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Vintage K22-E woofer longevity (Heresy I)


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My pair of Heresy I comes with K22-E alnico woofers.  They are 40+ years old.  I'm wondering if the accordion woofer surrounds will dry rot like other vintage woofers with rubber surrounds.  If something breaks down in these vintage woofers due to aging, what usually goes first?

 

These speakers like to be played loud.  Is it possible to have too much woofer excursion resulting in damage?  I'm driving them with 11W SET tube amp.  Is it too little power to worry about damaging the drivers?

 

Thanks.

 

 

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I doubt 11 Watts would be much cause for concern, but Alnico's magnetic strength is known to weaken when subjected to at least high currents in the voice coil.  I don't know how or whether time in and of itself takes a toll.  But they can be re-energized in any event.

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8 minutes ago, glens said:

I doubt 11 Watts would be much cause for concern, but Alnico's magnetic strength is known to weaken when subjected to at least high currents in the voice coil.  I don't know how or whether time in and of itself takes a toll.  But they can be re-energized in any event.

 

How can I tell if the alnico drivers are out of spec?  The speakers sound great to my ears.

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9 hours ago, klipschhornfan said:

My pair of Heresy I comes with K22-E alnico woofers.  They are 40+ years old.  I'm wondering if the accordion woofer surrounds will dry rot like other vintage woofers with rubber surrounds.  If something breaks down in these vintage woofers due to aging, what usually goes first?

 

These speakers like to be played loud.  Is it possible to have too much woofer excursion resulting in damage?  I'm driving them with 11W SET tube amp.  Is it too little power to worry about damaging the drivers?

 

Thanks.

 

 

 

11 watts (what tubes get 11 watts SET?) is too little to worry about driver damage, save the tweeter, maybe.  Watch out for electronic squeaks and pops fooling with the inputs while the power is on.  

 

I have a '67 and a '68 H700 with AlNiCo E-V woofers, still woofing nicely.  The spider and surround are in good shape.  The treated cloth does not breakdown like the '80s foam surrounds. 

 

AlNiCo magnets can lose strength from mechanical shock, high EM field strength and heat.  Possibly age.  Only detailed testing can determine if the magnet is weak.  If you can't hear anything,  I'm sure they're fine.  Only a speaker maker would have the device to magnetize the woofer, like Great Plains Audio.  The machine appears to need a cavity shaped to the particular driver.

 

 

Since your woofer is a -E, look for a 67- manufacturer code.  If it has that it is made by Eminence and you can call them to see what they say. 

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I got a pair of 22s in my Heresies that I am am freshening up.
The only thing that I noticed on inspection was that the cloth surround was rather dry to the touch compared to my GPA414s. But they were much newer.
Wonder if they should be treated once in a while. At least the surrounds don’t rot.

To counter potential sag from 40 years of gravity I Did considered monting the woofers upsidedown when putting them back in the cab. But the leads didn’t reach far enough to get to the crossover so I dropped the idea.
They sound great anyway


Sent from my iPhone using Tapatalk

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On 4/23/2019 at 8:12 AM, klipschhornfan said:

 

How can I tell if the alnico drivers are out of spec?  The speakers sound great to my ears.

I think you answered your own question...

 

The old adage applies - "If it ain't broke..."

 

Now if you want to upgrade or play with rolling drivers  - that's another thing entirely!

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the reason that Alnico drives can lose magnetic charge is because of heat build up this can occur most often by pro use at very high play levels. If you are concerned you could always send the drivers to Great Plains Audio who are Altec and they can recharge your woofer to as new condition. If your drivers have not suffered hard use they may be fine. If they sound good to you  why worry? You might rather pend the money on a pair of subs. Be careful while visiting the Altec site as those drivers can lead you down the path to the dark side of the Lansing Heritage as drivers designed by James B. Lansing will steal you away from the Klipsch light in which you are basking at the moment, such is their tremendous design and build quality.

 

https://greatplainsaudio.com/

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