A once common yet unseen device

i've got something a little bit unusual to show you today for a change no this is a bit out of the ordering this is the kind of thing that most people watching this the vast majority of people won't have ever seen one of these before and yet conversely the vast majority of people watching this will have probably used one of these or something very similar to it so a bit of a conundrum that and i thought rather than tell you up front exactly what it is i'll show you a few pictures of it and see if you can figure it out for yourself now it might help if i switch it on so i'll do that now that gives you a bit more of a clue as to what's going on i'm sure you could figure out that was tape in the top of it before we can see now that the tape is circulating around inside the machine now i'd imagine this guessing game is getting a little bit old quite quickly so i'll tell you exactly what this thing is now this is an announcement machine this is the machine that here in the uk the gpo back in the time this thing was in use would put in a telephone exchange and it would play an announcement it's a temporary type of device because it's got handles on the side the idea is you move it from one location to another where it's needed the kind of thing that this would do the job of is if say a phone number had been changed or discontinued then you put this thing in and there'd be an announcement that played when you rang that number to say you know this number is no longer in operation please redial using blah blah blah it would of course be more useful than having that phone number ring as a dead tone however these things would be used for a certain amount of time until hardly anyone was ringing that number and then these would be disconnected and then you get the dead tone on the line this would go on to do something else but they weren't just for things like that there's more uses that these were put to in fact the chap who gave this one to me a nice chap called neil who lives locally he sent me an email about this first of all he said i've got a piece of kit you might be interested in it's an old gpo telephones recorded announcement machine back in his youth as an apprentice with gpo telephones one of his jobs was to make the tape loops up now he'd get reels of tape that contained the announcements ready done and those would be sent out to major exchanges and then he'd splice a loop of that tape into one of these machines and he says the last time he made a tape up like this was for the santa line and that's when children would ring up a telephone number at christmas and father christmas would read a short story to them now this isn't that machine this is another one that he saved from being thrown away back in the day most of these things would have just been binned so he's had this one in his garage for decades and he thought it might be something that i'd be interested in showing to you now he did test it prior to sending it off to me just to see if it worked and unfortunately it wasn't spinning so i had to get that sorted to start with i'll show you the insides of it to show you what it was that was the issue but also neither of us know what's on this tape so let's see if we can find that out as well one quite common problem with a brushed electric motor like this when it's been sitting around in the same position for a long time that can develop as a dead spot a point where no electrical connection is being made so when you turn it on it just doesn't do anything the simple solution for this one was just to move it into a different position then when it switched on there was a connection and it carried on spinning freely on the back here we can see this was made by a company called sontranic chc group limited they're at edgware middlesex england the model of the device is a 9a announcer and the serial number is 1941. and those details repeated on this sticker on the bottom of the case the last thing printed on here 84-4 will indicate this was manufactured in 1984 and you'll also see that same date code at the top right of this sticker on the solenoid now to separate the two halves of the case i have to unplug these two rca plugs you'll see the wire from this runs up and into the top of the case there and that just goes straight to the tape head so looking at the bottom of the machine here we've got the two amplifier boards at the back there and into each of those would plug one of those wires that runs from the top and those in turn are driven by these two transformers labeled up as tf1 and tf2 and that goes from this main power supply here so if you were to dial in your call would be connected up with this socket on the back here and depending upon no doubt what number you rank you'd either be listening back to this amplifier board or that one there and here we've got outputs for those two tracks one for each and this is so the engineer could plug his headset in and listen back to the tape and next to each of these is a pot that you can adjust with a screwdriver to adjust the output level for the headset and then you can tighten that up there now to the right of there we've got the tape control we've got stop in the middle continuous run which is what i'm using to get the machine to play and normally it would be in this remote position on the right which would mean it would only activate once a call came in now of course my plan to listen back to the tapes involves plugging something into here there is one catch though these are non-standard sockets they might look like you could put a normal quarter inch headphone jack in and indeed you can get it in there up to a point but it won't go any further so it won't make connection with the pins i was warned about this by neil he said he got some special plugs that i could have but he didn't have the molding and as it happens i do have some of these sockets anyway so what i'm going to do i'm just going to swap the one that's in there out for this one which of course is designed to fit a normal quarter inch plug now i'm just putting a bit of tip x on the end here so i don't mix them up i know that that is the pin that goes furthest away from the socket now i've just pulled the cover off and they're soldered on i thought they would use spades on there but never mind i'll desolder them and put them back on the new one now as i take these off i just want to temp your expectations because it's very likely the tape in here is just going to be something incredibly mundane it's very likely to be a short message saying that a line is no longer in operation to redial using an alternative number the only reason i want you to temp your expectations is when i reveal what was on a station announcement cartridge once an answer phone that said this line is no longer in operation a lot of people got very angry with me as though somehow i'd know what was on the tape before i played it but you could assume from this one this is not going to be a lost beatles recording this is just going to be somebody saying the telephone line doesn't work anymore so just bear that in my home please right well those seem fine so let's put it back together and see what it's got to say for itself now that's weird i'm getting absolutely nothing out of either output i've got the volumes on both turned up to maximum as well now it's very unlikely that the last tape in here would have nothing on it at all it would still have the last message that this machine played so there's something in here we just need to be able to hear it i suspect i've wired these things up wrong i'll just take the wires straight out of the case and i'll have a bit of a play around with them right so let me explain what's been going on this is plugged into my amplified speakers you might better hear the buzz there so i've got the sockets on here and i've been using the crocodile clips or alligator clips with every possible combination for both tracks and i'm hearing absolutely nothing at all but that tells me something the fact i'm hearing nothing not even tape hiss means that there's something going wrong with the amplification circuitry so the next thing that i can try to see what's on this tape is to take those two wires the ones with the rca plugs on the end which came straight from the tape head and with those plug those into something and then amplify the heck out of that and then eventually we should be able to hear what's on the tape so let's get on with that these speakers have a built-in phono preamp the thing that's designed for amplifying a record player that amplifies things a lot and i thought if i just put those outputs into these speakers turned it into the phono mode we might be able to hear something well just have a listen to this now i don't know if you could hear that from the camera's microphone i'll put the lavalier up to the speaker in a moment but you might have noticed it's only coming out of one speaker and that tells me there's only one of the two tracks that's got a recording on it i have swapped the plugs around on the back and it just still has the one announcement so we've got one announcement still on the tape not the most exciting thing as we suspected a little bit muffled given the amplification system i've used to try and hear it but at least we could hear it so let me play it to you again through the speaker the code you have now is no longer available please reveal your number using the full sdd code as shown in your phone booth there will be no extra charge for the call if further assistance is required please bring operator services so that's exactly the kind of announcement that i expected to find on this tape and while it's not the most interesting thing in the world i think that is a good demonstration of why this existed to take a boring job away from a person and automate it now this thing every time you were to ring in the tape would just start at the point at last left off at which might mean it starts in the middle of the announcement but it's just a matter of waiting a few seconds because it's only a short announcement for it to come back round to the start again and then when you hang up it leaves off at that point and starts off for the next person in that same position now when i first previewed this video on patreon i got quite a few questions about it so i thought it's best if i were to add in an extra section to clear up some of those things before it went live on youtube so answering some of those questions here first off i'd been asked if i'd wired the output plugs on the front up correctly i mean i don't know who knows i don't know what the correct wiring should have been for those but remember when nothing came through them i then took the wires off those solder points took the leads out of the front and tried every possible combination of connection between both of those plugs to a wire that went straight into my powered speakers without so much as a crackle coming through on either track absolutely nothing so the audio just wasn't getting through to those wires at all from the amplifiers that were inside the machine i was asked about the amplifiers did i try swapping the rca plugs over on each one in case one of them was dead and the other one wasn't i did i was playing around with this thing for a few days so every possible simple option was tried before i moved on to the next thing now i do have a theory about this though and it's just a theory but the fact there was no sound whatsoever coming out of this made me feel that maybe those amplifiers are deactivated unless this machine is wired into an exchange via that red socket on the back panel i mean this device isn't designed to be used anywhere other than in an exchange so that is a possibility it was also pointed out that the tape was muffled when i played it back due to the riaa equalization on my follow preamp and yes indeed it was muffled my plan was just to find out what was on the tape and i managed to achieve that so for me that was the job done now if that announcement had been more historically interesting it might have been worth me making more of an effort to try and get a better quality of sound out of it but in this case i think we heard all we needed to and then moving on to the tape transport now this was a section that i initially shot but i didn't include but since quite a few people ask questions about this and why the tape isn't in a cartridge or a cassette i've decided to edit this section in so of course we're all familiar with the idea of a tape player having two reels and many might assume that when a tape is playing it's the real on the right that's the one responsible for pulling the tape through the machine but the truth is the right reel is just taking up slack and the left reel is letting out that slack while retaining tension the thing that's actually pulling the tape through is just the little pinch roller in the bottom so when you have a machine with a small amount of tape as in the case of this announcement machine it's just got the same announcement by the way repeated three times on that piece of tape before it splices back together again so you don't really need anywhere to store loads of tape with this system there's far less to go wrong if you're not dealing with cartridges and things you've just got a pinch roller that pulls the tape across the head it's designed to be very reliable and as simple as possible it's just one big motor and a solenoid to move that pinch roller up against the caps down to engage playback there was no need to make this more complicated as a further demonstration of the reliability of a system like this you may recognize this picture from one of my earlier videos about cassette tape duplication behind the large clear panel on the front of this machine is a loop of tape which would hold a duplication master of a cassette album and that tape loop would cycle around inside this machine at an incredibly high speed whilst it was being copied to cassette after cassette hundreds and hundreds of times with extreme reliability you may also have seen a similar looking tape loop inside an echo machine again a machine that needs to be very reliable because over the years we've come to associate tape that's come off for real as being something that's encountering a problem it's easy to assume when you see a system like this that it's something that's going to be prone to tangles but it's the exact opposite if you wanted a highly reliable tape loop well you didn't need any reels so a very simple machine but i think a fascinating one to see in action and thanks to neil for passing it over to me it's the first time i've ever seen one of these things and yet at some point in my life i've definitely heard the audio being played from one so it's good to finally join those two things together so i hope you've enjoyed having a look at this one here today but that's it for the moment as always thanks for watching [Music] [Music] you

Channel: Techmoan

Views: 492,320

Rating: 4.9666333 out of 5

Keywords: Techmoan, 4K, 1980s, GPO, Announcement, Machine, 1990s, Telephone, Vintage, Tech, Retrotech, Tape

Id: 3z8z0sbLsrw

Length: 15min 2sec (902 seconds)

Published: Sat Jul 03 2021