Sansa e200 v1 noise

[yapper]

I think it is common knowledge that the e200 is 'noisy' and if I understand the cause correctly it is due to electrical noise generate during flash access.

Has anyone experimented with adding 'slugging' to the routines that access flash to see if it is possible to reduce the noise? In other words deliberately slow down repeated flash access.

[saratoga]

Yeah I played with it a lot, its definitely possible.  Adjusting the transfer rate definitely shifts the frequency around.  I'd planned to hook up the system to a preamp, then record the power spectral density of the noise at various transfer rates.

I assumed that the noise is the result of mixing in the amplifier between the SD clock the SD bus.  Presumably we could work out a model such that a lot of the noise can be shifted out of the audio band to higher frequencies.  I haven't gotten around to it yet, and its kind of annoying since I don't really understand the SD driver yet.