Mid-range replacement/repair

[onkyoman]

Hi, I have a pair of JBL R-133 speakers that I bought new sometime between 1981 - 1982. A few years back I had the woofers re-coned and radiators replaced mainly from moisture/rotting issues from being in storage for a long period of time. They have since sounded great, just like new, but recently the mid-ranges are showing the same kind of wear. They are stamped 305G-1. After doing a little searching Harmon said they have a 305G-3, another speaker company in Calif. said that that those have been replaced by a C1003. Now I just want to make sure that I get the right replacement (size as well as quality) OR whould you suggest repairing the ones I have? (the Co. that did my woofers is no longer around).
Thanks in advance, Dave

[duaneage]

The C1003 is used in the Control1 series today. It is a 4 inch woofer with a shielded magnet. I am not sure if it would be a drop in replacement for what you have but your choices are limited.

I would suggest scouting eBay for replacement drivers like what you have.

The C1003 has a strange impedance curve that goes very low, around 2.3 ohms, in the midrange band. The crossover network for the woofer uses a .2mh coil, a 4 ohm resistor, and a 20 uf capacitor to smooth out the midrange response a bit. You would definately have to rework the crossover network for them to sound right.

[GordonW]

I'd be inclined to go with the 305G-3. The 1003 just isn't designed for that little back-chamber.

Regards,
Gordon.

[onkyoman]

Thanks all for the replys.
Harmon finially got back to me and said according to them a 305G-3 is an 8" woofer and the 305G-1 is a 12" woofer???????
Alot of help they turned out to be, I think I will be better off just checking the classifieds and ebay every now and then

[norealtalent]

I have a box of NOS consumer replacement speakers. If you post a pic of yours I will tell you if I have a pair .