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Registered Member #7267
Joined: Tue Oct 16 2012, 12:16AM
Location: Detroit, Michigan
Posts: 407
EasternVoltageResearch wrote ...
Longer cables could be worse. These could act as antennas and the longer they are, the more efficient they have at picking up noise.
how does this apply to fiber optic cable though? I use fiber optic and yet the notes 'get stuck' (on continuously until power is shut off to the MIDI board) at distances both less than and greater than about 15ft from the coil.
Steve Conner wrote ...
Hung note usually means that the MIDI Note-Off message got lost, so the note carries on for ever. If the synth doesn't have an All Notes Off button, you have to bash away on the keyboard until you send another Note-Off for the note that got stuck.
That's what I always did in my home studio MIDI setup anyway.
hmm, that's interesting. It makes total sense, BUT... take two scenarios for example, in both scenarios the MIDI data out is from a laptop:
1) MIDI circuit board is <15ft away. Tesla coil is really small/mini size. connected using BNC cable, and everything runs fine at about 70% input voltage with no hung notes or no problems. Notes only hang up what a spark strikes an object.
2) MIDI circuit board is >15ft away. Tesla coil is small/medium size (around 1500W, just an estimate). connected using fiber optic cable, and the notes begin to hang up after 15% input voltage. So it appears as if the power into the coil is somehow related to the cause of the stuck notes
So, what would you theorize as to the cause for the MIDI Note-Off message getting lost in both scenarios? sorry the given information is limited for both cases, but basically you have one where it works practically fine at a reasonable distance from the coil using a BNC cable, and another where it does not work at all using fiber optic at a distance I would consider 'safe', as I generally dont like to be closer than 15ft to a coil of that size
I'll note that from my experience, it seems as if it may have something to do with the power in to the coil and the USB device itself. Any time a note hangs up, its never been a problem with the laptop or the MIDI circuit as far as I could tell. The USB device becomes disabled and the computer no longer recognizes the device until you unplug/re-plug it in and manually select the device under a 'device options' within the MIDI sofware
Registered Member #2288
Joined: Wed Aug 12 2009, 10:42PM
Location: Cambridge, MA
Posts: 179
I've experienced similar things. Based on the evidence here, I'd say with 99.9% probability, it is hardware related, and is related to either the computer or the USB adapter. I'd say its more likely to be the USB adapter from what I've seen, but it could be either.
One thing I've done to help is to dramatically shorten the USB cable. I actually cut the cable in the USB adapter, made it about an inch long, and then re-soldered it to the board in the MIDI adapter. This made it quite a bit better. I then covered the whole adapter, USB cable, and MIDI cable in aluminum foil, making sure to securely connect that shield to the USB port as well as the metal chassis of the interrupter (if its in a metal chassis... its much more important to shield the USB adapter so that should be the first priority).
Also, try running the laptop on battery if you haven't already. Apparently that can help if the computer is the source of the trouble rather than the adapter.
Registered Member #1642
Joined: Sun Aug 17 2008, 11:36PM
Location: Black Canyon City
Posts: 96
Interesting. I didn't know there was a different type of controller available out there. I am running Eric's dual channel TeslaSynth MIDI controller in my portable system and have run several types of USB to MIDI converters using PC and Laptops and have never experienced the issues you are referring to. I think the only thing that would cause these "lock-ups" to occur would be errors in the software code in the controller itself. I personally do not believe in using "battery controlled devices" in any of my stage equipment and have cables running all over the place, so I don't think this is the problem. However, I am using fiber from the controller to the Tesla Coils and regardless of the size of coil being used for any particular audition, have never had any issues. I do need a wireless mouse as I can't use the touch pad on the laptop when a coil is running. There should be no reason to have to cover any of the equipment with aluminum foil. Perhaps there's not enough ground pads on the controller's circuit board.
Does anyone have a link where I might be able to see more info on this new controller?
Registered Member #5300
Joined: Thu Jun 14 2012, 12:00AM
Location: California
Posts: 31
dude_500 wrote ...
One thing I've done to help is to dramatically shorten the USB cable. I actually cut the cable in the USB adapter, made it about an inch long, and then re-soldered it to the board in the MIDI adapter. This made it quite a bit better. I then covered the whole adapter, USB cable, and MIDI cable in aluminum foil, making sure to securely connect that shield to the USB port as well as the metal chassis of the interrupter (if its in a metal chassis... its much more important to shield the USB adapter so that should be the first priority).
Also, try running the laptop on battery if you haven't already. Apparently that can help if the computer is the source of the trouble rather than the adapter.
Hmm...I'll try wrapping the whole thing in foil. Seeing as how my interrupter is not in any chassis, how should I go about the foiling? Every time I've run from the PC, as well, it's been just battery powered.
I'm convinced at this point that it is an issue with the adapter, so I just need a reliable way to combat the issue. I'm looking into other adapters as well.
Registered Member #30
Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706
Is the FlexiBrute's MIDI input optoisolated? You might have a problem with excessive common mode voltage across the optoisolator causing something to arc. Try connecting the ground rail of the interrupter (eg the shell of the BNC output) to the ground rail of your laptop (pick it up at the shield of another USB socket or an audio jack etc) This will short out any common-mode voltage seen by the opto.
Also try wrapping the USB cable from the USB-MIDI adapter several times through a ferrite ring of the sort you might use to make a GDT.
Registered Member #15
Joined: Thu Feb 02 2006, 01:11PM
Location:
Posts: 3068
Yes, the flexiBrute's MIDI input is optoisolated.
I agree that you shouldn't have to wrap anything with aluminum foil, although it would be beneficial to have the board installed in a shielded enclosure.
Steve is correct that a "hung note" is usually the result of a MIDI NOTE OFF being lost in the datastream.
I do appreciate all the feedback on this and find any and all feedback, both positive and negative, helps us to continue to improve our designs and provide better products for our customers.
I will take this up with our software developer and see if he has any insight into the issues you are having.
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PC Output to MIDI Interrupter
