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1986 AK-2 K-horns new to me.


Escoffee

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Congrats on your new purchase! I was so close to bidding on these but NJ was just too far away. Seeing these slip by after years of searching was the last straw that drove me to settle for a pair of Cornwalls!

 

I hope you get them sounding as you would like.

 

 

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2 hours ago, mboxler said:

I'm a little surprised that Klipsch authorized the use of electrolytic capacitors to replace the original film capacitors across the woofer.  I believe Michael Crites did the same thing on the AK-3 he sells.  Good to know!

 

 

Yes, I was thinking the same thing. Here is a picture of the large original caps in the woofer chamber. Maybe someone can explain the benefits of the substitution.

 

596833489_AK-2x-overbasssection.JPG.f60a8777d9a7fb44d02ccbe50a15bf1f.JPG

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8 minutes ago, Kahuna said:

Congrats on your new purchase! I was so close to bidding on these but NJ was just too far away. Seeing these slip by after years of searching was the last straw that drove me to settle for a pair of Cornwalls!

 

I hope you get them sounding as you would like.

 

 

Thanks for that, I've been looking for a local pair for a long while, a few here and there in upstate ny, and virginia, but i dont have a vehicle large enough to do that myself.  these are in very clean shape original owner appeared to have just bought them and left them in place.

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On 6/27/2022 at 11:30 PM, geoff. said:

@Escoffee et al.

 

I would suggest some double sided tape between the caps and the mounts.  @Dave A and @Crankysoldermeister got me thinking about this in a couple of their threads. It eliminates the the waistbanding and indentations associated with this technique. Another benefit of the tape is the zipties don’t need to be as tight.

 

You’ll need to have the ziptie eyelet pretty much where it’s final resting place is before dropping the tape on as it will stick it too. I had spares but your kit is probably specific. 

 

And if I haven’t mentioned it yet, leave the leads as long as they come to keep as much of the heat from the soldering iron from smoking the guts of those JEMs (see what I did there?). I think most recommend a 40 watt iron? 

 

Looking forward to hearing your impressions, at your convenience. The only thing I get when I’m in a hurry is frustrated. 

 

 

 

76C4A235-8CB2-4942-9B9C-66B49921B7C9.jpeg

Appreciate the insight!  I've never used a zip tie holder like this, I usually use hot glue on crossovers but will try this the Klipsch way :)

 

Is there a common belief on replacing the 'internal' wiring on these? the original stuff is very sticky and i suspect starting to oxidize.

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29 minutes ago, Escoffee said:

Is there a common belief on replacing the 'internal' wiring on these? the original stuff is very sticky and i suspect starting to oxidize.

The plastic insulation on that batch of wire caused a chemical reaction with the copper. If you cut and strip the wire, it will be difficult to clean and solder properly. Now is a good time for you to replace it.

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36 minutes ago, Escoffee said:

the original stuff is starting to oxidize.

the Monster type wire jacket used in the AK-2  crossovers is known to deteriorate ,  and contaminate  the copper , which can cause shorts , the problem  was mostly at the solder joints or the ends   , if I were you , I would cut it off , all of it ,  no exception , unless you think  you can salvage it by shortening .

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On 6/28/2022 at 3:48 AM, Escoffee said:

Sorry about the delay. Been tied up with other things and haven’t had a chance to work on these. 
 

here’s a pic of the kit. I was hesitant to post as I think its a great service jem provides, having done all the leg work to locate the parts and ensure they’re to spec with Roy.  He shipped same day and I had them in 2 more in hand.

35256B62-0587-43B1-A351-F79CDDF7A63A.jpeg

D3F0C655-1B92-4CF5-BCAA-9A6E52015A13.jpeg

So have you tried those caps in the meantime? What is your impression? Thanks.

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3 minutes ago, Escoffee said:

sorry no updates yet. Coaching little league is getting in the way at the moment. enjoying the speakers in the meantime :)

 

👍😀Enjoy the time with the little league, it is going so damn fast that they are growing up.

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  • 1 month later...
On 6/20/2022 at 8:19 PM, mboxler said:

 

I mentioned in another thread that it appears Klipsch liked to have around 3mh inductance across the K-55M, hence the different parallel inductor values for the T4A and T5A.  Seems to me that, in order to get the same 3mh using a 3636, one would need to use a 3.5mh inductor in parallel with taps 0-3 of the 3636???  I measure 20mh between taps 0-3 on my 3636.  
 

 

Dean said it well...I'm full of plots 🙂

 

I didn't have a 3.5mh inductor, but did have a 3.3mh air core.  I cheated and used a ferrous screw of just the right length to place in the center of the inductor and raise the inductance to 3.5mh.

 

As I thought, the 3.5mh inductor in parallel with the inductance between taps 0 - 3 of the 3636 got me to my target 3mh.  The brown plot is that voltage across my K-55-M.  I then replaced the 3.5mh with a 5.2mh (no 5mh per the schematic in my stash), resulting in the blue plot.  Tried to get rid of the 60hz spikes and the harmonics, but failed.  The path to the -4db point differs, but not sure the difference is audible.

 

 

 

 

AK-3 3636 3.5mh vs 5.2mh.jpg

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15 minutes ago, Schu said:

isn't the little 'bark' in this area an issue?

 

 

Untitled-1.jpg

 

I can only assume that the high pass to the K-55-M was overdamped (if that's the bark you are referring to) to compensate for the new low pass to the woofer.  The AK-3 voltage to the woofer is down 3db around 350hz and drops quickly (12db per octave) after that.

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While Klipsch was waiting for the engineering samples from EV, they were using the two port K-55-V (Atlas) to develop the network, the Type AK. The expectation was that the EV driver would essentially be the same as the Atlas.
 

What showed up however was a much hotter driver. They rebalanced the network to account for the difference, and the result was the AK-2. They went forward with the network builds while waiting for the production drivers.

 

When the production drivers showed up, to their surprise, they measured like they had originally expected - essentially the same as the K-55-V they had used to develop the Type AK. At some point (undetermined, too long ago and no one remembers exactly) - they rebalanced the network, which became the AK-3.
 

Notice that the AK and AK-3 are identical except for the shunt cap in the woofer section (100uF vs 140uF). 

 

This all confirmed by John Allen, Jim Hunter, Kerry Geist, and even Roy has recollection of it. 
 

Frequency response is not exactly the same, but sensitivity is. 

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  • 5 months later...

OK, I finally got around to swapping caps in both speakers. The Kit was well documented, and very easy to follow. Given the rising cost of everything (mostly labor) I consider it fairly priced.  It included everything outside of the shrink tubing and new wiring both which are optional. 

 

Here is a list of all the modifications that were made:

  • Sealed bass bins to wall using 3/4" rubber pipe insulation
  • Sealed bass bin door and crossover panel using gasket tape
  • Replaced the tacky monster wiring with 14/16/18ga (bass, mid, tweeter) wire leftover from a madisound kit.
  • Recapped Crossovers using JEM provided AK2 kit.

 

There was a large increase in overall dynamics, and a little better definition in the mids. I feel like they're a bit clearer as well. Whether this is due to sealing the bass section better, or the recapping I'm not sure. the large caps on the bass bin door were physically deforming so I suspect that had a bit to do with it. 

 

I am still a bit surprised at how pushed back the vocals remained, and am thinking about trying a different network (Crites AA, or A4500 with his tweeter, open to suggestions). I generally listen at lower volumes, and 'laid back' music like Wilco, My bloody valentine, Grandaddy etc. which already have vocals deep in the mix.

 

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Edited by Escoffee
Removed out of phase comments and plot. See updated plot further down
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