Leslie 222 Pre-Amp Circuit Verification
So i posted here a while ago regarding a Leslie 222 Pre-Amp schematic diagram and got absolutely flamed because it was straight AI. This drove me to actually know wtf is going on, so i grinded for a bit, and now Im back. I recently just got all of the parts I ordered and would like a final check on my basic pre-amp schematic before plugging anything in.
I do plan to switch the leslie by injecting DC voltage straight into T1 centertap (controlled by a switch and a DCDC converter) but will wait to do this after I am getting sound out of the speaker. This post is just about the audio signal chain; the DC injection side is a separate piece I'll sort out after this part is verified.
There is a drawing, but incase you cannot read my trash hand writing and poor schematic drawing skills, here is the brief explanation:
Keyboard → 330Ω series (R1) + 1N4148 clamp diodes to ±12V → C1 (1µF, DC block) → NE5532 pin 3, configured as a plain unity-gain voltage follower (pin 2 wired straight to pin 1, no feedback resistors) → pin 1 output → C3 (2.2µF, DC block) → 10kΩ audio pot as a post-buffer level control (wiper to output) → 100Ω series resistor (R4) → transformer primary.
100kΩ bias resistor (R2) from pin 3 to true ground — kept separate from supply decoupling.
±12V dual-rail supply (Mean Well RT-50B), 0.1µF decoupling at both supply pins.
Second op-amp half unused, tied off per standard practice (inverting/non-inverting pins jumpered, non-inverting input grounded).
Separate question: after tying two ~84Ω half-windings together at their common pins to form what should be a single ~167Ω secondary, I'm reading a dead short (0Ω) across the two outer pins instead of the expected sum. Does this suggest the half-windings are tied in the wrong phase/sense relative to each other, or is there another likely cause for a short appearing here?