Recone question

[LE15-Thumper]

Will a 121A kit fit in a 2203A ?

[BooBoo Magoo]

121A kit goes into 2130, K120, 121A, 121H, 124A, 124H, 2202, 2202H, 2203, 2203H, and 2204H baskets.

[edgewound]

There is alot of misunderstanding about the interchangeability of some JBL recone kits/frame-motor assy's.

Yes, the 121A is reconed with a C8R121A, and C8R2203 recone kit is not available ...BUT....I've seen too many people say that 2202 and 2220's can be reconed with other 12" & 15" kits respectiveley. They CANNOT!!! 2202 & 2220 are unique drivers designed for their own kits to be used for high efficiency midbass and midrange. While it's true that the voice coil will physically fit in the other 4" coil motors, the position of the coil in the gap will be be off from the correct static starting point, due to deeper gaps and shorter voice coils. Nowhere in the JBL "Goes Into" list are alternate kits listed for each of these unique frames. I've seen numerous times from other Service Centers and eBay that ,eg., a 2220 frame was reconed with a 2225 or E140 recone kit. That's just plain wrong as far as JBL is concerned and at best you'll end up with a driver loaded with distortion. If there's something I'm missing here...please point it out to me....other wise this practice is incorrect as far as JBL Service is concerned.

Thanks,

Edgewound

[BooBoo Magoo]

2202 & 2220 are unique driversWhat specific physical attribute does the 2202 basket have that the 2203 basket doesn't have?

[edgewound]

Magnetic gap is deeper...thicker top plate....no?

[BooBoo Magoo]

I thought all those baskets mentioned were using the .280 top plate and the .057 gap. Flux density in all of them should be 1.2 T

[edgewound]

When I was trained at JBL, I was told that 2202/2220 are unique and wont accept other recone kits satisfactorily...since a 2202 is basically a 12" version of 2220

[BooBoo Magoo]

Ok. Maybe a different spider pad or something.

[edgewound]

Well...if i'm incorrect...and lord knows I have been in the past...I'd appreciate the opportunity to become a better educated JBL'er...anyone?


Humbly,

Edgewound

[Zilch]

121A/H, 124A, 2202A/B/H/J and 2203A/H are on the May, 1988 JBL Cone Kit Interchangeablility list together with D120F, D131, E120, and K120,

whereas,

"2220A/B/C/H/J (130A/B/H) has a unique voice coil gap and is not compatible with other [15" Frame] models."

[BooBoo Magoo]

I wouldn't bother reconing the E120 as a 121H though as it has a thicker ferrite donut and higher flux density.

[edgewound]

Fair enough...I'll make a note.

But the E120 to 121/2203 would make a fine hotrodded woofer, in the same spirit as the E140 to 2235 conversion.

I guess I owe an apology to this thead. I misread the original question. Had a bit of mental dyslexia....must've been the heat from the earlier trail hike with my kids....So sorry:o:


Edgewound

[Zilch]

"E130 and E140 are 1 dB higher nominal flux than others (1.35T versus 1.2T) and will definitely yield a different response with other cone kits, typically 1 dB more midrange (piston band efficiency) and 1 dB less bass (low frequency damping). Any change is the customer's choice and liability."

We are not afraid.... :D

[BooBoo Magoo]

We are not afraid.... :DYes, we surmised that from the Quick and Dirty 4430 thread.

Red = 121 cone assembly in 121 basket
Grn = 121 cone assembly in E120 basket

2.0 cu ft sealed

[BooBoo Magoo]

Red = 121 cone assembly in 121 basket
Grn = 121 cone assembly in E120 basket

2.0 cu ft sealed with B212 filter

[BooBoo Magoo]

Red = 121 cone assembly in 121 basket
Grn = 121 cone assembly in E120 basket

2.0 cu ft vented

[BooBoo Magoo]

Red = 121 cone assembly in 121 basket
Grn = 121 cone assembly in E120 basket

2.0 cu ft vented with B212 filter

[BooBoo Magoo]

Maximally flat vented alignments.

Red = 121 cone assembly in 121 basket - 1.65 cu ft tuned to 26 Hz
Grn = 121 cone assembly in E120 basket - 0.95 cu ft tuned to 32 Hz

[BooBoo Magoo]

E130 and E140 are 1 dB higher nominal flux than others (1.35T versus 1.2T) and will definitely yield a different response with other cone kits, typically 1 dB more midrange (piston band efficiency) and 1 dB less bass (low frequency damping). Any change is the customer's choice and liability.

A design goal of the 121 was to extend VLF response compared with the 124/2203. The 121 and 124/2203 shared the same magnetic assembly, basket, cone, voice coil and surround. The 121 had an additional 60 grams added to the mass controlling ring and the spider was significantly stiffened. Using a more powerful E120 basket would be counterproductive to the design intent of that particular cone assembly. It is possible however that an end user would not be able to discern a difference.