Freshly produced azimuth alignment tape for your VIC anyone?

[pixel]

Picture a screaming red tape you slap into your datassette and give it a treat with a screwdriver while the tape runs until the software is telling you that the job is done.

The package would be a complete treat containing:

* head cleaning tape
* azimuth alignment tape with manual
* Phillips crosshead size 0 screwdriver

Target price is €20 with the minimum of 20 pre–orders (no payment required beforehand of course).

The tape would be produced and recorded by a professional tape manufacturer to get it absolutely right. Development will span several weeks – I got a special deal with the manufacturer that makes it possible at all.

Pre–order anyone? Your datassette will never screw up again.

[groepaz]

the problem with that approach is that a lot of tapes were recorded with whatever "wrong" azimuth, and you want to align the datasette to each specific tape in order to read it

[pixel]

the problem with that approach is that a lot of tapes were recorded with whatever "wrong" azimuth, and you want to align the datasette to each specific tape in order to read it

I can picture that. Wouldn't it be a good thing on average anyway? I assumed that many original games weren't produced with arrays of datassettes.

[groepaz]

perhaps not - but then you can just use one of these original games for aligning

[pixel]

perhaps not - but then you can just use one of these original games for aligning

"Just"? B| Have mercy! With just a 30yo tape, no visual feedback… yeargh! Näh. Too much trouble. If a dedicated solution isn't enough action one could still train his dog to realign a datassette.

[Kakemoms]

perhaps not - but then you can just use one of these original games for aligning

Well, 300 baud... and a 16KByte game takes 437 seconds to load... Just need to tweak the screw one more time if it didn't..
Its going to take all weekend.. if your old 16K game still loads that is.

[groepaz]

obviously you need to be able to load an alignment program by some other means (i assume most people have a floppy drive, so thats no problem). and then aligning is a matter of seconds, no matter what tape is the reference (and using the one you want to load is always best).

[eslapion]

The datasette is an interesting beast with analog and digital components but a lot more analog than digital.

I have never seen any software capable of telling the intensity of the analog signal BEFORE it is converted into digital by the schmitt-trigger and that signal is really the indicator for head alignment quality. Therefore, using an oscilloscope or some means of amplitude metering is IMHO a million times better than any software.

You don't need to load any software to do that, in fact you don't even need a VIC-20 or C64 attached to the datasette. All you need to do is provide the datasette with the right voltages at the proper pins on the connector and tap the analog amplified signal on the electronics board.

[groepaz]

however in practise, a simple program is all you need to align it... and obviously its a whole lot easier for normal people (who probably dont have a scope)

[eslapion]

however in practise, a simple program is all you need to align it... and obviously its a whole lot easier for normal people (who probably dont have a scope)

A simple analog or digital multimeter is just as fine as a scope in the case of the datasette - it uses much lower frequencies than a disk drive.

A software can only tell whether you have a signal or not. Going the analog way, you can tell at exactly what adjustment you will find the strongest possible signal.

[groepaz]

a digital multimeter wont help you much at all. and quite the contrary, a software like this can very well (and surprisingly accurately) tell you if the signal is "good" or "bad". actually it works so well, that i'd never bother to use a scope instead, its just pointless.

[eslapion]

a digital multimeter wont help you much at all. and quite the contrary, a software like this can very well (and surprisingly accurately) tell you if the signal is "good" or "bad". actually it works so well, that i'd never bother to use a scope instead, its just pointless.

How can it tell the amplitude of the analog signal before it's turned into a square wave?

From what I saw, a true RMS digital meter set to AC does an excellent job at finding the peak setting.

I use a Meterman 37XR and use the signal strength bar instead of the numbers and its super quick and easy.

[groepaz]

How can it tell the amplitude of the analog signal before it's turned into a square wave?

you cant. what the program does is measuring how long individual pulses are and visualises them in a scatter plot. then you turn the azimuth screw until you get two or three (depending on format) sharp lines. this equals the optimal signal peak. (the same principle can actually be used for aligning disk drives as well if you own some kind of flux sampler device... show a histogram plot for data from a track, and then adjust until its as sharp as possible. works surprisingly well too)

From what I saw, a true RMS digital meter set to AC does an excellent job at finding the peak setting. I use a Meterman 37XR and use the signal strength bar instead of the numbers and its super quick and easy.

the problem is that a lot of digital multimeters, especially the cheap kind normal people own, are way too slow and all you get is a bunch of jumping values that dont help you a single bit.

[tokra]

Any solution that does not require to get/purchase/hunt for extra hardware wins IMO. So I'd say there is no real need for the initial product idea pixel offered if the same can be done software-only with nearly as good results.

[eslapion]

what the program does is measuring how long individual pulses are and visualises them in a scatter plot. then you turn the azimuth screw until you get two or three (depending on format) sharp lines. this equals the optimal signal peak. (the same principle can actually be used for aligning disk drives as well if you own some kind of flux sampler device... show a histogram plot for data from a track, and then adjust until its as sharp as possible. works surprisingly well too)

I get it, you're using a property of the integrator function on the analog stage, the pulse width will vary according to the amplitude of the signal being fed to the schmitt-trigger.

I suppose all you need is a tape that carries a recording of a nice square wave that's just a bit above the cut-off frequency of the low-pass filter of the playback stage. Something like 3kHz should do the trick.

Of course, you gotta make sure this tape is recorded with a tape deck that has studio quality alignment but that's something a lot of specialized audio/music shops can do for you at a small fee.