Nobody except us old grey-hairs know anything about ORTDs. And the market for them except in very narrow circles in the professional trade is dead. In the pro trade they are still in use for archives and sometimes as a signal processor to create a different "voicing" for a given digital track.
BTW I restored an old Webcor wire recorder for a studio engineer that planned to use it as an "effect" with guitar and vocal tracks. I completed the job and found some fascinating stuff on the spools he provided. There was a blank spool or two that I suggested he use instead of the ones with recorded material that he should perhaps save.
In procuring an ORTD bear in mind that replacement parts for many of them may be unobtainium.
To give you an idea of how soft the market is on ORTDs I got for nothing a Berlant Concertone transport with one mono electronics unit, but the transport is fitted with stereo heads--IIRC, and the PO was looking for another electronics unit to complete the thing. He was a pretty savvy old dude that had a prominent position with Philips before retiring and running a tree farm here in W MA. And had been a long-time customer of mine that ran many interesting pieces of vintage tube gear by Fisher, Scott, etc...Then his health finally failed him at about age 80, and he called me to come take a lot of stuff away--including the Berlant.
I received a Crown ORTD under similar circumstances--for zilch. I gave it to a friend of mine that would appreciate it. I am up to my armpits in ORTDs--mostly of Teac parentage...
Oh and any vintage recorded reel tape collection is worth its weight in gold--IMHO.
