CrossBow777 wrote:I I was trying to plug an old school cassette tape into it to record the wave file playback onto cassette tape to
try and get some stuff to load up on my old Vic-20. (I wasn't successful btw...). But somehow in the process I plugged the cord into the Mic input or
something and next thing I know I have no more audio audible from the PC? Checked everything, uninstalled the drivers..reinstalled..etc. Dead silence.
Oh, my. Sorry to hear! 😢
#1 Cassette tapes have mono in, line-out has stereo out. Without any adapters, you'll short L and R channels (or R and ground). That's bad. Never short a transmitter (output).
#2 Old computer tape drives use square wave signals. Overamplification (distortion) is a good thing here, so maybe the volume of you PC was too low..
#3 Without galvanic insulation, a lot of things can go wrong. Ground-loops, potential difference, sheet current, etc.
#4 Some microphone inputs carry phantom voltage, meant to power microphones. At least the usual ones designed for electrec microphones (condenser mic; not dynamic mics).
(For completeness, some models also use a dedicated pin for +5v or so. These may have two black rings on the mic plug.)
https://en.wikipedia.org/wiki/Electret_microphone
https://en.wikipedia.org/wiki/Phantom_power
IMHO, it would be best to use a simple audio transformer next time. Or an old PSU transformer (12v/220v, 6v/120v etc)..
If you can't get one, insert a condenser in the line (for L/R each). And use proper plugs. Never insert a connector into something it wasn't meant for.
Here's a text file from '87 that was part of RDSSTV2, an old SSTV program for IBM PCs..
(In this scenario, it was meant for the cassette player's speaker-out -> PC's Sound-In route.)
transform.png
As you can see, interfacing a computer by using a transformer isn't hard. In fact, you could get that specific AF transformer from RadioShack still.
If you're using Line-In, just connect one wire to Line-In's ground and another one to L or R (or both).
But if it was the other way round, I would insert an extra condenser (capacitor) on the Mic-in side of the recorder,
say 10uF or so (wild guess), as a substitude for the condenser mic (and since the WAVE is mono, you only need L or R from Line-Out/SPK out).
Last, but not least, here's another piece that I found. It was meant for interfacing radios to PC soundcards.
AudioConnection.jpg
Edit: It doesn't matter whether or not you use the absolute correct parts here. Simply use what you have at hands.
Remember: Using "wrong" parts for galvanic isolation is better than using no parts (and thus, no isolation) at all.. 😀
Edit: Some edits. Sorry, I'm a bit sleepy (it's night in my place).. 😅
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