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Thanks, I will post some pics when I build them. I had the parts for the first crossover in my shopping cart then I saw the 2nd version. Now I need to figure out if one crossover design is better or if they are just different... lol. This brings some questions for anyone who is reading. 

 

Which crossover design is the better universal for the LaScala?

What is the purpose of the 1uf bypass caps?

 

Thanks in advanced for any answers. 

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18 hours ago, Mikerodrig27 said:

Awesome! Thanks! There is a ton of great info on this forum.

 

Okay, so what I am gathering is that the version that I posted sends ~1000hz and below to the woofer and roughly 410hz and up to the mid/tweet. The other version that I see posted puts everything ~500hz and below to the woofer ~500hz and up to the mid/tweet. Let me know if this sounds right. 

 

In other words, there should be less mingling between the woofer and the squawker with the 2005 version that I see posted. 

sootshegood job on your build! Looks like a lot of nice boutique parts. Is the point of the bypass cap to save a little money by not having to purchase a 40uf expensive cap vs a 39uf less expensive cap?

 

 

In response to some of your queries. 

 

None of the crossovers are better than the others....they are slightly different flavours /sounds. Some folks will prefer one over the other, so hard to say which one you will prefer. All of them will work with the LS. FWIW, my preference is for the one that I posted. I thought it had a much smoother integration between the 3 drivers.

 

The purpose of the bypass caps is not to save money by having a 39uf cap instead of a 40uf cap. The bypass caps are 0.01uf, so the main caps remain at 40uf. The idea behind it is to impart some of the flavour of a really expensive cap into the main capacitors. To give you an idea, the 40uf caps cost me $284 Aust dollars each & the Dueland bypass caps cost me $25.75 for each 0.01uf cap. 

 

Don't overthink things too much, just have fun experimenting.

 

Cheers.

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Sootshe, thanks! I appreciate the detailed answer. 

 

I hope this thread serves as a good resource for people in the future. I added ALK engineering as a tag. Everything that I have seen here are schematics that he has released for the public to use. This thread will hopefully work to his advantage as people will get to build and hear how he voices his crossovers. When I Emailed Al K, he was very pleasant and responded very quickly so I would like to see him get something out of this.

 

I ordered the autotransformers. For anyone looking into this, you can order them on Bob Crite's website. The model 3619 that was originally used has been discontinued. You can use the model 3636 in it's place. From what I have seen, it is more expensive but offers more adjustability.  
 

Thanks again to everyone for the input! I feel confident in ordering parts and building a universal crossover!

Edited by Mikerodrig27
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9 hours ago, Mikerodrig27 said:

Sootshe, thanks! I appreciate the detailed answer. 

 

I hope this thread serves as a good resource for people in the future. I added ALK engineering as a tag. Everything that I have seen here are schematics that he has released for the public to use. This thread will hopefully work to his advantage as people will get to build and hear how he voices his crossovers. When I Emailed Al K, he was very pleasant and responded very quickly so I would like to see him get something out of this.

 

I ordered the autotransformers. For anyone looking into this, you can order them on Bob Crite's website. The model 3619 that was originally used has been discontinued. You can use the model 3636 in it's place. From what I have seen, it is more expensive but offers more adjustability.  
 

Thanks again to everyone for the input! I feel confident in ordering parts and building a universal crossover!

Mike, help me overcome  my ignorance. What does the inductor on the woofer do to cut off the woofer and why do some crossovers also have a cap and others don’t?

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6 hours ago, Madman1 said:

What does the inductor on the woofer do to cut off the woofer

 

Inductors are used to block AC signals, capacitors block DC signals. Placed in series with the woofer, will roll off the upper end, crossing to the midrange.

 

As the freq. goes up, less will get through a given inductance.

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  • 4 weeks later...

Okay, so I ordered the parts from Meniscus and built the crossovers. 

 

A couple of slight value changes due to part availability. 

 

I ordered two caps to make up the 7.5uf vs just the one as I wanted to use Clarity Cap CSA's. A 2.7 and a 4.7. 

 

I used a 1.5mH inductor for the woofer vs the 1.3. I figured I could undwind it to make the 1.3 but I am using it as is for now. 

 

I am using a 47uf cap vs the 48uf. I can find a really nice 1uf cap to run in parallel. 

 

Lastly, I have the 3636 autotransformer vs the 3619. Al K said it is a good replacement. 

 

So want to wanted to ask you guys is, are the taps the same as in the schematic?

 

+ of squawker to 2, - of squawker to 5

ground to 0, positive from mid(2.2uf, 10ohm and .3mH junction) to 5

 

What do you guys run with your stock laScala setups? I I have the K-55-M, the K77 and the K43 woofer (industrial)

 

So far, the crossover is a major upgrade over the old original AL crossover which is to be expected due to it's bad reputation. However, I don't feel that the mid range and high range clarity is as good or natural as I expected. The woofer doesn't really sound to strong either... Lol. I will eventually be running a sub with these so I am sure that will solve a lot of the low end issues. 

20210413_233339.jpg

Edited by Mikerodrig27
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The K43 is a great woofer, with better upper bass than the K-33, but less on the bottom end of things. My LaScalas have K-33s, but the MWM cabinets I have use the K-43s. Currently my K-33s are disconnected and the woofer connections are to the MWM cabinets.

 

Your crossovers look great.

 

52 minutes ago, Mikerodrig27 said:

Lastly, I have the 3636 autotransformer vs the 3619. Al K said it is a good replacement. 

 

So want to wanted to ask you guys is, are the taps the same as in the schematic?

 

This may help:

 

autotransformer_guide.jpg

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Thank you Marvel.

 

Okay, so then the universal crossover already has the swamping resistor so I need to use the constant impedance table. in parallel with the 2.2uf cap

 

5 gets positive

0 gets ground

taps are 5 & 2 for the squawker with 2 being positive to flip the phase 180*. 

 

Has everyone been satisfied with this setup so far? After using these speakers more, I can see how they would sound really great in a large room. Right now they are roughly 7' apart center to center, and I an about 7' from them. When I finish them and test them in their final spot, they will be 9 1/2' apart and I will be 10' from them.

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Hmmmm.....yes, 5 is positive & 0 is negative...see attached....but the input will vary according to the level of attenuation you want .....as will the output. Refer to attached. 

 

I wouldn't be "flipping the phase" as I believe this design has a phase reversal built in to it.

 

You really need to connect according to the attached input & output chart for the 3636.

3636 ATTENUATION LIST.pdf ALK Uni with 3636.pdf

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Yes, that you showed in the PDF with the 0 and 5 connection is how I have it. I double checked, I have all the taps set right. I followed the polarity of the universal schematic. After listening to the LaScalas for a while, I like them. I ended using them with a Marantz 2218 and they sounded terrific. The Firstwatt F6 with a B1 Korg Nutube is voiced a little thin on the bottom for the LaScalas. I may try them with a Threshold S/500 and upgraded Adcom GFP-565. The adcom is a little softer on top and the threshold is very strong for bass. I feel like that may be a winner with them. 
 

On 4/20/2021 at 6:41 PM, sootshe said:

Hmmmm.....yes, 5 is positive & 0 is negative...see attached....but the input will vary according to the level of attenuation you want .....as will the output. Refer to attached. 

 

I wouldn't be "flipping the phase" as I believe this design has a phase reversal built in to it.

 

You really need to connect according to the attached input & output chart for the 3636.

3636 ATTENUATION LIST.pdf 24.71 kB · 1 download ALK Uni with 3636.pdf 486.58 kB · 2 downloads

 

 

Thanks everyone for all of your help!

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  • 2 months later...

Here is a cleaned up schematic with the correct values for LaScala's with Type AA or Heresy's with Type E crossover. 

 

After listening for sometime, I discovered a low mid-range bloom in the LaScala's and added the 80uF cap across the woofer making the woofer section 12dB/octave. I can't find the REW graph I generated when I added the 80uF cap, but it definitely took care of the anomaly. 

 

Edit: I should remind members looking at this thread that my LaScala's are ported, so you may or may not need the 80uF cap. Experiment and decide. 

 

You can attenuate the midrange and tweeter to your liking. 1011782944_KlipschHeritageCrossover_NKSType_v1.1.0_072621.thumb.jpg.66c56b260a42929d4c63a8ef3e7585af.jpg

Edited by Curious_George
Clarification
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  • 8 months later...

I have 3 of the early adjustable ALK universals and have tried to find the parts to duplicate the 3rd one so I would have a second pair now that Al no longer sells them. Originally, the extra one was purchased for a belle center channel that i no longer own so that crossover is just sitting around unused. I have the universals in my Klipschorns and they sound fantastic and really want to have a pair for my belles and lascalas as well. The belles have the crites AA that do sound much better than the stock crossover but not nearly as dynamic as the ALK. I posted in the Garage sale section looking for a single 3619 autotransformer to buy a while back to make a duplicate of the extra crossover i have no avail, also tried crites with no luck. I also didnt have much luck finding the musicaps or harmony caps that are in mine either though. I have seen some newer model ALK that use the sonicaps that probably sound just as good though. Hopefully you can post some pics of how the 3636 autotrasformer is wired up in comparison to the 3619 and what caps you chose to use.

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You can use any film and foil to replace the Harmony bypass capacitors. https://www.parts-express.com/Audiocap-PPT-Theta-1.0uF-200V-Film-Foil-Capacitor-027-722

 

You can use a 3636 in place of the 3619. You wire them the same. They share many common connections (but not all). How are you tapped out right now? Are you using the stock drivers?

 

If you build a new set from scratch for your LaScalas, you can dispense with the bypass capacitors.

 

You can substitute the Hovland with this part: https://www.parts-express.com/Jantzen-7028-2.2uF-Alumen-Z-Cap-100-VDC-Aluminum-Foil-Capacitor-027-4604

 

You can substitute the 7.5uF with a 6.8uF. I was Al's licensed builder for these for many years and he okayed this substitution. Again, use a film and foil. I would probably use a Theta here. https://www.soniccraft.com/product_info.php/audiocap-theta-7uf-200vdc-p-74

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Has anyone experimented with placing the low pass to the squawker after the autoformer?  It would seem that doing so would allow one to attach the tweeter circuit to any output tap for attenuation, if needed.  Granted, the inductor and capacitor values would need to be changed, but this eliminates the need for a tweeter attenuator.

 

For fun I whipped up a simple circuit.  It consists of a 24uf capacitor in series with a .75mh inductor.  I placed a 1.3uf capacitor across the squawker output terminals.

 

On the following graph, the green plot is the voltage across a K55M using the ALK Universal (taps x - 4).  The orange plot is the test circuit.  Other than the voltage drop caused by the Universal's autoformer, the plots are pretty close.  I'm sure with some component tweaking they could be even closer.

 

Just a thought.

 

Mike  
 

Adj Universal to Squawker.jpg

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Crankysoldermeister, thank you for the info, that answers alot of questions for me. My Klipschorns have Crites woofers, the older crites ct125 tweeters (might try some of the newer tweeters here soon though from davea or crites) and the stock k55 and k400 horn. My belles are factory except for crites AA network, and the lascalas are factory, but might upgrade the tweeters in the lascalas and belles at some point in the future. Currently for the universals in my klipschorns are tapped on the X and 0 settings.

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