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How About Creating a Modern Cassette Player?
- Thread starter Fosi Audio
- Start date
I don't know how you folks up there did it but that's how us folks down here did it. One of the perks of having a motorcycle of my own (and even though my girl friend's parents were cool with her riding on the motorcycle with me): for Friday date night I always borrowed my dad's station wagon so that we could find our own cozy spot to park.
Robin L
Master Contributor
Thing is, I worked in Tower Records, Berkeley, during the peak years for cassettes, just as CDs first started to appear on the shelves of our store. Mid 1980s. Initially, I was in charge of the Classical cassette section, then accessories (which included blank cassettes). And when I worked in the Classical cassette department all the tapes had Dolby B. So, while the companies selling the recorders were making recorders with multiple types of Dolby and other types of noise reduction - don't forget DBX - the companies mass duplicating cassettes were sticking to Dolby B.Most of my friends were using Dolby C for their mic tapes and radio show recordings.
I do not know anyone that bought more than 2 or 3 commercial tapes.
They bought the albums & then recorded those to use as their tapes in the garage or backyard (or the occasional mixed tape for their love "significant other" that they would enjoy on a date in the car at lover's lane (or in my crowds use case, in the boat while water skiing).
As a result of the extra signal processing, Dolby C-type recordings will sound distorted when played back on equipment that does not have the required Dolby C decoding circuitry.
Some of this harshness can be mitigated by using Dolby B on playback, which serves to reduce the strength of the high frequencies.
Dolby C first appeared on higher-end cassette decks in the 1980s. The first commercially available cassette deck with Dolby C was the NAD 6150C, which came onto the market around 1981. Dolby C was also used on professional video equipment for the audio tracks of the Betacam and Umatic SP videocassette formats. In Japan, the first cassette deck with Dolby C was the AD-FF5 from Aiwa. Cassette decks with Dolby C also included Dolby B for backward compatibility, and were usually labeled as having "Dolby B-C NR".
Dolby HX/HX-Pro[edit]
Further information: Adaptive biasing
The Dolby HX circuitry driven by the industry-standard NEC uPC1297 integrated circuit. It modulates the incoming bias current and injects it into the two channels of the stereo recording head via two ferrite transformers.
Magnetic tape is inherently non-linear in nature due to hysteresis of the magnetic material. If an analog signal were recorded directly onto magnetic tape, its reproduction would be extremely distorted due to this non-linearity. To overcome this, a high-frequency signal, known as bias, is mixed in with the recorded signal, which "pushes" the envelope of the signal into the linear region. If the audio signal contains strong high-frequency content (in particular from percussion instruments such as hi-hat cymbals), this adds to the constant bias causing magnetic saturation on the tape. Dynamic, or adaptive, biasing automatically reduces the bias signal in the presence of strong high-frequency signals, making it possible to record at a higher signal level.
The original Dolby HX, where HX stands for Headroom eXtension, was invented in 1979 by Kenneth Gundry of Dolby Laboratories, and was rejected by the industry for its inherent flaws. Bang & Olufsen continued work in the same direction, which resulted in a 1981 patent (EP 0046410) by Jørgen Selmer Jensen.[22] Bang & Olufsen immediately licensed HX-Pro to Dolby Laboratories, stipulating a priority period of several years for use in consumer products, to protect their own Beocord 9000 cassette tape deck.[23][24] By the middle of the 1980s the Bang & Olufsen system, marketed through Dolby Laboratories, became an industry standard under the name of Dolby HX Pro.
HX-Pro only applies during the recording process. The improved signal-to-noise ratio is available no matter which tape deck the tape is played back on, and therefore HX-Pro is not a noise-reduction system in the same way as Dolby A, B, C, and S, although it does help to improve noise reduction encode/decode tracking accuracy by reducing tape non-linearity. Some record companies issued HX-Pro pre-recorded cassette tapes during the late 1980s and early 1990s.
Later I was recording concerts and sometimes making cassettes of those concerts for the performers. They usually preferred no noise reduction, hearing dynamic anomalies with Dolby B. I got the very best results with Metal tapes without noise reduction, recorded on a machine that could handle "hot" recording levels. I didn't like any of the noise reduction schemes, but DBX was the worst.
Me too. I also found those BSAF abrasive chrome tapes to have a nice hot top end to the high frequencies.
Robin L
Master Contributor
There were Sony Metal tapes in ceramic housings that could take more signal than any other. They're going for stupid expensive prices on Ebay now:
Very nice. Screwed together too. I like a nice shell for making test tapes. I bought all my own Sony calibration tapes but I needed a 6 and 10 second tape and so I split open the shell, cut the tape to length and then used those tapes for testing auto reverse mechanisms. A super handy 6 and 10 second tape is very rare.
Robin L
Master Contributor
Ebay is selling these for over $200 per.
That's not surprising. How much where they when new and a current offering?
Robin L
Master Contributor
$12 in 1995 dollars. Not cheap.
That's actually not that bad considering what a person is getting and what making one entails. Tape technology is some pretty cool stuff.
Robin L
Master Contributor
I was dubbing from DATs which invariably were better and cost about as much.
I used to service Sony DAT players in warranty. Being a Sony they where a wonder of engineering but I saw lotsa reasons for doubt about the longevity of the format. What was your experience like when using DAT machines at that level you where at? Where they easy to get along with, fussy, have breakdowns or require too much service?
Robin L
Master Contributor
I managed to get a couple of Technics DA-10s worked on by a tech to record at 44.1 with no problems with tape duplication. One had issues with the transport. It was more expensive to repair than to replace. The tape was the biggest problem, it could jam up, rendering itself useless. I'm so much happier with current recorders using Micro SD storage and no moving parts. Not to mention 24 bit recording, which makes things so much easier.
I feared using my DAT calibration tapes for the same reason(s). One tape eaten can mean a loss of multiple hundreds of dollars in DAT era dollars that was a pain in the butt.
Things have come a longgg way and I'm very curious where they will go.
If you are focused on optimizing sound quality, some sort of Nakamichi-style head auto-alignment is a must.
I'd also want A/D conversion so I could quickly digitize my old cassette tapes (and thus also a means to transfer the file, e.g. USB)
It would also of course have to have settings for Type I vs II etc tape playback.
If it had those things, I'd buy one.
And all the flavors of Dolby NR would be nice, but when did that ever work properly in cassette decks anyway?
I'd also want A/D conversion so I could quickly digitize my old cassette tapes (and thus also a means to transfer the file, e.g. USB)
It would also of course have to have settings for Type I vs II etc tape playback.
If it had those things, I'd buy one.
And all the flavors of Dolby NR would be nice, but when did that ever work properly in cassette decks anyway?
Robin L
Master Contributor
If you are focused on sound quality, you're better off with a handheld digital recorder.
Last time I had a project transferring cassettes to digital storage (a thumb drive, for what it's worth), I used a handheld digital recorder and an old dual-well dubbing cassette deck. There were a lot of tapes, the sound quality of those tapes was grim so such niceties as proper head alignment were beside the point. Dumped and edited the recordings into an iMac. The client was very happy with the results, dumped the transfers into his cloud so he could play them on the road.
I still have that cassette deck, haven't had the need to use it for about a decade.
Exactly.
Wouldn't really work by itself for digitizing cassettes, would it? Which is what I'm specifying. So no, I'm not better off. Unless you're sure an external DAC would be better than one they could include in the propsed cassette player.
I 've done that, too. But see how tht differs from what I propose? I bolded it just in case. And without auto-aligning playback, the SQ was never as good as it could be, unless you went in and did it manually for each tape.
(Which is also what I did. 'Grim' tape quality and all: it still made a difference)
(You didn t really need a dual well deck for this, but I'm sure you know that. At one time the market even featured consumer cassette decks built for converting old tapes to digital, but these came out after my project, and from what I saw they didn't have auto alignment.)
Robin L
Master Contributor
I think you mean ADC. Easier to monitor/adjust levels when transferring to the handheld deck.
Having worked with hundreds of cassettes, I know there are real limits to the possible fidelity of the medium. Auto-alignment would really drive up the cost of the cassette deck.
I sincerely doubt it would have made a difference with these tapes; they sounded like dubs of dubs.
The dual well deck was what I had on hand.
I'm amazed auto azimuth alignment is even in the discussion.
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