How About Creating a Modern Cassette Player?

[EJ3]

I'm amazed auto azimuth alignment is even in the discussion.

I just want to record family stuff & recordings that I made in the studio when I was on radio programs, etc.
Speeches & things like that to digital.
As far as video is concerned, I just managed to get my mother's parents snow skiing wedding in 1929 Salzburg (the state, not the City, Austria) transferred from 9.5 MM film to digital DVD's & Thumb drives>
That completes my family video's from 1929-1965.

 

[Doodski]

As far as video is concerned, I just managed to get my mother's parents snow skiing wedding in 1929 Salzburg (the state, not the City, Austria) transferred from 9.5 MM film to digital DVD's & Thumb drives>
That completes my family video's from 1929-1965.

I'll start here with this comment because it is a great comment and really made my morning thus far. I will also add that I had a catastrophic event and lost PCs, all records, photos and videos that I had. So for that matter to see you are backing up your life makes me happy happy!

I just want to record family stuff & recordings that I made in the studio when I was on radio programs, etc.
Speeches & things like that to digital.

Yes, I can dig it. I was using a online backup service with backups every 4 hours and it was very effective and silently operating in the background. Then I decided that maybe I was overdoing it and I bought a hardware encrypted thumb drive for backup.

Kingston IronKey Locker+ 50 Encrypted USB Flash Drive - Kingston Technology

Kingston IronKey Locker+ 50 is an enhanced USB drive that provides consumer-grade security with AES hardware-encryption in XTS mode including safeguards against Brute Force attacks and BadUSB. The built-in virtual keyboard shields passwords from keyloggers or screenloggers.

www.kingston.com

 

[Robin L]

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 think you mean ADC. Easier to monitor levels.

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.

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.

(Which is also what I did. 'Grim' tape quality and all: it still made a difference)

I sincerely doubt it would have made a difference with these tapes, they sounded like dubs of dubs.(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.)

 

[EJ3]

I'll start here with this comment because it is a great comment and really made my morning thus far. I will also add that I had a catastrophic event and lost PCs, all records, photos and videos that I had. So for that matter to see you are backing up your life makes me happy happy!

Yes, I can dig it. I was using a online backup service with backups every 4 hours and it was very effective and silently operating in the background. Then I decided that maybe I was overdoing it and I bought a hardware encrypted thumb drive for backup.

Kingston IronKey Locker+ 50 Encrypted USB Flash Drive - Kingston Technology

Kingston IronKey Locker+ 50 is an enhanced USB drive that provides consumer-grade security with AES hardware-encryption in XTS mode including safeguards against Brute Force attacks and BadUSB. The built-in virtual keyboard shields passwords from keyloggers or screenloggers.

www.kingston.com

Thanks! I am currently using DVD's as the backup to the thumb drives. By this time next year I will be doing additional stuff.
My mother lives 12 miles away & we both have copies of this stuff.
But there is a lot more that she has that I do not. This coming Sept will be the start of changing that.
My wife arrived here Feb 28 (after being overseas for nigh on 18 months, so I am concentrating on being with her at the moment, as she will be gone again Sept.& October & then again January-June.
Priorities revolve around whether she is here or not, as you might imagine.

 

[dweeeeb2]

compact design:

 

[EJ3]

View attachment 368925compact design:

SONY did something quite a bit smaller that could also record 120 minutes(technically it was not a standard cassette or a mini cassette but it was a cassette of sorts [it did not take off in the market, though]{& was based on DAT technology}):

 

[JCM800]

Q: What makes tape mechs so complicated? I’m not suggesting they aren’t but they seem fairly basic - spin the pickup reel at a controlled speed and engage the reader head.

Would it be feasible to create a whole new mech using modern tech? Surely we have modern motors and digital speed controls that are much more accurate than a fly wheel and 182 tiny gears? Go minimalist, simplify all the crap and strive for accuracy.

In theory:
1. Big ass brass flywheel
2. Accurate motor
3. Digital speed control
4. Manual tape head engage / disengage a’la lowering a stylus onto a record

I’m sure I’m wrong but why? This is all hypothetical, not an actual suggestion.

 

[Doodski]

Q: What makes tape mechs so complicated? I’m not suggesting they aren’t but they seem fairly basic - spin the pickup reel at a controlled speed and engage the reader head.

Would it be feasible to create a whole new mech using modern tech? Surely we have modern motors and digital speed controls that are much more accurate than a fly wheel and 182 tiny gears? Go minimalist, simplify all the crap and strive for accuracy.

In theory:
1. Big ass brass flywheel
2. Accurate motor
3. Digital speed control
4. Manual tape head engage / disengage a’la lowering a stylus onto a record

I’m sure I’m wrong but why? This is all hypothetical, not an actual suggestion.

O' BoY... we could be here for awhile only limited by the fingers and effort of those with cassette will and knowledge...LoL.

Skewing of the tape path is a major issue as well as wow and flutter, gear noise, bearing(s) integrity and on and on.
Basically a cassette mechanism is a very high accuracy device that is designed to repeatedly pass a veryyy thin ribbon thing across a path with spinning rubber tire(s), spinning capstain(s), rotating drive cogs with clutches and all sorts of mechanical trigger shifter things, cams, ramps, springs and many parts of this stuff must be very hard finely polished metal surfaces and that makes it difficult to manufacture with reliability and repeatability. Considering one is going to use a wow and flutter meter after to confirm the proper operation of the mechanisms then there are no shortcuts.

 

[Robin L]

O' BoY... we could be here for awhile only limited by the fingers and effort of those with cassette will and knowledge...LoL.

Skewing of the tape path is a major issue as well as wow and flutter, gear noise, bearing(s) integrity and on and on.
Basically a cassette mechanism is a very high accuracy device that is designed to repeatedly pass a veryyy thin ribbon thing across a path with spinning rubber tire(s), spinning capstain(s), rotating drive cogs with clutches and all sorts of mechanical trigger shifter things, cams, ramps, springs and many parts of this stuff must be very hard finely polished metal surfaces and that makes it difficult to manufacture with reliability and repeatability. Considering one is going to use a wow and flutter meter after to confirm the proper operation of the mechanisms then there are no shortcuts.

And if you want to throw in auto-alignment for the tape heads, the complexity and costs go up several levels of magnitude.

 

[Doodski]

And if you want to throw in auto-alignment for the tape heads, the complexity and costs go up several levels of magnitude.

O' BoY! LoL... I've seen and worked on thousands of car, portable, personal and home audio cassette decks and when one adds in auto azimuth alignment things get very complex very fast. We have not even added in extra hard tape heads, high integrity bearings, direct drive, dual capstain etc. All these high end features come when auto azimuth is introduced into the build.

 

[JCM800]

O' BoY! LoL... I've seen and worked on thousands of car, portable, personal and home audio cassette decks and when one adds in auto azimuth alignment things get very complex very fast. We have not even added in extra hard tape heads, high integrity bearings, direct drive, dual capstain etc. All these high end features come when auto azimuth is introduced into the build.

Fascinating! Appreciate the serious replies to a silly hypothetical.

 

[Doodski]

Fascinating! Appreciate the serious replies to a silly hypothetical.

I was floored when I read that a cassette mechanism would be developed.

 

[JCM800]

Are alignment and azimuth adjustments on par with adjusting a turntable?

 

[Doodski]

Are alignment and azimuth adjustments on par with adjusting a turntable?

It depends. Some head assemblies/azimuths have multiple alignment adjustments but overall I think a turntable is more fussy if really calibrating everything that should be done BUT to align a tape azimuth a calibrated azimuth alignment tape is required and that must be purchased plus a 3 k Hz speed tape and Dolby calibration tape too if somebody is going to calibrate the Dolby stuff. So... all in all a cassette requires more expensive calibration gear and a frequency counter plus a oscilloscope but if a person is handy with the oscilloscope time base they can determine the speed and calibrate it using the oscilloscope rather than a frequency counter.

 

[splitting_ears]

Are alignment and azimuth adjustments on par with adjusting a turntable?

I adjust it by ear to get the best high frequency response. Monitoring in sum (L+R) or difference (L-R) mode can make this process much easier.

Just be aware that each cassette will end up with a slightly different optimum setting.

 

[EJ3]

O' BoY! LoL... I've seen and worked on thousands of car, portable, personal and home audio cassette decks and when one adds in auto azimuth alignment things get very complex very fast. We have not even added in extra hard tape heads, high integrity bearings, direct drive, dual capstain etc. All these high end features come when auto azimuth is introduced into the build.

3 heads & the fact that they wear down is another aspect needing materials & precision that are costly to minimize this problem.
Also: the cassette itself needs to be a high precision item or it will negate the decks precision.

 

[JCM800]

The Dolby HX circuitry...

Were chips involved on all the Dolby cassette stuff? Were they AD/DA'ing the audio?

 

[mhardy6647]

Were chips involved on all the Dolby cassette stuff? Were they AD/DA'ing the audio?

No "D[igital]" involved, that's for sure. Dolby B was a multi (3?) band compander, and steadfastly analog.
Did the earliest implementations of Dolby "B" (the version for cassette tape) use ICs for the compander circuit? I don't know.
I have an elderly Advent add-on Dolby box in the basement. I could look.
Or, we can check the schematics of some early consumer decks with Dolby B.
EDIT: Just looked at the schematic of the Advent 201 cassette deck from 1971 (Wollensak transport & Advent electronics -- AFAIK). I see only discrete components on the schematic in the service manual from https://www.hifiengine.com/manual_library/advent/201.shtml

All of the electronics appear to be on on PC board (albeit a densely packed one).
Screenshot from the above-mentioned SM from hifiengine.

The Advent 201 deck, FWIW. It was a stereo deck, despite the presence of only one VU meter. The meter could show the level of either channel or some sort of amalgam of the two channels' signal level (switch selectable).

source: https://www.positive-feedback.com/Issue16/advent.htm

Heathkit also had a cassette deck kit based on the same Wollensak transport, but with their own electronics -- and two meters!

source: https://www.worldradiohistory.com/Archive-Catalogs/Consumer/Heathkit-1974-03.pdf pg. 68

 

[sergeauckland]

The earlier Dolby B was all discrete, but IC versions soon became available. The first implementations of Dolby C used two Dolby B processors in series, each one with different time constants. Those were in turn replaced by dedicated ICs.

However, there was a slight but audible difference between the early and later versions of Dolby C, such that tapes done on one wouldn't decode perfectly on the other.

S

 

[EJ3]

The earlier Dolby B was all discrete, but IC versions soon became available. The first implementations of Dolby C used two Dolby B processors in series, each one with different time constants. Those were in turn replaced by dedicated ICs.

However, there was a slight but audible difference between the early and later versions of Dolby C, such that tapes done on one wouldn't decode perfectly on the other.

S

I see that there is an S at the end of this post.
Where you going to mention "Dolby S" ?