Ampeg Opto Comp Compressor

This is both a tool and a beauty filter for your sound, it sounds natural but it's also very fast (a bit too fast) so it can be used as a peak limiter. It's got medium flexibility, the release is great, it can be extremely slow, though I never turn it past 10 o'clock.

Now the bad stuff.
It does darken the sound slightly even with the compression knob at 0 and has a quiet-yet-present hissing noise when active, even with everything at 0 with no signal coming in or out of it. The lack of an Attack knob can make it a bit beginner-friendly but it could have been set slower because now it can choke the sound sometimes.
The internal option of a -15db pan is useful but maybe too extreme, it can be used if you boost everything on your active bass but this could be way better if it just had an input trim pot, like an 1176, since it has a fixed threshold.

For the price it's ok but I wouldn't buy it again, I would try a DynaComp Mini because it has 2 Attack modes and fixed, medium-fast release.

It's so weird to me that this compressor pedal is advertised as a BASS compressor (even though there is no indication of it on the pedal itself). Here's why.

I bough it because I needed a compressor pedal for my tenor sax pedalboard (as low notes on a sax may be very honky). Since optical compressors are preferrable for wind instruments, and I wanted something affordable, I got this one. Even before I tried it with my sax, I tried it with guitar and oh my - I wouldn't want another compressor for a guitar, that's for sure! I'm one of those guys who have been playing the guitar for around 20 years and still can't play good enough, but with this pedal I started sounding so much better and smoother that I didn't want to stop playing once I plugged it in.
But again, I bought it mainly for sax pedalboard and I couldn't be happier about it. All the issues with lower notes are gone - since I'm playing with a looper, it's pretty important that the sound stays consistent. It doesn't kill all the dynamics, however. You can of course do more or less extreme setting on this pedal too, if that's your vibe.
The build quality is great. I love the simplistic and tasteful design, and especially the knobs. I also appreciate the possibility of using a 9V battery - since my power brick is already busy. The footswitch is a bit too stiff to my taste though, but on this pedal it's a good thing, since it's always on (unlike my Ibanes ES-3 for example, where with such a stiff footswitch you have to tap tempo :D).
All in all, it's an amazing pedal. Again, do not think of it as a bass specific compressor. Try it with other instruments or even with vocals and I'm almost sure you will fall in love with it.