tomaswv
Probably had very much to do with his 300m’s only having an extremely low 10k input impedance. Where your 500m’s have very nice high 200k input impedance 20 x higher!!.
There is no spec on the output impedance of magic streamer and how the volume is done, (could be high if they don't spec it)
Where your 851N has very low 0.15 Ohm output impedance better than most preamps.
Cheers George