I Need A Little "Electronic" Advice

Hey All. Been very busy gigging this year, so I haven’t spent much time on the forum lately.

I am working with a great drummer, but in most cases, we share the same power source. He has a small ancient fan with a rotary on/off switch. When he switches the fan, it knocks my main keyboard out (powered by computer usb). To fix it, I have to reboot my computer. It only started this in the last 3 gigs. We are using the same power cords and gear all year without a problem. We are scratching our heads on this one. Haven’t tried different cords or strips, because we are always packed up for tomorrow’s gig. or rushing to setup. It would be easier to diagnose with replacements, but we did use two seperate power cords from two sources at the last gig…same situation. When I need to reboot, it takes a long time for Cantabile to shut down, and shutting down the computer. I offered another fan, but he is set on HIS. He blames the computer.

Any ideas?

Find him a different circuit and buy him a decent 12ga. extension cord. :smirk:


Hey Corky,

Glad to see you here again.

In electrical engineering, a device called a ‘zero crossing switch’ is often used in such cases. It switches its state on/off only when the mains sine wave passes through zero. The component that makes this possible is called a triac, but I have no idea where such a ‘smart’ switch can be found on the market.
As an alternative, I would say that it’s better not to share high power supplies or those with motors/inductors that generate very high spikes when switched on or off.
Sorry, I know this is a bit of a tech answer. But this is what I would do.

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Hi Corky,

I don’t get this part, does the laptop have a working battery? If so you’d think that it would keep the keyboard powered up via the laptop USB regardless of the potential voltage drop you seem to be experiencing. If the battery is good then a test of the situation with the laptop powered only by the battery on fan startup would give more clues to the problem. It sure sounds like a voltage drop (caused by startup current surge in the fan) problem from your description.

Very busy this year too, glad you’re out there rockin’! :slight_smile:


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HAHA! Yeah, we have heavy duty extension cords…just that damn, ancient rotary switch.

Makes sense. It must be spiking my laptop. Never liked those switches. :frowning_face:

It does have a good battery. The secondary keyboard isn’t affected. The main shuts down, and Cantabile somewhat freezes…then the blue circle of death for 5 minutes. The main key is directly in computer usb. The secondary is on a usb hub directly into laptop usb. Just really strange. Wasn’t fun during gig.

Glad you are busy too. I am rockin’ for sure. :sunglasses:

Hmm. If the battery is good, it’s most likely a high voltage spike generated by the fan motor that’s disrupting the USB communication.


Tell your drummer to buy a good capacitor+inductor line filter.

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Now I’m puzzled. So do you have a really bad voltage drop? OMG what a big mess.
What about to say your drummer to don’t touch the fan switch? On or off. Mark!

If you get circle of death then the PC is getting starved enough that it occurs to me that the system you have with all the keyboards and audio interfaces connected can only work with the power supply connected and that the battery backup is not getting it done. You should check to see if the system you have can run on battery only as a stand alone test and check the battery setting in Windows to make sure they are set to switch over and mirror plugged in settings when there is an interruption to the AC power supply.

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That’s what I told him. Turn on your fan before I power on !!!

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Yes, my system can run everything on battery. I will do a test to be sure. Great idea to check my settings!


What about a small UPS on Corky’s rig? One of those small ones that can power the whole rig for a minute or so at most.
I had one in my Emulator3 and Kurzweil days when all my sounds were in RAM and it took two days to load them. :astonished:
They are not expensive, and most notably, they also act as a filter on the AC, wiping out the voltage transients and stabilizing it.

:rofl: :rofl: :rofl:

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Well, that would be the best fix for all digital gear on stage but it would be his call as to if he wanted to get one. Great idea!

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I actually used a UPS on my PA system in the 90’s, after a low voltage took out my Studiomaster mixer. It also took out a Bass amp. Some places are iffy about their power wiring. Might be a good idea to buy one. I really don’t know how much longer I will keep doing this. But, I am still buying stuff!! Most everyone I know are quitting or dying. I am not a good solo act :laughing:


Break out the gauze, wrap yourself up and become the return of Nash the Slash … :grin:

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I also play little, but when I do, I like things to work well. I hate predictable failures that are not fixed in advance. There are already too many unpredictable things.

By the way, should I listen Nash the Slash? :rofl:

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I prefer AC set to 78 degrees (F) and then run fans in each room (don’t like that living in a refrigerator feeling). I’ve been buying Lasko 3 speed fans that eventually need a new capacitor, maybe that’s what’s happening to the drummers fan. If it’s a little slow to start that’s why.

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We’ve been playing a lot outside. The heat has been brutal. Real feel was at 114

I run small Honeywell fan to cool our Soundcraft Ui24R digital mixer on days like that. I love playing outdoors but possible heat and storm activity is the drawback.

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