USB connection cutting out on stage

[Steve A]

Had a nightmare scenario at a gig recently where the USB connection between my Novation keyboard and my laptop kept dropping out. Fortunately I managed to work out that it was my smoke machine that was causing it - I was using one of those manual hard wired remote controllers and although it's never happened before, on this occasion pressing the button was presumably creating some sort of mains spike that was enough to upset things.

Does anybody have any suggestions as to how I can make my USB connection spike proof (if indeed that is the reason)?

[chris...]

presumably creating some sort of mains spike that was enough to upset things.

Try the laptop on battery ?

Or, if pressing the "smoke" button hurts, then...um...er...

[G-Doubleyou]

Low frequencies can disturb a laptop's hard drive, SSDs are the solution.

[Guillermo Navarrete]

Hello Steve A,

If you are on Windows 7 or 8 there is an option call "USB Selective Suspend"

Under certain circumstances it can happen that the "USB Selective Suspend" option in the Windows 7 and Windows 8 "Power Options" can have a negative effect on connected USB devices.

Some known symptoms are:

Error messages while working with our software related to the audio device in use because it is not available anymore.
Crashes when loading projects.
If you encounter any of these or similar symptoms it is recommended to disable the "USB Selective Suspend" in the Windows Control Panel -> Power Options -> Change plan settings -> Change advanced power settings -> USB settings -> USB selective suspend setting

Note that there are either one or two entries depending on whether you have a portable device or a stationary system without an additional battery. In any case, all entries should be set to "Disabled".

I hope this helps!
Best regards,
GN

[damoore]

Have you got the smoke machine on a separate power strip from the rest of your rig? That, and making sure your rig's power strip has RF filtering (not just the MOV protection) might help.

The other thing would be to keep the wired remote well away from the usb connection. It could be inducing voltages into the USB circuit when it switches that cause problems.

The fact that you have not had this happen before, and if your layout was the same as before, it may be that the smoke machine was pulling down the power voltage enough to make your controller unhappy. The laptop should be buffered by the battery enough to not care, so its most likely to be the controller that was affected. If this is the case, then getting your rig (but not the smoke machine) on an UPS could help.

The common theme here is isolating the smoke machine from the rest of your rig as much as possible.

[Steve A]

Hi everyone, I appreciate the responses.

On this occasion, it was on a separate socket/extension but all the power on stage was from the same ring so not much in the way of true isolation. I always ask if there is a separate supply for lights/effects but usually the answer is no!

However, now you mention it the cable in this case did cross close to the USB cable - almost touching in fact - which is almost certainly not how I've had it before. I suspect there is a clue here!

The keyboard gets its power from the USB cable as well incidentally.

I'd be happy to try an RF filter on the mains connection if it is likely to afford some protection. Even if I'm not using my smoke machine in future, if my USB connection is susceptible to interfence to rogue mains fluctuations, I guess it could happen anywhere!

The USB Selective Suspend suggestion is interestring although I'm using a MacBook here - I wonder if there is a Mac equivalent.

[ef37a]

Put the mains filter on the smoke machine!

And fit it as close to the machine as is practicable, i.e. chop the mains lead down to 300mm or so and put the filtered strip there. Things like microwave ovens have some serious, heavy duty RF filtering in them but, logically they fit it INSIDE the casing.

Might be worth contacting the makers of the smoke machine to see if there are any mods. Modern kit has to be tested to ensure it does not radiate such crap.

And, you could try some clipon ferrite absorbers on the usb lead. Maplin have 'em.
Dave.