dug them out of the burn pile. Yikes! If you don't plan on trying to refurb them or mod them, at least keep the inductors and the transformers. That stuff costs money, and if you ever do build an AA like in Deang's thread, they might come in handy. You would need 2 of the 2.5'mH's and the transformers are 6db, which is actually one of the settings on the AA's T2A. Who knows, you might like that setting?

 

Also, many of the inductors on that network are used on the AL-3. 

Edited by mustang guy
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Costs for different mods and levels of restoration, not including shipping to wherever you live.

  1. AL wdecho mod - $19
  2. AL wdecho mod with Crites recap kit - $99
  3. AL to AA - $97
  4. AL to AA with Crites recap kit - $177
  5. AL to AL-3 - $224
  6. AL to AL-3 with Crites recap kit - $291

 

You might want to make a note to clarify if the prices are each, or for a pair.

+++

 

Great thread Craig, you did a LOT of work to make a comprehensive work from beginning to end, including chasing down cost options.

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Costs for different mods and levels of restoration, not including shipping to wherever you live.

  1. AL wdecho mod - $19
  2. AL wdecho mod with Crites recap kit - $99
  3. AL to AA - $97
  4. AL to AA with Crites recap kit - $177
  5. AL to AL-3 - $224
  6. AL to AL-3 with Crites recap kit - $291

 

You might want to make a note to clarify if the prices are each, or for a pair.

+++

 

Great thread Craig, you did a LOT of work to make a comprehensive work from beginning to end, including chasing down cost options.

 

Prices are per pair. They are also listed on the OP with some breakdowns.

 

Thanks for bringing this up.

 

 

Mustang Guy , thank you for all of your pictures and work.

You are welcome. 

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a pair of AL's going in the burn pile  -  Who wants em'?

XH5R9Wi.jpg

Matt ♪ ♫ ♪

Sometimes it is just best to take Ol' Yeller out behind the woodshed.

I have seen one set of ALs here that I got from you, I sent to a member, who has sent to another member.....

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You can add then add a L-pad to the mid and tailor the sound for your room. 

 

Thank you for posting this.  I have a very dumb question. 

 

What value of L pad (range of resistance) and if you put it parallel to the mid (and maybe add one to the tweeter) doesn't the added resistance throw off the values of the caps (meaning that the caps are specked on the transformer and a 16 ohm mid and 8 ohm tweeter)?

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The T3A used in the AL only provides an attenuation value of 6db. The T4A used in the AL-3 only provides an attenuation value of 4db. Most of the AL crossovers are not like the AL schematic posted above. Most do not have the zener diodes. I think those were only in the Pro model Lascalas.

Bob Crites

My '89 walnut stained birch lacquer LS had ALs with the zeners, and as far as I know, were the original crossovers.

Bruce

Edited by Marvel
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You can add then add a L-pad to the mid and tailor the sound for your room. 

 

Thank you for posting this.  I have a very dumb question. 

 

What value of L pad (range of resistance) and if you put it parallel to the mid (and maybe add one to the tweeter) doesn't the added resistance throw off the values of the caps (meaning that the caps are specked on the transformer and a 16 ohm mid and 8 ohm tweeter)?

 

This is the reason for L-pads, they keep the same resistance where the crossover is not compromised. One could attenuate a driver with just a resistor but then the crossover points are changed in the crossover network. If you research L-pads just using 2 resistors you questions will be answered if you understand Ohms law concerning resistors in parallel. You will not need too much attenuation to achieve what is needed so a common L-pad from Parts express will work. A 16 ohm one for the midrange in Heritage speakers and an 8 ohm for the tweeter. Most will be satisfied with just the mid adjustment. Here is an example of what you want.

 

http://www.parts-express.com/speaker-l-pad-attenuator-50w-mono-3-8-shaft-16-ohm--260-254

 

 

I personally just use resistors for attenuation but it is a touch more trouble doing so with some trial runs. It takes longer to achieve what is desired. It is much easier to just throw an L-pad in the circuit and it is more easy to adjust the mids to suit your room and taste. If you care to dive more deeper into electronic circuitry here is a calculator to determine the resistors you need for the attenuation you desire.

 

http://www.diyaudioandvideo.com/Calculator/DriverAttenuationLPadCircuit/

 

Got it, thanks.

 

1 resistor in series 1 in parallel.  I just figured out why they call it an "L" pad. 

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This seemed like as good a place as any for the link. Stumbled onto it on Craigslist. Was going to grab it but changed my mind.

 

http://sfbay.craigslist.org/sby/ele/5685038165.html

That is a great find. Those autoformers are T2A's basically. The chokes look high quality too. If I were building caps, I would ****** those up at that price. 

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OMG, you are kidding me right? Unbelievable timing! I hardly ever go to the Bay Area anymore.

 

I am so sorry man! Not that this helps any, but I was just in San Jose on Friday morning picking up some '84 La Scalas. I would have been happy to do it.

Edited by jorjen
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