# This cassette player is built into an 8-track cartridge ## Метаданные - **Канал:** Technology Connections - **YouTube:** https://www.youtube.com/watch?v=8I4Jc-WLsrs - **Источник:** https://ekstraktznaniy.ru/video/23393 ## Транскрипт ### Segment 1 (00:00 - 05:00) [] Hello and welcome to No Effort November, a series of videos for the month of November where no effort is made. Have you heard of these newfangled compact cassettes? Everybody's got them these days and tons of new music is being released on these little things all the time! But what if all you've got is an 8-track player? Well, have no fear of being left behind because Kraco's got you covered with this. Just pop the tape you'd like to play into this thing, then shove it into your 8-track player and blammo! You're listening to the latest hits like one of the cool kids. I love a good adapter and this may be my very favorite one because it's delightfully clever. It uses one of the weirdest and arguably worst features of the 8-track cartridge format to create a surprisingly competent cassette player which passes the signals on the cassette tape directly into the playback heads of an 8-track player so you can listen to the cassette. I don't remember when I first learned about these things, but back in the day I was given an old Zenith console radio set with a record changer, AM/FM tuner, and of course an 8-track player. And probably while perusing eBay for 8-track-related nonsense to play in that thing, I found one of these for sale. This is not the one I had back then - it broke and I threw it away. But I've tracked down another one for this video. And this is that! To explain what's so clever about this, first we need to look at the 8-track cartridge and its design. The 8-track was the first majorly successful consumer tape cartridge. It was based on an endless loop cartridge format developed for radio, but for success in the consumer market, it was cost cut to oblivion. A design of Richard Krauss, the Stereo 8 cartridge hit the scene in 1964 and it used conventional 1/4 inch magnetic tape. But it split the fundamental elements of a magnetic tape transport between the playback device and the cartridge itself. See, magnetic tape is really just a thin plastic film covered in powdered rust. When you drag that rusty tape past a tiny electromagnet called a tape head, you can store information on that tape by magnetizing the rust particles. A sound signal which is fed to the head modulates the strength of the magnetic field it produces. And since the tape is moving past as this happens, the powdered rust becomes magnetized in the same pattern as the original signal. In other words, a recording of that signal is now present on the tape. And when you move this newly magnetized tape past the head again, but this time without sending signals into the head, the varying magnetization on the tape will create an electrical signal inside the tape head which can be sent to an amplifier to recover the original signal and thus the sound. That's the basics of recording audio onto magnetic tape. But to do it well, you need a mechanism which can smoothly pull the tape past the head at a very steady speed. That's accomplished with a capstan and pinch roller. The metal capstan is spun by a motor at a constant and precise RPM, and the rubber pinch roller jams itself up against the spinning capstan. Stick some tape between the two spinny bits, and it's going to be pulled along at a steady speed. If you give the capstan a bit of heft with the help of a flywheel, you can make this happen incredibly smoothly, which is good for keeping the audio signals from sounding warbly and weird. In a reel-to-reel tape recorder, you have a supply reel of tape, the tape transport with the tape heads, capstan, and pinch roller, and then you have a take-up reel, which uh takes up the tape after it's gone through the transport. But this whole contraption is pretty bulky and inconvenient. Now, you could put the two reels into some sort of box and then create a tape transport which interacts with that box... which is what a cassette is. But those tape transports are somewhat mechanically intricate, which makes them fairly expensive to produce. I mean, you gotta have parts that move the pinch roller into the capstan, you gotta have some way to move the tape in both directions so you can rewind it... I mean, it's just a whole ordeal. The 8-track format, on the other hand, took everything out of the tape transport except for the spinning capstan and the playback heads. The pinch roller became part of the cartridge itself with the tape riding along its outer circumference. And with the help of this notch here and a little spring tension, the 8-track player simply jams the cartridge and thus the pinch roller right into the capstan inside the machine. Since the tape is now sandwiched between the capstan and the pinch roller inside the cartridge ### Segment 2 (05:00 - 10:00) [5:00] this simple arrangement was all that was needed for nice and smooth tape movement. And to make it even simpler, 8-tracks contain a tape loop rather than two separate reels of tape. Tape is pulled from the center of that loop, travels up and over the top of the cartridge, then back down the pinch roller before finally ending up at the edge of the loop. This somewhat odd arrangement forces the tape to sort of slide past itself, but since the tape is pulled out from the center of the loop where the diameter is smallest, the tape is naturally kept in tension. The... rather large catch is that this form of loop prevents the tape from being moved backwards. No rewinding is possible with an 8-track: you just have to keep going forward until you're back at the start of the loop. That's not the end of the world, though, thanks to the format's party trick (which also explains why it's called the 8-track). The tape holds eight parallel audio tracks recorded across its width. They're interleaved as four programs of stereo sound, and the 8-track player used a mechanism which would physically move the playback heads to realign them with each of the four programs. This extra complexity belied some of the cost savings, but it meant that a hypothetical album with 12 songs on it would be recorded onto an 8-track as four loops with three songs each. And with a button on the 8-track player which lets you step through the four programs, you could kind of skip around and get to a specific song. [Music plays] [song playing abruptly changes] [another change - each change occurred mid-song] And while it was physically impossible for the tape to move backwards without the loop getting very badly undone, many players such as this offered a fast forward option to make queuing up a specific song at least a little bit easier. [very high-pitched squeaky fast music plays] And of course, 8-track players could also step to the next program automatically. This was accomplished with a piece of foil on the splice point of the tape loop. Electrical contacts inside the 8-track player were pressed against the tape and they had a modest voltage placed across them. When the foil splice bridged those two contacts, that voltage was fed to a small solenoid that pulls down on this lever which steps the heads to the next program with the help of this spinning cam thing. This was a pretty clever trick, but splitting up a loop of tape into four programs with the exact same length made programming rather difficult. So albums released on 8-track would tend to have the songs in a different order than the LP release or they might have weirdly long gaps between certain songs. Or - much worse - they might actually split a track across two programs which leads to a small gap in the sound in the middle of a song in addition to some audible clicks and pops. Not ideal. However, the format was stupid simple. Just shove the thing in and it starts playing without a fuss. And for its time, they were quite robust. Tape doesn't care about vibrations like conventional records do. And that made tape formats a great choice for cars. In fact, that's where 8-tracks first became popular. These days, 8-tracks are generally not well appreciated. For one, many of them now have issues with degradation of the pinch roller or the foam pads which keep the tape pressed up against the heads. And so they often need repair - just ask Techmoan. And they were never made all that well. I tried to demonstrate how they handled albums which split tracks across the program change with this cartridge, but the moment the splice made its way through the pinch roller and capstan... the tape broke. It broke! Right on camera. Even if they weren't prone to these issues with their rather restrictive playback limitations, they're a little annoying to use. However, 8-tracks sound better than you might realize in large part because the tape travels at 3 and 3/4 inches per second, twice the linear speed of a compact cassette. And that allows it to record higher frequency sound signals, which increases fidelity. It's definitely not great by today's standards, but it's not really all that bad. Here are a few examples - and I'll note that this is by no means a good 8-track player. ### Segment 3 (10:00 - 15:00) [10:00] It's pretty basic and it has that delightfully 1970s "we are really trying to make this look like a digital device with seven segment displays, but this is really a piece of plastic in front of four incandescent light bulbs" aesthetic. But hopefully it gives you a sense of what the format was capable of. [STAR WARS] [a much quieter and more obscure part of the soundtrack] [Get Together by The Youngbloods] [ope, now it's some instrumental thing] [The chorus of Aretha Franklin's I Say A Little Prayer] [You Don't Have To Say You Love Me] [instrumental section of Get Together] [and now it's the Mills Brothers] [and now some quieter classical music which reveals quite a lot of tape hiss] Now, if you're wondering why there's so much noise, part of that is this 8- track player's kind of terrible preamp, but also the track width is identical to a compact cassette. And since eight tracks peaked before tape formulations got very good and noise reduction technologies like Dolby B took hold, they tend to have more tape noise than you'd want. Not exactly high fidelity, but far from terrible. Still, by the late 1970s, the format was starting to fall out of fashion. For one, the cartridges were quite chonky and took up a good deal of space. The compact cassette was quite a lot smaller and thinner. And here's a fun twist: this is actually an older format than the 8-track. This came out in 1963 and 1964. You might think it odd that the 8-track even happened then, but the compact cassette's very slow 1 and 7/8 inches per second tape speed initially gave it quite poor fidelity which made it awful for music. At first, this was mainly sold as a format for dictation machines and similar applications. But before long, with the benefit of innovations in tape formulations and improved recording and playback heads, cassettes could sound just as good as an 8-track and indeed much better once features like Dolby noise reduction became standard. And all without any of the 8-track's weirdness. But there were plenty of people out there who had, say, a car with a perfectly good 8-track player in there. As new music releases on 8-tracks started to dwindle, those folks would be left behind unless they upgraded their radios. That was annoying, especially since the radio part still worked fine for traffic reports and Casey Kasem's Top 40. Rudolf Van Kreuningen simply would not stand for this reality and so he designed this thing. Now, I will note that this is not the first product which worked like this. Tom T. Tsuji patented a similar device in 1969, and there were several designs over the years. However, this one features plenty of refinements and its clever arrangement of parts makes it much less bulky than those other designs. Here's what's so clever about these things: Since 8-track players all have that spinning capstan, if you can transfer that rotational movement into a drivetrain of some kind, you could use the motor of an 8-track player to actually drive a cassette transport. And that's exactly what this does. What was a pinch roller in an actual 8-track became a drive wheel in this adapter. And with the help of some belts and simple mechanical linkages, it can use the motor inside an 8-track player to run a simple cassette player. As luck would have it, the compact cassette and the 8-track cartridge have nearly identical widths. And with the cassette slotted in like this, the adapter is just a tiny bit longer than a standard 8-track cartridge. When this control lever is slid over to the play position, this idler wheel is jammed against the drive wheel. A flat belt made of some kind of cloth or paper to give it a grippy texture transfers that movement over to the pinch roller of the cassette transport. That is a little strange. Ideally, it should be driving the capstan and the pinch roller should simply spin freely. This design is exactly backwards, probably because it wouldn't be possible to spin the capstan fast enough if directly driven, but the capstan does at least have a substantial flywheel to dampen vibrations and speed, so it works well enough. At least... when these were new. This one's playing pretty warbly these days, though it's clear it got lots of use based on the wear shown on the pinch roller and heads. ### Segment 4 (15:00 - 20:00) [15:00] Now, I was a little worried this would be the case. The original one I had the same weird belt in it, and before long, it tore itself to shreds. I could never get it to work properly again, which is why I got rid of it. But through the magic of buying two of them, I was prepared for this eventuality. And this one's new in box! Look, it's perfect for use in home 8-track players, car 8-track players, and patent pending! This one is a later revision and production was moved from Japan to Korea. When I tried it out, it played fine for approximately two seconds and then started slowing down. And then came to a stop. Guess I gotta crack this one open, too, then. And inside here, I found a surprise. This revision uses a standard rubber belt rather than... whatever that is. The original belt had simply stretched just a little too much over the last 40 years or so and gave up. But after a quick run through my bag o' belts, I found one that mostly works. It's not right, but it'll do well enough for this video. And after buttoning it back together, I gave it a test run. Great news, this one isn't warbly at all! Some less great news, it's running a little too slow and it's really not able to keep a steady speed. I can't quite figure out why as everything in here seems to spin freely, but well, let's give it a listen. [various music samples, with surprisingly good quality! ] [doin' some testing here] [a slow, poppy/jazzy theme reveals how the speed isn't quite steady, especially in the horns] [8-bit/electronic music again belies how the speed is drifting, but it sounds decent otherwise] [ooh it's particularly bad here] Aside from its issues with speed, I find it remarkable how well this works. It doesn't sound bad at all! Other than the high noise floor of this particular 8-track player, it sounds just as you would expect a cassette to. So, there's really nothing to complain about here! This is a very basic tape transport - it can only move the tape forward, which was common in some of the cheapest cassette players out there, but it does at least offer a fast forward option. Interestingly, the patent suggests a rewind option was in the cards, but that was apparently dropped before production. You could, of course, flip the tape over and select fast forward to rewind, which is what you'd have to do with a cheap car stereo anyway so, honestly, this is amazing for what it is. But here's the even amazinger part. You might have wondered how the heck it's getting the signals from the cassette tape into the 8-track player. If you've seen those cassette adapters before, you'll know that you can actually just run a sound signal through a second tape head acting as a transducer and then shove it into a cassette shell such that it'll point at the playback heads of a cassette player. The magnetic field produced by the transducer in the adapter will be coupled into the playback heads. That's essentially what's going on here, though the transducer is a little different. You'll see why shortly. But hold on. Those cassette adapters rely on the amplifier in your CD Walkman or whatever to produce the power required for coupling the signal into the cassette player's heads. There's no way an actual tape head detecting the tiny variations in flux on an actual tape can produce enough power for that coupling to work. And indeed, that wouldn't work. So, the adapter contains an amplifier which boosts the strength of the signal coming from the play head before sending it to the transducer. While that amplifier could be powered by some sort of battery, you could instead get a little power from the circuit inside the 8-track player which detects the foil strip to advance it to the next program. ### Segment 5 (20:00 - 25:00) [20:00] That's why the adapter has these spring-loaded metal fingers. These will come into contact with the contacts inside the 8-track player and scavenge a tiny bit of current from them which is delivered to a small amplifier board. And that meant this thing could work without any batteries. I love this solution! Why bother with a battery when every 8-track player out there has a couple of electrical contacts that are always powered? So long as the amplifier circuit consumes a small enough amount of current that there's no risk of the step solenoid engaging the advance mechanism, you can just use that. And it's not like this introduced any risk to the 8-track mechanism: If somehow one of these feelers managed to short the contacts together when inserting the adapter, all that would happen is the advanced solenoid would fire. I suppose it's possible that if alignment went very wrong, these could keep those contacts bridged together and thus the solenoid would become locked on. But the way that these pivot away from each other makes that seem really unlikely. Now, something that I was hoping the patent would answer, but sadly it didn't, was the range of voltages this thing's amplifier board can work with. I can't imagine every 8-track player design out there used the same voltage for the step solenoid circuit. For one thing, those in cars are definitely going to have a DC voltage placed across them, but those in the home, as far as I know, might have an AC voltage across those contacts. As it turns out, this one does put DC voltage across those contacts, 14 volts to be precise, but I can't imagine that was certain to be the case. The amplifier board does have a few zener diodes on there which are probably clamping the voltage down for the little amp chip in there in addition to providing rectification. And with so many capacitors on that board, I think it's likely some of them are smoothing out an AC input to prevent audible buzzing. So, I suspect this was designed to work with pretty much any power supply it found. And though I only have a sample size of two, so far it's worked in every 8-track player I've tried it with! Regardless, while there might be some 8-track players out there which won't be able to use this thing, I still love the idea. It's taking the weird decisions of the 8-track (placing the pinch roller inside the cartridge and using that foil strip to advance the program) and putting them to an entirely new use. A use which just so happens to make an 8-track player capable of playing an entirely different format! And in doing so making them useful even when 8-track tapes stopped getting made. Oh, and remember that thing I mentioned about the transducer? So this is in fact a stereo coupler and the cassette player has stereo heads. So it reproduces stereo sound from a cassette just fine. But because on an 8-track the two channels of a stereo program are interleaved on the tape and the play head physically moves up and down, the coupler needs to produce a detectable signal over a pretty wide range. I suppose it didn't strictly need to - they could have simply told users to set the 8-track player to a specific program, but this adapter works pretty well regardless of which one is selected. Actually, I was surprised to discover stereo separation is perfect no matter which program you're on. I fully expected programs one and four to exhibit a little bleed through since either the left or right channel head is close to the border between the two channels on the transducer. But nope! The middle programs do seem to sound a little better, but as far as getting good stereo separation it doesn't seem to matter which one you pick. Lastly - you know I had to - I wanted to see what would happen if I put my Bluetooth cassette adapter into this 8-track adapter. I had to fight with it a little bit as this roller thing was triggering the adapter's auto stop mechanism, but once I got it to cooperate... [music plays] heck yes. This is a ridiculous signal chain: Bluetooth audio to a DAC in this thing, amplified and output to a cassette tape head and then coupled into a second cassette tape head after which it is amplified again in the adapter and sent through the 8-track adapter's transducer before finally getting into the 8-track player's heads where it's amplified again and sent out the line jacks. But hey, it works! And if you've got a classic car with an 8-track player which you want to keep completely stock, this is a viable, if quite weird, way to give it Bluetooth audio. I did discover though that for whatever reason, the signal is attenuated quite a lot when the control lever is fully engaged. This happens with both of these adapters. I'm not sure if it's an alignment issue or what, but between that and the fiddliness of the auto stop ### Segment 6 (25:00 - 27:00) [25:00] if I were to actually use this as a convoluted Bluetooth adapter, I would probably find or make something of just the right size which could be jammed in there to force the lever to stay in the middle position. And hey, using this cassette adapter it won't matter how warbly the belts in the cassette mechanism of the 8-track adapter are, so that's a plus. Heck, the belts could be broken and it would still work. Though, of course, uh there are more conventional 8-track adapter solutions out there, and realistically, you should just use one of those. But man, there's just something about this that tickles my brain like nothing else. It's just so clever! And even though there's really not much to it, it manages to work quite well. For your sake, I truly wish these were working as they were new. It's a bummer that neither one of these is playing quite right, but I know they would have back in 1982 based on the one I had before. Oh, and I should note, specifically for cars, there were also 8-track adapters with an FM tuner. Plenty of cars with eight track players only had AM radios, but with one of those, you could bring your car into the future! At least... a bit. Oh, oops. Sorry. ♫ inconsistently smooth jazz ♫ Have no fear because Kraco's got you... Oh. farts!... with the tape riding along its outer circumference. I keep screwing this line up... travels up and over the pinch roller and then across the top of - Oh, I didn't fact check that. Hold on. Yep, that's backwaaards. What was a pinch roller ind an actual 8-track... Did I say "ind an? " We'll restart. That'll fix it... and then shove it into a cashette sell. [dissapointed, but humorously] Well, sometimes roonerspisms happen... and if I put my Bluetooth cassette adapter into the 8-track adapter [plasticky struggling] it's not workin' ooh boy the end music is really making a rubber-band-like push and pull with the speed change. It's interesting how it's way more noticeable in some instruments than others. I guess you'd call that... wow factor.