SounDuke Posted May 7, 2005 Report Share Posted May 7, 2005 Hi everyone, I read a lot of topics regarding jitter and signal interference between pots, but none seem to solve my problem.I have the following hardware on my MB64:1x core2x din I didn't stuff the hc165 on the DIN because I'm experiencing problem with pots and I would like to solve that issue first. They are connected on j5 of the core so I have 8 pots w/o multiplexers. 6 are knobs, 2 are sliders. The pots are connected near the core and they work perfectly, but I experience a lot of interference when I connect the 2 sliders. It is quite normal since the faders are connected via ribbon cable to j5 pins through a subD 25 pole port to another panel (about 2 metres of cable) and the Vss Vdd and wiper cable (4 in total) are very near. I have random data ONLY from the 2 faders, when I move the knobs or when I touch nothing.Is there a solution to this? note that the faders cables are very near to the display cables too, I tried to stuff a cap (different values from 330 pF to 1 mF) between Vss and Vdd, but I noticed only a small reduction of signal noise. Is the length of the cable the problem? Thanks in advance! Quote Link to comment Share on other sites More sharing options...
SounDuke Posted May 7, 2005 Author Report Share Posted May 7, 2005 I forgot: I donwloaded Thorsten's jitter_monitor app and I see jitter values from 01 to 06, worst case 08. I don't pretend to eliminate jittering, but at least eliminate the random data from the 2 faders. Quote Link to comment Share on other sites More sharing options...
SounDuke Posted May 7, 2005 Author Report Share Posted May 7, 2005 Well, it happens that sometimes the two faders send random values of the controllers they are assigned to. And every time I move them or move the knobs the MB sends out those damned random values from the faders... I'm in a deadlock, it seems like the supply pin of the faders are floating, is this because of the length of the cables? I can't use shielded cables since they're too thick for my purpose.. Any idea? Quote Link to comment Share on other sites More sharing options...
TK. Posted May 7, 2005 Report Share Posted May 7, 2005 Hi,It could help to supply the faders directly from J2, to add 100 nF caps between the +5V/Ground pins of each fader, and in addition a 100nF cap between the wiper pin and ground. But in general, without shielded cables you won't have much luck - over such a distance they are really required. Also the sub-d port you are using is not the best choice for analog signals.Best Regards, Thorsten. Quote Link to comment Share on other sites More sharing options...
SounDuke Posted May 7, 2005 Author Report Share Posted May 7, 2005 I had tried this yet, in fact improvements were very slight. TK, do you think that mantaining the sub D port but using shielded cable I can fix the problem? I should use shielded cables for every pin of faders (Vss Vdd and wiper right?) and has anyone got an hint on good shielded cables without exagerated dimensions? thanks Quote Link to comment Share on other sites More sharing options...
TK. Posted May 8, 2005 Report Share Posted May 8, 2005 I think that such a cable should be ok:it's cheap and especially thin. You can use one wire for the wiper, another for +5V, and the shield for ground> do you think that mantaining the sub D port but using shielded cable I can fix the problem?not when you want to achieve lowest jitter, but so long your fader only send 7bit values, it could workBest Regards, Thorsten. Quote Link to comment Share on other sites More sharing options...
SounDuke Posted May 11, 2005 Author Report Share Posted May 11, 2005 Thank you Thorsten ;)I found a way out to customize my MB64 design, your help is truly valuable.As soon as I complete that damned case I'll post photos on forums! :D Quote Link to comment Share on other sites More sharing options...
SounDuke Posted May 12, 2005 Author Report Share Posted May 12, 2005 In my new design, I was wondering if I'll encounter problem with the following setup:I built a pedalboard with 60 keys, installed in it 2 DINx4 and I'd like to connect J1 of the first DINx4 on a 9 poles subD port. 2 m away I have another panel stuffed with core, LCD with the 4 navigation buttons near and 8 pots and another subD 9pole port.I would like to connect the 4 buttons to the female subD on the panel with the pots and the remaining 5 poles to J9 of core, so that core J9 and DIN J1 are connected this way, while the 4 buttons are connected to the serial pins of Dinx4. Do you think I'll have jitter problems? Since those are not analog signal I assume that I'll avoid self-playing keys right? The cables which are near and 2 m long are the connections between core J9 and din J1 + serial pin to buttons. Thanks! Quote Link to comment Share on other sites More sharing options...
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