The AEA TRP500 is a preamplifier specifically designed for dynamic microphones, i.e. plunger coils and ribbons. It delivers an impressive 85dB maximum gain (10 times more gain than usual!) and an extremely high input impedance of 100kOhm. It is well known that the main problem when working with classic, American ribbon microphones is the need for a lot of preamplification, especially with low noise, so that the microphones can be used sensibly, e.g. for acoustic guitar, singers or as room microphones. The consistent transfer of this need into a product AEA has not only mastered with the TRP500, but strictly speaking even overfulfilled, so that you will have peace with this
Although that would actually be enough, the developers have also designed the input stages of the TRP500 to be very high-impedance: As known from guitar pickups, the perceived detail and transient response of a recording increases with the impedance. In addition, there is a straightening of the frequency response, which is extremely useful for ribbons: After all, they are usually almost ideal pressure gradient receivers with figure-of-8 polar pattern and correspondingly bent bass and treble band.