I'm sure that tape pack and holdback tensions do create minor speed variations across the heads for the length of a reel, but none that can induce a pitch change as great as I experienced when the Scully was running from head to tail with a musical drop of a half-step in pitch. I know that _was_ consistant, since I had opening and closing show music cues that I could check that exhibited the same pitch change.
Richard L. Hess wrote:
Rod,
I'm sure you know, but I'd like to point out that in constant torque (as opposed to constant tension) machines, this speed variation was variable throughout the tape pack.
Classic Ampex machines were mostly constant torque. There was a constant tension option for certain versions of the AG-440.
Cheers,
Richard