#1

searched the forum and docs twice now… couldn’t find the answer, though i’d swear i saw it here somewhere before.

wondering if i can disable norns from charging its battery while i have it plugged into usb power? the point being that when i play live gigs i don’t trust the battery to last long enough (one of my norns is fine but the other one has a wonky battery life) and for peace of mind i like to use a usb power bank just to make sure they don’t die.

however, when they are plugged in via usb for charging, i then get noise on the line out. this is easily confirmed by disconnecting the usb from the power supply, then the line out is quiet. op-1 and op-z for example have an option to have them running on external power but not charge the battery at the same time to cancel line noise. wondering if norns has a similar function?

thanks!

#2

Do you experience this using clean power and/or shielded cables?

#3

no, it doesn’t. the charge controller might support that through i2c though? now i’m curious.

but i’d be surprised if you got line noise from a battery bank (as opposed to a USB charger or computer port.)

FWIW, the battery is easily replaceable.

two more things i’d consider:

  • is the noise equally bad with the headphones output? (with extra buffering and gain)
  • can you minimize the length of unbalanced cable runs from the norns? (e.g., using a DI or mixer with balanced outs - i submix to an A&H zed-6 for shows these days and it does wonders for the noise floor.)
#4

thanks for your response! yeah i’m using a portable battery charger thing, nothing fancy or very powerful but just powerful enough to meet the specs i think.

and you’re totally right, i should just replace the one battery. i still have voodoo vibes about going on stage with only batteries. looks like i will get over it now!!! hope you’re well!

@tyleretters i get the line noise on both units when using portable power from a power bank or also from having it plugged into wall power. i’m not sure what clean power is though. i’ve tried several usb cables, and i have super good quality custom made cables too. but no idea if they are shielded. so i’ll look into that angle, thanks!!

#5

you should not get noise if you have one powerbank per norns or other device. are they sharing? any time a bunch of devices are powered by the same source you have potential for ground loops, which i suspect is what you’re hearing? because the internal charger basically turns off when the battery is full.

of course, that’s a lot of powerbanks

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#6

I also am also highly reluctant to go onstage with battery anything. I think I’m going to change that with norns, though!

After playing a lot of dive bars I invested in one of these: https://www.furmanpower.com/product/15a-standard-power-conditioner-wlights-and-digital-meter-M-8DX

Arguably my favorite piece of gear!

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#7

i was having ground noise issues when multiple norns were plugged into the same USB power bank.

i discovered that plugging them into their own USB power bricks stopped all of that nonsense.

also…for some reason…they really like Apple power cubes and these weird glowing USB power bricks i found in a toy section of Wal-Mart years ago.
:stuck_out_tongue:

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#8

yes! that must be it- i had a fancy pants usb battery which was powerful enough to charge both norns from its ports… thought i was being clever by saving on gear to pack. i’ll downgrade to some more smaller and portable battery packs to cure my battery ocd on stage. can’t try it out at the moment but in one week i’m back in business and it sounds like this was the cause. thanks for the fast help!

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