Moodring Voltages

[diablochris6]

Per the voltages Madbean posted on the Moodring build doc, I see that pin 1 of IC4 is 4.16V and pin 16 of the Pt2399 is down to 2.52V. Anybody care to help me understand why this drop happens? Are the resistors leading to the PT2399 acting as voltage dividers?

[m-Kresol]

I'll try to do my best with my very rudamental understanding of electronics. Also, I have no idea of your level so I'll try to be as basic as possible.
From Pin1 of IC4A you have a 10k resistor. According to the laws of Kirchhoff the sum of voltages in a circuit is 0 (hard to explain for me, look it up on wikipedia if you're not familiar with it), which means that you have to have a voltage drop over this resistor. The voltage drop is depending on the initial voltage of course and the resistors in this specific part of the circuit. After that first voltage drop you have a crossing to R14 and R31 which forms a "loaded voltage divider" (if that is the correct english term). So the voltage is split according to the respective resistance values. Also, there is another voltage drop over R14 leading to the reduced voltage on Pin16 of the Pt2399.
hope that helps a little.

[madbean]

Per the voltages Madbean posted on the Moodring build doc, I see that pin 1 of IC4 is 4.16V and pin 16 of the Pt2399 is down to 2.52V. Anybody care to help me understand why this drop happens? Are the resistors leading to the PT2399 acting as voltage dividers?

Pin16 of the PT2399 is the input, not power pin. It is fixed at the bias voltage of the PT2399, which is about 2.5v. Pin1 is the power which should be about 5v.
For pin1 of IC4 - 4.5 is expected, but DMM can act as a small voltage divider when you measure pins on an IC. It's not terribly concerning to measure a slightly small voltage there, AFAIK.

[diablochris6]

Thanks for the info, guys. I haven't had to touch basic physics for a decade, so I am a bit rusty. After looking at the PT2399 block diagram, I see that the opamp relating to pins 15 & 16 would get the 2.5V supply. I was curious how the circuit interacts between IC4 and the Pt2399. I am just trying to wrap my head around how the extra PT2399 works with the reverb pedals such as the Moodring and Ghost Echo.

And, huzzah! This is my 100th post! Glad to be part of an open community where I can learn so much.