I'm not sure I would agree with Kirkus' assessment of FETs limiting bandwidth. Its all in how you design the circuit.
I can't think of a good reason for such a low input impedance, unless the equipment was originally designed for studio use, in which case I can think of some excellent reasons. When we built our MP-1 preamp, despite it being the first balanced line preamp made for home use, it did not occur to us to not support the balanced standard (A.K.A. AES48).
So our preamps (which are tube and have a patented direct-coupled output, as a means to get around having to use a line transformer) have no problems driving input impedances this low, since this sort of thing is common with the balanced standard.
This being the simpler explanation (support of the balanced standard), I suspect it to be the correct one.
At any rate you are not limited to solid state preamps, you can use tube preamps and the latter does not have to have a line output transformer to do the job.
I can't think of a good reason for such a low input impedance, unless the equipment was originally designed for studio use, in which case I can think of some excellent reasons. When we built our MP-1 preamp, despite it being the first balanced line preamp made for home use, it did not occur to us to not support the balanced standard (A.K.A. AES48).
So our preamps (which are tube and have a patented direct-coupled output, as a means to get around having to use a line transformer) have no problems driving input impedances this low, since this sort of thing is common with the balanced standard.
This being the simpler explanation (support of the balanced standard), I suspect it to be the correct one.
At any rate you are not limited to solid state preamps, you can use tube preamps and the latter does not have to have a line output transformer to do the job.