Powering devices over USB

Hello :slight_smile:
I’m considering getting a Zynthian to use it conjointly with my Squarp Pyramid sequencer, Akai keyboards, ROLI blocks and Axoloti core (not necessarily all together).
All of these are powered over USB, and I know that the Pi cannot output unlimited power (I think the Pi 3 and 4 are limited to 1200mA in total, given it’s USB it’s 5V so max 6W of total power consumption available, which isn’t a lot). Did you experiment issues with powering external devices from the zynthian?

Use a usb hub with external power …

Yes, I wanted to know if I had to go that route, as it makes the whole stuff less nomad.
I plan to mostly use the Zynthian with a power bank.

The M-Audio Keystation 61 MK2 (200mA) midi-keyboard and the Korg Nanokontrol2 (100mA) midi controller worked without any problems without external only power from the RPi3 …

if your controllers do not have motors on the faders, then they probably consume a little current … 150-300 mA …

Hi @YPares

Welcome to the community. Zynthian requires a good PSU (3A recommended) with high quality cable (thick and with good quality connectors). Overlooking this or using poor quality supply / cable is a very frequent cause of issue with Zynthian. Many of us power many external devices directly from our Raspberry Pi USB interfaces without the need for an external powered USB hub, e.g. I have a screen and multichannel MIDI interface connected. (I have also used unpowered USB audio but currently have a self powered device.) The more devices you connect the more power you will need to supply and there is a chance that the load from your USB connected kit might drag down the Zynthian to the point where it starts to struggle (which will likely trigger xruns - holes / clicks in the audio) but if that were to happen then you could add a powered USB hub.

So my answer would be that it should be okay if you have a really good 3A (or higher) PSU and really good cables then you should be okay and there is a get-out-of-gaol card with the hub if you need it.

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Okay :slight_smile: Yeah I think I could find a power bank with a 3A output, that exists.

Not noticed a problem and I’ve powered a Roland A-88, and Alesis i/o trigger and various keyboards mice and recharged battery packs from a three without any obvious distress.

BTW side question, I notice in the tech specs https://zynthian.org/technical-specifications that it supports BLE. Has anybody used ROLI blocks wirelessly with the Zynthian? I thought BLE/Midi over BT was only available on OSX.

I seem to remember the general advice was turn off Bluetooth from Pi 3 days but I cant remember anyone trying it. I’ve got a bluetooth MIDI thingy from yamaha so I might give that a go. Once I get my select encoder working on this bloomin’ zynth. (dodgy sockets joined and separated too many times i suspect…)

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Did anybody find a audio box without latency? I used a Bluetooth box with cinch input. But even with cinch input it’s only usable for normal playback like 99% are using it for. But for live performance…no way…

Hi everyone,

Does anyone know how much current power can Zynthian/RPi4 deliver?

The Raspberry Pi demands several amps to support itself so it is unwise to load it with jeans current consuming devices. It can probably support about an amp but distributed across all its ports.

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