[Radio Wrangler]

Looking at the circuit, 330pf shunt, straight across the input would be very wasteful of the signal from a piezo-electric cartridge, but could be considered to be a load on a magnetic cartridge. The input impedance will not be friendly to piezo cartridges either.

So that starts me thinking it may be for magnetic cartridges.

But if it is, the 47k in the collector and 4.7k in the emitter say that the max open loop gain is only ten before the load the circuit drives and that 330k bias resistor in a feedback position come into play. With a typical magnetic cartridge giving around 5mV, I don't see there being enough gain. I also don't see the frequency response shaping needed for velocity-sensitive pick-ups.

A mystery. It doesn't seem to suit either common type of cartridge, and moving coil would be even further from its capabilities.

I can't say anything further until it's revealed what it is for.

David