Fosi ZH3 Balanced Headphone Amp & DAC Review

[Whatsthephuss]

Would it make any difference running this from pure DC, ie via a battery pack? just wondering.

There could be situations where it would make a difference imo. The first room I used the ZH3 in had an odd noise, but the next room I moved it to on a different circuit did not have any of that noise. Only heard it with my most sensitive headphones, RCA input, and high gain (volume >24). The $20 Fosi DC filter actually reduced the noise, and changing the op amps also made an audible difference in the level of this noise. Most measurements of these things (power filters, cables & op amps) seem to be taken under ideal conditions but I’d be more interested to see this gear tested in “stressful” noisy environments to see if there are situations where it makes a difference. Using a battery would be a reasonable solution imo if I was only limited to the dirty power in the first room I had my setup.

 

[milanjeromos]

Anyone tried to measure the RCA input? Would be super important for my use.

 

[jjk1]

Does anyone know what frequencies in the bass and treble that the tone control are centered at?
Thanks

 

[Fletcher Munson]

I have been running one of these as my main DAC pre-amp
I just got an Apollon Purifi Eigentakt 1ET6525SA ST amp and am having a few "issues"
On my B&W Matrix speakers (quite sensitive) with the Amp on max gain (29dB), the volume pot on the ZH3 is fine, i don't really have to go much above 70%
However on my KEF Q Concertos speakers which are NOT very sensitive, i have to run the volume up to 90% to get decent sound.
So i sat and thought
I'm using the XLR balanced outputs of the ZH3 which fosi claim to be 4V out. So i got my meter... and a 0dB 1khz sine wave
These are the voltages on the ZH3 balanced output

Volume Measured Voltage (AC)
50 0.18V
70 0.56V
80 1.01V
90 1.8V
95 2.4V
99 (Max) 3.02V

And theres my problem. all the action takes place after 90% lol
And the claimed 4V appears to be 3V (3.02V reading was taken at 0dB. so missing roughly 2.5dB of the promised output?)

the Apollon is set to 29dB gain, which is high. even with the amp at "Full Throttle," the ZH3 still can't provide the voltage headroom needed for the KEFs.

Now i'm no expert so I'm only guessing a 1kz test tone is a fair test. Either way, kind of unsurprisingly the ZH3 isn't very useful as a pre-amp with these types of class D amps with 4ohm low sensitivity speakers. 8ohm fine, you get a decent travel in the volume pot

It seems the ZH3 is an excellent, clean headphone amp/DAC, but as a dedicated Pre-Amp for low-sensitivity setups, the log-taper and sub-4V output create a 'cliff-edge' volume experience where all the usable gain is crammed into the last 10% of the pot.

So what to do ? I'm no expert at all, feel free to poke holes. the thing was sold with balanced XLR out and pre-amp function, i was naively running it before my new amp arrived thinking it sounded amazing (it does!).

I'm not whining, i'm just sharing

 

[Whatsthephuss]

It seems the ZH3 is an excellent, clean headphone amp/DAC, but as a dedicated Pre-Amp for low-sensitivity setups, the log-taper and sub-4V output create a 'cliff-edge' volume experience where all the usable gain is crammed into the last 10% of the pot.

So what to do ?

Thanks for the info, that’s very informative! I use the ZH3 as a preamp for other amps too, but I have only ever used the front (PO) 4.4mm output which was measured on the first page of this thread. It looks like amirm measured 4.5V output on medium gain and 9V output on high gain.

 

[Bleib]

And the claimed 4V appears to be 3V (3.02V reading was taken at 0dB. so missing roughly 2.5dB of the promised output?)

OK, this should be verified

 

[Fletcher Munson]

OK, this should be verified

do you know the methodology of that measurement ? i just chose a 0dB 1khz as a guess

And even then i was feeding the tone into the ZH3 via optical from a streamer so is that a problem ?

Certainly the problem with all the power being in the last few % of the knob is there

 

[Bleib]

do you know the methodology of that measurement ? i just chose a 0dB 1khz as a guess

I don't have a multimeter but I could purchase one, but I'm also quite sure many here @ ASR could also check

 

[Fletcher Munson]

I don't have a multimeter but I could purchase one, but I'm also quite sure many here @ ASR could also check

I was feeding the tone in and measuring between pins 2-3 of the XLR out with an AC meter. volume set to max (99)

 

[Bleib]

Yeah, it's rather simple, discussed here for instance

How do I measure DAC output voltage?

Hi all, I'd like to measure the output voltage of my SMSL M500 DAC at various volume levels via the XLR and RCA outputs. How do I go about doing this? Will my multimeter (below) suffice? Your shared knowledge, as always, is much appreciated :)

www.audiosciencereview.com

Another source says 50hz gives a more reliable reading

 

[Fletcher Munson]

Yeah, it's rather simple, discussed here for instance

How do I measure DAC output voltage?

Hi all, I'd like to measure the output voltage of my SMSL M500 DAC at various volume levels via the XLR and RCA outputs. How do I go about doing this? Will my multimeter (below) suffice? Your shared knowledge, as always, is much appreciated :)

www.audiosciencereview.com

Another source says 50hz gives a more reliable reading

I used two meters both specced to 1kz AC and both show almost identical readings

 

[Whatsthephuss]

I did an interesting side by side with the Topping DX5II and Fosi ZH3 using HE6SEv2 headphones.

Feeding both the same exact digital signal from a WIIM streamer (with EQ enabled on WIIM, disabled on DX5II and ZH3), I plugged one side of the HE6SE into each amplifier. Both were set to high gain and I slowly increased volume to the max.

What surprised me is that the ZH3 sounded louder, and yet the side playing from the DX5II rattled the housing. Switching sides yielded the same results - ZH3 sounded just as loud and clear but DX5II side had a rattle. This is with the DX5II output set to “All” and changing that to only headphones seems to boost the headphone output level significantly, but there’s nothing mentioned about this is the manual.

For me, the Fosi unit is objectively better for listening to music due to the easy access to tone controls to dial in the Fletcher-Munson curve at low listening levels. The Topping device is better for those that want to look at a tiny screen for frequency data or play around with EQ on a computer. Two very different ways of engaging with music imo

 

[Bleib]

I have both of those units as well but I don't notice / hear any difference. But I always set the DX5 II to switch between outputs that I use, no need for ALL outputs active. I use HP SE output or XLR or SE separately.
Haven't played around with crossfood either, but I guess that will give the Topping the upper hand

 

[Whatsthephuss]

I have both of those units as well but I don't notice / hear any difference. But I always set the DX5 II to switch between outputs that I use, no need for ALL outputs active. I use HP SE output or XLR or SE separately.
Haven't played around with crossfood either, but I guess that will give the Topping the upper hand

I found the ability to have all outputs active with EQ on the XLR/RCA output to be one of the few advantages of the DX5II, but it’s probably not great on the power supply to have too much plugged in at once…

I haven’t updated the firmware of either and both have been very stable for me. I found EQ easier to do in the WIIM app, so that kind of takes away Toppings upper hand (for me).

 

[Bleib]

I haven’t updated the firmware of either

Well. the new Fosi firmware fixes the audio delay at least when using USB. Worth updating

 

[Whatsthephuss]

Well. the new Fosi firmware fixes the audio delay at least when using USB. Worth updating

Thanks I’ll check it out, but generally I don’t use these DACs with a computer so I haven’t had that issue.

What surprised me is that the ZH3 sounded louder, and yet the side playing from the DX5II rattled the housing. Switching sides yielded the same results - ZH3 sounded just as loud and clear but DX5II side had a rattle. This is with the DX5II output set to “All” and changing that to only headphones seems to boost the headphone output level significantly, but there’s nothing mentioned about this is the manual.

Checked this again and I can confirm some error on my part. Turns out the DX5II saves different gain levels when switching between All and HP Bal out, so that explains the different in level I experienced. When both set to the same level the output is the same even with all outputs active.

Again, I’m playing heavy bass music with output close to 0dbfs (WIIM at 99% with high shelf EQ cuts to create a bass shelf without clipping), the ZH3 side seems to have louder bass while the DX5II rattles the driver.

If you own both units and a balanced headphone you can try the same thing even without pushing the amps to their limit. Just plug each side of the headphone into a different amp and try to level match until you have a solid center image, then listen to the difference.

 

[Alastor]

I know it's a very odd comparison, but let's see if anyone can help me out. Between the very first generation of Ifi Zen Can + Zen Dac and the Fosi ZH3, is there going to be a huge difference in favor of either of the two options? I've used the Ifi "stack" for years on a desk and I now have another desk that requires a dac amp combo. The Fosi is a much newer product and at an attractive price, I'm wondering how it will compare to an older dac+amp combo in separate units.

 

[Whatsthephuss]

I know it's a very odd comparison, but let's see if anyone can help me out. Between the very first generation of Ifi Zen Can + Zen Dac and the Fosi ZH3, is there going to be a huge difference in favor of either of the two options? I've used the Ifi "stack" for years on a desk and I now have another desk that requires a dac amp combo. The Fosi is a much newer product and at an attractive price, I'm wondering how it will compare to an older dac+amp combo in separate units.

Here are the ASR reviews for the IfI Zen Can + Zen Dac to compare measurements:

ifi Zen CAN Review (Headphone Amp)

This is a review and detailed measurements of the ifi Zen CAN balanced headphone amplifier. It is on kind loan from a member and costs US $150 from Amazon including Prime shipping. The design is identical to new line of budget products from ifi: No, it is not just the pictures. The silver...

www.audiosciencereview.com

ifi Zen DAC and Headphone Amp Review

This is a review and detailed measurements of the ifi Zen balanced DAC and headphone amplifier. I purchased it from Amazon last week. The Zen DAC costs US $130 including free shipping. I must say, I am not a fan of the look of the Zen DAC. It hearkens back to 1960s furniture style which would...

www.audiosciencereview.com

For the price of the two IfI units plus shipping & tax you could probably get two Fosi ZH3 (which is what I ended up doing

But one Fosi ZH3 will do everything that the IfI Dac/Can do/does, and it may sound more transparent. If you have both you can compare and make your own judgement on how audible the difference is

 

[Antiaudiophile]

I've found the digital volume (which is lossless in this model) is required for my setup... I set 50% as the maximum loudness anything more and my amp peaks. I find I can get more gain out of my system this way. I keep my PC at 100% and adjust with DAC... This way the signal stays strong... if I change the volume with the PC I lose resolution.

 

[Antiaudiophile]

I know it's a very odd comparison, but let's see if anyone can help me out. Between the very first generation of Ifi Zen Can + Zen Dac and the Fosi ZH3, is there going to be a huge difference in favor of either of the two options? I've used the Ifi "stack" for years on a desk and I now have another desk that requires a dac amp combo. The Fosi is a much newer product and at an attractive price, I'm wondering how it will compare to an older dac+amp combo in separate units.

I upgraded to the Fosi ZH3 from a 2015 Matrix mini i pro... it has a much lower distortion rating and is less buggy with the software since it's newer. I think it sounds better too, but it's not an apples to apples comparison since I upgraded my amp when I got the Fosi.