Kiwi Ears Allegro Pro

Preface:

You can purchase Allegro Pro at the following link (not an affiliate link):
https://www.linsoul.com/products/kiwi-ears-allegro-pro?_pos=1&_psq=allego&_ss=e&_v=1.0

I’m not the one to usually focus on specifications and numbers. I focus more on how happy I am with the equipment’s sound and that’s it.

Disclaimer: This is a review unit from Linsoul however I retain full editorial control and the opinions expressed here are solely my own. I have not been paid or compensated by Linsoul, Kiwi Ears or any other entity for this review. My assessment is based solely on my personal experience with the product.

I do get to keep the unit after review but that had no influence over the opinions expressed below.

IEMs used for evaluation:

• Softears Volume S
• FiiO FH19
• Sennheiser IE900
• Letshouer Mystic 8

Introduction:

Kiwi Ears has carved a respected niche in the audio community, earning praise for their innovative and often value-leading IEM designs. From the impressive sonic landscapes of the Cadenza and Orchestra Lite to the intricate detail of the Quintet and the engaging KE4, their IEMs have consistently captured my attention. Now, while Kiwi Ears ventures into the realm of over-ear headphones, my focus today is on their latest DAC/AMP offering – the Allegro Pro, which appears to be the successor to their earlier Allegro Mini.



Box Contents:

• Kiwi Ears Allegro Pro
• User Manual

Specifications: (Sourced from Linsoul)

Unboxing Experience:​

The unboxing experience was fairly straightforward. The Allegro Pro came in a compact and cleanly designed box. Inside, the device itself was securely nestled in a foam insert, which gave a good first impression of protection. Alongside the Allegro Pro, I found some basic documentation, though nothing particularly extensive. The overall presentation was functional and efficient.






Design and Build:

The Allegro Pro features a sleek and minimalist design like it's predecessor, prioritizing portability with its compact form factor that slips easily into a pocket. The aluminum chassis feels reassuringly solid and well-constructed, suggesting good long-term durability. The device sports a clean and understated aesthetic with a matte finish. Its small size is a significant advantage for on-the-go listening without having the dongle dangle.

The physical layout of the Allegro Pro is functional. The USB Type-C connector is conveniently located at the top of the device. On the bottom face, you'll find a single multi-function button accompanied by an LED indicator. This button serves the purpose of cycling through the different sound modes offered by the Allegro Pro, with the LED providing visual feedback on the currently selected mode. On the right side of the device, you'll find the 4.4mm balanced headphone jack, catering to those who prefer a balanced connection. Conversely, the left side houses the more traditional 3.5mm single-ended headphone jack, ensuring compatibility with a wider range of IEMs and headphones.






Battery Drain (Used with Pixel 9 Pro XL & iPhone 16 Pro Max):

I tested the Allegro Pro with both my Pixel 9 Pro XL and my iPhone 16 Pro Max, and the battery drain was noticeable but not excessive. With the Pixel 9 Pro XL, using the Allegro Pro for a couple of hours of music playback using Apple Music and Tidal at moderate volume resulted in a roughly 15-20% battery decrease on the phone. The iPhone 16 Pro Max, fared slightly better, showing a similar percentage drop over a longer listening period. Of course, battery drain will vary depending on volume levels, the type of IEMs used, and other factors, but these figures give a general idea. It's safe to say that using the Allegro Pro will impact your phone's battery life, so you'll want to keep that in mind if you're planning on extended listening sessions away from a power source. It's not a deal-breaker, but it's something to be aware of.



Driveability:

My experience evaluating the Kiwi Ears Allegro Pro's driveability, focused exclusively on my Softears Volume S, FiiO FH19, Sennheiser IE900, and Letshouer Mystic 8 IEMs, reveals a generally competent power delivery. A significant positive was the remarkably low noise floor I observed with sensitive IEMs like the Softears Volume S and Sennheiser IE900. Even at higher volume levels without music, the absence of audible hiss was notable, ensuring a clean backdrop for critical listening and quiet musical passages. This clean power delivery across the audible spectrum was another positive, as the Allegro Pro provided a smooth and stable output without any discernible frequency imbalances across the IEMs in my collection. The likely low output impedance, inferred from the silent background with sensitive IEMs, further contributes positively by ensuring a faithful frequency response unaffected by the IEMs' impedance curves.

However, pushing the Allegro Pro with the slightly more demanding FiiO FH19 and Letshouer Mystic 8 at higher listening volumes hinted at a potential limitation in headroom. While sufficient volume was achieved, the dynamic range seemed to compress slightly during very loud and complex segments, suggesting that those who frequently listen at high SPLs or demand the utmost dynamic expression might find the Allegro Pro approaching its power ceiling. Additionally, a minor negative for users with exceptionally sensitive IEMs could be the granularity of the volume control at the very low end, where finer adjustments might be desired to pinpoint the ideal listening level, although this wasn't a significant issue with the IEMs I used.

During my testing, I also noticed that the Allegro Pro can get noticeably warm even at lower listening levels and when driving IEMs at higher volumes. However, this warmth seemed to stabilize and didn't become excessively hot during prolonged listening sessions, which I would consider within the realm of normal operation for a compact DAC/AMP.




Sound Analysis:

Tonality:

The Allegro Pro establishes a generally warm tonal foundation, lending a comforting character to extended listening sessions. This warmth doesn't overshadow the higher frequencies entirely; a touch of sparkle up top prevents a dull presentation. For instance, in Norah Jones' "Come Away With Me," the richness in her vocals and the piano's lower register is pleasing. Yet, the cymbal work, while present, might possess a slightly subdued brilliance compared to a more neutral presentation. On the other hand, Daft Punk's "Get Lucky" showcases the warm bassline effectively, and the crispness of the synthesizers and hi-hats remains discernible, though their ultimate airiness could be more pronounced.

Sub-Bass:

The Allegro Pro demonstrates commendable depth in the sub-bass region, capable of producing a satisfying rumble. This low-end extension adds a tangible physicality to tracks. Take Massive Attack's "Teardrop;" the deep bass pulses are felt with good presence, and they don't unduly intrude on Elizabeth Fraser's vocals. That said, the finest nuances in the texture of those ultra-low frequencies might be slightly smoothed over. In Kendrick Lamar's "Alright," the 808 hits with satisfying impact, and the decay is reasonably controlled, though perhaps lacking the absolute tightness and definition some of us might seek in this region.

Mid-Bass:

The mid-bass offers a satisfying punch, contributing to the rhythmic drive and providing weight to bass guitars and drums. This characteristic can be quite engaging for many genres. In Fleetwood Mac's "Go Your Own Way," the kick drum has a solid impact, and the bassline provides a good sense of groove. One could argue, however, that this region exhibits a hint of extra emphasis, which, while enjoyable, might subtly veil the lower midrange in exceptionally busy mixes. Similarly, Red Hot Chili Peppers' "Can't Stop" benefits from the energetic punch of the bass, yet the rapid-fire notes could possess marginally greater separation and definition.

Lower Midrange:

The Allegro Pro's lower midrange imparts a pleasant warmth and body to male vocals and instruments like cellos. This can add a richness and fullness to the sound. Listening to Johnny Cash's "Hurt," his voice resonates with a deep presence, and the acoustic guitar has a pleasingly organic quality. A potential trade-off of this warmth is that it occasionally softens the articulation and the finer details in this frequency range, potentially making complex passages sound a touch less distinct. With Tracy Chapman's "Fast Car," her voice has a grounded quality, yet the subtle nuances in her vocal texture might not be conveyed with absolute transparency.

Upper Midrange:

The upper midrange generally presents vocals and instruments with good clarity, avoiding overt harshness. This contributes to a fatigue-free listening experience. In Adele's "Someone Like You," her vocals are largely clear and understandable. Nevertheless, the utmost crispness and definition in the higher registers of her voice might be slightly rounded off. Similarly, with Yo-Yo Ma's Bach Cello Suite No. 1," the higher notes of the cello are smooth, but the very sharpest attacks might lack a touch of their inherent bite.

Lower Treble:

The lower treble contributes to a sense of detail and the initial crispness of percussive hits and guitar attacks. This region provides some of the perceived sharpness in the sound. In Steely Dan's "Peg," the hi-hats and guitar attacks are reasonably defined. Yet, the subtlest nuances in their decay and the air around them might not be as apparent as on more resolving systems. With Nirvana's "Smells Like Teen Spirit," the cymbal crashes have decent presence, but their overall texture and complexity could be more fully realized.

Upper Treble:

The Allegro Pro offers some extension into the upper treble, contributing to a sense of air. Sibilance is generally well-managed, which is a definite plus. In R.E.M.'s "Losing My Religion," the mandolin's shimmer is present, contributing to the track's atmosphere. However, the uppermost air and the delicate trailing ends of notes might feel somewhat truncated. With Diana Krall's "Peel Me Slowly," the brush strokes on the cymbals have a gentle sparkle, but the sense of open space and the finest micro-details in their decay could be improved.

Soundstage:

The soundstage presented by the Allegro Pro is more intimate and focused, rather than expansive. Instrument placement within this space is generally discernible. In Miles Davis' "So What," the instruments occupy distinct positions within the stereo image. However, the overall width and depth of the soundstage feel somewhat limited. Similarly, while Pink Floyd's "Dark Side of the Moon" creates a sense of movement, the sonic landscape doesn't extend far beyond the listener's head, resulting in a less immersive experience compared to DAC/AMPs with a wider and deeper presentation.

Layering and Separation:

The Allegro Pro generally provides good layering and separation of instruments in moderately complex arrangements, allowing individual elements to be distinguished. In The Beatles' "Strawberry Fields Forever," the various instrumental and vocal layers are reasonably well-defined. As the complexity increases, however, such as in Queen's "Bohemian Rhapsody," the individual layers can become somewhat less distinct, leading to a degree of congestion during the most densely packed passages. While the musicality remains, the ultimate level of separation in highly intricate mixes isn't its strongest suit.

Timbre:

The timbre of instruments and voices is generally natural, making for a pleasant listening experience. However, a subtle underlying smoothness can slightly alter the inherent character of some sounds. In Rebecca Pidgeon's "Spanish Harlem," her voice and the acoustic instruments sound largely realistic. Yet, the sharpness of percussive attacks might be subtly softened. Conversely, with Rage Against the Machine's "Killing in the Name," while the raw energy comes through, the utmost grit and edge of the guitars might be slightly diminished by this smoothing effect.

Coherence:

The Allegro Pro offers good coherence, with a relatively smooth integration across the frequency spectrum. The different frequency ranges blend together without obvious discontinuities. In Beethoven's Symphony No. 5," the transition between different instrumental sections feels relatively seamless. That being said, a subtle emphasis in the bass and lower midrange might occasionally give those frequencies a slightly more prominent role in the overall mix. Similarly, in Radiohead's "Paranoid Android," the various sonic elements work together cohesively, though the lower frequencies might possess a touch more weight than absolute neutrality would dictate.

Detail Retrieval:

The Allegro Pro provides a decent level of detail retrieval, allowing me to appreciate the core elements of the music. However, it might not unveil the most subtle micro-details present in the recording. In Dire Straits' "Sultans of Swing," the fingerpicking and vocal nuances are discernible. Yet, the faintest ambient cues and the subtle textures of the recording environment might be less apparent. With Charles Mingus' "Goodbye Pork Pie Hat," the interplay between instruments is conveyed, but the subtlest breaths and instrumental artifacts might remain somewhat veiled.

Microdynamics:

The Allegro Pro handles microdynamics reasonably well, allowing for the perception of subtle volume variations that contribute to musical expression. In Debussy's "Clair de Lune," the gentle swells and fades are noticeable. However, the finest gradations in volume might not be rendered with the utmost precision. Similarly, in Leonard Cohen's "Hallelujah," the shifts in his vocal intensity are conveyed, but the most delicate dynamic nuances might be somewhat compressed.

Macrodynamics:

The Allegro Pro delivers macrodynamics with good punch and engagement, effectively handling large-scale volume swings. In Tchaikovsky's "1812 Overture," the crescendos and loud passages have a satisfying impact. However, the subtlest gradations at the extreme ends of the dynamic range might be slightly less nuanced. Similarly, AC/DC's "Back in Black" has a good sense of raw power, but the subtle dynamic variations within the loud sections might be somewhat flattened.

Conclusion:

Well, if you're primarily an IEM user looking for a noticeable step up from the basic type c to 3.5mm dongle, the Allegro Pro definitely presents a compelling case. Its strongest suit, without a doubt, is its remarkably clean output and that it doesn't dangle around. That inky black noise floor, especially with sensitive IEMs, is a real treat, allowing those subtle musical nuances to shine through without any annoying hiss creeping in. Plus, it packs enough punch to drive a good variety of IEMs, from easy-going single drivers to more complex multi-BA setups, delivering a smooth and generally well-balanced sound. The inclusion of both balanced and single-ended outputs is a thoughtful touch too, offering flexibility for different IEM terminations. And let's not forget its compact and sturdy build – it feels like it can handle the rigors of being tossed in a bag.

However (you knew there was a 'however' coming, right?), it's not without its quirks. Those sound modes? Honestly, they feel a bit…underwhelming. I struggled to hear any significant differences, and I kind of wish that button did something more impactful, like toggling gain levels. Also, while it gets IEMs plenty loud, pushing it to the extreme with some models did hint at a ceiling in dynamic headroom. And yeah, the battery drain on my phone was noticeable, something to keep in mind for those long listening sessions on the go. Oh, and it does get a bit warm sometimes!

So, why consider the Allegro Pro over other options? If a super clean noise floor with IEMs is high on your priority list, and you appreciate a compact, well-built device with both balanced and unbalanced outputs, it's a strong contender. It offers a tangible sonic improvement over basic sources for IEM enthusiasts. But, if you're chasing dramatic sound signature alterations through EQ presets or need massive power reserves for demanding IEMs (though most aren't!), or are particularly sensitive to battery drain and device warmth, you might want to explore other avenues. For me, the Allegro Pro offers a solid and clean listening experience in a portable package – just don't expect those sound modes to be game-changers!

Linsoul Store links (None of them are affiliate links):

Linsoul website: https://www.linsoul.com/
Linsoul Aliexpress Store: https://ddaudio.aliexpress.com/store/2894006
Linsoul USA Amazon Store link: https://www.amazon.com/s?me=A267P2DT104U3C&marketplaceID=ATVPDKIKX0DER

Introduction

Kiwi Ears is continuing its unstoppable career and diversifying. Now it's the turn of Kiwi Ears to renew its T-shaped dongle: the Kiwi Ears Allegro Pro. This is the advanced version of the Mini model. Its design is similar, but it is now slightly larger and also more expensive. The new model has more power, thanks to the two SABRE ES9603 operational amplifiers. In addition, it has a button for switching sound modes, an RGB LED and is Nintendo Switch compatible. Of course, there are two headphone outputs: one 3.5mm and one 4.4mm. Designed for gamers, the Allegro Pro ensures effortless one-click connectivity with Nintendo Switch. No additional setup is required: simply connect them together. The Allegro Pro features three different sound modes tailored to specific use cases: Game mode for an immersive gaming experience (blue). Movie mode offers cinematic sound (green) and Music mode for high-fidelity music playback (red). The DAC used is a custom high-performance model, no brand name specified. In this review, as usual, I am going to perform power measurements of this small dongle, as well as a full sound analysis and other relevant issues.



Specifications

• DAC chip: Custom high-performance DAC.
• Operational amplifiers: 2xES9603.
• THD+N: < 0.006% (@32 ohms).
• Output power (3.5mm): 68mW @ 32 Ohms (THD+N <1%).
• Output power (4.4mm): 170mW @ 32 Ohms (THD+N <1%).
• SNR: ≥113dB (@32 ohms, A-weighted).
• Frequency response: 20 Hz - 40 kHz.
• Supported formats: PCM (up to 32bit/384kHz), DSD (DSD128, DSD64).
• LEDs: Blue: Game Mode. Red: Music mode. Green: Movie Mode.
• Input interface: USB-C.
• Output interfaces: 3.5mm single output, 4.4mm for balanced output.
• Starting price $53.99

Packaging

The Kiwi Ears Allegro PRO comes in a hard cardboard box measuring 80x80x31mm. The main side shows a real photo of the dongle on a light blue background. At the top left, the product features are shown. At the top right there is a short description, just like on the bottom of the box. On the back side there is more information. Here you can find the logos of the certifications it complies with, the brand and importer's contact details, a sketch of the top and rear view of the product and some warnings. On the sides of the box are the specifications of the product and its features. After lifting the lid, the dongle can be seen inside a black foam mould. In theory, an instruction manual should accompany the product, but there is nothing else, and no USB adapters. Just the product. As you can see, the contents are minimal.



Construction and Design

The Allegro PRO is T-shaped, but with some changes. It is slightly larger than the Mini version: the dimensions of the tablet are 42x15.5x12mm, but if we count the USB interface, the shape changes to 42x24x13mm. The full size of the Mini version was 38x24x12mm. Now, the colour is the same for all sides. On the top side is the brand logo, in a round plateau with a slight concave depression. On both sides there are similar structures, but instead of a concave part there are two fake metal buttons. They look like they might have some functionality, but they are only beautifiers because they do not click. The button is on the back of the USB connector. It is oval and is on one side; further to the left is a small hole with an RGB LED inside. On the underside is engraved the model name, as well as the maximum formats it plays (32B 384K). The USB Type-C male connector is located at the bottom of the front face and is elongated. It is mounted on an oval base. Seen from this side, the 3.5mm output is on the right and the 4.4mm output on the left.
It's a bit odd the way the top face looks, with those fake buttons. But it's a distinction from the Mini model, as well as having a darker metallic colour and lacking the black face that the Mini model had. It's correct and minimalist and includes the back button and the small RGB LED.



Connectivity

Not much is said about the compatibility of the product. I have only been able to test it with my Windows 10 computer and my Android mobile phone. It does specify that it is fully compatible with the Nintendo Switch when plugged in. My computer recognises it without any problems and it even has a microphone input, so it can be used as a sound input interface for gaming, talking, video conferencing, etc. It doesn't need drivers, but it doesn't have ASIO drivers either.
It has 3.5mm and 4.4mm BAL outputs.
It supports audio formats up to 32-bit/384 kHz and DSD128.



Operativity

Operation is very simple: plug and play. Tested on Windows 10 and Android. I don't own Nintendo Switch, which is immediately compatible after connection.
It has a rear button to switch between the four sound modes. Yes, because there is actually a fourth mode, which I'm going to call Standard Mode, because it seems to be devoid of filters:

• Game Mode: Blue LED.
• Movie Mode: Green LED.
• Music Mode: RED LED.
• Standard Mode: LED off.

Measures

As mentioned, there are 4 sound modes: Standard, Movie, Game and Music. The following measurements have been made with the mode I call Standard. I call it this way because the shape of the pure sine waves of fixed frequencies is not altered. In the rest of the modes, alterations in the waveforms are observed, as a result of the equalisation received. In the final section on Frequency Response, the influence of each sound mode can be observed.
On the other hand, unfortunately for my taste, the Kiwi Ears Allegro Pro does not have a flat frequency response, but has a clear drop in the low frequencies, which makes it a clearly bright dongle. The drop is 8dB at 20Hz compared to the flat curve, which does not reach up to 500Hz. At 100Hz the difference is almost 7dB and at 40Hz 4dB. For my taste and despite the fact that the Allegro Pro has 4 sound modes, at least one of them should be a reference and it is not the case. I understand that this is due to the DAC used. I don't like to call hi-fi those sources that don't have a flat response from 20Hz to 20KHz. Where has the bass gone?
As far as output impedance is concerned, SE is very low and tends to zero. A strange thing happens at BAL, it literally goes negative. This is due to the fact that a higher voltage is reached with a 100Ω load than without load. In this aspect it is very good.




No load SE

The output voltage at 20Hz is 720mV, at 100Hz 1.33V and at 1kHz 1.445V. The power drop in the bass is clearly visible.



15Ω SE

It is not possible to reach maximum volume at this impedance without visible distortion in pure sine waves.
The output voltage at 20Hz is 527mV, at 100Hz 1V and at 1kHz 1.076V. The power is 77mW and 72mA. Good.



33Ω SE

In this case, the maximum volume can be reached with this impedance.
The output voltage at 20Hz is 715mV, at 100Hz 1.335V and at 1kHz 1.439V. The power is 63mW and 44mA. Correct, when the specified power is 68mW. This would have implied an output voltage of 1.48V. The difference is minimal, we can leave it to the margin of error of the measuring devices, sources and measurement methods used.



100Ω SE

Again, it is possible to reach maximum volume with this impedance.
The output voltage at 20Hz is 719mV, at 100Hz 1.340V and at 1kHz 1.448V. Power is 21mW and 14.5mA.



No load BAL

The output voltage at 20Hz is 1.363V, at 100Hz 2.547V and at 1kHz 2.75V. Quite a steep drop in the sub-bass.



15Ω BAL

It is not possible to reach maximum volume at this impedance without visible distortion in pure sine waves.
The output voltage at 20Hz is 629mV, at 100Hz 1.234V and at 1kHz 1.331V. Power is 120mW and 89mA. Very good. Almost reaching the mythical value of 90mA and exceeding the value of the SE output.



33Ω BAL

It is not possible to reach maximum volume at this impedance without visible distortion in pure sine waves.
The output voltage at 20Hz is 1.104V, at 100Hz 2.106V and at 1kHz 2.262V. The power is 160mW and 69mA.
The specifications say it should be 170mW. With this value the voltage should be 2.33V. Same as above: very little difference and actually justified.



100Ω BAL

In this case, the maximum volume can be reached with this impedance.
The output voltage at 20Hz is 1.427V, at 100Hz 2.676V and at 1kHz 2.881V. The power is 83mW and 29mA.



Frequency Response

I measured the frequency response of the Allegro Pro from 5Hz to 40kHz. Surprisingly, there is no drop in the high frequencies. But there is a strong drop in the low frequencies. Between 5Hz and 1kHz there is a difference of almost 19dB, a world of difference. It should be noted that there is no noticeable difference between channels.
The different sound modes offer variations in frequency response. Standard mode is flat from 400Hz to 40kHz. The roll-off at 20Hz is 8dB.
The different modes have a difference in bass, with the Standard mode having the least bass. The others generate a bass gain that is maximised at 100Hz, while the Music mode has a hump above the flat response between 100 and 200Hz. However, it also has another clear gain hump around 8kHz of almost 1dB.
It seems odd, but Game mode is the mode that most closely resembles Standard mode, while Movie mode has a flat response distance that diverges from 500Hz, to a distance of 0.5dB at around 2kHz and 1.5db at around 10kHz.
Certainly, the music modes are to be able to test and enjoy those differences. But not having a Standard mode with a flat frequency response from 20Hz to 20kHz and having such a steep drop at 20Hz (8dB!!!) is not to my liking, nor is it a reliable source to be taken as a reference.
Finally, I have had to apply a soft filtering on the frequency responses of all modes, except for the Standard mode, because the signals show up as ‘noisy’.



Sound

It is clear that having filters (remember that in this case there are four different and different quantifiable modes) always makes reviews difficult and lengthy. That's why I prefer to concentrate on just one position and give a slight impression of the other modes. I am going to review the Allegro Pro in its non-described mode, the one without the LED on, which I have called Standard Mode as it has a ‘flatter’ response. The Game mode is quite similar to the Standard Mode and has a slightly wider soundstage and a more exalted bass. The difference between the two modes is only a few tenths of a dB, so it is difficult to find any real sonic differences. Movie Mode is the most exciting of the modes, as it gives a slight bass boost, but it also gives a distinctly brighter and splashier profile, something that may not be necessary in a dongle whose sound is already heavily bass-reduced. Finally, the Music mode seems to be looking for a bit more fun within that cooler sound. It adds a bit of upper bass and only raises the treble to its fullest extent. In my opinion, the Music mode should be the flattest, because of its name, but it is not.
On the other hand, it is good that the filters can be changed during playback to be able to check the differences between them.
To demonstrate that the differences in frequency response can also be extrapolated to the connected headphones, I used the Kiwi Ears Quintet as a reference. As can be seen in the graph, the differences in the filters are real.



But going back to the reference mode, which I call ‘Standard’, it is clear that this is a dongle intended for headphones with amplified bass. In the very low-frequency pure tone test, you can audibly see that the lower tone receives very little power. As can be seen in the comparative frequency response with the Kiwi Ears Quintet, used as a reference, there is a clear difference of 8 dB at 20 Hz, 4.5 dB at 30 Hz and 3.5 dB at 40 Hz. The curve evens out at approximately 150 Hz. When the waves start to become audible, with the Quintet this happens at 25 Hz, it can be observed that this first note is not very real and a clear audible coloured and wavy character is perceived. This effect is corrected at 30 Hz, showing a more realistic, natural and less coloured and vibratory sonority, although there is still this slight effect (I have looked for IEMS with low vibratory/ondulatory behaviour in my previous tests). At 40 Hz, the result is already much more appropriate and realistic. The translation of these results to real music is perceived as a lack of depth, volume and punch. The bass feels drier, more sterile and more responsive in the low-mid range. However, they still maintain a slight level of texture and appropriate elasticity. It is clear that, when using IEMS with a high sub-bass, the end result is not critical in any case. However, when using much more bass-neutral IEMS, the response is less satisfactory. In these cases, there can be a distinct lack of body, depth and volume, as well as a greater imbalance between bass, midrange and treble.
In the dirty, complex and unfiltered bass test, it is shown that the lower bass gives a greater sense of control to the set, while the loudness is not affected too much. It is true that the lack of body, depth and physical component is noticeable, but it is also true that the choice of headphones connected will minimise the effects greatly, so it is better to use headphones with full bass.
The mid-range of the Allegro Pro is enhanced by the lightness of the bass. The midrange is very explicit and feels clear, transparent and crisp. However, it is also perceived as slightly splashy, cold, somewhat sharp and lacking in body and physicality. This highlights the shortcomings of some IEMS in the first part of the media. In that respect, I prefer to pair the Allegro Pro with warmer IEMS, such as the Kiwi Ears KE4 or Aether. With other IEMS, such as the Quintet, its technical and brighter side is elevated, but its high sub-bass is also compensated/neutralised. On the negative side, the more technical IEMS can be more abrasive in the upper mids and treble without a gain in detail. Thus, male voices sound very clear and technical, but with a light base. However, the female voices gain in transparency, presence and energy. Although their sibilant character is also enhanced.
The Allegro Pro's treble is extended and boosted in all modes (to my ears, even in Standard mode), evident, energetic and full. There's a crisper, more vivid, splashy enhancement that excites most headphones I've tried. Without a doubt, the high range is a party for the treble-heads.
All modes improve the sense of soundstage spaciousness over the flatter-sounding Standard mode. Even in Game mode, this improvement is noticeable. In Music mode, you gain depth, and in Movie mode, in addition to the extra body in the base, you also gain volume and a clear improvement in the projection of the notes, which promotes a more expansive expressiveness and a more ethereal and volatile perception of the whole.
The positioning of the elements is clear and the separation is quite good. This type of characteristic is favoured by the lower volume and depth of the lower part of the ensemble.



Comparisons

EPZ TP35

Currently, the EPZ TP35 can be had for around $55, while the Kiwi Ears Allegro Pro has a starting price of $60. Roughly the same price. It's clear that the TP35 is a classic dongle, with a little window inside and a status LED. The Allegro Pro is T-shaped, with the audio outputs on both sides and the connection in the middle. It has a status button and an informative RGB LED, as well as four music modes. On the other hand, the TP35 has two buttons for adjusting volume, gain, filters and other functions. The size of the TP35 is small, with an almost identical length, but a larger width. In terms of power, the ET35 is more powerful for 100 Ω, while the Allegro Pro is more powerful for 15 and 33 Ω. The output impedance of both systems is very low. The fundamental difference is that the TP35 has a completely flat frequency response from 20 Hz to 20 kHz, while the Allegro Pro does not, as demonstrated in this article. As for the chips used, the TP35 uses a dual CS43198 with no associated amplifiers, while the Allegro Pro uses a custom high-performance DAC and two ES9603 amplifiers. It is clear that, while the DAC used by the TP35 is better, the power amplifier is superior in the Allegro Pro. In both cases, there is a sense of cost-cutting to meet the price point.
I have performed the sound tests with the standard mode activated on the Allegro Pro. The TP35's filters have no effect.
The sound differences are evident, even in Standard mode activated on the Allegro Pro: the low end of the TP35 is more natural, full, realistic, powerful and deep, while the upper mids and treble are more energetic, present, clear, crisp and crisp on the Allegro Pro.
In the very low-presence pure tone test, the Allegro Pro has very little presence compared to the TP35 below 40 Hz. Above that frequency it starts to be audible, but its behaviour is not as realistic as with the TP35, which sounds almost reference-like, natural, powerful, physical and deep. On the other hand, the Allegro Pro has a coloured oscillatory character that takes it away from a realistic representation. In real music, the TP35 presents organic, natural, deep, full, energetic, powerful and elastic bass with excellent performance. On the other hand, the Allegro Pro feels much drier, shallower, lacking in energy, coloured, undulating and vibrating, and with less volume. One misses a more natural elasticity, stickiness and texture.
In the mid-range, in its first half, there are differences in physical presence and body. While the Allegro Pro accentuates the hollowness present in the headphones at this stage, the TP35 demonstrates it without further ado, showing more warmth and a more organic, natural feel.
In the upper mids and treble, the Allegro Pro is more pronounced, lifted, clear, crisp and energetic. The TP35 is more restrained and balanced, but lacks the crisp, thin, energetic and extended brilliance of the Allegro Pro.
In itself, the Allegro Pro already has a clear expansive component to its sound, although it lacks the punch, breadth, volume and depth of the TP35's low end. The Allegro Pro comes across as cooler, more volatile and ethereal, even more gaseous, with more sparkle and brilliance. But it also feels a little more forced, slightly more unreal, both in its timbre and in the overall sonority of the music. The TP35 is more organic and natural, and feels more realistic, though also more muted and a little flatter. Although the level of detail seems more obvious, the micro-detail in the lower layers is just as visible in both elements. This means that bass does not mask detail and the layering of the TP35 is very good. With less depth, body and physicality in the low end, detail should appear more naked in the Allegro Pro, but it seems just as resolving. The sharper micro-detail is more vivid, clearly due to its greater presence and energy.



Conclusion

Enthusiasts who have read me know that I am very critical of sources that do not have a flat frequency response or that have high output impedances. That's because, in my opinion, an ideal source should be as faithful as possible to the input signal without altering it and should not alter the frequency response of the headphones connected to it. In the case of the Kiwi Ears Allegro Pro, I am faced with a source that has very low output impedance, but a clear and obvious 8 dB drop at the audible low end, which only smooths out at 400 Hz. It is true that at 90 Hz this difference with the flat response is less than 1 dB, but even so, this is a source that obviously modifies the signal response of the connected headphones. However, the Allegro Pro seems to have been designed for this purpose, as it has four sound modes that directly alter the frequency response over the entire audible range. These modes are Movie, Game and Music, plus the LED-free mode, which I call Standard because its FR is the most ‘normal’. Each sound mode alters the FR of the system in one way or another, and that is something that makes me value this dongle positively, not as a reference source, but as a source with a distinct and intended use. Its clear connection to the Nintendo Switch and those sound modes for gaming, movies and music imply a more specialised use that goes beyond just enjoying music.
On the other hand, the mini model has gained in power without increasing in size. The Allegro Pro is still a T-shaped dongle well suited for use with smartphones, as it has a microphone input and both 3.5 mm and 4.4 mm BAL audio outputs. Its sound is vibrant, bright, detailed, crisp, expressive and informative. However, it is also somewhat cold and dry. Thanks to the sound modes, these characteristics can even be improved, gaining in stage, projection, clarity and transparency.
In conclusion, I think the Kiwi Ears Allegro Pro can be a very good value secondary dongle for those who want to experience a different sound in their everyday life, as an alternative to the exclusive use of playing music.



Earphones and Sources Used During Analysis

• Xiaomi 13T.
• Hidizs AP80 PRO-X Red Copper LE.
• Kiwi Ears KE4.
• Kiwi Ears Quintet.
• Kiwi Ears Airoso.
• Kiwi Ears Aether.
• Yanyin Canon Pro.
• LetShuoer Mystic 8.
• LetShuoer Cadenza 4.
• Simgot EA1000.
• Simgot ET142.
• KiiBOOM Evoke.
• NiceHCK Himalaya.
• 7Hz Timeless II.

Purchase Link

You can read the full review in Spanish here

Kiwi Ears Allegro Pro
Kaitlyn Wu from Linsoul Audio invited me to review the new Kiwi Ears Allegro Pro DAC/AMP. The Allegro Pro is the upgrade to the original Allegro mini and retails for £60.
Product link:
www.linsoul.com/products/kiwi-ears-allegro-pro

The Packaging
The Allegro Pro is presented in a neat square box with a teal-coloured background. The front bears an image of the product along with branding and a list of the salient features. Specifications and other product details are printed on the other faces of the box. Inside, the dongle nestles in a foam cut-out.

Build and Design
The Allegro Pro has an all-metal construction and is very well made. The top features a 3D Kiwi Ears logo with what appear to be functional buttons but they are purely decorative. There are two outputs, 3.5mm single-ended and 4.4mm balanced. There is a small button on the underside which toggles between the various digital filters (see below).
The unit can also be used in standard mode with the function switched off.

The unit connects via a male USB-C plug and derives power from the host device.

Internally there are two ES9603 op-amps, and a "high quality digital to analogue converter" (type not specified). The unit is compatible with DSD up to DSD 128 and PCM up to 32bit/384kHz and features Nintendo Switch compatibility.

In Use
The unit was auditioned with a Hidizs AP80 Pro X DAP and various IEMs, principally the Kiwi Ears Airoso, via the 4.4mm balanced output with a pure copper cable. The power drain was very low compared to my other dongles and resulted in a much more extended play time. The Kinera Celest CD20 and Penon OS133 both depleted the AP80 Pro X's battery much more quickly. The Allegro Pro proved to be very efficient with even the most demanding IEMs such as planars being powered adequately at moderate settings of the volume dial. The sound Impressions below were auditioned with the sound modes switched off.

Sound Impressions
Right from the first few bars of music the Allegro Pro displayed an extraordinary level of detail and information. There was a notable sense of immediacy and speed in the reproduction which surprised me and transformed the sound of the IEMs used with it. Based on a powerful transient attack, the bass was deep, tight and impactful, midrange was open, informative and natural and the treble was highly transparent and extended with copious levels of detail. There was a touch of "spice" in the upper range which was rather addictive and the vocal performance was outstanding with both male and female voices clearly projected above their accompaniment and displaying impressive clarity. This also applied to solo instruments which were full of detail with a natural timbre.

The soundstage and imaging were first class and there was a good balance between the technical and musical. The overall sound profile was neutral/bright and airy with a wonderful "freshness" in the presentation.

Sound Modes
In addition to the standard mode, the Allegro Pro features three switchable sound modes which are indicated by different coloured LEDs. These are as follows:

Game Mode: Blue LED
Movie Mode: Green LED
Music Mode: Red LED

The differences between the various modes were subtle but audible. This is what I found, compared to no selection.

Game Mode:
The most noticeable change was in the soundstage which became wider but more shallow, emphasising left to right movement but reducing depth. There was a slight brightening of tonality which sometimes became thin in nature.

Movie Mode:
There was an increase in atmosphere with a more immediate impression. The tonality was warmer and more natural with a larger soundstage. I preferred this setting to the others.

Music Mode:
Transient response was a little softer, and there seemed to be a reduction in treble energy leading to a loss of detail, although the overall effect was more relaxing to listen to, with the final result similar to a "meta" style tuning.

Partnering IEMs
The Allegro Pro was revealing and neutral in character and was able to display the individual sound of different IEMs in an authentic fashion. Due to its inherent tonality, IEMs with a warmer sound were the best match whereas cooler-tuned models lost a little in musicality with the technical aspect magnified by the Allegro Pro's own character.

Kiwi Ears Airoso
The Airoso was the principal model used in testing, although the similarities between the IEM and source were sometimes "too much of a good thing", with a laser-like transient performance, high levels of detail and a bias towards the upper part of the spectrum and I found myself wishing for a little more depth and weight. However the excitement factor and engagement were addictive and I frequently returned to the Airoso after auditioning other models.

KZ PRX
Planar models are notorious for their thirst for power and the PRX was no exception. However the Allegro Pro proved more than capable of driving it to high volume levels where its abilities became more evident. The profile was more balanced than the Airoso above with a deeper and warmer bass region. Mids were a little recessed but still displayed good projection and the treble was nicely judged with plenty of detail and no trace of aggression or harshness. The staging was expansive with high levels of separation and precise imaging.

KZ Zenith
The "New Meta" style tuning of the Zenith blended very well with the assertive and detailed nature of the Allegro Pro. This resulted in a natural easy going and relaxed sound yet not lacking in detail and enjoyment. There was a little more bass presence which added some welcome weight and the rest of the frequency range was well balanced with a gently rolled off treble. There wad a little less detail here but the pleasing balance encouraged extended listening.

Fiio FD3
This powerful single DD proved to be an excellent match for the Allegro Pro. Its warm, mild V shaping received some extra life and verve which lifted its performance to a higher tier. The inherent authentic timbre of the FD3 lost none of its authenticity but gained in speed and impact with improved levels of detail. The overall profile was more well balanced with the recessed mids becoming more forward and producing a very satisfying result.

Tin Hifi T3
This model is now approaching six years old but the Allegro Pro breathed new life into it with the end result very similar to the Kiwi Ears Airoso. Bright, immediate, speedy and detailed were the keywords here with an extra bit of depth and power not present in the Kiwi Ears model. Staging and other technicalities also improved and there was a high level of enjoyment. This served to remind one of the importance of a quality source, which the Allegro Pro most certainly is.

Comparisons
As not all the models compared below have a balanced facility, these comparisons were made using a single-ended 3.5mm termination. The Hidizs AP80 Pro X DAP was used as a transport.

Penon OS133
This dongle employs the CX31993 DAC chip and is a simple USB-C plug and play design. It has a high quality cable and is well made. Its power drain is fairly modest giving a decent length of play time. In contrast to the Allegro Pro, the OS133 has a warm, musical presentation with a very spacious stage. Although not overtly or obviously detailed, close listening reveals that nothing is really missing in comparison with the Allegro Pro, it is just presented in a less assertive fashion and the music has a more flowing character with less emphasis on the technical aspects.

Kinera Celest CD20
This DAC/AMP uses the latest ESS chip, the 9039Q2M, and is more fully featured than the Allegro Pro, having a gain control and volume buttons. It has a 4.4mm balanced output in addition to a standard 3.5mm single-ended socket. The CD20 is very powerful and has a broadly similar sound to the Allegro Pro, being clean, bright and technically adept with a speedy transient response. Where it differs from the Allegro Pro is in the bass where there is a weightier presentation and a fine texture. The staging is deeper with a fine representation of studio ambience, the Allegro Pro having a shorter decay. In mids and treble, they are equal in quality with a very similar tonality. The CD20 draws a lot more power than the Allegro Pro and as a result, the play time is shorter.

Fiio KA11
This simple USB-C dongle is equipped with the CS43131 DAC unit and, like the Penon model above, is a plug and play device. It has a robust output and is capable of driving IEMs of low sensitivity very well. It does draw more power than some other dongles and gets quite warm in use. The sound profile is very different from that of the Allegro Pro, having a noticeable mid-bass emphasis, a forward midrange and a bright treble which is not as refined as the Kiwi Ears design. The staging is not as expansive as the other models here and extended listening sometimes results in fatigue. It is more suited to rock and modern music than classical or ambient material.

Conclusion
Well made and competitively priced, the Allegro Pro acquits itself very well across a range of genres. Its lively, impactful, highly detailed and resolving delivery both enchants and entertains in equal measure. It is very economical in drawing power from the host device, resulting in extended play time. If a gain facility and volume controls had been featured, the Allegro Pro would have been almost unbeatable in its price bracket. However, it is still a high-performing DAC/AMP with a neat and convenient form factor and is highly recommended.