Aion FX Theseus - Incorrect Voltages on IC2

[cvv]

I have built my first pedal, an Aion FX Theseus in kit form (docs -> https://aionfx.com/app/files/docs/theseus_kit_documentation.pdf).

I am getting sound out of both sides, but when checking to make sure I really did get _everything_ right I checked the voltage readings against those on page 30 of the docs and found an anomaly.

The reference voltages (from the docs) are from a 9.6V supply:
  IC1                          IC2
Pin Voltage                  Pin Voltage
1     4.66                    1    4.64
2     4.67                    2    4.64
3     4.25                    3    4.22
4     0.00                    4    0.00
5     4.57                    5    4.54
6     4.57                    6    4.54
7     4.56                    7    4.53
8     9.15                    8    9.15

And my voltages from a 9.4V supply are:
  IC1                          IC2
Pin Voltage                  Pin Voltage
1     4.56                    1    4.47
2     4.57                    2    4.50
3     4.19                    3    4.48
4     0.00                    4    0.00
5     4.48                    5    4.12
6     4.50                    6    4.58
7     4.47                    7    4.56
8     8.97                    8    8.98

From the above it would seem that the voltage on my IC2 pin 5 should be at pin 3 (schematic is on page 28 of the docs if that helps).

After searching I could not find a similar issue, so asking here in the hope that someone might know what I've done wrong.

Many thanks in advance.

[FiveseveN]

It's fine.

[cvv]

It's fine.

Thank you for the quick reply! If you are able to, would you mind taking a look at the schematic? The reason I ask is that I believe (based on my non-electrical engineering background) that the voltages shown in the docs are incorrect if the schematic is correct. As the two sides of the pedal are essentially mirrors, in reading the schematics the voltages from IC1 and IC2 should match as follows (IC1 is the first number in in each tuple):
[1, 7]
[2, 6]
[3, 5]
[4, 4]
[5, 3]
[6, 2]
[7, 1]
[8, 8]

This is from my reading of the schematic and if the schematic is correct (and my reading is too), then my voltages are matching correctly and the voltage readings in the docs are wrong. And if that is the case, I'd like to let Axion know so that others may not get confused in the future.

Again, thank you and Happy New Year!

[FiveseveN]

the voltages from IC1 and IC2 should match as follows

Yes, you got it.
Keep in mind that the doc mentions "Your measured voltages won't be exactly the same due to variance in power supplies and component tolerances". The readings will also depend on your meter's input impedance. In fact the only reason IC1 pin 3 and IC2 pin 5 (the non-inverting inputs) read lower is because they are connected to the voltage source through a high impedance (1M) and are loaded down by the meter. In reality the op amps present an even lighter load so the actual voltage is closer to the nominal half-supply reference, just like the other input and output pins.
As for the table in the doc, yes it's probably a typo or a slip where they assumed the two dual op amps used the same layout.

[antonis]

As long as non-inverting input voltage isn't higher (even slightly) than output/inverting input one, you're generally fine..

[duck_arse]

and ............ welcome to the forum.

[cvv]

the voltages from IC1 and IC2 should match as follows

Yes, you got it.
Keep in mind that the doc mentions "Your measured voltages won't be exactly the same due to variance in power supplies and component tolerances". The readings will also depend on your meter's input impedance. In fact the only reason IC1 pin 3 and IC2 pin 5 (the non-inverting inputs) read lower is because they are connected to the voltage source through a high impedance (1M) and are loaded down by the meter. In reality the op amps present an even lighter load so the actual voltage is closer to the nominal half-supply reference, just like the other input and output pins.
As for the table in the doc, yes it's probably a typo or a slip where they assumed the two dual op amps used the same layout.

Thank you for taking the time to look at the schematics as well as your explaining "why's" of what I am experiencing! Genuinely appreciated!!

[antonis]

Thank you for taking the time to look at the schematics as well as your explaining "why's" of what I am experiencing!

You see, there is a vast minority of Romanians (like FiveseveN) who aren't neither bloodthirsty vampires nor howling wolves..

[cvv]

and ............ welcome to the forum.

Thank you!!