solid@ariel.UUCP (01/05/84)
I have heard that there was an article in BYTE magazine about a year ago which tells how to build a interface to a standard cassette player instead of buying Commodore's special data cassette. I would appreciate any information about this that anyone may have, which issue it is in, has anyone build and used it... ? 1) Does it work well, how is the quality? 2) Are the part easily available? 3) How expesive is it to build? etc... Dave Plaisted AT&T ISL Holmdel, NJ 1K-321 (203) 834-3080
ejk47@ihuxn.UUCP (Ed Kufeldt, ihuxn ejk47) (01/06/84)
Dave if this is the same article I think it is, Don't waste
your time. The article I refer to used standard TTL gates and
tried biasing them to work towards the analog side. The interface
recorded beautifully, but you could not read tapes that were recorded
on another machine. A friend and I built a couple of these interfaces,
and we spent months trying to get them to work before we finally sent them
to the scrap-pile. I designed an interface using Op-Amps and it has
been working fine for over a year. The circuit I designed works with
all the tapes I have purchased and is compatible with most recorders in
the $30.00 range.
Ed Kufeldt
BTLzdollas@uiuccsb.UUCP (01/11/84)
#R:ariel:-53600:uiuccsb:16800005:000:1636
uiuccsb!dollas Jan 7 05:00:00 1984
With respect to the interface kit I do not know a lot. However, the
interface itself is trivial (a design of my own works fine for me and I
have made three more sets for friends -none of which has problems). A
design -it turned out that mine is similar to it- can also be found at the
September's issue of Popular Electronics. The hardware cost about $5. The
success of the design largely depends on the cassette recorder, and it
usually takes one hour in order to find the volume and tone levels that
give the best results. In terms of time, it can be done in an evening,
it takes two to four hours (most of the time is spent drilling holes in
the box, stripping cables, etc, the actual connections of the electronics
take around half an hour).
Another aspect is the tape that you use. I found -the hard way- that a
good tape is essential, so I use TDK SA-90 (this is not an advertisment, I
pay for my tapes), and usually I buy a 90 minute SA-90 and load it in the
shells of many bargain tapes (those 3 for $1), so the search time is
smaller.
If you -or any other netter- are interested in my design, drop me a
line (my address follows) or send me some electronic mail and I will be
glad to send you a copy.
Apostolos Dollas
Dept. of Computer Science
Univ. of Illinois
1304 W Springfield
Urbana, Illinois 61801
or, ...!pur-ee!uiucdcs!uiuccsb!dollasdollas@uiuccsb.UUCP (01/11/84)
#R:ariel:-53600:uiuccsb:16800006:000:1417
uiuccsb!dollas Jan 7 18:20:00 1984
In the previous response the setting of volume levels appears
to be the problem (as I mentioned in my previous note it does take
time to adjust it); if the design with the op-amps works better, by
all means go for it. By the way there is no address of the sender,
could I have a copy of that design?
By the way it just occured to me that the design in the Popular
Electronics article does not work with tapes pre-recorded on
other cassette recorders because they invert the signal once in the
recording and once in the playback. If the signal is double-inverted
in the recording AND double inverted in the playback it should work;
at least I had no problems with the company's tape of the Victerm
program. The 7414 chip that is used has six gates anyway, so there is
plenty of gates (actually I use one of the spares to dub a tape to
another while it is loading).
Just trying to guess, the circuit with the op-amps seems to me that
would be based around either a diff-amp or zero crossings (in order
to get the TTL levels the Commodore wants). Does this work with the
+5v the Commodore provides or an external source is needed? is there
a Schmitt trigger buffer to (and from) the Commodore? I am very
curious about this design, so please don' let me hang by my thumbs.
Apostolos Dollas
(my address and path is in the first response of this message)