By skylab001 Sat Dec 05, 2009 9:53 pm
I just noticed today for the first time, sample retention. I had not noticed it previously, it seemed to always string samples that were in memory....or so I thought. It happened when I was sampling a bunch of keys and no percussion or drums, It faintly played back drums. The machine was just turned on and no disk had been loaded since yesterday. So this has me thinking that there is somewhere in circuit that is holding a low charge when the device is off allowing a chip to retain these samples. I also noticed a little distortion in the sounds which is something I have found in other devices that retain sound on a ram chip and the power is low. I have a couple battery powered devices that I have made in the past that will record small 8-bit phrases and when the battery begins to die the audio gets more distorted and eventually becomes noise. So either the RAM is retaining or there is another IC, maybe a sample and hold chip that has the ability to retain the samples as well.....maybe a sampling buffer......or gasp.....the DSP?? Since my knowledge of digital circuits is small and the MPC is much like an 80's computer I hope a tech with MPC60 experience who knows the circuit may lend some advice as to what chip or part of the circuit has potential to be storing these sample. That could get us closer to knowing what the problem is.