Sony
MZ-RH1 mic input noise by John Beale Dec. 2006
The MZ-RH1 mic input amplifier has a relatively low noise floor. In the
highest gain setting, I measured my model (s/n 5041476) to have an
input noise at -122 dBu
(unweighted), with the input being a shielded 150 ohm metal-film
resistor to ground on each channel, at 20 deg. C. When the internal
memory
buffer fills and the minidisc motor spins up to write out the data to
disc,
which happens approximately 6 seconds out of every 26 second period in
PCM recording mode, it creates about 2 dB of additional noise. It looks
more significant than it sounds in the left-hand illustration. In the
expanded plot on the right you can see that the noise spikes are very
short in duration, and audibly they sound like a faint sputtering noise.
Click on image below for larger view
RH1 input noise, amplified
noise, expanded horizontal scale
RH1 motor noise.mp3 (6 seconds
off, 6 seconds on, 3 seconds off)
input: 150 ohm resistor to ground on each channel; shielded.
