Mechanical analog computer history...Heathkit

On Wed, 9 May 2001, Bruce Ray wrote: To tell the truth, I dunno that one. The EC-1, a small table-top unit with 7 (or9?) opamps seems to be available without a lot of searching. A year or so ago I turned up three or four of them in the $200 ->$500 range. So they're out there. Several Listmembers own and operate them, so they would be better able to give you the Heath Part Numbers of the manuals. Doug...? The EC-400 docs I had accumulated went to Germany with the machine, so I have no record now of what the exact PNs of them are. Again.. I was very kindly assisted in this matter by two Members, who might also be willing to step in and provide that specific info. Since the EC-400 was also sold as a (really big!) kit, there is a book for each module model ordered aith the unit... not all EC-400 had the same module complement. Then there was the overall assebly book and one (or more) Operator's manuals. If you are going to find and use an analogue computer... there are others out there as well... EAI, ComDyna, Systron-Donner, etc... but there are also some very good basic texts, mostly from the 50's and early 60's.. on the art of Analogue Computing. An abebooks.com or bilbliofind.com search on "Analog Computing" or 'Analogue Computers" will turn up some likely titles. And, a couple of years ago, I had a bit of correspondence with a gentleman who was building an analog machine from scratch using 741 opamp ICs... I wonder what became of that? Good luck in finding a Machine... if analog computing texts turn out to be elusive.. my small library of such texts also accompanied the EC-400 to Germany, so perhpas I can persuade the New Owner to give you the titles and authors to refine your search. I'd still own the EC-400, but I'm currently living and working in India, and I didn't think it would fit in carry-on baggage. :) Cheers John