I love my Helios 100, it's one of my favorite amps. However I do think it needs a boost to get the most out of it. To me it sounds and feels like they stuffed a hotrodded Plexi in the preamp and paired that with a modernized, stiff power section. However the lower gain input on ch2 is kind of the hidden gem of the amp and although it doesn't seem to get much mainstream attention, is very much worth checking out. And the clean channel is better than it has any right to be, considering it doesn't even use the tonestack. All you can adjust on it is a 3-way bright switch but that's enough.
Here's a Nuno riff I was messing around with during Nuno Fever a couple weeks back. I'm using a RAT as a boost, but mostly as a bass cut. The Drive knob is set just high enough to not choke out the guitar, so like 8:00 or so. Level is at 3:00.
Guitar -> RAT as a boost -> Helios 100 -> Suhr RL -> mix of GB and v30 4x12 IR's
Here's the same playing reamped through the same settings and IRs but no RAT boost. As you can hear, the RAT definitely helps with clarity.
Here's a test riff I was working out a while back. Double tracked through the Helios 100.
I used a Boss GE-7 for a clean boost with slight bass cut.
An old In Flames riff. Same Boss GE-7 boost as above, but dialed in to be just a bit smoother:
A melodic line I was messing around with for a tone test. Again, GE-7 for clean boost: