Radio Mystery: The Echoplex from Kahn Research Laboratories

 I saw this ad in the December 1965 issue of QST (50th anniversary issue), page 159:

But other than a blurb I found in the October 26, 1962 issue of Electronics magazine, page 90:

I found no other information on the Echoplex on the internet.  There is another item called the Echoplex but it's for adding reverb to sound using magnetic tape.  

The QST ad says it is patented but I couldn't find any of Leonard Kahn's patents that seem to deal with the Echoplex:

https://www.google.com/search?tbo=p&tbm=pts&hl=en&q=ininventor:leonard+ininventor:r+ininventor:kahn&num=100#q=ininventor:leonard+ininventor:r+ininventor:kahn&hl=en&tbm=pts&ei=uH_sT52YBcmB0QH1m9TnBQ&start=0&sa=N&bav=on.2,or.r_gc.r_pw.r_qf.,cf.osb&fp=123741d24e153dc7&biw=1024&bih=605

It sure sounds interesting although that $399.60 inflates to over $3700 today:

Also I suspect that the receiving station AND transmitting station would both require one.

Leonard Kahn was a famous engineer known for the Symmetra-Peak which was sold to radio stations.  W3AM has more on the Symmetra-Peak here and a design for a modern day op-amp version:

https://web.archive.org/web/20190430101941/http://www.w3am.com/8poleapf.html

I guess I'll never know exactly what the Echoplex did or how well it worked.

Best Regards,
Chuck, WB9KZY
http://wb9kzy.com/ham.htm