[Coco] Coco Cassette interface help

Dave Philipsen dave at davebiz.com
Tue Feb 28 15:46:32 EST 2017

A couple of things to keep in mind. The comparator is set up for higher level signals as would drive an 8-ohm speaker in a small tape player.  You could tweak it to work on lower amplitude signals probably by just fiddling with resistor values.  Also, the comparator is basically an op amp. If you need an amplifier *and* a comparator you could probably use two of the op amps in a quad op amp package.


> On Feb 28, 2017, at 1:25 PM, RETRO Innovations <go4retro at go4retro.com> wrote:
>> On 2/28/2017 1:05 PM, Dave Philipsen wrote:
>> All you want to do is amplify the signal that is coming from the CoCo cassette out. Use a capacitor to de-couple it from the comparator circuit. It won't matter if there's DC bias on the output of the op amp because you will effectively remove it with the cap.
> True, and I will give it a shot, but I'll continue to search for a way to make the comparator idea work alone.  Amplifying the source only to get it "over the bias" of the comparator just seems wrong to me :-)
> Still, I already was thinking of your idea, in the context of using an LM386 to amp the signal brute force to get it to work.  So, I agree it's a workable solution.  Thanks for the suggestion.
> I am also going to see if I can feed some known signals into the comparator to see if I have messed up the design.
> Jim
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