Update, 21/10/2020: The TL071 OP Amp's open loop frequency response and phase shift was obtained from the TL071 data sheet online. It's frequency response resembles an amplifier with high DC gain, and with one low frequency pole, ie -3dB point.
My experimental headphone amplifier (Headphone Amp) has one TL071 in a non-inverting, unity gain configuration. On examining the data sheet, one can see that at unity gain, the TL071 has a bandwidth of approximately 4Mhz. Also, from a stability point of view, note the phase shift at 4Mhz at around -100°!
With the inclusion of a 1.5nF load capacitor CL, it is no surprize then that the amp was destabilizing. My temporary circuit layout must have also possessed sufficient parasitic capacitance to render the TL071 almost unuseable. Removing the 1.5nF additional load returned the amp to stability.
21/10/2020: Subject to corrections, and additions.
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