Gee, Fred, I didn't know we lived in different worlds! How interesting that the ARSC List is our 
"parallel medium." ;)

Anyway, to address your specific points ...

I thought if you have a loop with one big capstan drive and pinchrollers on the beginning (left side 
of the capstan) and end (right side of the capstan) of the loop, if you made the right one slightly 
tighter you'd loosen the tension in the loop, and if you made the left one slightly tighter, you'd 
tighten the tension in the loop. I'm no physicist (as I'm sure you'll remind me), so I might well be 
wrong about that. Since you seem to know, can you explain what mechanism would tighten or loosen the 
tension in the loop, and whether that would be desireable?

Also, do you agree with my theory that a tension-within-the-loop adjustment would be a way to 
flatten thin but warped/bent/cupped cassette tape against the heads for better and more uniform 
contact? Come to think of it, because cassettes are B-wind, could you accomplish this with a 
pressure roller gently pushing the tape against a play head at the bottom of the loop, just have a 
spring tension adjustment on the roller?

Finally, I never said there wasn't valuable stuff on cassettes that needs recovering, I just said 
that economics being what they are in "my" world (ie the real world), such a thing has never been 
constructed, to my knowledge.

Shai made a point, too, that he thinks you'd need to chop off some of the plastic in front of the 
exposed tape. I was wondering if you could keep the tension outside the loop so soft that you could 
just pull some tape out the middle of the front, in front of the pressure pad, and then gently spool 
it in and out with either very gentle reel drives or some sort of a servo system on the reel motors? 
This further driving the cost up and putting it out of economic posibilities in the world most of us 
seem to inhabit. That said, if you ever build such a thing, I'd sure like to see it in action!

-- Tom Fine

----- Original Message ----- 
From: "Fred Thal" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, June 27, 2012 12:50 AM
Subject: Re: [ARSCLIST] Cassette Tape Playback issues (was Free - Cassette tapes)

> Tom Fine:
>> the tape would be pulled out the middle of the shell and put in a little isolated-loop drive
> Transports to play Philips Compact Cassette tapes (loaded in-shell)
> with a loop pulled outside the shell have been built.
>> Better still would be a way to adjust the two pinchrollers so you could
>> vary the tension/wrap on the heads.
> Tension and wrap are never (intentionally) controlled by pinch
> rollers. Where did you get that idea?
>> Probably not worth rigging up such a beast for lowly cassettes.
> Perhaps not in your world. But we have seen instances where missing
> segments of original master tapes have been found only on the session
> safety cassettes.
> Fred Thal
> ATAE Studer / Audio Transfer Laboratory