The PENON TAIL Portable Cirrus Logic Headphone Amplifier

DISCLAIMER

I would like to thank Penon for providing this unit.

The Penon Tail can be gotten here: https://penonaudio.com/penon-tail.html (no affiliate links).




SPECIFICATIONS/COMPATIBILITY

• DAC Chip: Dual CS43131 Cirrus Logic chips
• Output ports: 3.5 mm single-ended and 4.4 mm balanced
• Typical output Power: 3.5 mm single-ended: 45mW (@32 Ω) or 8.07mW (@600 Ω); 4.4 mm balanced: 151.25mW (@32 Ω) or 29.4mW (@600 Ω)
• Playback: PCM up to 32 bit/384 kHz; DSD 256
• THD+N: -103 dB for 4.4 mm port; 100 dB for 3.5 mm port
• Crosstalk: -135 dB for 4.4 mm port; -85 dB for 3.5 mm port
• Dynamic range: 135 dB
• Frequency response: 20 Hz - 20 kHz
• S/N: 130 dB for 4.4 mm port; 125 dB for 3.5 mm port
• Tested at: $74.90 USD

The Penon Tail is a plug-and-play dongle. As a Windows 10 user, I did not require any additional drivers to be installed - it was easily recognized on various Windows and Android devices. However, I cannot vouch for its compatibility with Apple products, as I'm not an Apple ecosystem user.


ACCESSORIES

Other than the dongle, the packaging comes with:
- Lightning to USB-C cable
- USB-C to USB-C cable
- Leatherette pouch
- Plastic case



The accessories are truly generous for a sub-$100 dongle. Perhaps a small nitpick would be the omission of a USB-A to USB-C adapter for laptops and PCs, but otherwise, the Tail surely puts to shame pricier dongles with a lesser accessory spread.

Though the 2 cables are on the shorter side, they are supple and well-braided with a fabric sheath, with reinforcement of the insertion point of the cable to prevent fraying.

Last but not least, the plastic case and button leatherette pouch are practical additions for carrying the dongle around.


DESIGN/FUNCTION



The Tail is fashioned from aluminum, and is very solidly built. One side of the dongle is painted white, while the other faces are highlighted in a catchy gold tint.

This dongle is very light, weighing in at around 18 g. Coupled with portable and compact dimensions, it easily fits in a pocket or small bag.

This DAC/AMP has no screen or LED lights. Neither does it have an app, PEQ or DAC filters, so it is pretty no frills.




On one end, we have the USB-C port for data/power feeding.




The opposite end houses a 3.5 mm (single-ended) and 4.4 mm (balanced) port, with the latter nicely reinforced with gold-plating.




On the lateral side of the fuselage, we find 3 buttons. The outer 2 deal with volume controls, and the middle one is a pause/play button. This is a handy feature, as most dongle rivals do not have a pause button to momentarily stop music, necessitating users to go to the upstream source to do so. Sadly, the Tail's volume controls are not independent, and the volume steps are not the most finely-tuned.




Directly opposite these 3 buttons lies a single button - the gain switch - which is a useful option for hard to drive gear.


INTERNALS

This DAC/AMP's engine are dual CS43131 chips. It allows playback of PCM up to 32bit/384kHz, and DSD up to DSD256.

The Tail also utilizes a low-noise power line, with an accurate femtosecond crystal oscillator. Indeed, as we will read below, the noise floor is remarkably absent, with a dark hiss-free background.


SOUND/PERFORMANCE

I tested the Penon Tail with only Android phones and Windows laptops and PCs. Once again, I'm not an Apple user, so I can't confirm its performance with Apple gear.

On phones, I used the HiBy Music Player, with USB bit perfect OTG activated on a Samsung S22.


Tonally, the Tail is quite neutral, yet musical. Sonics are clean and transparent. Bass is textured and speedy with no obscuration of the midrange. There is a mild upper treble roll-off and some rounded note-edges to shave off sibilance and fatigue. Overall, we thus have a pleasant tonal balance that should please most consumers.

In technicalities, this DAC/AMP has good soundstage width, though depth and height are about average. It isn't the most micro-detailed dongle (but the Tail doesn't come across as overly fatiguing as such), and imaging is relatively accurate for a sub-$100 dongle.

Power-wise, the Penon Tail is marketed to pump out 45 mW (@32 Ω) or 8.07 mW (@600 Ω) on single-ended, and 151.25 mW (@32 Ω) or 29.4 mW (@600 Ω) on balanced, which is par for the course for most modern day dongles. It isn't the most powerful dongle per se, but should be able to handle the majority of IEMs, other than outliers.

As per usual practice, I put all my sources through a crucible testing of my hardest to drive gear:
1) Final Audio E5000 (low sensitivity at 93 dB/mW)
2) Sennheiser HD650 (high impedance at 300 ohm)
3) Yinman 600 ohm (600 ohm impedance and 87 db/mW sensitivity)

The E5000 was sufficiently driven with serviceable headroom; bass was decently textured with rather nimble speed. Dynamics were okay, though soundstage was a tinge compressed.

The HD650 was juiced adequately in terms of volume, though bass tightness, soundstage and dynamics were understandably not comparable to a desktop-grade amp. It sounded a tinge flat and "boring".

The final boss - the Yinman 600 ohm - which has a ridiculous double whammy of a low sensitivity coupled with high impedance, is not driven properly by most dongles, or even DAPs. Thus, it is no surprise - and actually no shame - that the Penon Tail also doesn't uproot any trees here, with the Yinman 600 ohm sounding one-noted in the bass with a distinct lack of dynamics.

I appreciate that this dongle does not get hot during usage, even when driving power-hungry behemoths. There is no hiss heard with sensitive IEMs, though there was a "pop" heard when disconnecting transducers, which is a slight annoyance.

We have no information on the output impedance specs of the Tail, but I hazard a guess that it is pretty low, as the very low impedance sets that were paired with the Tail didn't sound skewed in the frequency response.




COMPARISONS

Comparisons will be made against other sub-$100 USD dongles that utilize Cirrus DAC chips.

Simgot DEW4X

The DEW4X's engine are dual C43198 cirrus chips, and it has a warm-neutral tonality. It sounds thicker in note weight than the Tail, with a more laid-back soundscape. The DEW4X has independent volume controls with small steps.

Power specs are similar - on high gain via balanced, the DEW4X is rated for 150 mW output, which is almost identical to that on the Tail.

In terms of technicalities, the DEW4X is weaker in soundstage and micro-detailing, with imaging on par.


Fiio KA13

The KA13 is a neutral bright dongle that contains dual CS43131 chips. It is more fatiguing and harsh in the upper frequencies, and sounds a bit thinner and sterile than the Tail.

The KA13 has a Fiio control app for additional goodies to explore. The KA13 also has well-implemented independent volume controls with finely tuned steps.

The KA13 on 4.4 mm desktop mode pumps out 550 mW output (THD+N balanced＜0.0005% (32 Ω)), easily dwarfing that of the Tail. It can thus power more demanding gear with ease, though the KA13 gets much hotter during usage, with greater battery drain. One can't game physics after all.

In technicalities, the KA13 has a hair better micro-detailing and imaging, but loses to the Tail in soundstage.


CONCLUSIONS



The Tail is a decent dongle in the cut-throat sub-$100 USD market, especially for Cirrus DAC chip lovers who yearn for its neutrality without harshness. The midrange is very clean and transparent, with bass texturing a highlight. Musicality is certainly not lacking.

Accessories are second-to-none, with a very light and compact frame. The Tail also has a pause button, which is something neglected in other contender dongles. There are no hiss or heat issues, with a dark background heard during usage.

The Tail is quite no frills, in having no independent volume controls, no DAC filters, nor PEQ or app compatibility. Somewhat vexing is a "pop" sound heard on removing transducers, perhaps this can be fixed in future iterations with a "pop" suppression implemented. Of note, it isn't the most powerful dongle as of 2024, but should still power most stuff out there other than outliers.

All things considered, the Penon Tail does way more right than wrong, and should be in the conversation for a neutral and musical sub-$100 dongle.

I express everything in my cons: Penon tail is a donation to PENON, than you can throw it in the garbage and take something else.

List of owned dongle not in order:
Qwestyle M12
Ibasso dc03pro
Ibasso dc04pro
Fiio btr 7
Qudelix 5k
Moondrop dawn

Penon iems bought from Penon:
Vortex
Isn h50
2x Fan2
Serial

Cable from Penon:
Space

Penon Tail Review​

One of the nice things about this hobby is watching the endless march of technology render quality sound we would’ve paid a fortune for years ago become available for a mere fraction of the cost.

This is especially relevant to dongles, which have really gained popularity among audiophiles over the past several years.

It’s no surprise Penon have jumped onboard by developing their own Tail dongle. At under USD $75 its quite affordable, so when they offered to send me one in exchange for a review I was keen to learn how it stacks up against more expensive options.

What I’ve discovered is the Tail has all the sonic hallmarks of a Penon-tuned product.

Packaging​

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The USD $74 Penon Tail arrives in a small cardboard box, inside of which is a plastic hard case, a small leather accessories case and two cables, one USB-C to USB-C and the other USB-C to Lightning.

The plastic hard case is especially handy for carrying the dongle, a USB cable and perhaps a few sets of eartips and is something I wish other manufacturers included.

Features & Ergonomics​

As you’d expect from its’ lower price the Tail isn’t as impressive from a tech perspective as some of its’ rivals, but is still a fully-fledged dongle with everything you need. Sporting dual CS43131 DACs the Tail delivers 290mW to its’ 4.4mm jack, and supports PCM to 384kHz and DSD up to DSD256.

The Tail has two gains modes that are switchable with a physical button, there’s also two buttons for volume up and down and another for play/pause.

At 17.9 grams the Tail is the lightest dongle I’ve tried, yet its’ aluminium case feels smooth & durable. There isn’t quite the visual panache we see from more expensive dongles, but given the Tail’s modest price that feels acceptable.

Sound Performance​

I tested the Tail with a USB-C iPhone 15 Pro & M1 Macbook Air, using Noble Audio Spartacus IEMs.

The Tail has a very neutral, clean signature with powerful bass output, that also delivers the kind of forward midrange performance Penon has become known for. Sub bass in particular is quite elevated and bass texture is impressive, but midbass is kept in check to prevent excessive warmth from robbing the presentation of its’ neutrality, though the Tail never sounds cold or clinical.

Typical of Penon’s tuning is the impressive midrange resolution which allows vocals to grab & hold your attention very effectively, though I wouldn’t go so far as to categorise the Tail as mid-centric. Treble is a touch muted, and lacks the polish more expensive dongles provide. As a result tiny details in the upper frequencies can be obscured which might otherwise provide a greater sense of refinement.

On the technical front the soundstage is quite wide but stage depth lags behind that of expensive dongles, imaging isn’t bad but could be a touch more defined, and note weight is average. Dynamics however are very good, and overall resolution is commendable in the midrange but less impressive at either end of the frequency spectrum, without being low enough to be a problem.

Dongle Comparisons​

iFi Go Bar 10th Anniversary (USD $499)

Background noise is much higher on the 10th Anniversary, bass is punchier with more midbass output.

The 10th Anniversary is more coloured & less neutral, with more aggressiveness & note weight, slightly more soundstage depth, though resolution feels similar between the two as does imaging & dynamics.



Cayin RU7 (USD $289)

Despite the Tail’s impressive midrange the RU7 goes up another notch in that area with even richer, higher resolution vocals with greater lower midrange emphasis.

The RU7’s deeper soundstage feels more spacious, imaging is slightly clearer, dynamics are even higher despite the TAIL being no slouch in that area, and the RU7’s tonality is more relaxed and organic with slightly better note weight though the Tail may have a bit more groove & musicality.



Luxury & Precision W4 (USD $449)

The W4 really steps things up across the board with greater resolution across all frequencies, with higher quality treble being a particular standout.

In fact it’s the difference in technical performance rather than tonality that separates these two dongles as they’re both fairly neutral, with the W4 displaying clearer separation & imaging in a better organised stage, improved dynamics, more defined attack on individual notes and a deeper soundstage.

Conclusion​

The Penon Tail is light on features but heavy on value. If you’re looking for a toe-tapping source with a great midrange to pair with your phone or laptop I’m not sure you can do much better for $75.

Penon’s tuning philosophy is one with broad-based appeal, ironically especially here in the West despite Penon being an Eastern brand. Western audiophiles tend to love deep bass with warmer lower mids & treble kept in check, which is often the flavour of Penon products.

The Tail remains neutral enough it should pair quite well with most IEMs you throw at it, but there’s enough of that Penon flavour that it’s easy to recommend.

You can spend 3 or 4 times as much on a different dongle and get a bit more refinement & slightly stronger technicalities, but unless you’ve already spent over $1000 on your earphones you’ll generally get more value saving on your source to spend more on better IEMs.

It’s nice to see Penon branching out into different areas because when it comes to tuning audio products they know their stuff… hopefully there’s a Penon portable amp or DAP on the horizon!