There are so many audio products in the market, smart consumers will try all means to search for reliable reviews to make sure they buy a good product. That has always been a challenge for me when researching lesser known brands. Headphone amplifiers are not difficult to make, and they come in various shapes and sizes, from a small USB stick (like the Creative SXFI Amp) to the large desktop models, some powered by USB, others require AC power. To me, the important factors are the number of input and output connectors, the design, the audio quality, and finally the price.
Fosi Audio also has many headphone amps in its product list, but when they announced the new ZH3, I spotted one feature that makes it stand out in the cluttered audio market: an analog RCA input. You may think that having an analog input seems like an easy feature to include. I would think so too, but then why do manufacturers not include them in headphone amps, not even FiiO in their S$1,600 K19 desktop amp?
Well, most manufacturers take the easy way out when designing headphone amps, by going all-digital. Every input connectors you find in most digital amps are either USB, Optical, COAX, or HDMI. To support an analog input, the amp needs to process the analog signal and output to the various connectors. For outputs, since headphones are essentially analog, it is already handling analog audio, so it is easy to add more analog output connectors like RCA or 3.5mm Line Out. Premium amps will also include balanced output connectors like 4.4mm and XLR.
And the ZH3 handles analog inputs and supports balanced output. Not bad for a budget brand.
To review the ZH3, I use these reference tracks. I reviewed and compared it with these headphones – Fosi Audio i5, Sennheiser HD 800S, Audio-Technica ATH-ADX7000, and among them, I find the i5 allows me to hear more differences in the filter settings and across products.
ZH3 Overview
The Fosi Audio ZH3 is an all-in-one desktop hi-fi digital-to-analog converter (DAC), balanced headphone amp, as well as a preamp. It is fitted with XMOS XU316 USB audio processing, AKM AK4493SEQ DAC chip, OPA1612 opamps. It can handle 16 to 300-ohm headphones in 3.5mm and 4.4mm outputs, plus XLR, RCA outputs, as well as Opt-In, COAX-In, USB-In, plus analogue RCA inputs that is uncommon in a digital amp. It features a unique round LED display that intuitively lets you control settings using the digital knob, but also lets you adjust settings using an IR remote control. The body is wrapped with aluminium alloy with the design dimensions matching the Z-series family equipment. It has 12V trigger ports that let you allow synchronised power control across all compatible devices.
With this analog input connector, I can connect my turntable to the ZH3, and is one of the few desktop headphone amplifiers that can do that. And with the growing popularity of analog format, I hope more manufactuers can include this elementary option in their headphone amps.
In this full analog mode with RCA Input, the volume control is limited to 32 levels instead of 99. Gain level can be selected, and to drive the Fosi Audio i5 planar headphones, the level I needed is aroun 24 at high gain. When sending audio to AUX Out, you can use your amplifier or active speakers to increase volume level if the ZH3 volume is not adequate.
I like that the menu option is designed in a circular layout around the diameter which feels intuitive when using the knob to navigate. But it is actually easier to select the options from the remote control, which has dedicated buttons for filter, input, output, mute. In USB mode, the left-right arrow can even control the tracks on my device player like foobar2000.
The ZH3 supports two audio-processing feature. One is the EQ tone adjustment on the bass (+-12dB) and treble (+- 10dB), and the other is the digital filter which is built into the DAC chipset. The 6 digital filters alter the frequency response – attack, delay and rolloff. It is best that you try it yourself to determine which one you prefer, and for me, I prefer the “EXT HIGHS” and “WELL DEF”. In fact, the availability of this filter makes the evaluation of the ZH3 more subjective because given this is a chip-level filter, the BYPASS option does not bypass the filter.
As a headphone amp, I can find no fault with the ZH3. The audio delivery is excellent, highly resolving, clean, detailed. The design and presentation feels like it is made by an experienced team and appeals to global market. Its audio profile leans towards a dry, cosy, and thick sound, offering generous musical texture to be discovered. Treble does not reveal excessive air, midrange is controlled, bass is uncoloured.
The good thing with ZH3 is its versatility. It can support headphones from 16 to 300 ohms, it offers treble-bass tone adjustment, and filters to subtly shape the sound. These combo should be able to let you pair it with any headphones and tweak to match your preferred sound, be it more bass or brighter treble. For additional audio customisation, you can even swap the opamps.
Compare ZH3 to K7
The Fosi ZH3 has similar headphone amp specs as the Fosi K7, both using AK4493SEQ and OP1612 chips. But upon detailed listening, the sound is noticeably different. I find the K7 sounds more open, more spatial and dispersed. The upper frequencies sound little more prominent, less warm, more sibilant. Even after experimenting the ZH3 filters, I could not find a match to the K7 sound. Perhaps the K7 is tuned for the gamers hence the slightly more prominent treble and spatial presentation.
Personally, I find the K7 sound more pleasant to listen to casually. Plus, deciding between the ZH3 and K7 is a matter of whether you need a Bluetooth input (K7) or an analogue RCA input (ZH3). The K7 takes up less space on the desk, and I find it easier to adjust the treble and bass tones. The ZH3 looks better on a hi-fi rack, and it comes with a remote control to operate the features from a distance.
Verdict
The Fosi Zudio ZH3 is a versatile audio component that you can use as a headphone amp, a hi-fi preamp, or a desktop amp. It supports both analog and digital inputs, and outputs to balanced headphones, RCA and XLR. Its built-in EQ and filter controls allow tone adjustments. It has a special place in my home audio collection, as I pair it with my second turntable so I can listen to analog music at a separate corner. This amp retails for US$189 available at the Fosi Audio website.
Likes:
- Versatile inputs and outputs
- Powerful amp to drive headphones
- Remote control
- Intuitive menu design
Dislikes:
- Too many screws to remove for opamp rolling
- No digital output
