Small issue with Aion Cerulean (KOT single-channel)

[Elvis Cocho]

Hello everyone. I was wondering if I might get a little help with my single-channel KOT (older cerulean pcb) build using the Aion Cerulean board. I built it with only the first quad of diodes leaving diodes 4 through 8 out of the circuit. I kept it simple and put no other mods other than the hard-clipping mod as described on the build instructions. I used a standard SPDT (center-off) switch and I jumpered A1 to S1 and A2 to S2. Again, I followed the instructions exactly. Everything works, but I'm a little confused about what the switch does. I can clearly hear a difference between the switch in the middle position and the bottom position. But when I put the switch in the top position, There is no change in the sound. Did I happen to miss something on my build? There was nothing in the instructions about putting anything on S3, so there isn't anything going to that pad. Or was I supposed to use an on-on switch even though the instructions clearly say to use a center-off switch.

[GGBB]

It would really help if you could point us to the schematic where A1, A2, S1, S2, S3 mean something.

[Elvis Cocho]

I was hoping that I might get a reply from someone who has already built off the Aion Cerulean pcb, but you're absolutely right; a schematic would help. I appreciate the help in advance.

[GGBB]

If you didn't use all of the diodes, then half of the switch is non-functional. You could use an SPDT on-on or SPST switch instead and then you'll only have two positions.

[Elvis Cocho]

So, then the same switch I used also puts in the second set of diodes? I thought that was controlled by SW1, that's the switch that I left out of my build.

[GGBB]

The schematic is somewhat incomplete - it shows two switches but there are a whole bunch of connections that it doesn't bother to label properly - I guess there's a build doc to explain those. The only connections that appear to be clear are the SW1 connections, so I assumed you used the on-off-on switch for that with only one half of the diodes, giving you effectively a clipping switch that does on-off-off. If you had used all the diodes, and the diodes were different types to produce different clipping, you'd have three different modes - off, one set of diodes, and the other set of diodes. If you used SW2 - I have no idea from the schematic what that is supposed to be connected to.

[aion]

So, then the same switch I used also puts in the second set of diodes? I thought that was controlled by SW1, that's the switch that I left out of my build.

The diode clipping switch (SW1) allows you to choose between two different sets of diodes. If you only want to have one set of diodes available, then the switch isn't necessary. If you want to have only one set of diodes plus an "off" or diode-lift mode, you could use a SPDT on-on and omit the 2nd set of diodes. Or, you could put a different combination of diodes in the 2nd set and the switch would be able to select those.

The multi-function switch (SW2) can be used for hard clipping, in which case, like the soft clipping switch, it allows for switching between 2 sets of diodes. Same story here, if you only want one diode option plus an "off" mode then you could use a SPDT if you want.

Hope that clears things up!