Improving Timex/Sinclair Tape Loading
Posted: Sat Oct 19, 2013 7:09 pm
Hey.
A couple of times in this forum I've mentioned a "Scrubber-Dubber" that I built from a magazine article in 1983 or so. The article was called "Improving Timex/Sinclair Tape Loading" by Tim Stoner, and appeared in the September 1983 issue of "Computers & Electronics". Up until now, all I've had was a very poor 1983-technology photocopy of the article, with a hand-drawn copy of the circuit diagram and parts list, because the magazine chose to publish that part of the article as black on gray. (Grrrr.)
Time, effort, luck, and a few PayPal dollars have finally come together to allow me to obtain a better scan and electronic copy of this article. I offer it here to anyone who is interested in building the circuit. Tim, if you're out there and object to this, let me know and I'll take it down. Otherwise, thanks a million for this great device, which has let me read and LOAD programs otherwise deemed to be irretrievable from problem tapes over the years.
Short summary: The device uses a quad op amp to read and clean up a waveform between the tape player and the ZX81. It also provides a slave recorder "mic" output, so that you can make a clean copy of the original tape at the same time as the ZX81 LOADs, or without the computer entirely. (This was useful for cloning CHESS-CLOCK, which I never succeeded in cracking as I had CHESS from Side 1. Shhh,...) It works brilliantly.
Surely we all have .p files of our favorite programs by now, but just in case you've kept that one cassette with your Masters Thesis that you never could quite get to LOAD cleanly, building this little toy might be your ticket.
Ian
A couple of times in this forum I've mentioned a "Scrubber-Dubber" that I built from a magazine article in 1983 or so. The article was called "Improving Timex/Sinclair Tape Loading" by Tim Stoner, and appeared in the September 1983 issue of "Computers & Electronics". Up until now, all I've had was a very poor 1983-technology photocopy of the article, with a hand-drawn copy of the circuit diagram and parts list, because the magazine chose to publish that part of the article as black on gray. (Grrrr.)
Time, effort, luck, and a few PayPal dollars have finally come together to allow me to obtain a better scan and electronic copy of this article. I offer it here to anyone who is interested in building the circuit. Tim, if you're out there and object to this, let me know and I'll take it down. Otherwise, thanks a million for this great device, which has let me read and LOAD programs otherwise deemed to be irretrievable from problem tapes over the years.
Short summary: The device uses a quad op amp to read and clean up a waveform between the tape player and the ZX81. It also provides a slave recorder "mic" output, so that you can make a clean copy of the original tape at the same time as the ZX81 LOADs, or without the computer entirely. (This was useful for cloning CHESS-CLOCK, which I never succeeded in cracking as I had CHESS from Side 1. Shhh,...) It works brilliantly.
Surely we all have .p files of our favorite programs by now, but just in case you've kept that one cassette with your Masters Thesis that you never could quite get to LOAD cleanly, building this little toy might be your ticket.
Ian