Thought I'd start a new thread for this.
First step is to jot down a rough schematic for my PT01 so planning mods will be easier. Note that not all the components have the correct names yet.
Some things to note :
- This is for the PT01USB version, which has an extra connector (TE13) on the main board that sends the signal to the USB board, and the motor control circuit uses a different IC. The circuit looks broadly similar to the regular PT-01 however and the components have the same names.
- The top section of the schematic is the main audio/motor board, the bottom section is the power supply/IO board.
- Connector TE11 connects to TE12 via the black ribbon cable.
- The phono preamps are a common-emitter class A transistor design with no proper RIAA equalisation. This might actually be a good thing as most of us turn the bass down when cutting anyway.
- The L/R connectors on the black ribbon cable are actually AFTER the power amp. Wiring a fader in at this point probably isn't a great idea as they aren't really meant to handle that kind of power, but I guess if it works it works.
- A better place to put faders would probably be after the DC-blocking caps C8/C18, or perhaps after connector TE8 (the tone/volume knobs).
- For an AUX IN port, putting a couple of resistors in series with the AUX and connecting it to TE8 pins 1 and 3 (or 4 and 6 if you don't want it to be affected by the volume/tone knobs) would probably work.
Next step is to reverse-engineer the motor control section, hopefully ultrapitch will be doable.