So, I received it yesterday. I tried it out with my headphones only, I will try it out on my GK 2x12" Neo cabinet tomorrow but I can probably evaluate the preamp better through my headphones anyway.
The input pad definitely darkens the tone, probably drops the input impedance. Honestly, I wouldn’t obsess over the clip light. I can get the preamp to distort more with the pad engaged and the gain cranked, even if the LED never lights up. Without the pad it distorts in a nicer way, so it’s clearly hitting a different gain stage. You can get a decent amount of dirt out of it, but it’s not a high-gain amp. Sweet spot for the gain is roughly between 9 o’clock and 1 o’clock.
The compressor works, but most of the usable range is in the first little bit of the knob’s travel. By halfway it’s far too much for my taste, though I’m not into heavy compression anyway. To be fair, that’s been my experience with pretty much every bass compressor I’ve tried, pedal or amp: once you’re past a certain point, it’s way over the top. This one is very squashy, feels like a pretty high ratio, and once it kicks in it clamps hard. Around 9 o’clock it’s noticeable and sounds good. My pedal compressor is set up differently (shorter attack/release, lower ratio), so I’d still stick with that, but the amp’s comp is perfectly serviceable. The knob controls threshold, not input gain, so more compression means less volume. That’s probably more "honest" and the right way to do it since you really hear the compression working instead of the volume rising (which makes everything sound nicer), but it’s not as intuitive.
The EQ is nice and musical, not over the top. You can tweak it without it going weird or artificial too quickly. Feels like it’s got a limited range, maybe ±6 to 9 dB tops, which is fine by me — I’ve never boosted or cut more than 6 dB on bass anyway. “Flat” or close to it seems to be with the bass rolled back slightly, about 10 o’clock. I like the mid control, 2.5kHz is where I see myself using it at mostly, but 600 and 220Hz can be good places to cut (especially 600Hz) sometimes. The big master knob steps through in clicks and makes a bit of noise when you turn it, but I think it’s meant to be left in one place while you adjust volume with the other control (there are two).
For €355 brand new, I’m happy. It’s not a miracle amp head, but it does the job well.