Problems With The 4000 Analog (8) Output Option ?

Hey guys, I need a little help. I recently tried running my 4000 at 96 Khz and have been noticing a 'crackling noise' coming out of the analog outputs when I send the samples to their individual outputs and even when I am not. There is also an see-saw like up and down increase and decrease in db on the outputs while this is happening. When I bought the machine, the Analog Output Option was already installed and I have no other output options installed (as in the ADAT or S/pdif options), Although it seems to work fine at 44.1 Khz. Any suggestions on what might be the problem would certainly be appreciated. Thanks. - Reub.

had a similar problem with my 2k when i had it, reseating the board got rid of it.
Strange it only happens a 96khz though.
g

I have had this problem with my analog I/O expansion as well. I never did figure out the problem. In my case it was intermittent -- not every time time I used the machine but from time to time.

-illiac

Hey, I was wondering if it had anything to do with not having the S/Pdif or ADAT option installed, possibly being related to a clocking issue? I did try and re-seat it but to no avail but then again, maybe I'm doing the re-seating wrong ! I did notice two strange things though: 1) The outputs actually work fine at 44.1 Khz and, 2) When I applied a little pressure to the the the end of the output board's connection ribbon and held it down [where it meets with the lower connector board], I can get the crackling to stop, provided that I hold on to the end of the ribbon and apply pressure to where it meets the connection on the board. This makes me think that it could be the actual connection ribbon/cable, but I am not sure. Foge1's suggestions gave me a start in the right direction. Thanks ! If anyone else has any other suggestions on how to proceed, it would be much appreciated ! Thanks. - Reub

do you actually need 96k? can you hear a big difference? if not 44 cause your probably recording into 24,so your sound will be converted anyway.other than that replace perhaps the ribbon.wish I could be more helpful!

ReuBen KinKade wrote:Hey, I was wondering if it had anything to do with not having the S/Pdif or ADAT option installed, possibly being related to a clocking issue?

When I was experiencing this problem, I had the S/PDIF option card installed, and if anything it seemed to make the problem worse rather than better. Removing it did not make the problem go away altogether however. i began to wonder about a bad filter capacitor in the MPC's power supply, but I never got around to investigating that possibility any further.

FWIW,

-illiac

Thanks guys. That insight was very helpful Illiac, thanks ! I guess this will just be one of those things that I'll have to live; with in the MPC - Working in a 48Khz environment or sending it out to the factory. I prefer to work with things at 96 Khz because the tightness and imaging of the samples sound better in the mix field. Also, when I get the Wordclock option, clocking the MPC to a Big Ben or Atomic Clock will definitely clarify the imaging of the sound overall. I may just have to send the machine in. Other than that , I love 4000 ! If anyone has any other suggestions I'd appreciate it. Thanks guys.

ReuBen KinKade wrote:Also, when I get the Wordclock option, clocking the MPC to a Big Ben or Atomic Clock will definitely clarify the imaging of the sound overall.

I have a Big Ben, and I've clocked the MPC4000 to it, and it makes exactly no difference in the sound that I've been able to hear. I'd urge you to be unsentimental about word clocks, because they burn up your money if you don't really need one: get it if you have so many pieces of digital gear synched together that you can't easily daisy-chain the word clock, or if you have another esoteric requirement that the Big Ben satisfies, like deriving and distributing the word clock from an AES/EBU signal, something like that. Don't get it to improve sound, it won't do that, and there are a million better ways to do it that cost less and that actually work.

It sounds to me like you and I have exactly the same problem with the analog out option card. If you ever figure out what's going on, I'd love to know. I am in Beijing so I can't easily send mine in for repair, but if I knew what the problem was I might be able to fix it myself or get someone local to do it. thx.

-illiac