Some very "wishful" prices listed here for used gear. I especially enjoy the SP-3 listings...some say A-1, some do not. First of all, they were $595 when I started selling them. They went to $695 and then $795 (A-1 version). What many do not know is that we dealers were sent kits to upgrade the SP-3 units in stock to A-1 levels. I did this at my desk with a soldering iron. I think the kit was free to us, and it consisted of about 6-7 parts as I remember (someone can let me know if I remember correctly--it was 1974-5, so a LONG time ago).
The funny thing is that the prices asked for some of these are higher than newer and, frankly, better ARC pre-amps--specifically the two-chassis models and some of the newer Reference Series models.
Obviously, as a seller, you can ask any price you wish for an item. Wise buyers will recognize the silly price and choose another item.
Personally, I still use an SP-6B and would love to find a good D-150 I could afford!
I see a number of EC-21 crossovers, which I searched for over the years and finally found one. Funny! Also enjoyed the many "AR" cone speakers listed. Whatever...
Many of these are from overseas, thus are not compatible with US power unless converted. I have no idea how that works, but I am sure others do.