OP-1 and OP-Z connected together with MIDI and Sound output creates strong sound interference

OP-Z
#1

Hello,
I just got an OP-Z. And wanted to use it with OP-1 : the sequencer would be driving the music, while the OP-1 could alow me to add additional layers on the 4 tracks recorder.
For this I needed:

  • to mix both of their output to the same output : using a mixing table
  • to connect them together with MIDI so that they are synchronized
    Everything worked almost perfectly… except that… connecting the audio output together while both are connected for MIDI leads to a very noisy sound interference.
    This noise is so strong that it prevents any decent recording or work when connected together…

Here is a video that shows the issue:

Did anyone experience the same ?
This problem is a typical accidental amplification of some CPU/Microcontroller noise. It probably comes from the fact that one of these 2 devices are improperly shielded.
It’s frustrating because both come from the same brand and are impossible to work together.
As a side note: If you connected one of them to a power supply with ground, the noise gets lower… but still unacceptable…

Any experienced the same ?

#2

This could be USB noise. You can get around it by either disabling USB charging for one or both devices, or by using a filter on either the usb connections, or on the audio cables.

#3

Turning off USB charging on both devices can help, but it didn’t completely get rid of the noise for me. I bought a ground loop isolator off amazon and it cleaned up the noise perfectly.

#4

That sounds great ! Thanks for sharing
Now: how to you turn-off the USB charging feature :

  • On OP1 ?
  • On OPZ ?
#5

I am not sure how you filter things here : do you need a special USB Hub that shields signals properly ?
I tried a better mixing table (with ground power cable)… it kinda helped but still getting interferences in background…

#6

u can turn off usb charging on both op1 and opz.

if that doesn’t work, what u need is a ground loop isolator
some come in the form of a usb device.
others are audio.

the audio ones are cheaper than the usb. both should work fine.

#7

Thanks ! I will check these ‘loop isolators’ !
Does anyone know do we turn USB charging option in OP-Z and OP-1 ?

#8

its in the guide for both of them

for op1 is in the shift+com menu

for opz is some button combo that i dont know off the top of my head

look it up

#9

opz its hold screen+ note E2

#10

Cool. Thanks! I surprisingly missed these details in the Doc. while reading…

#11

I think my issue on the buzz sound is resolved. And yes : I had to cancel the USB power on OP-1 and OP-Z (“Screen” button + E2 Note).

Now, looks like I can’t put the OP-Z back to USB powering… “Screen” button + E2 Note doesn’t seem to toggle it back… but it’s another story

Thanks for your help, guys!

#12

Usb powering is probably switched on again after turning poweroff and on?