Difficult to load vs non-working cassettes

[Lardo Boffin]

Hi all

I have some games that load using a fairly broad band of volume and tone settings and some that only load at very specific settings (different to the others, obviously) and if the sliders are more than 1 or 2 mm out won't load.

I expect a degree of variability from the cassette manufacturers in terms of sound levels and quality but sometimes it is difficult to know whether a tape is just being picky or is in fact pinning for the fjords as it were.

Short of a lot of time spent rewinding and adjusting levels is there any way to know if a tape is dodgy or just being difficult? Has anyone written a program on the zeddy (or spectrum etc.) that tries to maybe just load the first block of data and reports whether or not it is ok? Having to load for 6 or 7 minutes before knowing whether it works or not can be a bit tiresome! I suspect another computer with a more forgiving cassette system would be a better host for such test software...

[blittled]

I'm no audio expert but I have a suggestion. Is there a way you can use a PC and capture the output and convert it to a wav format and post it? I'm sure some of the gurus here could then figure out a solution.

I used Audicity when I did just the opposite (digital to audio) to compare my output to an actual tape output.

[sirmorris]

You can't just listen to the first 30 seconds and judge whether something will work, unfortunately. It can drop out at any point, for whatever reason. Unlike some systems of the day that saved data in discrete blocks along with checksum data the zeddy just dumped it all in a big mess to the cassette and that was that. A single corrupt bit could spoil your recording.

As suggested a good thing to do is record the tape into the computer and literally have a look at it. It's usually fairly obvious where things have gone wrong

[Lardo Boffin]

You can't just listen to the first 30 seconds and judge whether something will work, unfortunately. It can drop out at any point, for whatever reason. Unlike some systems of the day that saved data in discrete blocks along with checksum data the zeddy just dumped it all in a big mess to the cassette and that was that. A single corrupt bit could spoil your recording.

As suggested a good thing to do is record the tape into the computer and literally have a look at it. It's usually fairly obvious where things have gone wrong

Fair point about the drop out at any point but given the lack of feedback about whether anything is loading at all it's difficult to tell if the volume / tone levels are set correctly and that is what is causing the load failure.

Maybe the changing patterns on the screen give a visual clue as to whether loading is working or not but unfortunately my TV blacks out during the process!

[makeit2day]

One thing I always did when recording was to unplug the EAR cable at the recorder. It seems there is some kind of feedback
generated when the ZX is SAVING that cause some distortion. Try this next time before saving your program. It has solved some
loading problem for me in the past. Choose good quality cassettes too.

[sirmorris]

^^ good advice right there for the future, though I believe this is historic data, yes?

There are tools available that take a WAV and make a P. There is one which I believe can perform some limited fixing of the data over at zx81stuff. I'm sure some emulators can read WAVs too.

Why not go ahead and record it if you can? Use a mono<->mono cable like the original zeddy tape lead. Don't do any processing of the signal (yet but be sure to record it nice and loud, though not so loud it clips.

It's not an easy process so unless the tape is MIA or of personal value then perhaps spend your time doing something more productive

[monzamess]

I used the ZX81 Tape Converter you referenced extensively to revive my 30+ year old programs stored on dodgy bargain cassettes. It has a realtime program listing so as you correct dropouts and errors, you can see results immediately. I revived my dumb old BASIC creations and thanks to ZXpand, I can run the .P files off of SD on my original TS1000 instead of messing with tape ever again.

[Moggy]

Tape scraper perhaps?
It usually does the trick.

viewtopic.php?f=6&t=467

[TMAOne]

There was also this hardware "solution" if you're into building circuits from back in the day.
viewtopic.php?t=1211&p=12734#p12734

[Lardo Boffin]

Tape scraper perhaps?
It usually does the trick.

viewtopic.php?f=6&t=467

Thanks. Will give that a look.