What causes the tape data to be heard on the speaker on the CPC 464?

[llopis]

So where would I then put the bypass capacitor ? From PIO input PIN to GND? And what dimension would be right?

The problem with connecting it directly to the PPI (or the output of the opamp, which is the same), is that you're going to get some feedback, capacitor or no capacitor. I haven't tested it, so it may work, or it may not. Ideally you would want to isolate the output of the opamp (or temporarily disconnect it completely) while you connect your own device.


By the way, I just released the video I mentioned earlier that might be relevant to this:



The most important thing related to this is that yes, all the audio circuitry will affect the signal beyond a certain frequency. And that if you're just testing, the BUSY signal on the printer port is a very tempting place to hook it up (it means you need to change the loader though).

[SerErris]

I am thinking of a rerouting (e.g. if I use the Raspi, cut off the original opamp and ingest the raspi singla). If not used path through the OPamp as original.