In the Old School build docs I mentioned that the LED on the PCB blinks with the tremolo so you could make it an external indicator if you like. What I failed to notice at the time is that the LED brightness is inverted from the tremolo amplitude. IOW, the LED dims as the tremolo peaks rather than the other way around. So, this might be confusing for some people who are used to seeing the LED get bright when the trem is loudest. Take that into consideration when building.
If anyone finds this super bothersome, you can try the following:
Locate the junction of the collector of the 50288 on the left side of the board (it's the bottom pin) and the 10K resistor R12. Use the continuity setting on your multimeter to verify which side of the 10K is the correct one.
Run a wire from that junction as follows:
wire -> new 10K resistor - > rate LED anode -> LED cathode connects to ground.
Make sure you can reverse this change because it may subtly change the waveform.
I would suggest sticking to a red or at most green LED, if you use blue or white you can increase the 10K a little.
If it's too dim, can reduce the 10K some, but I wouldn't go below 4.7K.
Correction #2: the voltage on the collector of T1 (2n5088 at the output) should be around 9.5, not 17v. Doc has been updated.
I'm so confused...
The black hole of tremolo indication.
So technically, the Tremolo works, doesn't it? Just the matter of the blinking the LED. Do I understand the issue correctly?
Yes.