The IIc’s are weird if you’re used to Marshalls. They’re very unforgiving and sound crappy if you haven’t dialed it in for that guitar. Once you get it right, they are magical though. Nothing else like them. The trick is that you have to think of the gain knob differently, and use very small moves on every adjustment.
- Turn the overdrive down to 1 or 2 temporarily so it doesn’t get in the way while you dial the gain and master
- Treat the gain knob as the “string feel” knob - not as a saturation knob like on a Marshall. If it’s too low, it will feel muffled. If it’s too high every string will thwack the same no matter how hard you hit it. Find the very narrow spot where it transitions between those. It’ll feel good and extra touch sensitive. Copy that to any other channels with the same model that you plan to use
- Then dial the master knob (and compensate with level). Start at 2 or so and sweep it up while picking single notes until everything gets suddenly more dynamic and 3d. Don’t go higher and don’t let the loudness fool you. You won’t hear it if you haven’t dialed the gain knob first.
- once you get those set, you can go back and bring the overdrive back up for the right level of saturation for the sound you’re looking for. You may have to do some fine adjustments on the master afterwards, but not the gain.
- Now you can finally start worrying about EQ. The bass knob is the flub control. Bring it down until the flub disappears on low strings, but not much more than that. The position will depend on how high you have the overdrive. You’ll probably have to fine tune the master again after EQ too.
- Now you can finally worry about the 5 band, which will make everything come together.
It’s worth the annoying process. Just remember the difference between not enough gain (string feel) and too much gain is like + or - 0.4 (or even less) on the knob. It’s that unforgiving. And it has to be set by ear for each guitar unless all of your pickups have similar output.
And I agree with the above about the Mark IV being much more forgiving. Dial it in the same way, but it’s a lot easier to get an acceptable sound with a parameter or two out of the sweet spot. It sounds less studio polished, but more fun to play loud.