On the Emulation of TU58s

[Paul Koning]

> On Jun 16, 2015, at 12:10 PM, tony duell <ard at p850ug1.demon.co.uk> wrote:
> 
>> 
>> As long as we're talking philosophy, what do y'all think about emulating the TU58 drive, vs. emulating the TU58 > *tape*?
>> 
>> I cannot properly express my opinion of that tape cartridge design even if I violate list rules about use of 
>> profanity. But the drive itself isn't all that bad, aside from not having enough motors to manipulate a 
>> well-designed tape cartridge mechanism.
> 
> The tape cartridge (along with QIC cartridges, etc) is an interesting design. Of course the general problem is 
> to run the tape at constant linear speed past the head while winding it off one reel onto the other. In general
> there have been 3 solutions to this.

Another solution is to avoid the problem entirely by not requiring constant linear speed.  That’s what DECtape (the real one) does.
> 
> One is to drive the tape itself using a capstan and maybe a pinch roller. Then have the takeup spool
> driven too fast with a slipping clutch in-line. And a weak brake on the supply spool. This of course is what
> was done in audio recorders (reel to reel and cassette), Video recorders (ditto), etc.

Or a variant: drive the takeup reel with a controlled torque motor and no slip clutch.  I think professional grade tape decks may have been built that way.

	paul