[QuadList] Capstan Information

[Don Norwood]

Hi John:

I don't know.  I have a 3000 that turns out tapes that play just fine on 
1200's which as you know, have exactly the same servo as the 2000.  In fact, 
the 3000 tapes also play OK on an RCA TR-70.

>From your description, I'd have to guess that something was wrong in the 
3000.  A lack of frame pulses on the control track could do that, but I'm 
not sure what else might trigger it.  The 3000 recordings should definitely 
be on-speed if the servo is setup correctly.  Playback on the 3000 is 
another issue however.  It's good enough to verify the recording, but in 
playback the drum is referenced to an internal oscillator so it may not 
playback exactly on-speed.

The 3000 transport is an interesting design for that era of quad recorders 
in that the capstan is more of a "governor" than a driving element.  Most of 
the tape motion is driven by the reel servo system, with the capstan only 
providing slight braking or drive as needed to maintain the correct speed as 
determined by it's tach frequency.  The design helped to prolong battery 
life by not wasting current on a capstan drive, thus keeping the transport 
power consumption essentially to only the amount required to move the tape.

Don Norwood
Digitrak Communications, Inc.
www.digitrakcom.com

-----Original Message----- 
From: John M
Sent: Wednesday, September 24, 2014 11:54 PM
To: 'Don Norwood' ; 'Quad List' ; Chill315 at aol.com
Subject: RE: [QuadList] Capstan Information

Just as an aside, Don, we found playing back a tape from a 3000 on a 2000
required the use of non standard tracking on the intersync - this was the
case for all 6 of our 2000's. Our Avr1 and AVR 2 just played it - what was
the go here?

John Miller
Creations Unlimited
Rocky River
NSW Australia