[78-L] recording times

[simmonssomer]

Changing the subject from cassette to reel to reel specs for those long gone 
days of yesteryear, I have an old three speed Tandberg 6000X  reel to reel 
in the basement which recorded at 1 7/8, 3 3/4 and 7 1/2 IPS. Even at 1 7/8 
it delivered freqency response of 50 to 9,000 hz. +/- 2 dB.  S/N ratio was 
64 dB at 7 1/2 IPS.  Amazing decks for the time. .  At 7 1/2 IPS frequency 
response was 40-20,000 Hz +- 2dB.   It handled 1200 or 1800 ft reels and 
could record in stereo or four channel mono.
Tandbergs were cutting edge back in those early 70's, and if I recall, it's 
specs outdistanced all consumer tape technologies at that time.

Al Simmons

----- Original Message ----- 
From: "Michael Biel" <mbiel at mbiel.com>
To: "78-L Mail List" <78-l at klickitat.78online.com>
Sent: Thursday, October 09, 2008 1:49 AM
Subject: Re: [78-L] recording times


> 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 o
> nly 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.
>