Yes, those old Ferrographs could be relied on no matter what. The BBC standardised on them and used them in every environment from rain forests to the Antarctic.
There's an interesting story about the 632H. (That's the stereo machine that played at 3.75"/7.5"/15" per second.) I saved up and bought the mono version (631H) as soon as I left school. It took months of saving, and I had to order it from Amateur Radio in Birmingham. A couple of years later I saw the stereo version on sale in Exchange & Mart for £95. I knew it would go quickly so I sent a postcard to the fellow in Southend, offering him £100. He replied by postcard saying that he'd had dozens of offers of the £95 but I was the only one offering more than he asked for, and could I come and collect it on Saturday. I didn't have a car, and on Saturday there was thick snow, so I set out on the bus for New Street Station, with a bag of tapes to use to test the machine, with wellies, a heavy raincoat, and a scarf. I cought a train to Euston, took the underground to Liverpool Street, and a train to Southend. When I got to Southend there had been no snow and it was blazing hot. To top it all I learned that he lived two miles from the station, so I set out, pouring with sweat, and everyone looking at me as though I was crazy, with all those clothes and wellies on a hot day.
I eventually reached the fellow's house. He was a classical musician who had been using the Ferrograph to record his orchestra. He was selling it because he'd bought a Levers-Rich 1/2" studio machine. I tried out the machine with my tapes of my chums and I strumming folk songs. But he was polite about it.
Then, after a couple of cups of tea I had to do the whole thing in reverse, but this time carrying, not only the test tapes, but the Ferrograph, which seemed to weight about the same as my Dad's Morris Oxford. But I made it home, and the Ferrograph was in constant use until I moved to California in 1980. I still have all the session tapes made on that machine, and they don't seem to have deteriorated over the years, (which I guess has more to do with the BASF tape than the Ferrograph.)
When I moved to California I realised that the two Ferrographs had to be left behind. Not only would they have cost a fortune to ship, but they were 240 volt units. I had no trouble selling them, and I imagine they're still in use to this day.
I still look on eBay, and maybe someday I'll buy another just for old times' sake. On the other hand, looking at retirement in a few years I might have the same problem in reverse; shipping them and all my other accumulations back to England.
