I have a related question:
I have a Fender Twin with a couple of JBL K120's in them. Like all K120's they are about 35 years old, give or take. Anyway, when playing my "Jerry sound" through them, I am getting what sounds like a microphonic tube sound at the high end, particularly when I play leads on the high E, B, and G strings. It gets less pronounced when I dial down the treble a little. Anyway, my amp guy is doing a load of work on my Twin trying to track down the problem, but after checking all the tubes and determining none of them were microphonic, he thinks that the speakers might need to be re-coned. He is still not 100% certain yet, and has some caps to change and other issues to address with my old twin, but we are not incredibly optimistic about it, which means I may have to re-cone one or both of them.
Now my questions are as follows, and both assume that the speakers need to be re-coned, even though I am not 100 sure yet:
1. What are the differences between the K120 and the E120? I always thought Garcia used the K120's, but just recently found out that he used the E120's. I also always assumed that K being a later letter in the alphabet, would designate the K series as better than the E series, but I was told this was not true.
2. I heard that some JBL's can be re-coned with the other cones/voice coils. So if this is true AND the E120 is a better speaker than the K120, can I have my K120's re-coned with E120 cones and voice coils? I called Simply Speakers yesterday and I didn't ask them this, but I did get a price. The guy told me that it costs $230.00 each speaker plus about $18.00 UPS ground shipping for both, which comes out to about $500.00 for the re-cone.
3. He also said that when you re-cone you should absolutely change the voice coil, and that the price he gave me includes both the re-coning and the voice coil. Is this a decent price? Do you guys know of and/or trust Simply Speakers?
Thanks guys!
The Gods of JBL Luck. Let my good fortune not offend! 
