Any diagram for expansion port EAR input?

[Ast A. Moore]

I checked the output with my scope and it's about 2,5 V square wave and all positive, like in his video.

That should be plenty. Congratulations.

[Lynxman]

I received my cheapo Bluetooth cassette adapter too now and have tried it. It's not as reliable as the EAR input circuit. I had to modify it to get it to work well. The little rubber drive wheel would jam and lock up the tape drive, and the head was crooked and not centered. I also lubricated the gears slightly. Not sure if the gears and the drive mechanism is even needed but it's smooth and doesn't jam now. It came with a mic which also serves as the on switch. I soldered on a little switch instead so that I don't have a microphone sticking out. It's convenient to not have to use a cable to load games though.

[Ast A. Moore]

Not sure about the +2, but on the +2A you don’t even need to press PLAY on the Datacorder to load games. The circuitry is active all the time.

[Joefish]

Thread from the Dead Question -

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128k:


+2:

If I completely rip out the cassette player board from a grey +2, swap that 390 grounding resistor for a 1K with a diode back up over it, haven't I then got the same cassette input circuit as a 48K Speccy? (From pin 4 on the now unused cassette connector, I mean).
Or maybe parallel piggy-back a 470 on the 680 to bring the 680:390 resistor pair down to the same ratio?

Ah, wait, no, there's then no capacitor actually in-line in the circuit. But can that then just go in anywhere? e.g. between a hypothetical cassette input jack socket and that there pin 4?

(No, I'm not going to build a whole new amplifier - it's got to be simpler than that!)

[Ast A. Moore]

If I completely rip out the cassette player board from a grey +2, swap that 390 grounding resistor for a 1K with a diode back up over it, haven't I then got the same cassette input circuit as a 48K Speccy? (From pin 4 on the now unused cassette connector, I mean).

Well, yes, aside from the capacitor, which is there just to remove any DC offset. If fact, looking at the values of the components, they are identical between a 48K Speccy and a Toastrack.

Ah, wait, no, there's then no capacitor actually in-line in the circuit. But can that then just go in anywhere? e.g. between a hypothetical cassette input jack socket and that there pin 4?

Technically, yes, although it might created some unwanted filtering via an RC circuit.

But why not replicate the circuitry exactly? It’s just a few of components anyway, and half of them are already on the board.

P.S. On my +2B, when I modded the 3.5 mm plug to accept an external audio input, I had to bypass C200 altogether. Otherwise, nothing would load with the weak audio signal produced by my phone or computer. (C200 is still in-circuit when loading from the built-in Datacorder, though.)