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digital input at cassette port
- Subject: digital input at cassette port
- From: "mspangler" <mspangler@gemsi.com>
- Date: 13 Mar 2006 19:56:53 -0800
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Is there a way to make the cassette input more TTL compatible? I need
another input, so I could jumper from the input capacitor to the 12k
resistor on the output of the op-amp, and get my TTL input that way.
But could the op-amp be retained, the resistors around it changed to
work with TTL instead of audio signals, there-by retaining some extra
over-voltage protection on the input?
Or would I do just as much good with a zener diode to ground on the big
jumper plan? So I would short out the capacitor C11, jump from the
op-amp side of R4, replace R-12 with a 5.1V zener diode, then connect
the other side of the jumper to the op-amp side of R20. Snip off the
op-amp, and that will work?
One related question, what is the maximum frequency response of a
non-platinum IIe pushbutton input?
Thanks,
Mike S.