T2 pro Linear power supply port issue

When i plug not plugged to the power USB cable to the i2s port - the power led turns to white. But how it is possible if there is no additional power? I believe it is something wrong and external power might not work properly.

Video proof

Hello, Maybe something here will help.

Nope it is another issue - cuz even not connected power cable leads to led color switch from red to white.
@Grooved do you have the same?
@Eric68 what do you think about it?


it has been found already, and it seems it’s not a problem on yours, but it’s how it’s designed. Once a cable is plugged, it’s detected and turns the light white.

There’s some kind of link between both ports, andit can actually use both power, with a priority on the one providing the highest voltage. I don’t know if it can be improved to only use current from I2S port even if his voltage is lower.

The only thing I found to be sure to use power only from I2S port, in case voltage from this one would be lower than voltage on the USB port, is to link the “I2S” port to the power supply and link the “USB” port not directly to the computer/smartphone but to a powered USB hub with power switch for each port.
I’ve turned the switch off so there’s no current on this port. It’s like using a cable with data wires only.

Anyway, I’m not sure it changes something on the playback quality, I’d like to test it by recording the Tone2 Pro output but to keep it clean, the best would be sync the Tone2 Pro with the ADC and I need SPDIF or ADAT signal for that. SPDIF Output will be available on a future firmware, but it’s not at this moment.

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Hi,yes. the cable is the point. You must use the special cable which has separate A4/B4 and A9/B9.
You can read more detail information from here.

can you recommend a cable?

I believe that such cable doesn’t exist on the market - and it should be custom made =(

I’ve run my own little experiment. I’m using an iFi nano iUSB3.0 (no longer made, but a nice little device) to provide separate signal and power to my Tone2 Pro. For signal, I’m using an AudioQuest Cinnamon USB A to C cable. For power, I’m using an Anker Powerline+ cable. Voltage is identical for both USB ports on the iUSB3.0. Here’s the current measurements I’m seeing with various connections.

Signal Cable Only (USB)

Power Cable Only (I2S)

Both, measuring the Power Cable

Both, measuring the Signal Cable

I don’t quite get why the last two (0.14A + 0.09A) don’t add up to 0.34A, but these results seem to be repeatable. I’m taking these measurements with the Tone2 Pro set to high power mode, no music playing at the time.

Are you trying to say that the anker power line did the trick? And it feeds the power to the t2 instead of signal port?
But anyway source matters too, i mean your ifi device.

Hmm, I’m not using an Anker power line. Just an Anker USB cable (Type A to USB-C).

Help me understand what you mean by “source matters too”?

Part of the point of my using the iFi iUSB3.0 was to ensure that the voltage between the two ports is matched (measures identical to three significant digits).

Hi,this is an issue,because the I2S port power outputs(A4/B4) act as the I2S Port power inputs(A9/B9), so the I2S port power is existing. And the light is turn white.

Hi,you can make it by yourself,it is so easy, first buy a USB C plug(24PIN),only connect A9/B9 to red line,let B4/A4 suspend,and connect A1/B1 or A12/B12 to black line.

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It would be great to see some video guide - because not everyone is familiar with soldering and schematics. Also it would be great to purchase such cable or adapter too.

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What I do when using the I2S port for power is use a piece of vinyl tape over the positive line of the data USB cable (on the type A side!). Keep ground and data lines of course. this prevents my USB hub from sending any power, thereby any noise (and there is a lot from this 12v 4a brick) coming from the USB hub PS or the PC itself. As far as I can tell, this is the easiest method to ensure that power is only coming from LPS (or whatever you have plugged into the I2S port for power) Subjectively, as long as its “clean enough” power, you probably wont notice much of a difference. I have used a very cheap 5v 1a LPS wall wart, 5v 3a LPS, the Khadas 24w type C wall wart, a 50000mah power pack, and 5v 3.4a from the USB hub. Only one I could obviously tell had lots of noise was the USB hub.

EDIT: Pics for clarification. This is the cable connected to your source.

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Awesome, definitely gonna try this! Yeah, I agree I prob won’t hear a difference. Armin from AudioScienceReview did heavy testing on linear PSU and measured minimal differences.

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