I remember those! I interned in a radio station in high school.
These delays were implemented with a "cart", an 8-track-style cartridge. The carts were usually used for commercials and occasionally music. They were cut to a minute or several minutes of 1/4" tape, specially lubed for repeated use. The delay unit was a specially wired cart machine.
The tape delay cart was just a cart with a very short loop, like 3 or 7 seconds. The cart machine had read and write heads and erase heads. The layout was, read, erase, write. So the delay machine would write the material from the write head, the tape would loop around, the material would be read off of the read head, then erased. If you turned the erase head off you'd get Frippertronics-like effects.
The carts would wear out fast, and in the course of a live show you'd have to replace them often, like every hour or so, usually during commercial.
The boards were wired up with sends so you could send the whole program thru the delay.
I remember the boards, usually an RCA BC-7A. The pots were huge and made of bakelite, and they had gold contacts in a radial step pattern. They were already ancient by the time I touched one. If you potted things up slowly you could hear the stepping.
Dunno why I just remembered all that from 30 years ago, but thanks for jogging my memory.
Fons Adriaensen wrote:
>On Mon, Jun 23, 2014 at 08:58:22PM -0700, Ken Restivo wrote:
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