The struggle is real, and the reward so sweet

[dirty_g]

Got the 1v/oct VCO working. For some reason I made it in the mirror image the first time around assuming the diagram must be the bottom of the board because the strips were visible…

Super stoked to have a working oscillator that I made myself looking at pictures on the internet though!

Made the core module only. One of the outputs is much louder than the other so I’ll check into that.

Just wanted to thank everyone for the help you’ve been giving with some of the other projects I attempted before this one. Great community here. I look forward to building out a great big behemoth of curious sounds!

[Caustic]

If the square is loudest, thats normal. The triangle will be quietest.

[antoine.pasde2]

Congrats!

@dirty_g

For some reason I made it in the mirror image the first time around assuming the diagram must be the bottom of the board because the strips were visible…

Makes perfect sense, now that you mention it, I’m surprised the mistake doesn’t happen more often.

@dirty_g

One of the outputs is much louder than the other so I’ll check into that.

The sawtooth has a lot more power in its harmonics so it may sound louder.

[Bitnik]

If you wired it back to front, does the music come out backwards? Asking for a friend.

[fredrik]

@dirty_g

One of the outputs is much louder than the other so I’ll check into that.

The different outputs on the 3340 have different voltage levels:

1222 Tuner VCO Module

Yeah, pulse is +Vcc minus voltage drop over the output transistor (which depends on current, but is nominally +Vcc−1.5V), while triangle output is fixed at +Vcc/3 (so 4 V with a 12 V supply) and any non-trivial load will affect the tuning (so you really want a buffer on that one). Ramp/sawtooth is +Vcc×2/3 (8 V), with more internal buffering. (there may be an argument for turning triangle or ramp into PWM outside the chip to make things more stable, cf the AS3340-HYB variant discussed here, but…

but different waveforms also have different RMS values (equivalent DC power), and as noted above different apparent loudness, due to different amounts of harmonics/overtones. Plus that your hearing isn’t exactly linear.

[Caustic]

TLDR;
That’s pretty normal, it gets ‘fixed’ when you have a mixer and a VCA.

[dirty_g]

That would’ve saved me a good amount of work, because I would’ve just kept it and boasted about the crazy sounds I made…

Wiring it backward, however, made me realize I need to read more about what these odd-looking little chips do, and sent me down the path of googling pinouts and trying to understand previously mysterious and arcane magics unfathomed by a guy whose previous electrical experiments have been limited to such mundane things as guitar effect bypass pedals.