Interesting bit of kit, cassette tape duplicator - Page 1
Forum section: electronics / general

author: Red Squirrel
author_rank: Super Contributor
timestamp: December 15, 2020, 04:27:44 am
content: I feel old calling this vintage, but it probably qualifies as that I guess. For such a simple purpose it's built like a tank, and weighs about as much as one.I help out with sound at my church and we were going through some old stuff and this was heading to the garbage so figured I'd grab it. I was curious and it would cost around $600 to ship to Australia so probably not a mailbag worthy item lol.

author: mathsquid
author_rank: Frequent Contributor
timestamp: December 17, 2020, 02:36:07 am
content: I haven't seen one of these in years, but we had one--possibly the exact same model--at my job when I was a college student. I worked in the office that did moved instructional equipment around campus, and did some limited audio and video copying and editing. We didn't use this thing all that often, but it definitely came in handy sometimes.

author: Ed.Kloonk
author_rank: Super Contributor
timestamp: December 17, 2020, 07:42:02 am
content: I dunno, man the fact that you put this in dodgy tech is apt cos I'm a hifi snob.

author: Simon
author_rank: Unknown
timestamp: December 17, 2020, 09:43:28 pm
content: The talking newspaper that I run used to use cassettes, boy am I glad we don't anymore and even the old farts are too as now they get through the duplication and dispatching faster with memory sticks even though the cassette duplicators did 19 cassettes at a time in 3 minutes.I really have to cringe when I hear stuff like that warm analogue sound of cassettes. I had a couple of cassettes as a teenager and did my own mix tape of some of my dad's music. But I can't say I enjoyed tape, it was something to be endured.The resurgence of tapes rode on the coat tails of the misconception that vynal was better than digital because the old farts that could not let go said so and for some reason the millennials re-enacted much like a cargo cult the actions and attitudes of their parents that grew up with vynal.Anyone that claims tape is better is suffering under several illusions.

author: Red Squirrel
author_rank: Super Contributor
timestamp: December 18, 2020, 12:34:17 am
content: Quote from: Ed.Kloonk on December 17, 2020, 07:42:02 amYeah I think my browser shifted the page last minute as I clicked the forum, meant to post in general chat lol. Oh I see it got moved now so all is good.

author: Red Squirrel
author_rank: Super Contributor
timestamp: December 18, 2020, 12:40:00 am
content: Quote from: Simon on December 17, 2020, 09:43:28 pmI was oddly obsessed with tapes as a kid, recording random stuff, editing, etc. I even had one of those "talkboy" recorders like in Home Alone. I still have a couple random tapes in a box somewhere, I pulled one out for kicks the other day when I was looking through some old stuff and found them, and played it and even recorded something on it for shits and giggles, just out of nostalgia. Found some old stuff I recorded as a kid. Something about Bin Laden lol. Think it was part of a school project or something. But yeah I don't think there's anything "warm" or nice about the quality. I can understand people who say that about records as they really do have a distinct sound, but tapes almost feel kind of muffled compared to something digital. But at the time it was "good enough". As long as you have a bic pen you can fix any tape.

author: retiredfeline
author_rank: Frequent Contributor
timestamp: December 18, 2020, 01:07:10 am
content: Back in the day, you could buy dual cassette entertainment systems where you could play on one deck and record on the other. I had one. The unit in the photo seems to be more industrial, probably could dupe at high speed.

author: Red Squirrel
author_rank: Super Contributor
timestamp: December 18, 2020, 01:23:29 am
content: Yeah that one is high speed, like maybe a minute or so for a tape. I might have to take it for a spin, it did not seem to be working when I plugged it in though, but maybe it's normal if there's no tape in it.

author: Cerebus
author_rank: Super Contributor
timestamp: December 18, 2020, 01:58:37 am
content: Quote from: Simon on December 17, 2020, 09:43:28 pmOf course if you've got anything recorded before about 1990, possibly later, it was most likely originally recorded on tape and you probably haven't even noticed. There's a world of difference between 2 tracks on 1/4" or 24 tracks on 2" tape running at 15 or 30 ips on a machine built around a hefty casting, and 4 tracks on an 1/8" tape running at 1 7/8" ips inside a little plastic case.

author: Cerebus
author_rank: Super Contributor
timestamp: December 18, 2020, 02:20:32 am
content: Quote from: Red Squirrel on December 18, 2020, 01:23:29 amAlmost certainly normal. Those things work at such a high speed (typically 15-30 times normal speed), and consequently with such high forces, that they needed to have careful servo control or they were just going to snap tapes. There's almost certainly a microswitch or optical detector that detects the presence of the cassette and an optical detector that detects the presence of actual tape.The better ones of these would use the tape presence detect to line up all the tapes at the point where the clear leader stopped and the tape started before starting the duplication run. They're not too fussy about speed, they can't be because there isn't enough leader in a cassette tape to get up to speed without stretching the tape with the force required. Instead they are fussy about keeping the lengths of the different tapes synchronised, that way acceleration at the start of the run and deceleration at the end of the run doesn't affect the copying as the tape speeds up and down. Very different to designing a standard speed tape recorder.

author: Ed.Kloonk
author_rank: Super Contributor
timestamp: December 18, 2020, 05:38:59 am
content: Quote from: Simon on December 17, 2020, 09:43:28 pmNever mind the sonic shity-ness, who remembers the tangled mess in the car?

author: Simon
author_rank: Unknown
timestamp: December 18, 2020, 08:24:05 am
content: Quote from: Cerebus on December 18, 2020, 01:58:37 amWe are talking consumer grade stuff here. Yes the masters were done on tape but very expensively in order to preserve the quality and not by a means that you could affordably use for distribution. I think the actual master would only be used a few times to produce duplication masters, it was rather tedious. For example my father never played his records, he would keep them safely having made a tape copy, so yes years later when we came to transfer them to computer and put them on CD you would not necessarily think they were from records as there was no cracking due to years of wear and handling.I think the problem for the analogue people is that they struggle to separate the idea of "data" from the signal/storage method used and think of them as one and the same. This was the downfall of the tapes and records. Had the sound been digitally encoded on the tape just as computers do onto tape drives the tape would have had no effect on the sound quality for as long as it remained decodable. But if that were the case you would still get claims about how the tape made the music sound better, I know this as a fact as I saw it on a CD!!!! yep, some asshole produced a blank CD and claimed that it had superior sound qualityI don't think in the Victorian times when they used punched cards to store music anyone claimed that they cardboard gave better tones and neither did the makers of the self playing pianos say so about their papers, ironically both of these technologies long before the advent of electronics beat MIDI to it.....

author: Ed.Kloonk
author_rank: Super Contributor
timestamp: December 18, 2020, 09:24:46 am
content: Quote from: Simon on December 18, 2020, 08:24:05 amThere were a number of attempts at digitizing the analog signal on an LP. All had dreadful results regarding reliable playback. There were a few digital tape formats, some were backward compatible some not so, all could have been the killer app but the record companies shot down every attempt.As for CDs, there were some dodgy D/A conversion done in the beginning. There was no real specification in that regard. There was one notorious model I recall that to save cost it had just one D/A converter and used a analog switch at high speed to separate the channels. It had a whole heap of filters on the output because the switching noise was horrendous, so they smoothed off the top end. Machines such as that is where some of the snobbery comes from.The other misunderstanding with CD's sounding better is in the compression and equalization applied the signal. It wasn't as easy to apply the same techniques on to Vinyl. LP's had a RIAA eq curve already applied so the bass didn't make the groove too phat. When 90's doof doof came along they had to moove to 12" singles so they could be played loudly at discos, and other reasons.I didn't mind fanboys in either camp, I just wished they'd compare apples with apples.

author: Syntax Error
author_rank: Frequent Contributor
timestamp: December 18, 2020, 10:23:53 am
content: Seeing the commercial audio visual equipment label on the back reminded me of this. The UNESCO World Day for Audiovisual Heritage - anual October 27thhttps://www.ccaaa.org/pages/news-and-activities/World-Day-for-Audiovisual-Heritage.htmlandhttps://www.iasa-web.org/world-day-audiovisual-heritageYes eev bloggers, it's a real thingKeep on surfing those dumpsters.

author: Simon
author_rank: Unknown
timestamp: December 18, 2020, 10:24:57 am
content: I would expect that using a tape for digital storage would have been expensive at the time. I suspect you would need more tape as now the resolving power of the medium that would determine the "sample rate" would need to be higher. Although analogue is not dealt with in terms of resolution or datarate because the medium mechanisms are too fuzzy to put a number on there is a physical limitation. For example we used to record loads of films on VHS long play to save money, the quality was visibly less as we were at the limit of the medium but we accepted it and the reason the standard speed of tape was twice long play was because that was what was required to achieve the effective data rate. If you want to digitise sound then what on the tape used to represent 1 "sample" now would be one bit in 32? so you would need 32 times the tape not to mention more expensive equipment. I suspect that discrete "0" and "1" can be store with slightly less tape than an analogue sample point due to the increased signal to noise ratio but it would still require much more tape for something no one understood and the mechanical issues of tapes would remain.It's the same with film. Although there is no resolution definition people chose their films carefully as they knew that an ISO100 ws finer than an ISO800 but ISO800 would allow photos in low light that would be pointless with ISO100, they never put a number on it but it was the same concept of resolution we have today because it was about the size of the crystals that defined the smallest detail that could be recorded so it was very akin to resolution but because the crystals were not an exact number per unit length nor were they in a defined grid like pixels they were just thought about as how grainy they were but it was the same concept.I started shooting on film as i could not afford a DSLR but i could afford a scanner that i still have that can scan 35mm film as a 50Mp image, obviously that image may or may not be usable as a 50Mp image it depends on the "speed" of the film and how grainy the image is.

author: Cerebus
author_rank: Super Contributor
timestamp: December 18, 2020, 01:24:04 pm
content: Quote from: Ed.Kloonk on December 18, 2020, 09:24:46 amI'd flip that around the other way. With vinyl it was necessary to very carefully apply compression to actually succeed in cutting a record. The guy with the fanciest compressor/expander/limiter was always the guy running the cutting rig. As well as the rather obvious aspect that if you have too large a waveform you can literally cut into the next groove there were also slew rate limits as there's a limit to the velocity that a stylus can track. Also don't forget that we're talking stereo here so you're cutting different signals into both of the side walls of the groove, so there's a depth of cut aspect as well as a width of cut aspect. That in turn means there are differential limits on how far the two tracks can deviate from each other. Then there's trying to trade off available track width with the length of music that you can record on the side of a disc. If you compare a vinyl record of a full orchestra piece with a wide dynamic range and the CD of the same you'll find that the vinyl version has been hugely compressed.

author: Cerebus
author_rank: Super Contributor
timestamp: December 18, 2020, 01:43:39 pm
content: Quote from: Simon on December 18, 2020, 10:24:57 amAh, you need to go and talk to Claude Shannon. In terms of Shannon Information Theory you can record the same amount ofinformationin the same available space whether you're going digital or analogue.QuoteActually the imaging professionals did think in resolution terms. If you go and look at old film datasheets you'll see resolving power quoted in "line pairs per millimetre" or some equivalent.Here'a a modulation transfer function curve from the datasheet for Kodak PLUS-X Pan film. Full datasheethere.So with that having an MTF of 100% at ~20 cycles per mm, you could say that was roughly the equivalent of 40 pixels/mm. (i.e. Usual Shannon limit rules, sample rate twice the maximum spacial frequency.)

author: Ed.Kloonk
author_rank: Super Contributor
timestamp: December 18, 2020, 03:28:18 pm
content: Quote from: Cerebus on December 18, 2020, 01:24:04 pmIndeed.