[78-L] recording times

[Michael Biel]

Swamp Daddy wrote:
> Joe:  Do you recall the days when casette decks had 2, and even 3, speeds?   Current decks have only one, the ultra slow 1-7/8ths ips.   Mine (an old Sharp) has 3-3/4 and 1-7/8 ips speeds (and I use the higher speed for my work).  When this deck fails again (it has been repaired a number of times), I may have to consider other means.
>   
As you will see below, this machine comes late in cassette history.  
With one exception, cassette machines were 1 7/8 only throughout the 60s 
and most of the 70s.

> >  The dust heap of technology has many, many things that came and went "quickly".   Most of them deserved "the went".  The odd, 3rd speed was the next one up:  7-1/2 ips. 

On cassettes?  Only on the recording board type machines, perhaps, but 
some of those tried to use the El-Cassette.

>     The main criteria for sucessful recording technology is "recording time".    Reel to reel started off I don't know where; but, when I first learned of it (before I could afford it) the speeds were 30 ips, and 15 ips. 

Actually, the first speed for plastic tape was one meter per second in 
1935.  (Which reminds me, I need to get back to the German researchers 
what the diameter of the capstan on my AEG Magnetophon is so we can see 
if it is a 1 meter or 30 IPS machine.  They dropped down to 30 -- 
instead of going up to 40 -- around 1938, and although my machine was 
made before that, it might have been modified.)

>   As recording technology improved (primarily in the heads back then)

and also the tape.  The tape BASF made for AEG had particles that were 
too large for high frequencies at slower speed.  3M and ORRadio were 
able to make better tape with finer particles post war here in the U.S. 
>  speeds went to 15 ips and 7-1/2 ips (more and more time on the same tape).  
Ampex, Stetchell-Hoffman, RangerTone, and Magnacord realized they could 
drop down to 15 IPS for pros, and Brush and Eicor realized they could 
use 7 1/2 for amateurs.
>  Still 'reel to reel' was the esoteric end of the hobby as LPs were preferred by most for both fidelity and convenience.    Electronics were getting better all the time meaning better fidelity and less hiss and high end harmonics; and, before you know it 3-3/4 speed was introduced which gave 60 minutes on a 7" reel (from a half-heimers memory on this one).   Now most consumer machines would have only 7-1/2 or 3-3/4 ips speeds. 
As tape continued to improve in the late 40s most machines dropped a 
lower speed down to 3 3/4 for amateurs.  But then came the big 
surprise.  I have a Revere T-100 from 1950 that is single speed 1 7/8.  
Most 100s are 3 3/4, but this one that I have was a special option that 
I don't see in catalogs -- but the machine exists and has painted 
time-guides for that speed.
>   My first machin
>  e was a Wollensack that had 15, 7-1/2 and 3-3/4 on it;

What model could that possibly be?  I have never, ever seen a Wollensak 
with a 15 ips speed let alone a 3 speed one, and I doubt you could come 
up with a Wollensak or Revere I have never seen or been inside of.  This 
includes the rack-mountable Revere which could take 10 1/2 inch reels.  
And that one model was the only machine that company ever made that took 
larger than 7-inch reels, and it is impractical to use 15 IPS with only 
small reels.

>  3-speed machines were not rare; but, not commonly used either. 
Are you kidding?????  You are talking about the 1950s, aren't you?  
3-speed machines were practically unknown until into the 1960s.  Even 
professional machines were -- and moat still are -- two speed.  Many 
don't even note the speeds on the speed switch.  Look at Ampex's.  
You'll find the speed switch just say High and Low.  You had to select a 
different motor on some or go inside on others to select which pair of 
speeds you wanted, either 7 1/2 and 15 or 7 1/2 and 3 3/4.  The 200 and 
300 might have had an option for 15 and 30.  The tube type 600, 601 and 
602 were all single speed.  The AG's were two speed, and boy was that a 
lousy mechanism.  The Magnicorder PT-6 was a single-speed machine which 
COULD be changed to 15 IPS by screwing on a larger capstan sleeve.  
Later ones might have had a 3 3/4 capstan with two sleeves optioning 7 
1/2 and 15 like the Maggi M30-33 had..    The only professional machine 
I know of from the 1950s that was 3 speed built-in is the 
Presto-designed Joint-Army-Navy.  I have one downstairs.  I'm not sure 
if the civilian Prestos7 are 3 speed. 
>  Reel to reel probably reached a peak when 4 track recording came in and was of decent quality (meaning 2 tracks for each direction doubling playing time without mounting a new tape.)
>   
This was needed to bring pre-recorded stereo tape down to a reasonable 
price point vs. stereo discs.  The first 4-track machines hit the market 
practically the same month as single groove stereo discs.

> Next, attention was paid to the convenience factor (as many objected to the laborious threading of tapes, possible damage, etc.)  It was noticed that most dictation machines were running at either 7-1/2 or 3-3/4 ips.
Once again, BALONEY.  NO dictating machine EVER ran at 7 1/2.  NONE.  
EVER.  NEVER.  I've seen reel to reel dictating machines from the 1950s 
at 1 7/8 and 15/16.  Some were at 3 3/4, but you have to remember that 
it is important to be able to play words or phrases in dictation over 
and over and over.  Too much tape moves at 7 1/2 to make it convenient.  
(There is an irony, however.  The 1939 report that General Electric made 
on the AEG Magnetophon -- the exact machine I have down in my basement 
-- was not very complimentary.  They called it a glorified dictating 
machine.  A 30 IPS or 1 Meter/S dictating machine!!!  The German 
researchers and I are still trying to figure out what was wrong, but it 
is a pre-bias machine.) 


>    So attempts were made to increase the fidelity on casettes.   This was achieved (and the 8 track slid in here for awhile because of the convenience factor, especially in cars); 
Your time line is screwy because there are many other pieces in the 
puzzle.  Before the Lear-Jet 8-track was the the car use of the 
Fidelipac cart as a 4-track.  Both of these were at 3 3/4.  But before 
these was the CBS-Revere single-hub cartridge im 1961 which used narrow 
tape at 1 7/8.  Prior to this was the RCA Cartridge in 1959, which was 
at 3 3/4 but was double-hub like the cassette became.   The continuous 
loop Fidelipac and Cosino carts had been used starting in the 50s for 
broadcast use at 7 1/2 with a re-cue tone designed by ATC.  The carts 
themselves had been invented for background music systems usually at 3 3/4.

> but, it was realized quickly that 7-1/2 and 3-3/4 would NOT allow the proper recording times on then available casettes.  This would make consumer acceptance low at best.
There never was any thought by Phillips to use any speed other than 1 7/8. It was an integral part of the design. The Philips Compact Cassette was a merger of the RCA shape and the CBS/Revere narrow 1 7/8-only tape. Until their patents ran out they didn't allow ANY manufacturer to make a machine that was anything other than 1 7/8 only  (except for LC when they threatened the Dutch company with dire consequences because they are the Library of CONGRESS).  There is another reason for their use of 1 7/8. Prior to the first cassette machine -- known here in the U.S. as the Norelco Carry-Corder 150 -- their battery portable was the Norelco Carry-Corder 100 which was a strangely designed machine which used only 3-inch reels at 1 7/8.  They had been working on this slow speed for a number of years, and in the early 60s were starting to offer it on their larger open reel machines as a 3rd speed.  In their research they realized that if the machine, heads, and tape were designed for only that one slow speed they could get better quality at that speed on single-speed machines than multi-speed machines.  The heads on multi-speed machines are compromises, and so is open reel tape stock.  Ideally, the tape stock for cassettes is especially designed for that speed.  


> In a short period of time when several manufacturers saw a good potential for this "easy to use" medium of casettes these problems were solved and audio casettes were standardized at 1-7/8 ips at decent fidelity. 
As I said above, the 1 7/8 speed was selected before the first machines 
were made. 

>  Better tapes, better electronics, etc.  And, even the shortest tapes would do 45 minutes (more than enough for an LPs worth of music).  

They could have gotten that time length at a faster speed.  That is not 
why 1 7/8 was chosen.

>  And, all pre-recorded music was/is done on 1-7/8 ips by agreement.
>
>   

ALL cassettes and machines were at 1 7/8 by LICENSE.  Philips would sue 
your butt off if you even thought of making a machine at a different 
speed.  You were not allowed to make a machine unless it was 1 7/8 speed 
only, and initially they also required the tape stock to be designed for 
the slow speed but this was not strictly enforced.  These restrictions 
lasted only as long as their design patents lasted.  Nakamichi got away 
with their dual speed machine -- the first on the market --  by not 
applying for a license. knowing that the last patent was set to expire 
in 6 months. 

> And DL is totally correct.  If you have a collection of Hi-Fi mags going back a few decades you will see amazing things in them that did NOT make it despite being bally-hooed about.  I recall the arguements (which still may be going on) among tube fans amplifiers about push-pull, class A, class AB, etc.
>
> Swamp Daddy
>
> PS-I don't claim to be the expert in all these areas; but, I've lived through these eras and read of most of these items many times over.  I've even owned a few of them.  In the last move (about 9 months ago) I finally got the nerve to throw away most old magazines I'd kept for years.  In hobbies other than audio too.
I haven't thrown out the old magazines.  I use them to double check my 
research, along with catalogs and spec sheets.   My daughter is starting 
to do a research project into classical records of the 48 to 68 era to 
help one of her professors, and she is starting to go thru all the mags 
and books and catalogs. 

Mike Biel  mbiel at mbiel.com