[78-L] half track tapes

[David Lennick]

Then somebody invented butterfly heads and the CBC bought Studers that had 
them, and all my nice tapes recorded at home on the Revox or Teac had problems 
if they'd been bulk erased because the Studers picked the WHUMP WHUMP WHUMP 
down the center channel.

Wollensak memories: My dad went through a few of these, starting with a 
half-track mono machine in 1959 and a quarter track model the following year. 
The pressure pads were always wearing out or falling off, so he'd "borrow" a 
felt hat from my little brother and trim away a little bit of the brim to make 
new pads. That hat got pretty narrow within a couple of years.

dl

Michael Biel wrote:
> At 09:41 AM 8/8/2009, you wrote:
>>> Remember the Wollensak with its dial for shifting the playback
>>> head down a millimetre or two to play half-track tapes with
>>> equal balance? Any other machines have a feature like that?
> 
> From: "Robert M. Bratcher Jr." <bratcher at pdq.net>
>> Which model is that? 
> 
> Wollensak T-1515-4, T-1616, T-1580 (I think that's the number), and
> several Revere's -- the stereo playback versions of the single knob and
> the pushbutton models if they have a suffix "-4".  All of their stereo
> playback machines from 1959 onwards were this way until they started
> making machines that recorded in stereo, and they also sold an adapter
> head-set.  The major purpose of the "Head Track Selector" was to enable
> the recording on the lower tracks on these machines which only recorded
> in mono.  This gave you four mono tracks, but they played back in
> stereo.  Since the 2-track tapes were so common back then, the extra
> notch to lower the head just slightly was quite handy.  The BEST thing
> these things could do was search out the best part of the tape for
> warped full track tapes.  It is still a very valuable technique to play
> back old full track tapes.  (The second best technique archives use is
> to have a quad-four head and pick out the ONE track which is the best.) 
> 
> 
> There may have been a mistake in an earlier posting about which track
> was weakened when playing a half-track stereo tape on a quarter-track
> machine.  It is the RIGHT channel which is weakened.  The Guard-Band
> space in-between the tracks is wider for stereo then it is for mono half
> track.  The lower track of the 4-track system will hit half on the
> guard-band and half on the lower track of the 2-track stereo tape, so it
> needs to be slightly lowered.  This also has the benefit of moving the
> upper track away from the edge of the tape which is where physical
> damage can first happen.  It also helps when recording a tape to be
> played on the full track Ampex portables 600, 601, and maybe the 602. 
> These machines had a slightly curved play head which avoided the upper
> and lower edges.  They completely miss the upper quarter-track.  The
> record head is flat and records the full width of the tape, but since
> portables might be working with damaged tape, this helped make the
> playback of full track tapes more consistant.  There might have been
> head-bump compensation.   
> 
>> I had a worn out Webcore Music Man that would shift the playback
>> head with a lever on the back of the head assembly. Threw it
>> away when it stopped playing tapes at 3.75 ips & was having
>> trouble with 7.5 ips. Belts were shot really bad but then 
>> I got it for free.....
>  
> The Wollensak/Revere device moved BOTH the Record/Play and the Erase
> heads.
> 
>> Today, of course, you just look for a Technics 1500 with the quarter-
>> and half-track playback heads. Still quite a few of them out there. dl
>  
>  Yes for 1.5k to 1.7k on the bay site. 
>  
> The Otari 5050 machines had an extra quarter track play head in the
> second of the 4 head blocks.  It was standard equipment until the Mark
> IV, when it became an option WHICH NOBODY TOLD ME WHEN I BOUGHT MARK IVs
> FOR MY SCHOOL.  So those last 4 machines have only three heads and
> screwed me up for playing my home recorded tapes.  I had to use the
> earlier ones we had there.  By the way, the record and play heads are
> exactly the right spacing for Staggered-Stereo playback!!  Set one track
> on play and the other on Sel-Rep and it will play them!!
> 
> Mike Biel  mbiel at mbiel.com
>