iFi ZEN Signature Set
Fresh ZEN series components keep coming from iFi Audio at an impressive pace. iFi’s cleverly spec’d entry level line continues to demonstrate the company has a keen eye on the voracious desktop HiFi market. A bit of a theme developed in the first round of ZEN products: excellent build, big league specs, audiophile sound, and extremely accessible pricing. The new ZEN Signature line marks the first variation on that theme. The Signature designation brings upgraded internal parts, a handful of interesting features and of course, sportier looks.
The ZEN Signature Set in for review here consists of the ZEN CAN Signature 6XX headphone amplifier and ZEN DAC Signature bundled together with a 4.4 mm Pentaconn balanced interconnect. The Set retails for $499 and the CAN and DAC are available separately for $249 each.
The Signature Set was originally conceived as a special run for Drop, so, iFi knew the Signatures had to stand out in a competitive field of high-value headphone amps and DACs. In a fresh approach I have not seen before, iFi custom tuned the ZEN CAN Signature 6XX specifically for the Sennheiser HD6XX, the all-time best-selling headphone on Drop. In addition to its large user base, the sonic character of the HD6XX also made it a great target. As popular as the HD6XX is, there seems to be endless fervent discussion about its sound, often characterized as natural and intimate but light on bass. Essentially, a cosmetic update of Sennheiser’s long running HD650, the HD6XX is also known to shine with high quality amplification, especially tube amplifiers.
Features & Specifications
As expected for special edition electronics, iFi has upgraded a handful of critical components in the signal path of the ZEN Signatures. Where the Set also shines is flexibility. The pair of components has an impressive array of inputs and outputs. Both the CAN and DAC have a 4.4 mm balanced preamp output, with an additional RCA pre-out on the DAC. Fortunately, the outputs on the DAC are switchable between line and preamp mode.
ZEN CAN Signature 6XX rear panel.
ZEN DAC Signature rear panel.
The dual outputs on the DAC are a fantastic feature that allows it to feed the CAN and a main amp simultaneously (also making for a more convenient review). Somehow, iFi managed to fit three inputs (RCA, 3.5 mm and 4.4mm balanced) on the back of the CAN, impressive considering the size and price of the unit.
The most interesting feature is the ActiveEQ button, or, as iFi calls it, the HD6XX button. The rightmost button on the face of the CAN Signature 6XX engages an analog EQ profile specifically designed to optimize the frequency response of the HD6XX. This button also has a second option, called XSpace, which is designed to increase the soundstage of recordings mixed for loudspeakers. One press of the button engages HD6XX mode, the second switches to XSpace mode, the third press engages both modes, and the fourth disengages both to return to normal operation.
Readers interested in the full specifications, including details about upgraded components, should visit iFi’s website (linked below). The one specification always worth discussing is power. In our current arms race of headphone amplification, 600 mW (balanced) or 1000 mW (single ended) into 16 ohms is not jaw dropping. Where power really counts here is into higher impedance loads. 756 mW (balanced) or 196 mW (single ended) into 300 ohms is more than enough to light up high impedance headphones like the HD6XX.
Packaging, Design & Build
The neatly packaged Set includes the ZEN DAC Signature and CAN Signature 6XX, two iPower X power supplies, a 1ft RCA interconnect, a 1ft USB cable, and an excellent 4.4mm Pentaconn interconnect. The Pentaconn cable retails for $69 and since this relatively new connector style is still hard to find it’s a nice bonus. The real story is the two iPower X power supplies which retail for $99 each. A great deal at face value, this also offers power skeptics a respectable opportunity to experiment with power tweaks. The iPower X cable is also a much more usable length than the cable on the wall wart that comes with the standard ZEN products.
iFi’s 4.4mm Pentaconn Interconnect.
The Signatures are dressed in midnight blue wraparound chassis with black anodized faceplates. Just like the originals, in evening attire. I’ve always loved the styling of the ZEN line but after some discussion with family and friends it’s more polarizing than I thought. The mid-century inspired shape of the face is not for everyone, apparently.
The build quality, though, is unimpeachable for the price. The review units had gorgeously finished metal volume knobs with good resistance which were a pleasure to use. The headphone input also inspired confidence that it would last many years.
Usability Considerations
For desktop use in a space limited situation, separates can be a tough sell. I, for one, appreciate the cleanliness of an integrated DAC/Amp. Especially because fitting two (or even one) iPower X wall warts into adjacent office power outlets is impossible.
Both units get iFi audio's new iPower X power supply—a $99 value (x2) and ship free with the set.
It’s tough to ask for more features but call me spoiled. Some S/PDIF inputs on the DAC would have taken it to the next level by enabling its use in a main system with multiple sources.
Review System
Headphones: Sennheiser HD650, Beyerdynamic DT770 Pro 250 Ohm, KZ ZSN Pro
Electronics: PS Audio Stellar Strata, Schiit Modi, Schiit Fulla, Bottlehead Crack 1.1 OTL, Xiang Sheng DAC-01A, Shanling M01
Speakers: Usher Audio SD-500, Wharfedale Diamond 10.2
Sources: Macbook Air, AmazonHD, 16-bit & 24-bit flac
The DT770, HD650, Fulla and Bottlehead Crack were generously loaned to me by my friend and Radiohead fanatic, Josh. Much appreciated.
Sound
A pair of components this flexible made for a tough review because even with a small collection of gear on hand the possible system configurations were numerous. I evaluated the Set as one, comparing it with integrated units like the Schiit Fulla, PS Audio Stellar Strata (review coming soon), and Xiang Sheng DAC-01A. Additionally, I evaluated each piece separately but dedicated more time to the CAN to ponder its specific mission of driving the HD6XX.
My experience with a recording right in the Sennheiser’s wheelhouse, Jon Batiste’s Anatomy of Angels: Live at the Village Vanguard (Verve) provides a representative impression of the Signature Set’s performance. There’s just something about recordings from the Village Vanguard—murmurs from the crowd, clinking of glasses—the space sounds so right. Is it acoustic perfection or hallowed ground? I hope to find out in person someday. In the meantime, I’ve been transported there by Rachael Price’s vocals on the third track, ‘The Very Thought of You. Through all my electronics, this track had a clean neutral presentation, that allowed the tight imaging of the HD6XX to come through. Most systems gave me the illusion of being up on stage with Price, just over pianist Batiste’s left shoulder. Some systems sounded a bit cramped. Switching to the ZEN Signature Set felt more like sitting in the audience and experiencing the whole room. Vocals were still large and centered and the orientation of the piano was about the same but more, shall we say, socially distant. Tiny details like individual whispers in the audience were more apparent. The listening experience became more about hearing the music in the space than hearing the music in my head.
Throughout the review my focus was mostly the Sennheisers but the DT770 got a thorough workout as well. They were just as easy for the CAN to drive as the Sennheisers (I never passed 12 noon on the volume knob on the lowest gain setting for either headphone) and maintained their characteristic V-curve with deep bass, slightly recessed vocals and good detail. It was clear that the ZEN was a fine match for headphones with different voicing than the HD6XX.
Trying out my cheap and cheerful KZ ZSN Pro to see how the ZEN fared with an IEM turned out to be quite interesting. These roughly $25 IEMs, which served many miles of pre-pandemic travel duty, have a unique personality. Definitely not neutral, they combine great detail and imaging with a lean, glassy tone and light bass. After spinning Bob Marley’s all time classic, Natty Dread (Island) on my Shanling M0 DAP, I switched to the ZEN Signatures and found the Set was able to seriously elevate these cheap IEMs. Body and bass came to life and I heard more music than I ever expected from a bargain IEM. I was forced to reconsider my thoughts about this familiar earphone.
I spent many sessions with the ZEN DAC Signature feeding the Bottlehead Crack 1.1 OTL. The Bottlehead is in some ways the opposite of the ZEN CAN. It’s a tubed based DIY kit with a simple all discrete point to point circuit. Both amps have one key similarity: they were designed to drive the same type of high impedance headphones. The Bottlehead website calls out Sennheiser, Beyerdynamic and AKG specifically. Hopefully some readers who are Sennheiser HD series enthusiasts have experience with Bottlehead as a point of reference. In general, the Bottlehead offers what the ZEN Can does, just more of it. More space, more exciting highs, and especially more bass from the HD650. On bass heavy grooves like Erykah Badu’s Bag Lady (Cheeba Sac Radio Edit) (Motown) the ZEN CAN Signature 6XX could still use some help down low and the Bottlehead obliged.
The Bottlehead proved a nice foil to the ZEN CAN Signature in one other area as well. It seemed to have just the right amount of edge in the highs to add serious realism to acoustic recordings while the ZEN was typically more polite. The implications here are a matter of personal preference and listening habits.
For a test of pure listenability, I selected a piece from the Fitzwilliam String Quartet’s Shostakovich: The String Quartets (Decca). It’s not the most famous Shostakovich quartet, but I am drawn to the Quartet No. 2 in A Major. It opens with a brooding intensity and the anxious tension carries on throughout the piece. Engrossing music to get lost in while sipping a whiskey. However, at around 35 minutes it’s a long quartet and on a harsh sounding system (headphones or loudspeakers) it’s tough to finish without listening fatigue. Strings are generally nicely rendered by the HD650, but through the ZEN Signatures the sound was liquid smooth. The Bottlehead gave more bite for extra realism, but for everyday listening with modestly priced headphones, the well-behaved ZEN seemed more approachable.
I’ve been getting into classic spiritual jazz lately and I’ve found Live in Paris 1975 (Transversales Disques) is a great entry into Pharoah Sander’s discography. Plenty of groovy, two-chord piano vamps and lyrical playing by Sanders make it more fun than challenging but there are still some exploratory moments which serve as great tests of dynamics. For example, on the opening track, ‘Love is Here 1’ Sanders seems to sing (or shout) into his sax for a few bars with a startling effect. Despite its good manners, the ZEN Signature Set managed to recreate this passage with intensity. This was just one micro-example of how the ZEN Signature Set’s dynamic ability makes for fun listening.
My trusty first generation Schiit Modi served as a reference point for a standalone DAC. The multiple inputs of the ZEN CAN made this a convenient comparison with headphones. I’ve enjoyed the Schiit Modi for many years, so I was surprised to find the ZEN DAC Signature trounced it in nearly every way. More space, detail and realism were apparent on most recordings. Surely, the current Modi would be a closer match, but this was still a neat comparison that at the very least reminded me how far budget DACs have come in the last few years.
Listening with headphones, I compared the USB input on the PS Audio Stellar Strata Integrated to the ZEN DAC Signature. While the ZEN held its own in terms of resolution I found it to have a bit more recessed spatial presentation than the Stellar Strata. This difference was less apparent when listening through loudspeakers. More specific details on the sound of the Stellar Strata will be highlighted in the upcoming Audiophilia review, but I can say the ZEN DAC compared well given its price.
The HD6XX button
Is the HD6XX button a panacea for all the common complaints about the HD6XX? The button does indeed thicken up the bass and add a touch more sparkle to the highs. I’ll be straightforward here though, the HD6XX button will not make the CAN sound like a whole new amp, or the HD6XX sound like a different headphone. The changes are appreciated but subtle. The XSpace option is not designed specifically for the HD6XX but it is nice to have when the intimate soundstage of the HD6XX doesn’t suit the mood. Engaging XSpace seems to add some reverb which provides a greater sense of space. The natural trade-off when increasing the soundstage is that vocals and individual instruments seem further away and therefore smaller. My takeaway is that the button is a well-executed bonus feature on an amp that is already a fine match for the HD6XX.
Conclusion
I wholeheartedly recommend the ZEN Signature Set ($499) based on its detailed, spacious, fun and eminently livable sound. The strength of its value proposition may vary by use case and individual need. The ZEN Signature Set is more than just a DAC/Amp combo—it’s damn close to a complete system. It’s a source, preamp, and headphone amplifier with cables and power conditioning. Careful consideration of the features, inputs and outputs is necessary to ensure full utilization of the Set. The sound certainly warrants it.
My first and most obvious recommendation is for HD6XX owners in need of amplification to check out to ZEN Signature Set. Again, the value proposition is strongest when buying the Set as opposed to just one of the two components. However, the Signature Set is targeted at enthusiasts who likely own a few (or several) headphones, amps and DACs. As such the Signature Set makes a great addition to a curated head-fi collection.
New audiophiles will certainly be well served by the Signature Set, especially when paired with the HD6XX. Still, the original ZEN DAC, with its built in headphone amp, shouldn’t be overlooked by anyone on a tight budget.
I found a level of engagement listening with the ZEN Signature Set and Sennheiser HD650 equal to or better than my several thousand dollar main system. A fine endorsement given the total system cost differential. Hence my most emphatic recommendation is for experienced audiophiles who have eschewed headphone listening for whatever reason to check out the ZEN Signature Set. Grab some HD6XXs (might as well grab a couple different ‘phones, too) and hear your favourite music for the first time all over again.
A variation on the ZEN theme did not immediately strike me as the most exciting review subject, however, the ZEN Signature Set quickly set my mind straight with endlessly enjoyable sound and cool features. Now, I must know: will we see a ZEN Phono Signature?
Further information: iFi Audio
