Tone2 Pro Flips to Mono?

I’ve noticed that, after switching from one album to another, usually at different sampling rates, my Tone2 Pro starts playing everything back in mono. I’ve confirmed by playing a track like this: Right Channel Identification by Sheffield Lab on TIDAL. On a track like this, sound is equal in level and comes from both channels when it should only come from one side.

To restore stereo operation, I have to remove power from the DAC. Using the dial to power it off and back on does not seem to help. Is anyone else experiencing this?

Hi @dsnyder0cnn,

I’ve tried to replicate going from this song Carol of the Bells by 2L on TIDAL to Zero by Smashing Pumpkins on TIDAL and then to Message In A Bottle by Sting on TIDAL
nothing happen. In other words, still getting stereo.


I’ll try to find a pair of tracks that reliably triggers this behavior. If I can, I’ll share.

Ok! that would be perfect. I’ve chosen random songs.

Hi @dsnyder0cnn
How many times you met with this issue?

And can you share more details on your setup, basically, we need to know if the issue is from the T2P and just in case the issue might from Amp/HPA or speakers if your setup with these.


My setup is not too unusual. Media player is Roon. Core is running on a 7th generation i5 NUC located in a closet. Endpoint (transport) is a Raspberry Pi 4 running VitOS and Roon Bridge. USB out of the RPi4 into an iFi Audio micro iUSB3.0 power and signal regenerator. USB out of that (AudioQuest Cinnamon) into the Tone2 Pro. Balanced RCA out of that into a THX AAA 789 headphone amp driving various headphones.

I listed for a couple of hours last night, and the DAC only flipped to mono once. After power cycling it, I replayed the same 3-4 songs from my history in the same order, but I could not get it to flip to mono again. Once it flips to mono, everything that I play is in mono until I power cycle. So strange.

Hi David,
Thanks for the information, and please do post here once you with any updates.

And double check here on the mono issue that you mentioned, which one below you are saying?

  1. One of the channel lose the sound
  2. Two channels mix into a sound

As for headphones(not speaker) setup, #1 should quite easy to distinguish no mater what kind of songs you are playing, but #2 is not that easy to sort it out once based on the songs that played.

BTW, did you try with another DAC and checked if there are similar issue there?


What I’m hearing is the two channels mixed together to mono. Identical signal from the left and right channels. For example, when I play a channel identification track that only has sound recorded in one channel, I hear exactly the same output from both channels when this problem is active.

I have not been able to reproduce this problem with any other DACs, and I have eight different DACs that are in regular rotation.


Will do further checking here, thanks for the feedback!

More listening last night with no recurrence of the flip to mono. I’m quite puzzled. Let me know if anyone else reports these symptoms. I don’t know how it could be related to components downstream from the DAC or even upstream, for that matter.

I’m currently just powering the Tone2 Pro from the USB input. I’ll try adding a 5V iFi iPower X to the “I2S” input to see if dual power makes the issue easier to reproduce.

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@dsnyder0cnn I tested this playlist and didn’t get a mono problem, but what I see is that all tracks are “Normal” or “High” so based on AAC files.
Could it be linked to your problem ? Was you coming from listening another track based on FLAC (“HiFi” or “Master”) ?

I don’t think so. That was just an example. The channel identification track I use is from a FLAC rip of a Stereophile Test CD that I bought ages ago. Roon uncompresses AAC streams to PCM before streaming to my endpoint anyway, so the DAC has no way to “know” what compression (or not) was used. I’ve not experienced this over the past couple of days. Puzzling. I’d like to either have a way to reliably reproduce it or for it to just never happen again. :slight_smile:

I was more thinking of a potential Tidal problem, with a mono conversion of AAC file when coming from a FLAC before that, even before it’s converted to PCM.