ZX-IDE tape loading

Any discussions related to the creation of new hardware or software for the ZX80 or ZX81
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nollkolltroll
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Location: Stockholm, Sweden

ZX-IDE tape loading

Post by nollkolltroll »

ZX-IDE has a potentially great feature that sends programs to a real ZX81 through a sound-card. Unfortunately I have not been able to get it to work. The speed-loader is simply an unachievable dream for me, since even the normal-speed loader fails midway through.
The same PC, sound-cards (3 tested) and ZX81s (2 tested) work perfectly when using files created with p2wav.
Looking at the wav produced with ZX-IDE I see that it is generated at 30kHz, p2wav produces 22050Hz files.
Resampling is a tricky business, and square-waves are especially tricky depending on what resampler is used. A file at 32, 44.1 or 48kHz would probably fare much better, so I hope it is possible to change. Very willing to try.
/Adam
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PokeMon
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Re: ZX-IDE tape loading

Post by PokeMon »

Well, the sampling frequency is not that important if you correct the timings internal. The reason for choosing a higher frequency (15 kHz) is to increase speed. But this depends on the soundcard as well as the output volume is decreased with higher frequencies. Anyway it should work with maximum output power. I plan to work on a newer and better adaptive loader in the winter. Keep in mind to avoid other players then the windows media player - the best way is to use a plain sound output with no filters at all. I never got VLC or other players to run - I think they modify the output with internal filters which change the output sound. I always use the internal sound creation without a special player.

Does it work at normal speed ?
nollkolltroll
Posts: 325
Joined: Sat Sep 27, 2014 8:02 pm
Location: Stockholm, Sweden

Re: ZX-IDE tape loading

Post by nollkolltroll »

No, normal speed does not work directly via ZX-IDE, nor does the generated wav work through other players. p2wav files does work regardless of player and soundcard.
/Adam
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PokeMon
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Re: ZX-IDE tape loading

Post by PokeMon »

Thats strange - do you use mono cables or mono adapters on both sides of the cable ?
nollkolltroll
Posts: 325
Joined: Sat Sep 27, 2014 8:02 pm
Location: Stockholm, Sweden

Re: ZX-IDE tape loading

Post by nollkolltroll »

I've tried mono-mono and mono-stereo cables, with no difference. p2wav-files work perfectly fine, ZX-IDE fails.
/Adam
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PokeMon
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Re: ZX-IDE tape loading

Post by PokeMon »

Then you have to use P2WAV. 8-)
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