I have an Ono, it is simple. Simply remove the cover. Look down at the circuit board. You'll notice its dual mono.
On each channel, there are two jumpers, one is located near a big cap, all 4 are CLEARLY marked. One set of jumpers reduces gain by 4dB, the other by 10dB. Note that not all Ono's have this capability, only the later ones do. Simple put jumpers on this pins to reduce gain. With all jumpers removed gain is full, and the Ono has lots of it. Email me if you're still confused.
On each channel, there are two jumpers, one is located near a big cap, all 4 are CLEARLY marked. One set of jumpers reduces gain by 4dB, the other by 10dB. Note that not all Ono's have this capability, only the later ones do. Simple put jumpers on this pins to reduce gain. With all jumpers removed gain is full, and the Ono has lots of it. Email me if you're still confused.