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power audio interface from charger

mla

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Hi,
couple of weeks ago I asked a question about the option of external power up and data transfer for audio interface with USB B port only.
I received a suggestion about needed adapters.
But I am stuck on power up point prior to testing data transfer.

My first test was performed using USB B (male) to USB C (female) adapter.
I posted the negative result and asked why the unit not powers up from a wall charger (tried 5V 2 and 3 amps) but
powers up when disconnect the cable from wall charger and insert it to computer port.

I mentioned and put the specs of amperage of computer port and wall charger in the same thread...
Wall charger has a higher amperage than computer USB 2 port.

Didn't have any answer about a possible issue.

So what is the "rocket" science behind this problem.
From one side wall charger provides more amperage but the unit not powers up.
From the other hand lower amperage computer port does work.
I used the same USB cable.

I cannot sleep :) without understanding what is going on...

So, today, a brilliant :) idea came to my mind.
Even the unit powered up from computer port using B to C adapter, I put aside the adapter and used an existing B to A cable that works for years for my DAW needs.
B connected to audio interface and A male to computer port.
I disconnected A connector from the computer port and connected it to wall charger (Samsung).
IT NOT WORKS. So the adapter not an issu.

My verdict: There is something in USB B port of audio interface box that does not allow power from an external charger.

I believe that somebody here have enough knowledge/experience for explaining what is the mistery behind 4 wires (2 for data 2 for power ? Am I mistaken?)

Thank you.
 

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AnalogSteph

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This interface may just need a real USB host on the other end to properly initialize. Chargers can be pretty dumb, they might just be connecting the data lines together or have some voltage divider networks between +5V and ground to signal their current capability. (USB PD tends to get more fancy.) Definitely nothing like a USB host in there.
 
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mla

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So, no way to provide a power from different source than a computer port? May be some not complex work around?

My goal was to use a splitter for powering up interface from a charger and then use a usb cable for recording to smartphone through usb.

After your explanation I connected smartphone to the interface using usb c to b adapter. It works fine.
So, theoretically I can record to the phone from interface. The question is how fast the phone battery will be drained.
I will test it... charging to 100% my Samsung Note9 than will try to record and see the battery life. if it will keep charge for 90 min it will be fine for me.
Will see...

Thank you very much
 

kemmler3D

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Hi,
couple of weeks ago I asked a question about the option of external power up and data transfer for audio interface with USB B port only.
I received a suggestion about needed adapters.
But I am stuck on power up point prior to testing data transfer.

My first test was performed using USB B (male) to USB C (female) adapter.
I posted the negative result and asked why the unit not powers up from a wall charger (tried 5V 2 and 3 amps) but
powers up when disconnect the cable from wall charger and insert it to computer port.

I mentioned and put the specs of amperage of computer port and wall charger in the same thread...
Wall charger has a higher amperage than computer USB 2 port.

Didn't have any answer about a possible issue.

So what is the "rocket" science behind this problem.
From one side wall charger provides more amperage but the unit not powers up.
From the other hand lower amperage computer port does work.
I used the same USB cable.

I cannot sleep :) without understanding what is going on...

So, today, a brilliant :) idea came to my mind.
Even the unit powered up from computer port using B to C adapter, I put aside the adapter and used an existing B to A cable that works for years for my DAW needs.
B connected to audio interface and A male to computer port.
I disconnected A connector from the computer port and connected it to wall charger (Samsung).
IT NOT WORKS. So the adapter not an issu.

My verdict: There is something in USB B port of audio interface box that does not allow power from an external charger.

I believe that somebody here have enough knowledge/experience for explaining what is the mistery behind 4 wires (2 for data 2 for power ? Am I mistaken?)

Thank you.
Long story short when it comes to USB-C connectors, sometimes it needs a specific type of connection to work. Because USB-C/PD spec includes modes for higher power (some go up to 100w) it needs to know the receiving device won't be damaged by the current.

Or like @AnalogSteph mentioned, it may need a real USB host to work, i.e. computer, smartphone, etc.

Have you tried it with a different charger? Look for one that has the same current rating as the DAC, that might help.
 
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unpluggged

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So, theoretically I can record to the phone from interface. The question is how fast the phone battery will be drained.
Just use a powered USB hub. Or, even better, one that can pass PD power through to your phone. That way you will have both devices (the interface and your phone) powered.
 
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mla

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thank you guys!
 

amirm

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That is very strange. Assuming I understand right that you have one USB cable for data and another for power, then the latter should work with anything. I have tested countless DACs that are that way and they work just as well with external power supplies as they do with computer USB ports.
 
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mla

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That is very strange. Assuming I understand right that you have one USB cable for data and another for power, then the latter should work with anything. I have tested countless DACs that are that way and they work just as well with external power supplies as they do with computer USB ports.
should :) ... but not works. I think @AnalogSteph explains the situation.
Lets forget about data... using usb C to C cable through C to B adapter (B in interface) works from phone (or from pc A port).
No GO from wall charger...
 

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mla

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first test result with cable from phone to interface:
90 min powered interface without any other action - 25% discharge.

The battery on my 5 years old Samsung NOTE9 4000mAh.

Tomorrow I will try to send a signal to interface and record on phone for seeing the impact.
I guess it will keep going for at least 2 hours. Yehh I have to disable WiFi :)
 

Ifrit

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There used to be the cables with dual USB A connectors in parallel precisely for this purpose, one of them was just the power, no data wires. I’ve seen those with USB B, mini and micro on the other end.

Your Lexicon cannot be used in standalone mode, so most likely it needs to see the host in order to operate, just power isn’t enough.
 
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mla

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There used to be the cables with dual USB A connectors in parallel precisely for this purpose, one of them was just the power, no data wires. I’ve seen those with USB B, mini and micro on the other end.

Your Lexicon cannot be used in standalone mode, so most likely it needs to see the host in order to operate, just power isn’t enough.
would this one be good?

can you find some on amazon (not aliexpress) and paste the link/s

thx.
 
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mla

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on my similar thread (was not related just to power, now I have more understanding)

I had a suggestion for the splitter needed https://aliexpress.com/item/1005003097221593.html
I cannot find it on amazon that I prefer.
 
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mla

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SOLVED :)

finally, I found the ideal solution that meets my needs...
No Y splitters...

I decided to try a recording from interface to Android phone using only B to C adapter and C/C cable.
And Dolby ON app. Connect, hit record button...

as you can see from the pic I recorded 76 min... when started recording the battery was on 90%
76 min ate 25% of battery. And it's very proportional (I checked after 10 and 30 min).
The recording continues... so it should be 150min =50%
It's more than enough for my goal. I need to record my sax performance.
Currently using EV Everse 8 battery powered fully blown active speaker and I am using wireless (powered) mic.
So thinking about power for interface was a bit of headache.

I was about ready to buy a portable recorder Zoom H4n Pro or Tascam DR-40X.
Interface/Pnone solution is a perfect solution. Also I found a nice Zoom interface (and it's battery powered).
My old Lexicon is a bit bulky but it's not a prob at all.

Thanks to all.
 

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mla

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also, with my "profound" :) base in electronics, I guess that 4000 mAh battery with the working time of the powered device shows that this old Lexicon needs someting below than 1Ah... whatever the theory, I am happy with a simple solution and it's result
 
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