Hi to all; this is my first post.
It was at the end of the seventies when I got a look at JBL. Here in Germany I think JBL was known for live like reproduction of music and from advertising with the pros. From 79' to 84' I bought L50, 4301B, L112, L150A and I liked them all, with the L150A the best. Whish I had them today, because for some reasons I sold everything in the second half of the eighties.
About five years ago the HiFi virus got me again. After various apeakers (diy and factory built) I came across a pair of 4301B, which were in really good condition. With some oiling of the veneer and a kit from Rick for the 116H woofers they looked like I bought them new two weeks ago. They sounded good, not only for nostalgic reasons, especialty in the bass part.
While reading in this forum I found the schematic of the network and decided to change to some better parts. I changed the tiny 1.2 mH iron coil to an air coil with 1.4 mm Wire (0.3 Ohm) and the 0.4 mH iron coil to an air coil with exact the same dcr.
For the caps I took intertechnik MKP's. (15+1.5 and 6.8+0.22). I also added to both 0,01 Vishay Roederstein caps because this can't hurt and they are cheap.
The result was readily audible in the whole range. The already good bass was crisper and clearer as well as the midrange. Subjectiv the LE26 sounded as if it went to 17 or 18k without any harshness.
So for its size and money I think this smallest of the 43xx series can hold its own against many others, new or old.