Tone2 Pro ear pain

I bought the tone2 to replace my tone1, but have not used it because it caused ear pain after a few seconds of use. I would guess that there’s some inaudible high frequency causing this, but I can’t be sure. I’ve tried using a different computer/phone and using the 3.5mm and 4.4mm outputs, but still have the same issue. Powering it through the I2S port with a phone charger and connecting to my computer with a usb cable with the power wire cut seems to reduce the effect a little, but it is still painful. I’m using the latest firmware, but it was also a problem with previous versions. Any ideas on how to fix this? Possibly defective?

1.Firstly I want to know the product you mentioned is tone2 or tone2 pro.Tone2 is a HiFi Mini Desktop DAC,and tone2 pro is a DAC + Headphone amplifier.

2.You can try to choose one filter you like,it has the 7 filters,you can refer to the instruction for the details.

3.If you want to use I2S port to power tone2,it is best to buy USB-A to C LPS cable from this website.,because the I2S port is not standard USB C definition.

I have the tone2 pro.
I will try using other filters, but initially I don’t feel a difference.
I’ll consider buying the cable, but I can’t tell if the issue is power related at the moment.


  • So you plug 3.5mm headphone and 4.4mm headphone into tone2 pro headphone connector directly.And I also want to know how much is the impedance of your headphone.If your headphone impedance is very low(1),you should try to enter gain mode to select the low gain.

1.For 3.5mm headphone,the value is less then 23ohm.For 4.4mm headphone,the value is less than 50ohm.

  • About the filters,there is a little difference on the timbre between them.

  • Another attention I want to remind you is that do not use the convert cable from 3.5mm to 4.4mm or from 4.4mm to 3.5mm.

My headphone’s impedence is 63ohms.
I normally use it with the tone1 with a headphone amp(rca to rca). Swapping the tone1 for the tone2 pro lead to the discomfort/pain I mentioned.
I have tested the 3.5mm jack of the tone2 pro at both low and high gain with those headphones and earphones(16ohm), but still develop the ear pain.
I bought a 4.4mm cable to use with the earphones to test the 4.4mm output, but had the same problem.
I tested the other filters a few hours ago. I feel like some of them make a small difference, but still developed the discomfort after a few minutes.
I asked someone else to try using the tone2 pro with their phone, they said they felt dizzy after a few minutes.

I think my firmware was corrupted. I did the firmware update again to the same version and I don’t experience the ear pain anymore. Would corrupted firmware be able to cause the effect I described?


  • If you use 16ohm earphone,you should choose low gain mode.

  • It is best that do not use 4.4mm cable to test 3.5mm headphone,it may cause R cold pin and L cold pin short out.

What is the version of your update firmware?

It’s 1.41, I used tone2pro-xmos-v1.41-221201.bin

Actually I don’t think it’s related to the firmware. I started to feel uncomfortable again after using it.

Can you take a high resolution photo or video about how to play with tone2 pro? Thanks.

The aluminum box is the tone1, I have tried swapping it for the tone2 pro. It is connected to a headphone amp with rca cables. I also tried using a 6.35mm to 3.5mm adapter and using earphones with mmcx to 3.5mm and 4.4mm cables. Every case gives me ear pain. I think the tone2 pro is defective, I do not have this problem with the tone1.


  • Every cases you mentioned is OK.

  • I want to make sure with you If the ear pain you said is distortion or having a lot of noise,or any else.Can you descibe the details about your feeling?

  • Do you remember what is the firmware version of your inital tone2 pro?

I don’t think it’s distortion, everything sounded like it was supposed to. It feels like high frequency noise, but I can’t hear it. It’s a sharp pain in the ear when I use headphones. When I use earphones, it’s not immediately noticeable, but hurts after a few minutes. The other person I had try it said they felt dizzy and had a slight headache.
The firmware version should be v1.00. I updated for every firmware release and tested it, but something always felt off so I never used it.

I know it maybe related to the MCU firmware, do you update MCU firmware by ST-Link from the bottom of tone2 pro? As to the picture shown below.

If you not,you can try to do this as the video we released.

I have done the upgrade once before from V1.00 to V1.20. Should I try doing it again?

You can try to update the new MCU firmware by ST-Link.

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Flashing the MCU firmware resolved the issue. I have been using it for ~40 minutes now without experiencing the pain. Thank you for your help.

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@Eric68 I don’t think the problem actually went away. Flashing the firmware did reduce the intensity, but it still feels uncomfortable to use. I tried using it every once in a while to make sure, but it seems like the problem is still there.

Can you send us to check,please?