TL;DR cassete tape recorder sounds cool when pushed by a headphone amp, here's two vids showing it off.
First, recorder directly pushing the speaker cab:
Second, recorder into TPA3118 amp:
Long version:
A while ago, I acquired a Sony TCM-S64V "cassette-corder" to experiment with lo-fi recording. Recently, I discovered I could use it as a guitar amp by plugging a tape adapter into a headphone amp, pressing "play", then engaging the pause switch (which stops the motor, but keeps the audio circuit on). Since I kinda like it too much and was afraid of possibly damaging it with this experimentation, I found a similar (but more bare-bones in features) TCM-S63 "cassette-corder", cleaned and repaired it, and proceeded to use it in front of my headphone amps and got the exact same great tones as my other "cassette-corder".
It feels just like pushing the front end of a big amp.
I especially like the very compressed start of the attack in the notes. I wonder if it's core saturation from the tape heads, kinda like if you pushed a tube power amp so hard the output transformer started saturating...
I'll leave the analysis of that to you all.
Lastly, to clafiry, the signal chain is:
Guitar>headphone amp>cassette adapter in recorder>out (cabinet or p.a.).
[EDIT]
And for anyone curious, the schematic for these recorders is freely available on Elektrotanya: https://elektrotanya.com/sony_tcm-s63_s64v_s65_s66v.pdf/download.html