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TraiZor

jittering?

29 posts in this topic

Sometimes the midi in led of the rm1x lights up... that means that a midi value has changed without even touching the midibox.

This is annoying, especially with the sequencer! notes change from time to time. I checked the dynamic jitter filter, but doesn't really help.

What should I do? Placing some caps?

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Normaly jittering values should be history, most users don't notice this anymore...

How did you connect the pots to the AINx4 module, are you able to send me a photo so that I can give you some suggestions regarding the wiring? Alternatively you can describe it: how long are the cables, how did you connect the pots together?

From my experience this is the best wiring method: starlike

pot_wiring.jpg

Best Regards, Thorsten.

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Hi Thorsten,

the cables to the main board are approx 40cm long, and the pots are connected starlike.

hmm, seems like i can't attach pictures on this forum. I'll look for some space where i can upload it.

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alright, as I can see here:

traizor_pots.jpg

you are not using the original layouts, so I will remind some design tips, how to eliminate pot jittering. Just check the suggestions step by step, one of them could be the reason why the analog signals get unstable:

  • increase the input voltage of the 7805 (MBHP core module, J1). If this voltage is too low (< 7V), the 5V output of the voltage regulator will begin to oscillate. But don't increase the input voltage above 10V, because on this way the 7805 gets very hot and will oscillate again due to temperature noise. -> Best results with 7V-10V
  • ensure that the pots, the PIC and the analog multiplexers are working on the same voltage level, here a diagramm:
    voltage_issue.gif
    the power connections to the pots, analog multiplexers and to the PIC have to be wired starlike
  • if you own a multimeter, check the voltage levels on the pots. They must be the same like on the PIC: 0/+5V. You can ensure this on the following way: connect one probe with the +5V pin of a pot, the other probe with the Vdd pin of the PIC (pin #11): the voltage drop must be 0(!)V. Thereafter check the 0V pin with Vss of the PIC (pin #12), voltage drop must be 0V as well. The voltage drop between the 5V and the 0V pin of a pot must be 5V of course...
  • if this doesn't help to find the problem, reduce the cable length! In my box, the multiplexers are placed very near by the pots, so that the cables are very short.
    mbhp_ain_8.jpg
    For the analog outputs of the multiplexers I've used a 50cm ribbon cable, so here the length doesn't matter.

Let me know if one of these ideas helped.

Best Regards, Thorsten.

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Hi Thorsten,

I have checked these notes step by step and found this:

- input voltage is 8,6V, should be fine. (btw, i've attached a colling plate on the 7805)

- I've made an extra wire to make the power supply starlike.

- I checked these voltages and these are 0V.

However, the jittering doesn't stop  :-/

I can reduce the cable length, but I don't like that option. Is there an option with placing little caps on the pots or something?

And what about a metal/wooden casing?

Regards, TraiZor

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Yes! It worked!  ;D

I had forgotten another wire..   8)

Now it seems to be stable. It didn't jitter for a few minutes, so I think that it's jitter-proof now :)

Thank you, Thorsten!   ;D

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Cooool! I *love* these kind of solved problems! :D

Best Regards, Thorsten.

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I have almost the same problem but only with my sliders the pots are ok, some times, slider one sends a message to ableton live and apears as 7/95 on the midi assing screen but some times ocilates like 6/95,7/95,8/95,13/95, some times the volume is jittering alot, or even other slider some times sends the same message that was previously assigened with other slider.

bellow is a sheet of my wiring i have 2 joysitcks but am showing those as two pots inside a box (for the signal [pot middle] wire the longest is not more than 40cm.

Is this wiring correct????????????????

7f3159bb5e.gif

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Hi Rigo,

are the components already mounted on a metal penal? Then it could be required to ground the outer metal case of the faders.

It would also be interesting, which jitter is displayed by the "jitter mon" application

Best Regards, Thorsten.

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Hi Thorsten

Yes in fact everything is mounted in the aluminum front panel,which is not grounded at the time I do the checking because I have to separate the entire pannel to get acces to the modules, I have done some checking agian using the first input on (coreJ5) for the four outputs on in the AIN well for the first output( i guess it should be called the first multiplexer) all 8 pots work good, using the same input conected to the 2nd multeplexer and grounding all others  it gives me some erratic messages, the 3rd multiplexer that has 2 sliders and grounding all others same thing,  the 4th(all) sliders is totaly a mess, am going to try to ground every single pot and slider to check if it works, any sugestions to ground the pots? for the sliders i can use the mounting pins but should I just try to solder the outer shell of the pots? when I ground all J5 inputs the module only sends the first upload request, and then it just stays there, no random messages or anything that may show a short cuircuit in the core

I just confirm it is not jittering it sends random messeges,

it is sending messages that are assing to other pots, even if i do not touch them,

and well i assum that the messages are not that random because it is only for the chorus and reverb CC

this is not the actual screen of midi ox monitor but the idea is the same:

183    91      1          6

180    95      44        5

183    91      4          6

180    95      44        5

183    96      100        5

180    95      44        5

183    91      4          8

176    90      120      16

177    90      95        5

180    95      97        15

Thank you  :)

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Also I forgot, how do I run the"jitter mon" application?

Than you again

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well I tried to ground the outer shells for the sliders and pots but, still having same problem, I remember at the time I placed the multiplexers the power was on (by accident), could it be that I have faulty multiplexers because of that???

thank you

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The jitter monitor is a special MIOS application which can be downloaded from http://www.ucapps.de/mios_download.html

You could try this out by swapping the 4051 chips. If different MIDI events are sent, you know that there is a problem with the multiplexer.

and well i assum that the messages are not that random because it is only for the chorus and reverb CC

this is not the actual screen of midi ox monitor but the idea is the same:

183    91      1          6

180    95      44        5

183    91      4          6

180    95      44        5

183    96      100        5

180    95      44        5

183    91      4          8

176    90      120      16

177    90      95        5

180    95      97        15

With hexadecimal output debugging would be easier, because the midibox64.ini file (part of mk_syx.zip) contains the mapping. This means: if you map the events to the pot number, you know exactly which analog inputs are sending random values...

Best Regards, Thorsten.

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Hi TK

ok If am getting this right, I should first check with the one "good" 4051  into the other sockets? if the good pots correspond to the good 4051 I guess i should change the faulty 4051s. and abount jitter monitor if i Have the midi box64 uploaded do i just upload the main  file (jitter mon) when it asks for the upload request at the turn on?

I don't understand that "The pin has to be selected with two inc/dec buttons"

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You don't know the good 4051 yet, therefore just swap two of them in the hope to see any differences

The jitter monitor allows you to select the analog input which should be measured with two buttons. One button, which increments the number, another which decrements the number. See the main.asm file, on which digital inputs they are expected (you could also change the digital pins if required)

Best Regards, Thorsten.

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do i have to have a din module?

am confused, hehehe i dont know anything about electronics so it is kind of difficult to understand, about the jitter mon do i just upload it to the core???? and turn it it to check what happens?

am reading the asm, shows than at DIN#0  it decrements and at DIN#1 it increments, so where is din 0 or 1 do i have to conect abutton to those pins and the oter pin in the switch to ground?

this is my box, one core, one ain, no lcd, so if the jitter mon is uploaded to the core is it going to respond to those buttons? so i can select the ain pin an see if it is jittering so i can go one at a time and check? like "multiplexer #1- pot#1, multiplexer#1-pot#2, and so on, and also is it going to show everything in the midi ox imput screen?

am very sorry that am not getting it, sorry.

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am confused, hehehe i dont know anything about electronics so it is kind of difficult to understand, about the jitter mon do i just upload it to the core? and turn it it to check what happens?

am reading the asm, shows than at DIN#0  it decrements and at DIN#1 it increments, so where is din 0 or 1 do i have to conect abutton to those pins and the oter pin in the switch to ground?

If you have already MIOS on the core, just upload the jittermon and - when the jitter meassurement is done - upload the origanal application again.

To swich through the pots, you`ll need at least 1 digital in for one buton. So you need at least one 74HC165 connected to the core. Minimal circuit can be found on the DIN page (http://www.ucapps.de/mbhp/mbhp_dinx1.pdf).

this is my box, one core, one ain, no lcd, so if the jitter mon is uploaded to the core is it going to respond to those buttons? so i can select the ain pin an see if it is jittering so i can go one at a time and check? like "multiplexer #1- pot#1, multiplexer#1-pot#2, and so on, and also is it going to show everything in the midi ox imput screen?

Sorry but you need a LCD as jitter mon doesn't send any midi values but shows the values on the LCD. So before buying a LCD it would be easier to follow Thorstens tip to swap the 4051s and see what's happening.

Raphael

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ok I understand it now, thank you raphael

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Ok

Well I still have the problem but I found some more information;

-I changed the pot sets( I have 4 sets of 8 pots each)

now I know that the wiring and pots are ok since every set of pots that I conect to the J1 pins (A0,A1,A2.....Vd) are flawless, very stable, no jittering no strange messages. I conected all 4 sets of pots (one at a time off course) to the J1 Pins and all worked perfectly, then I swaped all 4051 to the first socket the one that corresponds to J1 and every single one works perfectly also, what should I do then? it seems that everything that I connect to J1 works no matter of wich 4051 is in that socket and J2, J3, and J4 are not working correctly, regardless of the 4051s, what should I do, buy a new AIN board?

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Alright! I don't think that you need a new AIN board, just debug the current one.

There are some bridges, are they all soldered properly? Note especially the flexible cable connections (yellow thin wires in the mbhp_ainx4.gif file) - You could also add some more solder to the pins of sockets and connectors, maybe this already helps!

Best Regards, Thorsten.

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Hi there TK

Am using an AIN R2 are those thin yellow wires still in the R2?

Thank you

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hm... don't remember - Smash?

Best Regards, Thorsten.

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Also I almost forgot,

On IC#1 with the multiplexer in and no power, I check with the conductivity and if I put the common end on pin #1 has conductivity(beeps) with pins 6,7 and 8 but this does not happen with the rest of the 4051s, is it ok? is that ok?

Thank you

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I just checked R2 has only 2 Jumpers.

So I think I should start to un-solder and re-solder everything back again.

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