OPT in Com mode?

Hey folks,


I remember having known what this does at some point, but it’s function escapes me now.

What exactly does OPT(fourth option) do in the com menu?
Checked the manual but it’s not mentioned.

Thanks!

From memory I think OPT gives you the option to disable/enable charging while plugged in to eliminate ground noise.

Screen Shot 2017-11-02 at 2.03.54 PM

Ah, thanks

In my experience, it doesn’t make much difference to the ground loop noise. Only real way to eliminate this is to actually pull the USB-cord out.

I use this option to not confuse my battery with endless charge on/off action.
But I’m not sure if this really helps…

In my experience, it doesn't make much difference to the ground loop noise. Only real way to eliminate this is to actually pull the USB-cord out.

a cheap ground loop isolator will eliminate the noise completely too, if u need to keep the USB plugged in

Yeah, but not all USB isolators provide power, only data. Especially cheap ones I’m guessing? If that’s the case, it makes no practical difference to putting the unit into OPT mode.

i’m using an audio ground loop isolator w/ 1/8" input and output.

https://www.amazon.com/Mpow-Ground-Isolator-System-Stereo/dp/B019393MV2

solved my ground loop issues right away when the OPT function didn’t cut it

the USB isolators are more expensive and i haven’t tried them.

i don’t think the OPT function is the same as using an isolator.

I have a cheap USB isolator somewhere. I’ll check if it transfers power and report back tomorrow.


OPT probably just disables the charging circuitry and doesn’t galvanically isolate anything.

the ones i’ve seen only limit the amount of power it can supply. like 200mA max or something.


i’ve seen newer ones since then tho that surpass this limit.

Okay, as promised I’ve tested it with my cheap AliExpress sourced USB galvanic isolator. I think I’ve paid around € 9,- for it delivered.


I had the OP-1 mounted in Disk Mode through this cheap USB galvanic isolator. It seems to drop voltage from 5.0 > 4.4 and current from 0.45 A > 0.19 A. Data lines are operational and the unit mounts on the MacBook’s desktop.

https://ibb.co/d9hzoG

So that 200mA is almost spot on. :slight_smile: