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Super AA (Alk Jr) Exchange


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I bought an early pair of Al's A-series crossovers and liked the bass and midrange, but thought the tweeters were too HOT. 

 

I've collected several K-77/T-35 response curves.  Note the "hump" in the response curve from about 4k to 9k and :

msg-43-0-11040000-1424308713_thumb.jpg

 

Now, look at the type AA's tweeter filter's response.

SAAtweet.gif

Since most K-55-Vs struggle to get to 6k Hz, what is wrong with the Type AA's filters? 

 

Were I you, I would rebuild your Type AAs with premium caps and air-core inductors and replace the T2A with a newer version and add a band-pass inductor on the squawker like below.  I think you can get autoformers from Bob Crites.  If you have square magnet K-77-Ms, or other tweeters, disconnect the KLiP diodes:

 

msg-43-0-01480000-1424308646_thumb.jpg

I actually used a 0.35 mH instead of 0.4 as it calculates at a little higher frequency, but either will be just fine. 

K-77-m & Crites Freq_rsp.gif

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I converted my 1979 lascala recapped AAs to the Super AAs myself based on ALK documentation.  They are excellent IMHO and well worth the effort to make the change one way or another.  Cost me about $80.00 to do it myself.  I also had DeanG built Super AAs in some lascalas I owned years ago (which led me to do these recent ones)..........and they were excellent as well.  ALK sells tweeter attenuators if you need that.  This lastest build "as is" on ALK's site today is just right for me.

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1 hour ago, John Albright said:

I bought an early pair of Al's A-series crossovers and liked the bass and midrange, but thought the tweeters were too HOT. 

 

I've collected several K-77/T-35 response curves.  Note the "hump" in the response curve from about 4k to 9k and :

msg-43-0-11040000-1424308713_thumb.jpg

 

Now, look at the type AA's tweeter filter's response.

SAAtweet.gif

Since most K-55-Vs struggle to get to 6k Hz, what is wrong with the Type AA's filters? 

 

Were I you, I would rebuild your Type AAs with premium caps and air-core inductors and replace the T2A with a newer version and add a band-pass inductor on the squawker like below.  I think you can get autoformers from Bob Crites.  If you have square magnet K-77-Ms, or other tweeters, disconnect the KLiP diodes:

 

msg-43-0-01480000-1424308646_thumb.jpg

I actually used a 0.35 mH instead of 0.4 as it calculates at a little higher frequency, but either will be just fine. 

K-77-m & Crites Freq_rsp.gif

 

Whats the result of adding the band pass inductor? .35 or .4?

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Thanks - I have both the original square magnet and Crite's CT-125 to choose from at home, so if I go the way of the Super/Jr and find the original too hot, the CT-125 might sound tamer. If  I do stick with a straight AA, I don't anticipate doing anything bigger than a recap - at least for starters!  While I was comparing the Super exchange against the Crites recap package, reading thru more of the forum I see the Russian PIO, Dayton 1%, and Jantzens.  These seem to be among the modest budget directions that people are going when replacing the oil cans.

 

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On 8/29/2017 at 2:03 PM, muel said:

 

Whats the result of adding the band pass inductor? .35 or .4?

 

All Atlas/Klipsch K-55-Vs have a response "bounce" around 9k Hz.  The inductor tames that bounce a little.  Plus, capacitors and inductors shift phase 90 deg., in opposite directions, so it's a minor attempt at reducing total phase shift and comes from an OLD "Loudspeaker Design Cookbook" I read in college. 

post-2142-13819498806984_thumb.gif

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15 hours ago, John Albright said:

 

All Atlas/Klipsch K-55-Vs have a response "bounce" around 9k Hz.  The inductor tames that bounce a little.  Plus, capacitors and inductors shift phase 90 deg., in opposite directions, so it's a minor attempt at reducing total phase shift and comes from an OLD "Loudspeaker Design Cookbook" I read in college. 

post-2142-13819498806984_thumb.gif

Oh that's right... this has been mentioned before but I've forgotten the details.  So the other solution is the dual phase plug or the 55g?  What effect is there with the inductor with those drivers?  I can't seem to find that old thread.

 

Starting with a recap of the AA's is the right way to go.  You could always go to the "Super AA" later but I'd be inclined to pick up some used AA's to send those in vs. sending in your newly recapped AA's.  You could always sell the pair you don't like as much.  Both roads are good!

 

As far as caps for the AA's I'm a big fan of the Jupiters.  I have them in almost everything except the Super AA's have V-cap OIMP's.  I admit you are buying fractions with the cost difference of the Jupiters but I have no regrets at all!   I'd say spend your money on fixing your room first... diffusion, absorption panels, bass traps... Taking care of those first reflections and proper placement of speakers as well as your seat does more to clean up the music than anything.   

 

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7 hours ago, muel said:

   I'd say spend your money on fixing your room first... diffusion, absorption panels, bass traps... Taking care of those first reflections and proper placement of speakers as well as your seat does more to clean up the music than anything.   

 

Best money you can spend towards the audio hobby. Seriously.

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11 hours ago, muel said:

Oh that's right... this has been mentioned before but I've forgotten the details.  So the other solution is the dual phase plug or the 55g?  What effect is there with the inductor with those drivers?  I can't seem to find that old thread.  ............

 

.   I'd say spend your money on fixing your room first diffusion, absorption panels, bass traps... Taking care of those first reflections and proper placement of speakers as well as your seat does more to clean up the music than anything.   

 

 

If you look at the graph above, the -V does it, too, just not as badly and ~1k Hz lower. 

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You have to deal with everything in the chain if you want the best attainable sound - the room of course, is also a factor. 

 

I never saw the point in throwing thousands into equipment, and then freaking out over the prospect of having to spend more than a few dollars on capacitors. The Litz coils are overrated - I never could hear a difference with them (which is why I stopped using them).  

 

I wouldn't bother with the "Super AA". One of the strengths of the original design was the ability to attenuate the midrange to accommodate personal taste - which the budget version of the Super AA doesn't provide. The network just drops the midrange output 3dB, which will leave low level listeners disappointed. You're basically locked in - and at normal listening levels, the overall sound is dry, and the midrange too recessed.

 

The page says "the Super AA - X", which is misleading. The Super AA and Super-X are not the same. The latter provides attenuation in 1dB increments. 

 

The Klipsch Type A and AA were originally built with somewhat lossy parts (when compared to what's available today). Build with vintage type capacitors and the sound is fat and bold - just like the way it's supposed to be. 

 

FR plots only tell part of the story. 

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It doesn't help that the current iteration of the Super AA isn't like the Super AA I used to build. The original Super AA and Alk Jr. are the same - and I built ALL of those. The Super-X uses premium parts, and provides 1dB increments in attenuation - and I built ALL of those.

 

The current "Super AA" uses entry level caps, crusty old autoformers, and fixed attenuation. There's nothing "super" about it at all - unless you think a benign impedance is the end all in filter design. 

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I have to respectably disagree. :)  I recapped my AAs to some satisfaction but the current ALK Super AA or whatever you want to call it was a big improvement from that.  Even with the so called cheap parts and old Klipsch coils it still makes a huge improvement.  Yeah.........if you listen at really low levels, don't bother.  But the balance of the drivers is very good actually.  You get to really hear some lascala bass and turning it up things stay composed and clear.  Squawker bandpass is  key.  No harshness.  Well worth $80.

 

Heck it cost me over $100 for groceries just to "tailgate" at home yesterday for Georgia football.

 

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Well sure, when you knock 6dB off of the midrange and 3dB off of tweeter - you're going hear more bass. I'm sure it sounds more balanced when you lean on the volume.

 

I don't run a bandpass - it's not harsh either. I could run anything - but I run the Type A (four parts). I do run Dave's horn though - and the Allen drivers.

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Hey, not knocking the exotics at all.  It's an $80 upgrade.  I can' think of a better value.  Surely though it won't deliver the ultimate low level details of the your boutique stuff.  Never meant to insinuate that.

 

But for folks who listen at decent to the louder levels and want a budget upgrade that offers superior clarity at those volumes the ALK solution trounces a simple AA cap upgrade with budget parts.

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"Value" and "improvement" (or "better")  are pretty subjective terms.... "trounce" is a pretty strong one!

They are all compromises of some sort and what the OP wanted to hear about was the pros and cons.  

I skipped the pros and cons and went straight to what I would do which is to try both.  

 

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On ‎9‎/‎6‎/‎2017 at 0:27 PM, muel said:

"Value" and "improvement" (or "better")  are pretty subjective terms.... "trounce" is a pretty strong one!

They are all compromises of some sort and what the OP wanted to hear about was the pros and cons.  

I skipped the pros and cons and went straight to what I would do which is to try both.  

 

Thanks - I really appreciate all the ideas - altho making a decision to do just one is harder than ever!

 

To be sure, when weighing the two, I was assuming a comparison of approximately equal value. That is, an Super AA/Alk Jr is about $99 for Al to do, while a (sonicap) recap kit is $96. I didn't want to spend a whole lot more. These 55 year old ears I figure aren't investing much more...yet - I'm all ears!

 

Perhaps my post should have been...I got an old pair of AA's and $100 in my pocket. How do I best spend it?  (Or am I really short changing myself, which seems consensus).

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