Tape recording levels
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Inspired as ever by Mike's videos, I've been trying to get an Altair to save and load data from a reel-to-reel tape recorder, in my case an Akai 4000DS. The Akai has phono inputs and outputs on the back and also a Microphone input and a Headphone output on the front panel. I am able to save BASIC programs to tape -- I know they're there because I can listen to them as audio recordings -- but I can't get the Altair to load them back. I suspect the problem is the signal levels.
The Akai has VU meters on the front, and I've been setting the record level so that the signal takes the needle to the top of the white zone (up to 0) but not further right into the red zone (above 0). I adjust the playback to get the same level. Does that sound about right to anyone? I can do this via the phono or Mic/Headphone sockets and the result is the same in each case: it records okay and plays back giving what seems to my ears like undistorted reproduction, but the Altair just ignores the recording so that CLOAD "T" in BASIC just hangs.
If I switch out the Akai reel-to-real tape recorder and try a cheap mono audio-cassette recorder with Automatic Volume Control using the Microphone and Headphone sockets, it all works fine: there is nothing to set for recording and the playback at about one-third maximum volume enables the recorded BASIC file to be reloaded.
Anyone know if there any diagnostics I can try to see if I've got the levels wrong? I have a modern digital multimeter but don't know how to use an oscilloscope. (This might be the time to learn!)
Regards
Gabriel Egan
The Akai has VU meters on the front, and I've been setting the record level so that the signal takes the needle to the top of the white zone (up to 0) but not further right into the red zone (above 0). I adjust the playback to get the same level. Does that sound about right to anyone? I can do this via the phono or Mic/Headphone sockets and the result is the same in each case: it records okay and plays back giving what seems to my ears like undistorted reproduction, but the Altair just ignores the recording so that CLOAD "T" in BASIC just hangs.
If I switch out the Akai reel-to-real tape recorder and try a cheap mono audio-cassette recorder with Automatic Volume Control using the Microphone and Headphone sockets, it all works fine: there is nothing to set for recording and the playback at about one-third maximum volume enables the recorded BASIC file to be reloaded.
Anyone know if there any diagnostics I can try to see if I've got the levels wrong? I have a modern digital multimeter but don't know how to use an oscilloscope. (This might be the time to learn!)
Regards
Gabriel Egan