Fosi ZH3 Balanced Headphone Amp & DAC Review

[Whatsthephuss]

Don't have any issues powering your headphones?

The ZH3 has no problems driving any of my headphones to adequate levels. Neither of them do. The DX5II just has more power than is needed, and this became apparent when I turned the volume up to -2dbfs on high gain.

I think there may be a misunderstanding about what I said about the DX5II being capable of driving my headphones into distortion. The HPA itself is incredibly clean, but it has enough power to drive all them beyond what they’re capable of handling. In the pro sound speaker world we use limiters to prevent such events, but the topping HPA has no limiters at all. So with improper gain staging it’s possible for the input device to get turned up and all of the sudden the HPA is amplifying beyond what the headphones can handle. With pro sound speakers there’s general recommendations for what size amp a speaker driver should be used with based on power handling specs, and using an overpowered amplifier on a driver without a limiter is not something I’d go out and recommend to people…

 

[Reynaldo]

When I received the Fosi ZH3, I tested the power supply and the LED didn't light up.
After about 30 seconds, the LED lit up.
Disconnecting the power supply, the LED slowly went out.
Almost certainly a capacitor problem.
I connected the DAC directly to my iFi iPower Elite 12Vdc power supply.
The Fosi ZH3, with everything I tested, is working very well; I haven't found any problems.

 

[Chanur]

When I received the Fosi ZH3, I tested the power supply and the LED didn't light up.
After about 30 seconds, the LED lit up.
Disconnecting the power supply, the LED slowly went out.
Almost certainly a capacitor problem.
I connected the DAC directly to my iFi iPower Elite 12Vdc power supply.
The Fosi ZH3, with everything I tested, is working very well; I haven't found any problems.

I saw a video where they said using one of these ifi power supplies really helped the amps sound. I was skeptical but sounds like it's helping after all.

Do you have experience with the Fiio K13 by chance?

 

[RandomEar]

I saw a video where they said using one of these ifi power supplies really helped the amps sound. I was skeptical but sounds like it's helping after all.

It's just helping trigger the placebo effect. You do not listen to the power supply. The member you quote had either a defective PSU or a defective ZH3 and needed to replace one of them. Clearly, there is an audible difference between "device silent because no power" and "device powered and working normally" - but that's it.

 

[Chanur]

It's just helping trigger the placebo effect. You do not listen to the power supply. The member you quote had either a defective PSU or a defective ZH3 and needed to replace one of them. Clearly, there is an audible difference between "device silent because no power" and "device powered and working normally" - but that's it.

That's kind of what I was wondering/thinking.

 

[Reynaldo]

I've never owned the Fiio K13.
In this video they are testing the Fosi ZD3 and from 11:45 onwards he explains why changing the power source improves performance.

 

[Bleib]

They would need more than a multimeter to prove it though

 

[RandomEar]

I've never owned the Fiio K13.
In this video they are testing the Fosi ZD3 and from 11:45 onwards he explains why changing the power source improves performance.

They are just talking audiophile nonsense. They don't explain and don't measure or correctly test anything of value, as far as I can see. Holding a voltmeter to a 9 V regulator and measuring 9 V is... not surprising.

Also, the forum rules ask all members to give a short summary of videos they post. Please do so.

 

[Gekel]

Just got a ZH3 as replacement of my dying DAC, and have a question....

The LO output works as expected. I can hear sound coming out of my active loudspeakers, and the DAC is accepted and identified as DAC on my machine, both using optical and USB for connecting, but: I have plugged in two different headphones now to the 6.35mm PO out at the front, and no matter what I choose as output in the menu, I have zero sound. Is there any trick or is the DAC defect?

 

[Reynaldo]

Just got a ZH3 as replacement of my dying DAC, and have a question....

The LO output works as expected. I can hear sound coming out of my active loudspeakers, and the DAC is accepted and identified as DAC on my machine, both using optical and USB for connecting, but: I have plugged in two different headphones now to the 6.35mm PO out at the front, and no matter what I choose as output in the menu, I have zero sound. Is there any trick or is the DAC defect?

It's working normally here.
Did you increase the volume in PO?

Sorry to ask, just to confirm.

There is a Gain function; put it in H.

 

[Gekel]

Yes, it doesn't really work.

Exception:
If I use PO as output, put gain to H and turn volume up, I can hear music, but I have to go over vol 55 to even understand anything, and on 99 it is still so quiet that I still hear every click of my mechanical keyboard while typing this text here.

Looks to me like some kind of amp is defect, which would be annoying, but it can be at least fixed.

[edit]
I still have no idea how this happened, but it was a software problem somewhere in the whole chain. I was already taking a video I wanted to submit to Fosi (they asked for one), when at the second or third time I switched between sources and output, the whole thing started working.

Interesting...

 

[nOOky]

I'm happy with the Fosi after a couple of months using it. I initially bought it for the XLR out connections and USB input. I run Edifier MR5's connected via XLR output from the device and Windows 11 found and configured it as soon as I powered it up. I use a USB A 2.0 cable to the USB C input. I mostly listen to music via Amazon Music Unlimited. It took playing with settings in the app and Windows to ensure I was passing through the best sound settings I could, but it sounds awesome and fairly transparent as far as I can discern.

The best part is I can run two different headphones at the same time, so either the wife can sit and listen with me or I can switch quickly if I'm comparing them to each other. The settings on the unit took a bit to figure out and dial in, but the manual eventually got me there along with Google.

My settings for headphones are USB - PO - Bass 0 Treble 0 - Input gain H - UAC 2.0 - Filter NAT. SMOOTH - Bypass Yes. Speakers Input is USB of course.

Highly recommended.

 

[Chanur]

I had DX5II but sold it due to unreliable dsp. Surprisingly it did not sound as good at full volume high gain driving HE6SE vs the ZH3.

The ZH3 is the only one that has adjustable tone controls on the unit itself, and it’s also the only option that has analog inputs, if either of those matter to you.

If you’re predominantly using a computer or streamer (WIIM) that are DSP capable, then the extra EQ features on those other units don’t really justify spending ~2-3x the price of the ZH3 (w/ discounts).

I think I'll get a WiiM Mini or something for this. Since I plan to primarily use it with Spotify for now. I may even be able to use my Schiit Modi/Magni 3+ stack.

 

[sikamikaniko]

Note: My English is basic, so I used Gemini to help translate and organize these technical details.

Setup:

• Source: Audient iD44 MKII
• Connection: SPDIF (Toslink)
• Device: Fosi Audio ZH3 (Headphone Amp/DAC)

The Problem: I am experiencing a loss of audio information when monitoring isolated tracks in my DAW. When soloing a Kick drum loop, the ZH3 consistently "skips" or fails to play certain hits, especially the second one in quick successions. This does not happen when monitoring directly from the Audient iD44 MKII.

Troubleshooting & Findings: I suspected an aggressive "Auto-Mute" or "Power-saving" circuit. To test this, I injected a 19kHz pilot tone at -80dBFS. With this tone active, the issue disappears completely and no hits are skipped.

This confirms the DAC/Amp has a signal-threshold gate that disconnects the output during silence, causing "wake-up" latency that clips transients. However, keeping a pilot tone active is not a professional solution for music production.

Questions:

1. Is this a known hardware behavior of the ZH3?
2. Is there a firmware update or a hidden setting to disable this "Auto-Mute" function?
3. Are there more professional workarounds than injecting a high-frequency tone?

 

[Henrik]

Note: My English is basic, so I used Gemini to help translate and organize these technical details.

Setup:

• Source: Audient iD44 MKII
• Connection: SPDIF (Toslink)
• Device: Fosi Audio ZH3 (Headphone Amp/DAC)

The Problem: I am experiencing a loss of audio information when monitoring isolated tracks in my DAW. When soloing a Kick drum loop, the ZH3 consistently "skips" or fails to play certain hits, especially the second one in quick successions. This does not happen when monitoring directly from the Audient iD44 MKII.

Troubleshooting & Findings: I suspected an aggressive "Auto-Mute" or "Power-saving" circuit. To test this, I injected a 19kHz pilot tone at -80dBFS. With this tone active, the issue disappears completely and no hits are skipped.

This confirms the DAC/Amp has a signal-threshold gate that disconnects the output during silence, causing "wake-up" latency that clips transients. However, keeping a pilot tone active is not a professional solution for music production.

Questions:

1. Is this a known hardware behavior of the ZH3?
2. Is there a firmware update or a hidden setting to disable this "Auto-Mute" function?
3. Are there more professional workarounds than injecting a high-frequency tone?

That's a great report
Perhaps you have the same issue as I did and others, which can be fixed by a firmware update. I wrote about it on gearspace last year: https://gearspace.com/board/showpost.php?p=17653536&postcount=34

When was your ZH3 purchased?

 

[sikamikaniko]

That's a great report
Perhaps you have the same issue as I did and others, which can be fixed by a firmware update. I wrote about it on gearspace last year: https://gearspace.com/board/showpost.php?p=17653536&postcount=34

When was your ZH3 purchased?

I bought it during the last Black Friday via the Fosi Official Store on AliExpress. I need to check the firmware version; I’ve never actually connected it via USB.

Did it happen to you over SPDIF as well, or only via USB?

 

[Henrik]

Did it happen to you over SPDIF as well, or only via USB?

I didn't try SPDIF. I only use USB.

 

[Bleib]

Now that I've used it a quite a bit more the only bug I've experienced is that the screen doesn't always turn off. Have to interact with it again and then the long 2 minute countdown begins

 

[Reynaldo]

Now that I've used it a quite a bit more the only bug I've experienced is that the screen doesn't always turn off. Have to interact with it again and then the long 2 minute countdown begins

I don't have this bug.
Mine turns off the screen correctly after 2 minutes.

 

[sikamikaniko]

That's a great report
Perhaps you have the same issue as I did and others, which can be fixed by a firmware update. I wrote about it on gearspace last year: https://gearspace.com/board/showpost.php?p=17653536&postcount=34

When was your ZH3 purchased?

I finally updated the firmware that's supposed to fix the issue, but it only works in USB mode, definitely not SPDIF.