iPhone 17 Pro not working with USB DAC SMSL SU-1

Something definitely with powering via USB-C.

I recently got my SMSL SU-1 upgraded and one part of upgrade: power is separated from USB-C via external power supply and on the same OS version (26.0.1) DAC was connected to my iPhone 17 Pro Max. Before upgrade I had the same issue as topic starter.

Maybe it is fixed in recent 26.1 OS version, but I will not be able to check this, because now my SMSL is using USB-C just for data transfer.

aircooledcafe wrote:

The device is function fine and has no firmware updates nor should it need any.

It works with no issues with every other iOS devices.

This also does not explain why I can not change the "Wired Accessory" setting as well, no matter what accessory is connected.

There is an issue with this setting on some iPhone 17 Pro models. You are likely seeing a statement that your phone is managed by your organization? Apple is aware of this issue and an update should come in the future to address this.

It has nothing to do with your DAC. And no, there is no published bug report. But I too can't change the setting, so I spoke with a Senior Apple Advisor last night, who confirmed this is a known issue and one which will be resolved in an update.

No - I send it to some engineer in my country (Ukraine) who made upgrades of audio part (capacitors, op-amps etc...). And making power supply external - just small part of this. Actually cost of upgrade was $110 - what is bigger than cost of device itself :)

But I think just make external power will be much more simple.

Also I breafly search internet and there are some topics on reddit about making this and even more and less efforts:

"Just get a usb otg 2in1 adapter. They allow for seperate power supply and data inputs."

But again - I think this is f... of Apple - I saw in youtube issues with other devices on 17-th models

Have you tried contacting the manufacturer of the device to see if they have a fix for their hardware?

If this is a universal issue, maybe they are aware or have a firmware update.

Do you use a VPN or antivirus software?

“Is there a bug report anywhere where apple has acknowledged they are fixing this?”

User to user support forum.

We have no idea or any way of knowing.