MP3 player loading troubles on ZX81

[doctorsf]

Hi everybody

I aim to load programs with a MP3 player.
I use Wav shaped programs.
I know that there is some trouble trying this because MP3 players are a bit weak. So I tried many solutions (direct, mono cables, speakers, etc).
unfortnuately no way to load any program. Even when (I think) the output level is fine, it looks like some kind of saturation...

Here a video of my trouble.
https://www.youtube.com/watch?v=tFDQaqINOAc
What do you think of it ?

Thanks.

[bola_dor]

May be too loud?

[XavSnap]

Hi,
The blue screen mean "No Signal" !
Something's wrong with the ULA ?

[bola_dor]

Hi,
The blue screen mean "No Signal" !
Something's wrong with the ULA ?

Some TV detect the loading screens as "no signal".. and some are able to deactivate the blue screen in the menu.. most now don't

[XavSnap]

Sound level too high : (big black strips)

Sound level too low : (little black strips)

Sound level too good: (0/0)

(Big stips=1 and littles=0)

On emulator the green line trigger (wav window) don't get the real time thru the wav forme…

POP up the volume !!!

[doctorsf]

If I lower the volume then it does like if it was waiting for the signal... no signal... There is no gap beetween no signal and too loud...

XavSnap you mean that I should play it louder ?

[XavSnap]

Yes, raise the volume… and check if your play have a "Sound Output security" system to preserve the Zx81 EAR socket !
Or put HP amplifier between the player and the black box...

[doctorsf]

No it doesn't change anything... I think I'm gonna give up with this computer... It has no interest if I cannot load a program...

[1024MAK]

The volume has to be at exactly the right level. Too low and the ZX81 will not hear the signal. Too high and it will not detect the data. It (along with the ZX80) are some of the most difficult U.K. 1980s machine to get to load reliably from tape.

It’s not helped by most modern audio devices (lap tops, mobile ’phones, MP3 players etc.) not being able to produce a loud enough audio signal.

I also recommend using the shortest length program you can find, so that it’s less frustrating when trying to find the correct volume level.

The Ear socket on the ZX81 is designed only for mono 3.5mm plugs. The contacts don’t line up correctly for a stereo plug. If you have a stereo audio source, the lead or adapter should only pass through one of the two stereo audio channels (conventionally this is the left channel, but if the right channel also carries the signal, it does not really matter which channel is used). You should not use an adapter that joins the two stereo channels together. As the output amplifiers in your stereo audio source may fight one another (like a short circuit).

And a mono 3.5mm plug does not work properly in a stereo socket, as the contacts don’t line up.

Mark

[XavSnap]

Hi Mark,

I tryed a fastload from AGB (new dumped rom): http://zx81.ordi5.free.fr/CartesZx81/AG ... d_Monitor/

And i can't load any programs on EO from a wav…
I tried to pick up the bottom wav sound … and the program seem working !!!

My question: Is there any problems if the ground/positive sound input are reversed, reversed signal… or some fumes ?

In a standard format, both levels (up and low triggers) can be catch to convert to a P file… but on a real Zx81, the trigger is the up signal or the bottom one ?