It is a single transistor preamp (there is also an entry ID)
controls are the input gain and feedback, which is the output volume but it also colors the sound (it's not super practical as it is the same button for both functions but hey we cope)

There is a pad (something like-15dB) and a button "thick" which increases the frequency sensibilté serious preamp.

UTILIZATION

...

SOUND QUALITY

It's really great.
on the other hand is not transparent at all so it depends on taste and sound sources.

I do not recommend having germanium as your only preamp.
For example, I have a TPA-200b summit of audio which is really transparent and germanium. I like that each time a choice if I want to sound rather then of colored lens or according to what I want to take issue.

The sound of the germanium is warm, I would say "vintage".
I use a micro Soundelux U195 and it works very well.
I must admit that I used even more as the Summit TPA-200B (although it costs around 2500 euros, stereo), especially for vocals and acoustic guitars.

Here, therefore I love
By PS I try to go against when samples in (since my sampler, it sounds orchestral instruments, percussion, scratching) or when a virtual guitar amp and Vox Tonelab as well , it works poorly. For this application I feel that a transparent preamp works best.

OVERALL OPINION

In conclusion, I think it's an excellent preamp!
in combination to have another more neutral preamp.

But remember that this is a preamp so some unusual not like at all.
Also, there are combinations of mic / preamp that work better than others so obviously my opinion only reflects my own experience (the U195)