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MTX 512 loading problem

Posted: 26 Dec 2018 12:28
by oldster54
Have just got my old MTX512 out, after my grandson asked me about my early computers. It still works, but I have lost the only tape recorder that had the correct connectors on it : EAR MIC (cassette) i.e. 3.5 mm jack plugs. What can I do to modify other connectors, to enable me to load programs onto my 512?

Re: MTX 512 loading problem

Posted: 26 Dec 2018 13:01
by Martin A
There's a few options:

The "modern" hardware route:
a) SD card storage www.nyangau.org/rememorizer/rememorizer.htm
b) Compact flash storage*** http://primrosebank.net/computers/mtx/p ... fx/cfx.htm

or tape replacement:
WAV file recordings of some of the software can be obtained from
http://primrosebank.net/computers/mtx/m ... _files.htm
http://www.mtxworld.dk/download.php
With a suitable 3.5 stereo to 3.5 mono jack lead (a 3.5 stereo to 3.5 stereo may work too) the WAV file can be played on a PC and loaded as if it were a tape. Files can be "saved to a PC too.
It's also possible to burn an audio CD of WAV files and load them from a CD player.

alternative tape connectors:
It might be possible to use a twin phono to 3.5 stereo lead, and use the aux output found on some "HiFi" systems, but I've no idea if the levels would be OK.
Back in the day there were tape decks that had 5 (or 7??) pin DIN connectors that were used with a DIN to 2 x 3.5 and 1x 2.5 jack breakout lead. The were common in the Acorn market as they had the tape remote control enabled.


*** A have to declare an interest here since I designed the CFX !

Re: MTX 512 loading problem

Posted: 26 Dec 2018 16:48
by 1024MAK
With regards to cables, the type of connector fitted to the MTX board for both the ear and mic sockets are mono 3.5mm types.
Stereo 3.5mm jack plugs are not compatible, as the contacts don’t line up correctly.

So for the MTX end, you really do need a mono 3.5mm jack plug.

If your source device has a 3.5mm stereo socket, I recommend this “3.5mm STEREO Jack Plug to 2 x MONO Jack Plugs SPLITTER Converter Cable Lead 1m” lead or a similar one. For loading, as long as the file is stereo, or the PC output is configured to output mono sound to both stereo channels, it does not matter which 3.5mm mono plug you use. If however there is audio on only one stereo channel, then you will have to try each plug in turn.

For both modern computers and other audio sources like CD players, etc, the signal level may not be enough, as the levels are limited compared to the levels available from old cassette decks of the 1980s. So you may need an amplifier. The cheap type of powered speakers for use with a PC are normally okay, as long as they have a headphone output.

Some cassette decks and various other older audio equipment, especially from European companies in the past did use DIN connectors. Three pin for mono, five pin for stereo, and seven pin if motor control was available for the cassette motor. All are backwards compatible. That is a five pin DIN plug goes in and works in a seven pin socket.

Speaking of cassette decks, Argos used to still sell a “shoe box” cassette deck. They still may...

Have fun :D

Mark

Re: MTX 512 loading problem

Posted: 27 Dec 2018 12:32
by oldster54
Hi Mark

Many thanks - I will give the options a try.

Viv