Commodore actually made their tapes nearly uncopyable by consumer equipment.... not sure how, but I tried a good many times to get them copied to no avail.
The blistering speed of the tape drive allowed 80 characters to be read in every second... but since the file was written to the tape twice in succession and it would read the second as a backup/verify of the load, that brought it down to a mean 40 characters a second... I was young when I got my first datasette (the European C2N rather than the American 1530) so my electrical engineering at age 8 was a little weak, but I deduced long after they had been scrapped in favour of the *ahem* "blistering" 1541 disk drives, that you could tie the data lines of two Datasettes together and make nearly perfect digital copies of the tapes. Still, the signal at around 720Hz clock was pretty impressive to listen to on a home audio device (assuming 80 chars per second, 8 bits per character and a parity bit for error detection - I'm not 100% sure if they used parity at all).
By the time the C64 rolled out with the 1541 drives, I was old enough to start taking screws out of things and making modifications... all my drives had device number selector switches... break connection #1, it changes from the default 8 to 9, break connection #2 and it changes to 10 and break both and it changes to 11. I also replaced the trim pots on the drive motor speed controller to ones that mounted through the case at the top (where I learned that all potentiometers did not carry the same sweep! Hmm... even at the lowest setting the motor is running too fast, what did I do wrong?) and a slot to view the 60Hz disc printed on the flywheel (set up a 60Hz fluorescent, turn the speed pot, when the disc appears to stop turning, it's within speed tolerance!)... the stuff was very easy to modify and there were books and books about all the internal workings. My modem had an immediate hang-up button - I'll let you imagine why you'd need to be able to drop carrier in a split second
... I had cold, warm and absolute reset buttons, a homemade tape dongle for whatever that game was that needed it.
Then my piece de resistance - I built an audio digitizer from scratch, plugged into the user port and used an ADC0820 IC to turn analog audio into digital audio. I could capture a wild 8KHz, 4 bit sample 8 or 9 seconds long! (and later in life, after I learned about data compression, I could capture enough of Moby's "Next is the E" to rebuild all the samples into the entire song) that's where I really got involved in digital audio. I was trying to figure out how to mix two samples... hmm.. add them - no that doesn't work and overflows, take every second sample from each and play them interleaved - that does work, but each sample is then half the resolution as... waitaminute... average them... VOILA! Now to mix them at different levels, you'd make them each a percentage of 200% before mixing them (say one sample at 150% (*1.5), one at 50% (*0.5) to get a 33% mix of sample B)... holy crap... now a delay, just average in the current sample at a position (samplerate X delay length in seconds) samples away, and using the same mix ratio as above... and reverb would be the same, only each delay would be delayed too... and thus, my interest in digital audio was born.
Though I still have no idea why the "clip" LED on the digitizer didn't work... still to this day... maybe the LED was in backwards or I had a bum LED.
Bren R.
