Hi,
I was wondering if my sammichFM is quiet. When I am using four instruments, I get in around 70% of maximum peak volume to my soundcard. The volumes are set in the user menu to 127, I am using the default patch instruments.
Mine is also soft and I’m pretty sure it’s due to the low power op-amps being used. I would recommend fixing it in post or putting a amp-stage (say a mixer or maybe a Cmoy Headphone Amp) in front of it is you need to boost the signals into your sound-card.
I would guess the reason the low-power op-amps were used was to keep the power supply solution simple as they can work with as low as +/- 2.5V.
The normal OPL board uses 12v and -12v OP amps. Which means building a more complex PSU.