Guys, I made another cable... no joy. Cassette input is tested and works fine. I have a small app in Assembler (loaded from MSX Basic) that listens to cassette input and plays back the signal on the audio chip. I am getting clear signal from the SVI cassette recorder, but nothing from the newly made cable plugged in to the headphones socket in the PC.

I will remind, the cable is audio jack <--> 8-pin cassette connector.

I took old Sony headphones (tested), cut off the headphones and reused the jack. I am sure many of you had to do the same at the time

The wire splits in two, one to the left headphone, the other one is to the right. Each black insulated wire has two inner (insulated) wires. In the left one, there are green and yellow wires. In the right one, there are red and yellow wires. The way my cable is now soldered is as follows:

LEFT

Audio jack ---------------- Green wire -------------------------> cassette output MSX
-------------------------------Yellow wire -----------------X

RIGHT

Audio jack ----------------- Red wire ---------------------------> cassette input MSX
-------------------------------Yellow wire ------------------------> Ground

The above is based on the assumption that the yellow wire to the headphones I removed, is the ground. Whereas green is left and the red is right. I soldered the yellow cable on the MSX connector end only once (what's the point of soldering the ground from both right and left insulated wires anyway... it leads to the same ground on the audio jack on the PC side. Unless I am completely wrong here and the yellow cable is not the ground...)

Could anyone help me with such a silly problem? :-)

Many thanks!

I think I have found the problem... The cable worked fine with my Sony HitBit MSX2. I will post more details shortly.

Um, weird, impedances maybe?

One more day of trying and absolutely no luck with the cassette cable for SVI-728. The same cable works flawlessly with my Sony MSX2. I do not know what to think I provided ground on the shield as well. No joy. Sony is still happy.

Has anyone actually tried loading stuff via this kind of cable from a PC, CD Player into the SVI?

No, my test was done over a standard old tape recorder; but I can try with a CD. If you're using a CD player try to change the volume and of course, disable all equalization parameters; maybe the SVI is more nutpicking than the SONY machines.
Btw, the cassette cable used in my tests was the one that comes with a SONY machine

First I would ground also the other yellow cable, but this should not be the problem.

Maybe the volume is not loud enough?

I have not tested this kind of stuff with SVI-728, but I remember using my home cassette player to load stuff to SVI-738. I remember that the volume setting needed to be relatively high.

jltursan: It would be great if you could try it with a CD player. I have only been playing with a PC. With my Sony machine, it took a few attempts to achieve reliable upload. I ended up using VLC media player to play back WAV files. I up the volume to the maximum and shifted the balance to the left speaker (mapped to the cassette input). The same did not work on my SVI. Turning the equaliser off was one of the first things I did.

NYYRIKKI: Yes, using a louder output device is certainly worth trying. The volume is on max on my PC, however I will try a stationary CD player. Yes, the volume from the SVI standard cassette recorder appear to be somewhat louder. SVI might be pickier than Sony in this respect...

I have tried loadig software via my laptop to my SVI 728, seems to work just fine, but noticed that high baudrates worked really bad. Volume need to be high.

Think high baudrate failed because of the relay (click sound in the SVI after load segments) msx was not ready when next part started from pc.

bennyroger: Can you publish the cable pin layout by any chance or perhaps publish a picture of the open connector on the MSX side? I will try loading stuff off a CD player with the louder output.

The cable is a standard MSX cassette cable with the pinlayout you can find on the faq or a good pinout webpage. You can also buy a ready cable from a guy in holland for only 4 Euros.

Bingo! It has finally worked. I have uploaded Athletic Land 2 from my PDA! The cable was fine (even though I had to re-solder it a dozen of times!). Its the low output volume of my notebook that caused me grief. It appears that SVI-728 expects a relatively strong signal compared to my Sony HB-F1XDmk2 which is much more tolerant in this respect. And, yes, high baud rates on the SVI did not work for me either.

PDA appears to be a handy device for pushing soft into SVI. I have a 1Gb card in it, so storage is not an issue.

Oh, well, one more problem out of the way.

Good work!, now you can try also to speed up the WAVs using PC audio tools. I've managed to load modified WAVs at 3000 bauds with the standard loading routines, sadly this trick doesn't work well with MP3 compression, at least not with a bitrate under 192Kbps.
If you want to try with higher baud rates for faster loading times, you can give a look to tools like Waver or MicroWaver.

So far, 1200-baud uploads are rock-solid. 2400 bauds are shaky (2 failures out of three attempts on average). I will try various media players on my PDA. Yes, I would ultimately like to achieve 3000 bauds by modifying WAVs. I am yet to try Waver and MicroWaver...