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WTB TAD 4002 Drivers


funkyhambone

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You want the TD-4002 with the snout.  It has a 2" (50.8 mm) dia. exit.

 

There is also a TD-4002Z without the snout that has a 1.53" (39 mm) dia. exit: that's the version that you should avoid.  I've read that people have had trouble finding the bolt-on snout for these to convert them to 2".

 

Chris

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I wouldn't believe there is much difference - mostly the weight of the unit is more than twice as heavy due to the alnico magnet rather than the neodymium magnet of the 4002.  The total magnetic flux density of both units is about the same.  The inner diameter of the exit is 1/16th inch less than the 4002. so you'd use a little more modeling clay on the interface of the driver's exit diameter to the K-402 horn throat.

 

I'd start with the same crossover settings for the 4002, and change them only if there were measured differences. I wouldn't expect that there would be many of those.

 

EDIT: I've attached a pdf table of the TAD compression drivers

 

tad_compressiom.pdf

 

Chris

Edited by Chris A
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If you are really serious about this, I will sell you mine for $2600 + shipping.  They are currently in use on K-402s and in perfect condition, and include all you need for use on your K402s.  I have all the original packaging and documentation.

 

These are virtually unobtainable and I doubt you will find any new.  They are over $3K new if you can find them.

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You might be wondering what the difference is between a K-69-A driver and a TAD TD-4002 (Be diaphragm) driver.  Here are the constructed impulse plots for both drivers taken in my room.  I don't have to say much about which one is better and by how much:

 

post-26262-0-55740000-1449613273_thumb.p

 

post-26262-0-37740000-1449610597_thumb.p

 

You can see the chattering frequency of the K-69-A by counting the number of peaks per millisecond.  The TAD doesn't have those.

 

Chris

Edited by Chris A
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You might be wondering what the difference is between a K-69-A driver and a TAD TD-4002 (Be diaphragm) driver.  Here are the constructed impulse plots for both drivers taken in my room.  I don't have to say much about which one is better and by how much:

 

attachicon.gifK-69-A on K-510 chatter impulse plot.png

 

attachicon.gifTAD TD-4002 impulse response.png

 

You can see the chattering frequency of the K-69-A by counting the number of peaks per millisecond.  The TAD doesn't have those.

 

Chris

Chris, that is quite a difference. Are these honest to goodness IRs or are they derived from the frequency response functions?

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They're deconvolved from relatively long upsweeps (10 Hz to 20 kHz).  That's why I said "constructed impulses".

 

Since the resolution of deconvolved upsweeps is somewhat legendary within the geophysical community (Vibroseis) going back to the early 70s, I actually prefer to see the deconvolved data rather than impulses because it tells you even more than the impulses without injecting even more nonlinearities of the driver at exceedingly high SPLs.

 

Note that the sweeps were done at about 108 dB( C ) at one metre in front of the speakers.

 

Chris

Edited by Chris A
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Probably by looking at the serial number on the diaphragm...

 

Here is an apparent source for replacement Be diaphragms for the 4002: http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=63180&d=1410852677

 

Chris

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I never opened mine but have seen many pics of the diaphragms.  The Berylliums are dark, the aluminum are silver.  That's about all I know.

 

It's not really important that it is original.  It is important that it is Beryllium.

 

Juniper, please let us know how your purchase turns out.  I would love to see a FR plot of the two.

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I never opened mine but have seen many pics of the diaphragms.  The Berylliums are dark, the aluminum are silver.  That's about all I know.

 

It's not really important that it is original.  It is important that it is Beryllium.

 

Juniper, please let us know how your purchase turns out.  I would love to see a FR plot of the two.

Mark will get the FR's when I can get my tech out with his gear and will post them, thanks for the heads up on the coloring, as my memory serves me the JBL be's I have seen with my friends system almost had a metallic blue colloring. Not like the Tad fram photos I looked up. THANKS AGAIN!!!

Edited by juniper
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Replacements are smooth and have no honeycomb covering.  Original have the honeycomb shield.  (though I don't think it's really honeycombed, probably round holes)

Thanks Coytee, they look just like that,with the shield. Now I have to decide or find the "acceptable" DCR range, the gentleman matched 2 sets for me to choose from 1 pair measuring 7.5 the other measuring 7.8?????

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