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 Post subject: Re: 3M Germanium Transistor part numbers
PostPosted: Feb Mon 12, 2018 2:46 am 
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Joined: Dec Tue 26, 2017 5:16 am
Posts: 16
“I with I still had that kind of ambition”

— One thing I am learning about getting older is, whatever your body and mind tries to dissuade from doing is exactly what you should do not feel like walking any more? Walk is what you need to do! Ambition failing? Do it for the sport of it anyways, soon enough the ambition comes back. (Maybe too obvious a “self-help” message in so sophisticated a forum but I find you can never hear it enough.)

“To try and get back on topic... there was another 3M Cantata like product on Ebay. The Message Repeater.
Maybe you saw it. It sold for $50

I just looked it up. Cannot really tell what it does but 3M must have been such an innovative company back then! Most people (including business schools) give the example of their Sticky Notes but these are even more impressive. Or this:

I found 20 of the tapes (hopefully the machine too one day!). On a lark, I transfered one of the tapes to an empty cassette shell. They do not fit 100%, maybe 3/4s. But because the tape is 1/8” and runs at 1-7/8 ips, a cassette player plays one of its two channels perfectly. If there were enough good stuff available, I would make a special cassette player with a full width, 2-channel playback head.

 Post subject: Re: 3M Germanium Transistor part numbers
PostPosted: Feb Mon 12, 2018 9:02 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 356
Location: los angeles, california, usa
I believe the 3M Message repeater was used to interject advertising messages over Muzak in department stores, or elsewhere. Remember "Attention K-Mart Shoppers!".

The 3M Revere M-2 cartridge music system. I have it in my eBay saved searches. They pop up from time to time. The last one was in a carrying case which looked kind of scuffed up. The unit though looked to be in mint condition. Not a scratch on it. It was priced at $150.00 and I didn't have the extra cash laying around. I cannot remember now if it was an auction or buy it now, but it was pulled and disappeared from ebay's records.

Funny thing about 3M and Revere. I remember reading that while 3M owned Revere Camera Company later on, both product lines were manufactured at the 3M factory under both names. Oddly they were competing against each other.

Donald R. Resor

 Post subject: Re: 3M Germanium Transistor part numbers
PostPosted: Feb Mon 12, 2018 3:01 pm 
New Member

Joined: Dec Tue 26, 2017 5:16 am
Posts: 16
Right now on my “restoration desk” I have 1) Two RCA SCP-2 and 2) One SCP-3 cartridge recorders 3) a 3M Cantata player 4) a Telex 8-Track changer and, of course, I am looking at the Revere M-2.

These are all amazing machines, marvels of mechanical logic. But they are also dinosaurs. They all work on brute force, with giant synchronous motors and 1940s style idlers. Comparing that to a near contemporaneous Philips cassette player, the contrast could not be starker. Interestingly, the Philips is also infinitely easier to fix, should there be one that does not already work. Its lightweight construction required no heavy grease that turned to glue with time and it is simply easier to handle. Whereas the RCA uses fabric slip belts, impossible to change without complete disassembly (IF you can find a replacement), the Philips has a felt slip ring for the take-up reel.

I have a 1963 Pontiac LeMans. It is an oddity in that, in a Detroit dead set on manufacturing live axle, prewar style cars, it has a transaxle, an incline 4-cylinder and a flexible drive shaft. It only lasted two years before GM went back to a live axle on that model too. Signs of hard times to come for the US industry were on every wall.

 Post subject: Re: 3M Germanium Transistor part numbers
PostPosted: Dec Wed 05, 2018 9:17 pm 

Joined: Feb Mon 06, 2012 7:24 pm
Posts: 2661
Location: Gold Country, (Stanislaus National Forest) California 95235
Tiptop wrote:
Cantata 700 also has a timer inside to start and stop it every 20 minutes.
There's another similar BGM system whose name escapes me at the moment that actually stops the tape for about a minute or 90 seconds depending on model. This is so - even though the songs would still be in all the same order - they wouldn't be at exactly the same time everytime it was played.
Tiptop wrote:
I took the tape out of one cartridge (which required repairs in any case) and tried playing it on an auto-reverse reel to reel. Interesting that even though tracks are laid out the same as regular 4-track, they are reversed in direction — music was playing backwards on all four tracks.
Four track/stereo or four track/quadraphonic? On a FTQ deck the front (1&3 corresponding to normal stereo on an FTS deck) should play backwards and the rear (2&4) should play forwards. Which of course would play backwards again if flipped over and played as Side 2 on an FTS deck.

You can easily tell what you have by playing the reel on a 4-track inline 4-channel deck and recording it onto an e.g. Tascam 424 MK 1 cassette portastudio - then take that cassette and play it in a Talking Book player for the blind. If all sides play correctly whether auto reverse or not - you do indeed have a 1:4/2:3 configuration.

On a normal deck - if both are backwards you have a 2:4/1:3 configuration. If both the LEFT tracks are forwards and both RIGHT tracks are backwards you have a 1:4/3:2 configuration and if the left is forwards and the right is backwards on Side 1 and vice-versa for Side 2 - you have a 1:4/2:3 configuration.

When I was first diddling with these back in the Paleozoic Days (ask my little grand nephews) I can't remember now the exact Akai model number it was - but it was in the 330D 630D family of 3-speed decks with a 4th speed you could get by removing the capstan sleeve and swapping out the pinch roller.

One of those both had 4-channel heads as well as the previously mentioned 1-7/8 IPS speed. I can't remember now whether it was quadraphonic and we just tapped out of the rear channels to get 2 mono forwards programs or whether it was stereo and the lower heads could be selected independently of the tape direction and we tapped off that way.

I DO know that we tracked it onto a 10-1/2 inch Teac 4-channel 3340 leftover from the music dept and used up all the equally leftover chrome LPR 35 CR tape to do so. A couple of years later we got a second 3340 and did it again patching the front to the rear and the rear to the front so all four sides would be forwards and set one at 7-1/2 and the other one at 15 so we'd end up with a 3-3/4 tape we could play on more machines than the 1-7/8.

In junior college we ran across a similar format but this time the forwards tracks were THREE and 4 instead of 2 and 4 and vice versa so we just re-patched and went about our business that way as I'm sure the mfgr did the reverse of to go from the half inch normally produced 4 track bin loop master onto the release dubs when making the original tapes.

When you get to the background music tape cartridges that don't play right at ANY normal speed gimme a holler because I repaired a couple of 3/4 speed two speed players specifically for the purpose. The high speed version does 11-1/4 (normally 15) and 5-5/8 (normally 7-1/2) and the second one does 2-13/16 (3-3/4) and 1-19/32 (1-7/8).

These were done to get an even hour of a program on a tape that when run at a normal speed would only give 3/4 the time. Halving the speed in the days before real good head and tape technology had been developed was unacceptable but due to needing
Tiptop wrote:
to prevent playing on unauthorized machines
there wasn't a lot of other choices besides this and reversing Side 1 and 2 to where all programs would play backwards, at the wrong speed or both when played on a normal commercial player.

Since back then very few people had four-channel inline quarter-inch tape decks except maybe audiophiles and radio stations they were covered. When bands started getting into that and the music started getting copied, they had to go to 3/4 speed tape.

But by the time the Library of Congress went to half-speed 4-track cassettes with varispeed, and the background music people had done the same with their 1-19/32 speed cassettes, it was very easy to pop that cassette into a talking book player, varispeed it up from 15/16 or down from 1-7/8 and record it real time onto a normal cassette (doubling the volume i.e two C-60s for each M-60 background music tape.

By then 4-track micro-cassette players were out as were the quarter speed Norwood type audiozine walkman type standard size cassette players. I used to take short ends off the chrome pancakes leftover from the duplicators, get the empty shells and load my own, then take these 4-track and odd speed mono background music cassettes, dub them to quarter-speed and get 6 hours or 12 hours on one C-90 or C-100 cassette since you could switch the feed from A to B and it would play over both sides of the headphones.

Everybody else had a huge bag of different cassettes I had like three tapes total in my pocket at any one time - so for awhile there - a whole bunch of kids were raiding their Dad's audiozine players that hadn't been used in forever laying at the bottom of a closet to get trod on and broken.

And don't forget the PolyConcept (RCA/Spirit of St. Louis) 1/8 inch 1-7/8 IPS open reel/CD decks that were out for awhile. Those only existed because the BGM people were looking for longer play in a smaller pkg in the days before cheap digital - so they had thousands of these decks commissioned which used the normal 1/8 inch cassette tape and the normal track configuration so they could use the current duplication houses.

That died a quick amd merciful death too after a couple years but now they had thousands of the transports left over. Somebody said `There's no CD changers out yet that are any good - we'll just put a radio and a CD deck in here and sell em to people who want to make their own 6 hour at a time programs.'

Everybody I knew that bought one had done the same thing years earlier on either their VHS Hi-Fi or F-1 units and could just put one on hit Record and set back.

And making your own Child Guidance Talk N Play tapes and your own Pocket Rocker tapes and your own Elvis Doll/Wurlitzer Toy Jukebox tapes and etc etc etc.

Same with the vertically modulated 16-inch transcriptions in the 30s and the 40s that were both the wrong type of modulation and the wrong size as well - or the Seeburg discs w the 2 inch hole that was too big or the 24 RPM disc recordings like in an Edison Voicewriter or the inside out recordings or ones that played with an underside mounted stylus like a CD or LaserDisc because the disc recording was counterclockwise etc etc etc.
Tiptop wrote:
re Message Machine - I would make a special cassette player with a full width, 2-channel playback head.
You can get by reasonably well with either a 1:1 real time Telex mono cassette duplicator like they used to have at church or school in the 60s to duplicate both sides of a mono cassette at once, or else you can do the same thing on a Grundig DCI cassette deck some of which have twin-track playback capability - both of of which I used to use in order to make cartridges for
Monarke4 wrote:
The 3M Revere M-2 cartridge music system
and the hoard of empty PlayTape and Revere cartridges that I inherited along with the players from the aforementioned school after the formats died a quick and painless death.
As far as
Tiptop wrote:
RCA Quick-Load Cartridge
in the early days of eBay there were several boatloads of empty unlabeled cartridges and blank boxes I got off a guy that used to work at Ampex Chicago where they duplicated the prerecorded tapes at.
I still have hundreds of them left over.

Occasionally I'll do a real-time dub off a reel to reel or CD onto the aforementioned LPR-35-CR chrome reel to reel - load it into the shell and give it to somebody with a player (or play it on my all wood Executive model) just to trip people out over how ``fabulous'' the 3-3/4 sound is. (ROFL)

There's also BGM systems both 4 track as well as 8 track that not only run a reverse left hand drive version of a Fidelipac cartridge - they run them at the same 3/4 speeds discussed above - so those are fun to run into as well along with the Akai MG 1212 Lambda version of a 12-track audio version of a Betamax that was in portastudios for awhile.

They had a left-side drive version of that as well so in the days before digital audio workstations you basically had to flip the tape upside down on one side and rewind to play it in a normal 1212.

Since IT was 3/4 speed as well, you either had to either find or make the drive pulley and belt in order to play it back on a normal 1212 or else you had to do like we did and get a one-inch 16-track with varispeed recording (very hard to come by most only had varispeed playback) set the speed for 1-1/4 times the speed and record that way which - since the playback would be 25% fast and the recording would also be 25% fast would result in a normal-speed dub from which you could then work.

And finally we have the CD that has 37.7 KHz and either 12 bit or 14 bit encoding instead of 44.1 16 bit - which you can retrieve by piping it through an F-1 portable digital recorder.

And now we have CD rippers MP3s and Torrenting.
So they didn't stop it - they just slowed it down a little bit for awhile.

2 kinds of men/tape. Low Noise/Wide Range.
LN=kind. WR=abrasive. Engineers=same thing.

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