Building a 136HS

[Guido]

I was under the impression that the 136HS has a 2226 core with a bucking magnet. So I ordered a C8R136 kit to build a 136HS from a 2226 core.

WRONG!
The 136HS must have a completely different geometry than the 2226. See the kit pics.

The coil looks like a C8R2245 coil. Length is 25mm

[Guido]

So I removed the aluminium spacer ring of the 2226 core.
This result in a 2225/2234/2235 geometry.

As the C8R136 uses a cupped spider with d=4-5mm the 25mm voice coil is centered with this geometry.

[Guido]

Well this modified 2226 core was reconed with the C8R136H kit.

This is the strange result:

[Guido]

So now I'm very interested in a picture of a real 136HS to find out what's going on here.

Here are the T/S specs of the real 136HS
Fs = 35 Hz
Xmax= 7.87 mm
Re= 5.0
Qts= 0.38
Qes= 0.4
Qms= 7.7
Vas= 153.5
Mms= 146 grams
Sd= 800 cm2
BL= 20 T/m

Could this FERRITE core be demagged? Due to Shock or heat or overload??

[spkrman57]

Guido,

You mentioned removing it:

"So I removed the aluminium spacer ring of the 2226 core."

This would be a good question for the recone experts!

Regards, Ron

[Guido]

No, the aluminium spacer is just a spacer.

[Earl K]

Hi Guido,

- Since the BL is low ( & conversely Qts has climbed ) , I'd have to guess that this coil ( # of coil-turns within the flux field ) was designed to work within a deeper gap ( perhaps the same gap depth as the 2245H ) .
- ie; If the wire used is a thicker gauge ( for power handling purposes ) there'll be a reduction in the total "turns" wound per given distance ( & therefore a drop in the BL product ) .

Can you get that 136HS kit out of the 2226 without damaging the kit ?

Do you have a 2220H core on hand to try instead ? I have one here ( basket with magnet / no cone kit ) if you need some measurements taken to help you approximate the spider & coil centering issues .

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[subwoof]

Apologies to Ian...

I believe the frame should be the 2227 - not the 2226. The gap is deeper ( like the 2220 types ) and the magnet is a bit stronger...?

This is the same scenario with that special 12 ( forgot the model ) that has the 2227 mag on a 2206 frame - it had rubber surrounds and deep ass coil I think.

There is a post / thread on this somewhere but the search function for some reason isn't very helpful lately..

sub

[Guido]

Thanks Sub

I have several 2227/ME150 cores here. Again completely different. The coil sits much deeper. Even deeper than on a 2226 cone kit.
Look at my coil. Won't work in a 2227.

Look here
http://www.audioheritage.org/vbullet...ad.php?t=13731

Damned, how does that 136HS look?

[Guido]

OK!

The C8R136 is designed to work in a 1,22T gap and this yields in a BL of 20N/A.
The 2226 core provides 1 Tesla. I measured only 0,95T with my Teslameter.

Maths:
0.95T/1.22T * 20N/A = 15.6 N/A

I measured 15.3 N/A

So even with the removed aluminium spacer which makes the 2226 geometry a 2225 geometry we can't glue a 2235 kit into that modified 2226 basket.
This would create another low B/L driver.
The 2226 gap has too low Flux density.

Arrrgh

[Fangio]

Someone else went down that route – and now the result is for sale

http://cgi.ebay.de/2-Stueck-JBL-2226...QQcmdZViewItem

No affiliation.

[Guido]

Someone else went down that route – and now the result is for sale

http://cgi.ebay.de/2-Stueck-JBL-2226...QQcmdZViewItem

No affiliation.

Don't buy these!!

This guy FOR SURE didn't remove the aluminium spacer which results in an 13mm VC offset.
I wonder that they "work" at all.

[alangood]

I pulled two heavy 136HS speaker cones out of the garbage at a trade fair, packed in cardboard, with plastic and polystyrene protective packing.

How do I test to see if they are healthy or dead?

I see that JBL discontinued them.

If they are dead, and any of you want them for parts; you're more than welcome.

Thank you.

Alan
[email protected]
New York City