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'76 La Scala - ALK Universal to Type A???


boleiro

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5 hours ago, henry4841 said:

Lots of discussions and in depth sound perceptions from those that have done some changing around. Played around with many different X-overs years ago and to be honest the differences between the ALK and A or AA is subtle at best. A small change in volume level can change anyone's opinion of which is better. In other words a volume increase comparing two electronic audio components can deceive you. For me doing away with the autotransformer and building a simple 1st order crossover network using resistors for attenuation sound best to me but that is another story. After experimenting with over 30 different X-over combinations I settled on the AA as being good enough even with the autotransformer. And and keeps my LaScala's stock making them easier to sell for my kids when the time comes. 

 

The OP says he does not listen loud so I honestly think he will be fine using the A network. If one likes the sound and something happens to the tweeters just replace them with ones that are not delicate like the stock ones. I like simple circuits and the A certainly fits the bill. 

as I've said I really like the ALK's with my LS's.  I'm just very curious about the more stock sound.  I've got all my components for the AA's... just need to get the time to sit down and do some soldering.  Excited to hear the (subtle) difference in sound with the AA xo's.  I'll probably end up modding them to try the type A too.  

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4 hours ago, ricktate said:

It is definitely hooked to tweeter its the ground wire. 

I use type A in my Scalas all stock drivers. 

 use type A with 4500hz mod and crites early tweeter on my K=horns to take load off mid drive. Love them both.  

I had built ALKs a long time ago didn't really think they worth all the money spent on parts. I sold them if anyone has them my name is on bottom of them. 

So I wold recoment type A with caps from Crites or JEM...but i noticed his are on high side. 

I see that now... have been looking at blown up pics of this XO and can see it now.  so it looks like I can use a bare solid 20ish awg wire to connect the negative terminals with the wire going under the positive leads.... right?

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Boleiro, please let us know your sound impressions after listening to the AA network and perhaps the A type as well. I personally had the impression that the A type sounds warm but delivers somehow less intelligibility. Perhaps its only me. I am very curious about your judgement. And as more others have stated it s also a question of preferred SPL. For me the AA type is a good compromise in terms of matching my low to mid SPL best.

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The type A is only a 6dB/octave slope on the tweeter and will allow more low frequency energy thru to the tweeter. This may be perceived as more "warm" or a slight bloom in the frequency area of 4 ~ 6kHz. 

 

The type AA is an 18dB/octave slope and much steeper although it is an older 18dB type alignment (still effective). The 18dB/octave slope will have less driver interaction and possibly a more "clinical" sound. 

 

I hate using audiophool adjectives, but people seem to understand when you use them. 

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1 hour ago, Curious_George said:

The type A is only a 6dB/octave slope on the tweeter and will allow more low frequency energy thru to the tweeter. This may be perceived as more "warm" or a slight bloom in the frequency area of 4 ~ 6kHz. 

 

The type AA is an 18dB/octave slope and much steeper although it is an older 18dB type alignment (still effective). The 18dB/octave slope will have less driver interaction and possibly a more "clinical" sound. 

 

I hate using audiophool adjectives, but people seem to understand when you use them. 

I find that the overall result of the AA does not sound clinical but very musical with a nice impression of rhythm, groove, timing and timbre. Maybe it's because the midrange stays down with a 6 dB filter and the bass stays up with a 6 dB filter. And the midrange is where the music is so important. This preserves a good feeling for fast impulses and a sound picture as if it were made of one piece. To use the adjective clinical, that's more my experience with the ALK universal crossover. Everything perception is very subjective of course.

Even though the type A network sounds very "warm", I find it inaccurate. I suspect that the overlap of the K77 to the K400/401 is too large and that this leads to uncontrolled overlaps and cancellations. Also, the old K77 is not really good in these lower frequencies, so additional distortion creates the impression of warmth, which could be the result of uncontrolled diaphragm movement of the K77.
With the new Lascala we have a completely different tweeter that intentionally goes down to 4500 Hz and the K401 is limited upwards with a low pass filter. This is more like ALK but may sound good, I haven't heard it yet. Maybe it suits modern music, higher SPL and powerful transistor amplifiers.

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  • 3 weeks later...

thanks Rolox... I figured as much.  I know it is odd to go from upgrade to stock.  I guess it's hard for me to appreciate the upgrade since I only know the upgrade.  I just have to know what stock sounds like. 

 

I guess I'll update, but the source for the correct value poly caps is out of stock until late September, so I should have those on order soon. 

 

I will for sure report back.  

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21 hours ago, KT88 said:

Do you mean that 2uF and 13 uF are not available (original values) or that even 2.2uF and 6.8uF (two in parallel) are not available? If the latter ones are to get, try them as I did with good success.

Hey KT88, you are correct... the poly 2uF and 13uF caps available from Jem are out of stock for the time being.  I did end up ordering the same caps you referenced earlier in the thread, Nichicon 2.2uF and 2 x 6.uF Kemet poly caps.  still need to wire up the AA xo's... been working hard to complete an outdoor pizza oven build before it gets too cold!  

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Thanks for reply, boleiro. Now these Kemets (and the Nichicons) are really cheap fortunately. If you listen to them I'm glad to hear your report. And I'm very curious how the sound might change when you later install perhaps these JEM caps when they become available again. I think the character of the caps should be quite similar. But I'm mainly interested (besides the differences when using the exact uF) in the difference if using two 6.8uF in parallel deviates from the original ESR of only one cap and if that is audible. 

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  • 2 months later...

wanted to check in with an update... finally got those polyester caps in the correct values and installed on homebrew type AA crossovers.  The difference was very apparent right away.  But it took awhile to start processing what the differences were that I was hearing from the ALK universal XO's.  And now it's impossible not to hear the difference between the two.  I have gone back and forth twice between the two and its amazing how subtle, and yet striking, the difference is.

 

The ALK's are more transparent than the AA's with a very clear top end and mid section.  The AA's seem to me to be a more lively feel to them, more of the band in the room thing.  They were warmer, and though a little less articulate than the ALK's, the AA's just have a very pleasant and fun sound.  And I swear the AA's gave more bass... though maybe thats just me.  The ALK's were very articulate and clear.  

 

The differences  between the two remind me of my experience rolling 12AX7 driver tubes in my integrated amp recently.  The AA's are like the Mullards, warm and luscious and the ALK's are more like the Telefunken's with a sweet clear tone.

 

I guess the AA's ended up being just what I hoped they would be... kind of more of that vintage hifi thing compared to the ALK's.  But there is no clear winner... really like them both for different reasons and my favorite XO's are the one ones I'm listening to at the time.  I guess I'll go back and forth for awhile, happily.

 

Might start looking at the tweeter upgrade now... never ending. 

 

thanks for all the help!

 

 

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That is a very nice comparison, boleiro. I like the AA for that points you describe it. I have an ALK Universal here at hand in a box which I purchased new in 2006 from Al. But I did not use it for more than 2 years then back. May be I also should again make a comparison.

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17 hours ago, boleiro said:

wanted to check in with an update... finally got those polyester caps in the correct values and installed on homebrew type AA crossovers.  The difference was very apparent right away.  But it took awhile to start processing what the differences were that I was hearing from the ALK universal XO's.  And now it's impossible not to hear the difference between the two.  I have gone back and forth twice between the two and its amazing how subtle, and yet striking, the difference is.

 

The ALK's are more transparent than the AA's with a very clear top end and mid section.  The AA's seem to me to be a more lively feel to them, more of the band in the room thing.  They were warmer, and though a little less articulate than the ALK's, the AA's just have a very pleasant and fun sound.  And I swear the AA's gave more bass... though maybe thats just me.  The ALK's were very articulate and clear.  

 

The differences  between the two remind me of my experience rolling 12AX7 driver tubes in my integrated amp recently.  The AA's are like the Mullards, warm and luscious and the ALK's are more like the Telefunken's with a sweet clear tone.

 

I guess the AA's ended up being just what I hoped they would be... kind of more of that vintage hifi thing compared to the ALK's.  But there is no clear winner... really like them both for different reasons and my favorite XO's are the one ones I'm listening to at the time.  I guess I'll go back and forth for awhile, happily.

 

Might start looking at the tweeter upgrade now... never ending. 

 

thanks for all the help!

 

 

 

In the end that is what it is all about - fun & enjoyment. Having multiple crossovers for a speaker is like having multiple amps or speakers or anything else audio related. 

 

 

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2 hours ago, Curious_George said:

 

In the end that is what it is all about - fun & enjoyment. Having multiple crossovers for a speaker is like having multiple amps or speakers or anything else audio related. 

 

THIS!  I really do feel like I have 2 different speakers at my disposal now.  I'm stuck on the AA's right now but I am sure I'll get the urge to switch it up soon enough and all I have to do is swap out the XO's.  

 

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