Activate the Differential Mode
Ratings
Pros
- Four different sound modes.
- Quite powerful for its price range for low-impedance headphones.
- Lively, energetic, clear, transparent, detailed and expansive sound.
- Very good ergonomics for use with smartphones.
- Automatic compatibility with Nintendo Switch.
- Very low output impedance.
- Microphone input for hands-free use with Smartphone.
Cons
- Heats up at low loads and high volume.
- Moderate power consumption.
- Clear voltage drop at low frequencies, frequency response not flat.
- No instruction manual, no USB to Type-A converter.
Purchase Link
https://www.linsoul.com/products/kiwi-ears-allegro-pro
Link to the WEB
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 42×15.5x12mm, 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.
SE No load
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.
SE 15Ω
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.
SE 33Ω
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.
SE 100Ω
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.
BAL No load
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.
BAL 15Ω
It’s 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.
BAL 33Ω
It’s 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.
BAL 100Ω
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’.
Note: ‘Pure Mode’ is the standard mode. I have also called it ‘Pure’ as it has no filters.
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 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.
