MB_LINK

[LO]

Hi

I am having a few problems with random midi data it doesnt happen that often but when it does it is very annoying

looks something like this:

00001140   1   2     B1    4D    0C    2  ---  Control Change        

00001145   1   2     B1    4D    0F    2  ---  Control Change        

00001149   1   2     B1    4B    5A    2  ---  Control Change        

00001151   1   2     B1    4B    5B    2  ---  Control Change        

0000115D   1   2     B1    4B    5C    2  ---  Control Change        

00001162   1   2     B1    48    19    2  ---  CC: Release Time      

00001163   1   2     B1    4B    5D    2  ---  Control Change        

0000116F   1   2     B1    4B    5E    2  ---  Control Change        

00001178   1   2     B1    4B    60    2  ---  Control Change        

00001181   1   2     B1    4B    61    2  ---  Control Change        

00001191   1   2     B1    4B    63    2  ---  Control Change        

0000119B   1   2     B1    4B    64    2  ---  Control Change  

this was when I was just moving 1 pot as you can see 1 lines data is different

It only seems to occour when I am using MB_LINK and I was wondering if it could be to do with the length of cable im using? (approx 1.5mtr) it is a shielded cable but I do not have it earthed.

I dont want to chop up the cable if this would not be the cause, as its a 25pin job and it will take forever to re-solder it

Any thoughts?

peace

LO

[TK.]

Hi LO,

it seems that this is no transmission error, since CC #4B is properly incremented (...5A, 5B, 5C, 5D, 5E...). On a bad MBLINK connection I would  assume a totally different - or invalid - MIDI event.

"B1 48 xx" is assigned to a pot, isn't it?

Did you seperate the analog from the digital wires (are the wires itself shielded, or only the whole cable?)

Do you have more logfiles?

Best Regards, Thorsten.

[pay_c]

The MIDI transmissions are relatively strong signals (I even could hear those unshielded ticks within my SID!). So pull the shielding of all MIDI signals in your box to ground (using shielded cables for all MIDI signals)!

This should also be the reason why it only happens when you turn a pot (sending data).

Greets

[LO]

Thanks  ::)

yes I have plenty more log files! (i'll post when I get home)

About shielding: the wires run in a 25core cable, only the outside of the cable is shielded (no internal) so the analog are not separated however this causes no problem when I bypass the midi MB_link connection and use standard midi?

So to shield my cable...... The cable has some foil underneath the outer plastic layer and some non-insulated wire strands. Do I just solder the non-insulated strands to the -ive connection? or do I solder them to the 25pin plug casing and then conect the other side of the plug to -ive on the P/Supply?

And should I only earth one end of the cable? (someone said that to me?)

Pretty basic stuff I guess but I dont know the answer! :-[

Cheer

LO

[TK.]

Hi LO,

so I think the reason is clear, the digital signals of the MIDI connection have influence on the analog signals. The proper solution: use two seperate shielded cables or use a cable where every single wire is shielded to ground.

To the non-insulated cables: connect them all to ground, maybe this already helps.

And should I only earth one end of the cable? (someone said that to me?)

This could also help. You're avoiding a ground loop in this way which can also influence the analog signals.

Best Regards, Thorsten.

[LO]

Thanks for the help :D

I will try it out and re-post if I have some luck!

Thanks

LO

[LO]

OK just got it sorted!

I tried seperating the midi signals from all the other wires this didnt work  :(

so i tried shortening the cable with the midi lines & seperating them and now it works; no random data!

;D

Strange but true although it may have been something else which changed as I made the change in cable length

peace