I have read a lot of opinions regarding the Black Finger and I think there is a big misunderstanding about this compressor

I have just ordered and received an unit, so I have made measurement and checked some values.
1) Test configuration : inserting the BF into a Presonus FireBox Sound Card :

Input and ouput level (unity gain) are set to 0,775V
RMS FS, test signal is 0dBFS@1kHz.
2) Noise
With Pre and Post gain set to max; the BF gain is 50dB and the noise reaches -40dB, a very bad value indeed, but don't forget that 50dB is a very hi gain.
With Pre and Post gain set to normal conditions, the BF gain is 0dB (unity gain) : Noise reaches now -91dB, a very good value which cannot be eared in normal situation.
3) Distortion :
A good value for a tube device, please note that I have fitted a RTC 12AX7S (Mullard anode box) and a Amperex Bugle Boy 12AX7 instead of the original 12AX7EH.
"Compress" potentiometer doesn't affect the distortion value.
4) Input impedance :
I checked twice the measurement, but it's true :
50kΩ !

A very very bad value, a passive bass cannot be directly plugged into the BF, it's a too low impedance. 1MΩ is a correct value but not 50kΩ.
This impedance is compatible with an active bass or with the output of another stomp box without any problem.
BF is a line level device but not a passive bass preamplifier.
5) Conclusions
The Black Finger doesn't generate any noise if it is correctly used :
it's a compressor, not a preamplifier :
- No passive bass directly plugged into the BF because of its low impedance and the consecutive noise generated by the high gain (passive basses have generally a low level output and needs some gain in order to reach a good level).
- Using an active bass with a high output level or after a boost/preamp pedal is OK
- Pre and Post gain should be only used to finely adjust the input level and to compensate the loss of level due to the compression process (makeup gain).
- The best solution is to insert the BF into the FxLoop of a preamplifier (Demeter VTPB 201 for my gig) with line level value (0,5 ~ 2VRMS); in this configuration the BF rules, noise cannot be eared
Shame on Electro Harmonix : they don't tell anything in their "documentation" sheet about levels and impedance. Why ?
The Black Finger is a killer : a fantastic compressor when it's correctly fitted in the amplification chain and finely adjusted : no noise, a very nice sound, punchy and beefy, sweet or sharped; this Sound Maker stays definitively in my pedalboard now
