This one has been bumping around the TB classifieds all week
For Sale - EHX Black Finger Compressor w/box - also great as an overdrive
*I'm in no way affiliated with this seller*, but I did also find it visually interesting when I came across it
Wish I had the money to spare and lived in the US, then I would have bought it.
I know it's not exactly expensive, but unfortunately I live on a pretty tight budget at the moment, should look better in a couple of months though.
But this pedal is not exactly rare to find as of yet though, as it was the last of that series of big tube pedals from EHX that went out of production, so some stores might even still have some in their stock.
I really ought to get me a spare one, in case something unfixable happens to the one I got, since it's my number one favorite pedal and it is quite essential for my tone.
Just adds a really nice touch to it, somehow enhancing my tone, but in a relatively subtle and non intrusive way, and I don't think it's just the tubes in it that does it.
And as said it is also amazingly great for adding just a slight touch of subtle very dynamic tuby grid and hair, or more pronounced tube overdrive for that matter, to your tone, if that is what you are going for.
On bass though I run it fairly clean, like setting the input gain to just before the tubes start to break up when I dig in the hardest, as said mainly using it as a tube preamp with the compression set to only softly starting to kick in when I begin to dig in, with a rather slow attack time too, and with most of the subtle compression applied to the lower frequency spectrum, but I actually use it as my main overdrive in my guitar setup.
Truly a great, and in my opinion underappreciated, pedal, even if it does have it share of dedicated followers, and actually cheap too compared to what you get.
This guy here uses one as his always on "tube colorizer/enhancer" as well (he mentions it shortly and gives a very brief demonstration around the 4:38 mark).:
He doesn't use quite the same settings as I do though.
I have mine set with more input gain, less compression, and in the "Lamp" mode (the source of the optical compression circuit), which gives a bit slower attack time and effects the higher frequency range less and the low end more, whereas the "Led" mode he uses his Black Finger in results in a, frequency wise, more linearly compression and a bit faster attack time.