Morphing AA crossovers into ALK

[kwingylee]

Last night, I finished morphing one of my Khorn's AA crossovers into ALK Universals. I used the existing inductors in the AAs and replaced all of the vintage capacitors with 1% Polypropylene caps from DAYTON. Of course I used the existing T2A transformer as well.

This means I added the additional components only to the squawker network: one 0.3mH inductor, the 2.2uF cap and the 10 ohm resister. I simply relay those on the existing AA board. I also left the connection from pin 4 of the T2A transformer to the squawker.

Comparing the sound of the two crossovers, the one with the ALK values definitely sounds a lot less forward. The speaker overall is much "mellower". The question I have is whether I should take the squawker output off a different pin? What do other ALK-U NW users have their squawker set to?

Thanks for the responses...

[Al Klappenberger]

I suggest you move the squawker tap from #4 down to #3. #4 is way to hot!

BTW: I'm not sure what you mean by " I used the existing inductors". You shouldn't because thier values are very WRONG and they are of poor quality. The only one you might be able to get away with reusing is the woofer inductor. If you do that the 24+24 uF should be replaced by 20 + 20uF or a single 39 uF.

Al k.

[kwingylee]

Al:

Al:

Thanks for the suggestion in moving the tab.

What I did definitely is a first step.I measured the inductance of both woofer inductors. They both read 2.4mH, which is what the ALK-Us specified. The tweeter inductor is currently 20% too high in value. Anyway, I liked the results enough that I changed the other AA crossover today so both sides now matched each other.

I used one single 40uF capacitor and multiple caps in parallel to make the 7.1uF.

I will live this combo for awhile before I swap out the 0.245mH in the tweeter circuit. I like the way the crossovers look AND sound now. I do have some alphacore inductors that I can use for the woofers.

[Al Klappenberger]

I checked out what effect the old AA .254 mHy inductor would have where the .20 mH should be with the computer. It causes the response of the tweeter filter to sag at the crossover. It's not as bad as the obvious glitch in the passband of the stock AA filter though. You still need to replace it with a .20 mHy Litz inductor ASAP.

AL K.

[kwingylee]

Thanks Al:

I will do as you have suggested.

[kwingylee]

AL:

Wife and I did some serious listening on the modded Khorns over the weekend. With the midrange horn connected to tap 3 vs the original tap 4 on the autotransformer. The speaker now sounds too distant and laid back. I prefer tap 4 better with the mod that I did. With the squawker on tap 4, the system defintely sound smoother over all and instruments are more clear.

I am still working on getting the 0.245mH inductor in the tweeter replaced. I am happy with the changes I have now.

Kwing

[Al Klappenberger]

The general consensus is that an intermediate setting is best. Between 0-3 and 0-4 on the 3619 there is X-4. That is where I set them. You might also try 2-5. This is just a bit "cooler" then 0-4. That means lifting the - lead of the K55 off ground.

Al K.

[kg4guy]

Al how many -db would 2-5 be?

[Al Klappenberger]

0-4 is 3.0 dB

2-5 is 3.8 dB

X-4 is 5.5 dB

0-3 is 6.0 dB

Al K.

[kg4guy]

Thanks as I am running K-55-M's in both of my LSI's and I think 0-4 is a little hot for them so just so I'm clear 2-5 on the T2A is -3.8 and where does the + lead go on the 2 or 5 I assume 2?

[Al Klappenberger]

Put the - on 2 and the + on 5.

Al K.

[kg4guy]

Thanks Al