Just my two cents, but I think you would be better off to sell them as is vs. spending money on mods. The mods can be fun to do, but most people that are in to speakers like the A-7's will be DIY'ers anyway and will want to take on the project, not have it already done.
For what it is worth, they were never my favorite loudspeaker. I used them for PA duty with various bands in the late 60's and early 70's, and they were decent, but not stellar. Most of us gave them up when better stuff from JBL came out.
I worked in a stereo shop in the early 70's and sold one pair through that store. We set them up in our listening room and tried them with all sorts of amp/preamp combos. They sounded good with strong dynamics, but there was no getting over the "shouty" sound of the horn and the bass was a bit limited. Again, not the best sounding speaker in the store in my (and the other listeners) opinion, but they are a legend - for live sound, the first full range easy-to-drive PA speaker that could be moved relatively easily.
For what it is worth, they were never my favorite loudspeaker. I used them for PA duty with various bands in the late 60's and early 70's, and they were decent, but not stellar. Most of us gave them up when better stuff from JBL came out.
I worked in a stereo shop in the early 70's and sold one pair through that store. We set them up in our listening room and tried them with all sorts of amp/preamp combos. They sounded good with strong dynamics, but there was no getting over the "shouty" sound of the horn and the bass was a bit limited. Again, not the best sounding speaker in the store in my (and the other listeners) opinion, but they are a legend - for live sound, the first full range easy-to-drive PA speaker that could be moved relatively easily.