Adding an audio jack plug lead to a C2N Datasette

  • Thread starter Thread starter Merlin
  • Start date Start date
  • Replies Replies 41
  • Views Views 23990
Merlin said:
2. I'm not sure if the audio signal needs to be inverted or not. The point where I am feeding in the audio signal is before the op-amp so the signal will get inverted as it passes through. Until I get the optimum audio level I can't solve this part.
Click to expand...

At least the WAW-PRG FAQ suggests inverting the waveform, if the conversion to tape doesn't work.
The few attempts that I've done recording WAV files back to tape, I got slightly better results with inverted files. Slightly because the 1531 could at least find the file even though the end result was a load error.
 
Once I've got the C64S adapter made up, I am going to record a TAP file to the Datasette and then record it back to the PC, to see what recording dB level was used by the Ptap program.

If this makes any sense, then I can adjust the levels of the sound card output from the speaker socket to keep the signal around that level.
 
A bit of an update...

After more tinkerage, I got to the state where the C64 said 'Found' and stopped the tape, after which it tried to load the program and failed.

The issue appears to be around the signal level being fed into the Inverter; it needs to be within a particular range and I think that I'm overloading it so the program gets washed out by the noise.

I'm going to try the approach that A1200 users employ with internal CD-ROM drives, and see if a resistor in the audio line will produce a suitably attenuated signal like a mixer. If I can get this right it should be less sensitive to different sound cards.
 
Blah I'm a retard it's too early in the morning disregard this post!
 
Last edited:
I've been speaking to TheCorfiot about this and the next step is to try some resistors as stated earlier. Work has been hectic recently so I've not had much spare time for this.

I will get around to this and try the resistors and report back.
 
@ SDG: Now that's a neat device! Almost tempted to order one but getting an Indivision for my A4000 currently has a higher priority.
 
Merlin, have you checked that the output from you PC's soundcard is clean? I am just wondering if system noise from the card could be mucking up the signal when you are playing it out? It might be worth making sure the line in and cd in is switched off when you are recording signal. Perhaps it would be best to record the wavs to an audio CD, then output from a good cd player?

You should also look out for clips in your original recorded signal, as I would expect this to foul things up, even if you drop the level for the output.
 
Resurrecting an old thread here, but seeing the Cassadapt is now discontinued, there is a solution to the problem, unfortunately I do not have the know how to follow a schematic but link follows (as a new member here my post count has to be greater than 1 to be able to submit links!...so see below)

---------- Post added at 10:41 ---------- Previous post was at 10:38 ----------

http://www.zimmers.net/anonftp/pub/cbm/documents/projects/interfaces/soundcard2tape.html

soundcard2tape.png


With C2N connectors now available without having to dissect an existing Datassette, this project on a breadboard would be quite feasible.

Also I am sure should anyone want to think about production of such units in absence of the Cassadapt there would be interest still within the community for such a purchase.
 
You could probably do this with any old tape deck with a line out (maybe headphone socket?), to a PC line in on the sound card?
 
back in 1983 ish.. my friend had a C64 ( I still had my dragon 32 drooling over his c64), he backed up his games via a 2nd C2n.

a small pcb (just tracks) plugged into C2N port and then two C2N's plugged in, 1 of these had a small speaker built in you could turn on or off and a "knob" fitted to ajust the azimuth of the heads, your could listen to the pitch and adjust it until its clear then simply load the game as normal but the 2nd C2N had record pressed with a blank tape in it. was a cool setup and much more reliable than a twin tape Amstrad hi-fi :)
 
AmiNeo said:
You could probably do this with any old tape deck with a line out (maybe headphone socket?), to a PC line in on the sound card?
Click to expand...
Yes you can. I have done that with all my tapes and managed to get almost everything across using an NAD 602 casette deck that I had. You'll have to fiddle a bit with the recording sometimes though as sometimes left is the best channel, other times the right, but it's definately doable. I was even able to restore games from tapes that I got from my cousin which I could never get to load properly back in the day, as they were probably recorded on datasette with a slightly different azimuth adjustment.

Some originals are a bit more tricky as they are multi-loading and despite them working fine in VICE, TAPclean would not sign off 100% on them, but it could come down to it not being compatible with the exact game.

Edit: I've also transferred stuff the other way. My tape deck has a VU meter so I adjusted the recording level to match the playback by looking at the turbo loader tone. Using square waves output, it seems to work fine both with normal programs, turbo programs or copies of originals and by recording it back it looks like the signal is a bit better. Actually, many original tapes seems to have a quite low recording level, probably to break double deck copies.
 
what about one of those audio tape from cd jobbies.. you know the fake audio cassette with a wire you plugged into a cd player or mp3 so you can play on an old in car tape player.
 
Sardine said:
what about one of those audio tape from cd jobbies.. you know the fake audio cassette with a wire you plugged into a cd player or mp3 so you can play on an old in car tape player.
Click to expand...


ive actually used one of those for my c64 at one point they do work.
and on my speccy couldnt try it on our cpc 464 as there wasent many tape files to try.
 
I am sorry if this may seem off topic but I was struggling for days in getting a .tap file back onto tape to read on my c64.

I was using my Sherwood Double Cassette Tape with the recording level at 7 then I read on the net it needs to be mono.

I was using a 3.5mm to left/right audio connectors.

I unplugged the right jack connector at the rear of my amp

All I did was simply went through one channel from my sound card and viola success :thumbsup:

This Method kept me going until my Ultimate Arrived :D
 
Resurrecting this thread.

I understand all the people on this thread who want a replacement for their Datasette, and the solutions are clever. I have all of those interfaces & mechanisms and they work well.

But I wish to keep using a real datasette. I am able to maintain these devices - i.e. I know how to clean paths, restore rubber belts and pinch rollers and calibrate the speed of the motor. I have done all of this with audio cassette decks and mechanically the datasette is similar.

I do encounter a problem with the datasette when trying to calibrate the speed of the motor (when a motor is playing too fast or slow). On an audio cassette deck, I have a special tape I made with a pure A440Hz sine wave. I play this cassette in a deck and use a guitar tuner to tell me how flat or sharp the tone is. I then calibrate the motor until the sine wave is playing at a true A440. This is how to re-adjust a cassette deck motor.

The problem, when doing this on a datasette, there is no way for me to hear the audio while calibrating the motor. Does anyone know of a program that will play the datasette's audio from the TV speaker (the C64 had such a program I seem to recall). The other option would be to tap into the datasette's circuit board and get a true analogue audio signal (before it hits the A/D converter) and feed this to an amp.

The beginning of this thread was heading that way (with the 3.5" headphone jack solution), then it veered off into datasette substitutes.

So does anyone know how I can "hear" the audio signal from the tape while the datasette is playing?

Thanks

EDIT: I did find this: http://blog.tomse.dk/2012/09/30/use-a-c-1530-datasette-as-tape-audio-player/#comment-240
 
Last edited:
You must log in or register to reply here.
Back
Top Bottom