Fosi ZH3 Balanced Headphone Amp & DAC Review

[Alexium]

They sound the same to me, no difference at all, both sound good. I have done level matched testing on DACs before and couldn't tell any difference at all between AKM, ESS, R2R dacs etc, so I don't see the point in doing any more testing. I think if someone ever posts a blind test where they successfully distinguish between two transparent DACs then I'd go out and buy them to test myself, but until that ever occurs (which it probably won't) then I will trust my initial experimentation i.e. there is no difference.

Unrelated to the product being discussed (I don't have it), but for what it's worth, I did tests some years ago with mid-range DACs and amps that are definitely worse than today's SOTA, also with 1990s CD players of vastly different price and level of sophistication, and my findings were the same. I could never hear any difference even when A/B-ing between the best and the absolute worst options.

I'm pointing out digital volume control steals purity as it steals information when you lower the volume it is nowhere even close to the same purity as analog at volume levels below 100%

What kind of digital control are we talking about? There are volume control ICs, they attenuate the input analog signal using a resistor ladder according to the digital control input. This is usually how digital volume control is implemented, not by simply attenuating the digital signal that goes into the DAC. I expect nothing less from Topping/SMSL, and I hope Fosi is doing the same.

 

[bungle]

What kind of digital control are we talking about? There are volume control ICs, they attenuate the input analog signal using a resistor ladder according to the digital control input. This is usually how digital volume control is implemented, not by simply attenuating the digital signal that goes into the DAC. I expect nothing less from Topping/SMSL, and I hope Fosi is doing the same.

No. It happens directly in DAC (chip) by changing the amplitude. Nothing to worry with modern DAC chips, like ZH3's ak4493seq. It is a solved problem. They use high resolution internally when calculating and dithering. Correct me if I am wrong. The expensive ones like Benchmark HPA4 uses what you are talking about (it gets expensive when you want to offer say 0,5db steps for whole range with resistors, with DAC internal volume, it is no problem at all). It is good (resistor approach), but I don't see it being any better (one could say "obsolete").

 

[rocksteady]

Is it me or fosi is a little expensive as compared to SMSL.

It's you...

 

[ThsM]

FYI
Amazon Prime Days started today. At amazon.de you can get it for 169,99€ with an additional 10% discount at checkout.

 

[onethreetwowaitthatswrong]

FYI
Amazon Prime Days started today. At amazon.de you can get it for 169,99€ with an additional 10% discount at checkout.

That's a really attractive price. In my country, without Prime; it's ~204€ with delivery, which makes it a somewhat tough choice against the Topping DX5 II, at around 300€, but packed with much more features like (experimental) PEQ, internal power, trigger...

 

[EPICURIOUS007]

What would be the use for that?

would love to see the rca output tested for sinad,
could be a good little preamp, save space and money lol

 

[Call me Ali]

Since it’s the same knob, does the flakiness of menu selection also extend to the volume control? That would be a dealbreaker.

I have a toaster/air fryer that is great except for an absolutely *terrible* rotary knob. Sometimes multiple clicks will do nothing; sometimes one click will shoot forward 4-5 selections. Absolutely infuriating. And something that got worse over time.

I just received mine a few days ago and the knob has been solid. It has a nice step feel. I didn't read the manual and wasn't sure how to get to all the settings and thought I had to double click or long click the knob, but I just needed to turn the knob to get to the next page.

 

[Call me Ali]

I was hoping to keep it in medium gain with my Beyerdynamic DT 770 250 ohm, but it just doesn't have enough power. Even at high gain, I can max the volume with some older recording that have a lower gain and not blow my eardrums out.

 

[bungle]

I was hoping to keep it in medium gain with my Beyerdynamic DT 770 250 ohm, but it just doesn't have enough power. Even at high gain, I can max the volume with some older recording that have a lower gain and not blow my eardrums out.

You need to use the balanced headphone output to get all the power. I am not sure if you can get balanced cable fitted to yours.

 

[Call me Ali]

You need to use the balanced headphone output to get all the power. I am not sure if you can get balanced cable fitted to yours.

Unfortunately the DT 770 pro has a non-detachable cord. I may look to see if I can mod it to add an mmcx connector and re-wire it internally.

 

[bungle]

Unfortunately the DT 770 pro has a non-detachable cord. I may look to see if I can mod it to add an mmcx connector and re-wire it internally.

How are you feeding the DAC, is it possible that input signal is already attenuated? If using Apple, check the midi. Or if player or whatever allow you to change volume, turn that to max first.

 

[onethreetwowaitthatswrong]

I like what Fosi is putting out there these days.

Still, I think you have to have a pretty firm $200 cap to prefer this to the Topping DX5II or the SMSL RAW-MDA 1. That extra $80-100 gets you a lot of improvement in sound and connectivity.

Those two are undoubtedly a notch or two better, but they both do not have an analog input.

That was my reasoning so far, but QC might very well make me go towards the Fosi still. The original DX5II thread looks like a circus show of various issues at each update and PEQ not working well and the SMSL, which doesn't have as many features (no PEQ, no trigger, less funny screen options) as the DX5II, doesn't look it's been spared by numerous issues as well. On the other hand, the Fosi boasts less features, but all working well, so at this point in time, what would be the concrete advantages (not counting not reliable PEQ yet then) of these two more expensive offerings ? Internal power supply ? That's nice, but is it enough ? Dual chip for balanced headphone output ? Would it be noticeable in sound quality ? A priori no (correct me if I'm wrong). Of course the Fosi is newer so maybe qc issues haven't arised yet, but from my readings here they still seem less prone to it.

 

[davmol]

The DX5II has a better screen and a better remote, along with the inbuilt PEQ. It also has XLR headphone out, Bluetooth input and 2.5x the power of the Fosi. If you don't need any of that then go for the Fosi, it's a bargain. I have both, no problems with either of them, they're both great.

 

[rocksteady]

This is a review, detailed measurements and listening test of Fosi ZH3 balanced stereo DAC and headphone amplifier/preamp. It was sent to me by the company. I can't find the price ($200?). It costs US $199.
View attachment 476977
The ZH3 is attractive and follows the design language of the newer Fosi products. I found the menu navigation with the front panel knob difficult. It would sometimes jump forward/back with little motion, other times it would take a few clicks. It was very frustrating. Fortunately the remote control doesn't have this issue. Back panel shows attractive set of features:
View attachment 476978
Like the inclusion of trigger and RCA inputs. Alas, I forgot to test that. Will do so later.

In the interest of time, I skipped over a few tests and focused on front panel headphone outputs only.

FOSI ZH3 Measurements
I started with medium gain and balanced headphone out:
View attachment 476979
Distortion is well below threshold of hearing. So SINAD is determined by noise alone. 113 dB nicely lands the ZH3 in our very competent bucket:
View attachment 476980
View attachment 476981

Here is the dynamic range:
View attachment 476982

At 4 volt, performance is more than you could ask for in this class. At 50 mv, initial measurements using balanced out was somewhat disappointing. Switching to unbalanced, remedied good bit of that:

View attachment 476983

Still, highly sensitive IEMs may experience a bit of noise.

IMD test shows the difference between balanced and unbalanced:
View attachment 476985

Default filter performance is typical and good:
View attachment 476986

There is almost no frequency dependency which is good:
View attachment 476987

Now we get to the impressive part which is available power and lack of any distortion/clipping:
View attachment 476988

View attachment 476989
It is especially impressive to see no clipping all the way up to 2.5 watts! I don't think I have seen this before. This is very useful for testing limits of headphone distortion. If you hear any distortion, it is the headphone and not the amplifier!

Fosi ZH3 Listening Tests
I chose to test the Dan Clark Audio E3 headphone with the ZH3. I used the high gain and with it, there was incredible fidelity and lots of headroom. I think I had the volume at 75 even at very high loudness. Detail in the music was amazing as was the bass impact. The combination melted my heart in how clean and dynamic the performance was!

Conclusions
If the price is as I expect, the ZH3 is an incredible offering with ultra low distortion yet a ton of power. It is attractive in design and capability. Listening performance was a delight even with my less sensitive headphone, proving the capability of the output stage. Yes, the noise figures could be a bit better but that will impact very few users with ultra sensitive IEMs.

The inclusion of analog input is a major hit for people like me who also need to integrate an analog source. Few DACs sport such a feature.

It is my pleasure to recommend the FOSI ZH3. Company sure has its eye on the ball as far as feature list and performance.

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As always, questions, comments, recommendations, etc. are welcome.

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Hi Armin. I suppose you didn't yet get the chance to test the RCA input? I would be very interested to find out how it performs...

 

[ejr]

This may be a dumb question but, does the gain control on the ZH3 apply only to headphone output? Does it have any affect on the output from the XLR connections?

I don't know a thing about gain. The only headphones I own are unbalanced (Sony 7506 and AT m40x) and I have never had to worry about it. I don't plan to use headphones with the ZH3. I just want to know if changing the gain setting will affect the output to my powered speakers. Thanks.

 

[bungle]

This may be a dumb question but, does the gain control on the ZH3 apply only to headphone output? Does it have any affect on the output from the XLR connections?

There are 3 outputs (or output modes):

1. PO = phones out and volume then works with headphones
2. LO = lineout, no preamp, volume does nothing to RCA/XLR (you can use external analog preamp, so ZH3 is pure DAC then)
3. AUX = preamp, volume works with RCA/XLR.

Some features like tone control only works with PO.

Because you will use it as preamp only, then keep it as AUX always, and that's it.

 

[ejr]

And the gain settings are only for the PO?

 

[bungle]

And the gain settings are only for the PO?

Ah, you meant High, Medium and Low setting, according to manual:

You can download the whole manual from here:

ZH3 | Welcome to our Support

support.fosiaudio.com

 

[Elekt9]

I have active speakers and an active subwoofer. Is it possible to connect the speakers to the XLR output and the subwoofer to the RCA output so that the signal goes to both the RCA and XLR outputs? Will this work? Does this mean the RCA and XLR outputs work simultaneously? And if so, should I set the output mode to AUX or LO?

 

[bungle]

I have active speakers and an active subwoofer. Is it possible to connect the speakers to the XLR output and the subwoofer to the RCA output so that the signal goes to both the RCA and XLR outputs? Will this work? Does this mean the RCA and XLR outputs work simultaneously? And if so, should I set the output mode to AUX or LO?

I am not sure, but you usually don’t want to feed low frequencies to main speakers when using a sub. Subs on the otherhand usually support routing signals through them where you can apply crossover, and from sub take RCA/XLRs to mains. Things like AVRs and miniDSP can work as a crossover too. I have genelec sub and mains, but I don't route things through sub, but I use minidsp for cross-over (at first I did it, but then removed the routing, it only added more cables and less flexibility compared to minidsp).