EAhibrid Integrated Cyber Filter Review

Introduction

EAhibird combines two brands, ENIGMAcoustics and hibrid. The former is already established in the Audiophile world with its speakers and SBESL™ technology – electrostatic diaphragms that are ultra-light and self-biased, i.e. no high-voltage bias is required.

My first encounter with EAhibird was with the PureDC-B1, a DC power supply based on Tesla 2170 Li-ion batteries, which impressed me sufficiently to purchase a personal set.

Steven Cheah, principal of Audio Basic offered me a chance to experience the EAL 2000 in my home setup. I never say no to audio goodies!

The very expensive gold-plated Telegartner connectors

The cables are quite flexible compared to some of the stiff rods I've tried

Description

According to EAhibird, the Integrated Cyber Filter allows one to "Experience the analog-like experience through innovative integrated technology."

Two models are available, the EAL 1000 (with copper conductors) and EAL 2000 (with silver-coated copper conductors).

The price of the Integrated Cyber Filter is as follows:-

EAL 1000

1.25M US$ 1,200

1.75M US$ 1,400

2.5M US$ 1,700

EAL 2000

1.25M US$ 1,950

1.75M US$ 2,250

2.5M US$ 2,650

Now, this is by no means cheap so let’s see whether these products can justify their cost? 

Visually, the cables look the part, and if the metal housing looks familiar, you are right. Continuing with the Tesla theme, the electronics are housed in a Cybertruckesque enclosure. 

Ethernet cables are made out of 4 conductor pairs and the circuit includes isolation transformers with ultra OCC coils (x4), common mode filters (x4) and a cap-coil noise filter circuit. EAhibrid also use a patent pending Advanced Waveform Restoration (AWR) circuit – a distortion reduction circuit that uses stable digital signal voltage technology modified from industrial servers and ICT equipment. The heavily shielded cables use immaculately made connectors, and the EAL2000 review sample uses gold-plated Telegartner connectors.

Turning to the cables, these consist of 22AWG conductors made out of silver-plated OCC copper cables. Each of the four pairs are aluminium foil shielded, followed by an additional double foil shielding and silver-plated OCC braided shield on the outer cable jacket. Yes, you read that right - even the braid uses silver-plated OCC copper!

 

 

 

 

Steven linked me up with Paul Huang, founder of EAhibrid who kindly answered my questions on the company and the Integrated Cyber Filter.

Q1. Could you explain more about the relationship between the ENIGMAcoustics and EAhibrid?

A1. (Paul supplied me with a write-up that explained his long acquaintance and consultancy work with ENIGMAcoustics from 2015. ENIGMA is primarily analog focused and EAhibrid was established in 2021 with ENIGMA’s support to target streaming and digital audio quality)  

In short, we were good friends in the beginning. For years, I’ve been their consultant between Hi End Audio and Pro Audio. And then ENIGMA supported and sold the battery tech to me.

Q2. I would like more information about how the AWR circuit works and its benefits to audio.

A2.    As per the information on our website, AWR is adapted from technology used in industrial servers created by others years ago with excellent performance on computers, but not for sound. The main thing AWR does is to channel out the digital noise by reducing ground noise. The result is better signal transmission accuracy and part of the overall grounding.

Q3. The isolation transformers are tiny! How hard are they to make and I assume that traditional network isolation transformers did not satisfy your standards.

A3. Those transformers need super-thin OCC copper and are handcrafted almost like MC cartridges. The master complains that he fails at making them because he always breaks the super-thin wire. But OCC transformers are good for sound in the old-fashioned way, so we still use them in our Cyber Filter.

Q4. I noticed that even the braided shield uses the same quality copper as the signal cables. Can you explain why this extra step was taken?

A4. The shielding material will affect the sound, which is very common on custom-made/hi-end cables. More importantly, we chose the correct directionality for all 8 cables; and the connectors, cables, and soldering, the Cyber Filter box is designed as one circuit. (especially on the ground issue). Additionally, audiophiles said “no ground on ethernet cable” might be better. That’s totally against our Star Ground System and chasing the hi-end sound of streaming.

Listening Tests

I tried the EAL2000 in two setups. In my main setup, I placed the EAL2000 directly between the Grimm MU1 streamer and my network switch. In my second setup, the Cyber Filter was interposed between a Wiim Ultra (used as a streamer only) and the room’s network switch. The brief details of the setups are as follows:-

Setup 1 (Secondary Setup)

Netgear switch – Cyber Filter – Wiim Ultra Streamer – Chord Hugo TT2 (used as DAC and preamp)

Schiit Aegir power amp

Tannoy Kensington GR speakers

Setup 2 (Main Setup)

Cisco switch – Cyber Filter – Grimm MU1 – Totaldac D1-Six DAC

Conrad Johnson GAT S2 preamp & Conrad Johnson ART27A power amp

Vivid Giya G4 speakers 

In both systems, music was streamed from Tidal. 

Although I’ve heard clear differences in experimenting with ethernet filters and aftermarket cables, nothing quite prepared me for the experience of the EAL2000.

In Setup 1, the transformation was akin to substituting my digital source and solid-state power amp for a fine turntable and tube amplification. A lot of the positive attributes of vinyl playback were observed including tonal density, much improved dynamics and a smooth flow that was fluid and free from grain. There was nothing sonically defective in using a generic LAN cable, but the sound was quite predictable - clear, precise and even. But there was no fooling yourself that you were listening to a digital source, with a more clinical approach and flatter soundstage presentation. 

I was most impressed that a LAN cable swap (albeit with filtering) could make such a profound change to the system. This has to be the neatest party trick to make cable skeptics lose faith in their religion. 

In Setup 2, the changes were also clearly observed, although it wasn’t quite the night and day difference heard on Setup 1. There was some chatter about the Grimm’s immunity to network gremlins, so the fact that there were clearly audible improvements surprised me. 

The most noticeable change in the sound was an increase in tonal density, and bass impact. While I didn’t notice an increase in soundstage width, there was definitely a deeper and added dimensionality to the soundstage. While the increase in vocal warmth added a pleasing glow, it did smooth out some texture and articulation. The strengths of the EAL2000 is definitely in how it makes your music sound more “analog” with more dynamics, tonal density and smooth flow. Besides a fluid ease to music, the best way to describe the effect was an increased vigour in bass lines and turning up the “contrast knob” on your system. In short, I experienced an analog-like experience on my digital audio setup - claim substantiated.  

Conclusions

The EAL2000 will likely not please users who prefer a sharp incisive sound, ruler-flat neutrality and start-stop on a dime agility. But for reluctant digital audio users who feel that their analog rigs sound superior, the EAL2000 may be the missing link to their everlasting digital audio happiness.    

This review unit was kindly provided to me by Audio Basic, the local dealer for EAhibrid.

EAhibrid Integrated Cyber Filter  - US$1,950 to US$ 2,650

Audio Basic

1 Coleman Street

#02-12, The Adelphi

Singapore 179803

http://audiobasic.blogspot.com

Aurender A1000 Network Player Review

Introduction

Time really flies. The last time I featured an Aurender product was in 2015 when I did a review for the N10 music streamer - a truly outstanding product. The A1000 featured here is a lot more friendly to the wallet, costing S$5,000 or US$ 3,500.  

As a quick recap, Aurender products are slightly different from the competition. Your music is stored locally - either by copying your files to the unit’s internal storage, or plugging in a thumb drive or hard drive to the USB port. Control and operation is via their in-house developed Conductor software. For best performance, music files are copied on-the-fly into an internal flash memory cache prior to playback. This means that you can’t simply stream your music from a UPnP audio server although you can play these files through a “folder view” mode. Most Aurender models are Roon ready while the A1000’s certification is in the works.

Aurender offers different levels of functionality from all-in-one units like the AP20 (just add speakers) to the two-box flagship N30SA that has separate boxes for streaming and storage. The A1000 is an all-in-one source, featuring analog outputs, multiple inputs and a preamplifier function. In a nod to video duties, this is the first Aurender product to include a HDMI ARC input, which makes it perfect for handling two-channel home theater duties.  

Technical Details

 

The A1000 is the new entry-level model for Aurender, slotting in below the A200. Curiously, the A1000 offers a few features missing from the pricier A200. Apart from the HDMI ARC input, the A1000 also offers dual-mono DAC chips, Bluetooth, a coaxial output, a USB input and a 12V trigger. However, the A200 justifies its price premium with a superior TCXO clock, double 2.5” drive slots, a double-isolated LAN port and a supercapacitor-based UPS. 

The A1000 measures 13.8x14x3.8 inches (W/D/H) and weighs 8.3 kg. As expected from an Aurender product, the unit is constructed from solid aluminium. A 6.9 inch IPS colour LCD panel displays the necessary information. A rotary knob controls volume while a series of buttons control the most essential operations. You can also use the supplied Bluetooth remote control or the Conductor app which runs on both iOS and Android devices.

On the inside, power is supplied through three toroidal transformers - one for the CPU board and the remaining two for each audio channel. Processing is handled by a quad-core 2GHz ARM Coretex-A55 processor. Internal storage is not supplied by default. Instead, a small tray on the rear slides out to accept a 2.5 inch solid-state or hard drive. The tray is secured by two thumb screws and you can have your drive installed in a few minutes without any tools - impressive! There is great attention to detail on the immaculately finished casework, solid aluminium knobs and even the cork-lined footers. You get great pride of ownership for an entry-level product.

The Aurender connects to your network via a 100/1000 ethernet port. There is no built-in wifi. Digital inputs consist of a coaxial, Toslink, USB-B and a HDMI ARC socket. A coaxial and USB-A socket digital output allows connection to an external DAC. The A1000 also has a Bluetooth receiver module (with AptX-HD support),

The DAC section is based on the AK4490REQ chip from Asahi Kasei, used here in mono mode. This supports decoding of PCM data up to 32 bits and 768 KHz sampling rates, as well as DSD streams up to DSD512. The A1000’s analog output is single-ended only. Cheaper products offer balanced outputs and much fancier DAC chips, so this was a bit of a surprise. Expensive DAC chips don’t guarantee good sound though, so I would prefer to judge the A1000 on its sonic merits. The Aurender does not offer any analog inputs, and the volume control operates in the digital domain, which will impact fidelity at low volume settings. 

Operation    

Setup was easy. I installed the Conductor App on my Android phone and followed the on-screen instructions. Aurender’s local dealer, X-audio supplied a 1 TB SSD to install, and I copied my test files to this via my PC. It is also possible to stream music via Tidal Connect, Spotify Connect, Airplay and Google Cast. The Conductor App is more suited for large-screen tablets, but I found it reliable and stable on my phone too. 

In operation, the bright display shows you the album art and track information, including the sampling rate. Rotating the knob changes the volume setting, and feels solid and smooth in use. The App provides a high degree of customisation, including fade in/out when changing tracks and a “critical listening mode” which claims to improve sound quality by shutting down all non-essential background computer activity and the front panel screen/buttons. The Conductor App is easy and intuitive to use. As far as streamers go, it is one of the better interfaces out there. 

One notable niggle - the HDMI ARC input often showed that there was no signal lock, even though there was sound. Sometimes, the wrong sampling rates were indicated and the volume behaviour was erratic. This is probably a software issue and owners of the A1000 should disable the preamp function or CEC control until this is fixed. All other inputs and functions worked without any issue.  

Sound Quality 

Conventional and outdated “wisdom” suggests that digital sources (especially streaming) sound brittle and lacking in body. However, music flows through the Aurender with a highly polished and confident tone. Bass is full, and there is no harshness that plagues the A1000. I was impressed with the coherent sound, quietness and the overall lack of glare. To use a well-worn cliche, the presentation is analog-like, with a smooth and rich flow. There is a full midbass and laidback midrange that made long listening sessions non-fatiguing. Although there is decent treble extension and sparkle, there is a slight restraint in the reproduction of air which made live recordings in particular sound less lively. This gives the Aurender a subtly dark and creamy tone. 

The Aurender does soundstaging and imaging like a champ. It offers a precise portrayal of sonic images, with decent width and depth. Separation of instruments and vocals is good, with a very neat presentation even during heavy mixes. Resolution is also above average. Subtle and fine detail in familiar recordings were reproduced competently. The warmth is not overdone and music retains a fair degree of “bite” and texture. An important note, this is with critical listening mode enabled - otherwise the performance level takes a significant hit.

I was pleased with the quality of the Bluetooth input too. I obtained very high-quality sound from my Google Pixel 7 Pro phone. There was also minimal lag, with videos playing with no discernible lip-sync issues.  

I connected a fully tricked-out Geschelli Labs J2S DAC to the Aurender via its USB output. My J2S DAC uses the top of the line AKM4499 DAC chip and is outfitted with a flagship linear power supply and Sparkos SS3602 opamps. The Aurender’s internal DAC sounded quieter, cleaner and more resolving by a significant margin. It is comforting to know that the Aurender’s DAC section is of suitably high quality and will be good enough for most users. Nevertheless, you can explore upgrading the DAC but be prepared for a significant financial investment to obtain meaningful improvements.  

Conclusion

The A1000 offers an excellent all-in-one streaming solution. Despite being an entry-level product, it performs well enough to satisfy most discerning audiophiles. My only reservation would be the glitches noticed on the HDMI ARC input. Hopefully Aurender is able to fix that via a firmware upgrade soon. Best Buy 

This review unit was kindly provided to me by X Audio, the local dealer for Aurender.

Aurender A1000 Network Player - S$5,000 or US$ 3,500

X Audio

Apex@Henderson

201 Henderson Road, #06-13

Singapore 159545

http://xaudio.sg

 

Weiss DAC204 Review

Introduction

Weiss is best known for their professional products which see use in studios worldwide. They have seen success too in their domestic products and I personally know a number of discerning audiophiles locally that use Weiss products. 

As an owner of an INT204 USB/DSD interface, I appreciate the level of quality and performance delivered. Not cheap by any means, but their products are priced reasonably, especially in the context of current high-end pricing.

Description

The Weiss DAC204 is a compact shoe-box-shaped device that combines the DAC board of the DAC205 with the functionality of the INT204 USB/DSD interface. The DAC205 offers only a Toslink and coaxial input, making the DAC204 the unit of choice if you require a USB input. Based on an oversampling sigma-delta D/A convertor, four paralleled D/A convertors are used per channel for superior signal-to-noise performance. High jitter suppression is claimed by virtue of several signal re-clocking schemes.

The USB input supports sampling frequencies of up to 384kHz and DSD64/128 (sampling frequencies of 352.8 and 384kHz are downsampled to half the original frequency). Two front panel toggle switches convert DSD signals to PCM at either 88.2kHz or 176.4kHz sampling rate and 16 or 24-bit word-length. The coaxial and Toslink inputs accept signals of up to 192kHz. 

The flexibility offered by the DAC204 is tremendous. Three digital outputs (coaxial, BNC and AES/EBU) allow digital signals to be routed to another DAC or digital recording device. For example, the DAC204 could be used with legacy DACs that neither have a USB input, nor DSD compatibility. 

Turning to the analog outputs, both single-ended and balanced outputs are available, with four selectable output voltages (0.23V to 7.5V for the balanced output, and 0.115V to 3.75V for the single-ended output). This allows the DAC204 to be adjusted based on the gain structure of your system. The higher voltage settings would be especially useful for passive preamp users. 

The power supply is off-board, with a medical-grade switched-mode power supplied. The DAC204 accepts a supply voltage between 6 to 9V DC, with a current requirement of 1050 ma at 6V or 700 ma at 9V. Weiss will also sell you the PSU101 universal power supply if you wish to upgrade the performance of the DAC204. Just be warned though, it's as expensive as the DAC itself!

In use

The Singapore distributor for Weiss kindly included a Plixir Elite 6V-6A power supply and Statement DC cable to try out with the DAC204. I used both the Plixir and the stock power supply during my evaluation. 

I hooked up an old CD player to the coaxial input to run-in the unit. None of the sampling frequency LEDs lit up although music flowed. Reading the manual again, I realised that the LEDs only light up when using the USB input. Apart from this initial scare, the DAC204 performed without any issues.  

Sound Quality

With the Plixir, the DAC204 impressed with a highly detailed and cohesive sonic performance. The first thing that strikes you is how music flowed without any particular frequency calling undue attention. 

Bass was tight and impactful and had good speed and tempo. Vocals had a mild laidback quality that provided some warmth to the human voice. High frequencies were reproduced with a clean and crisp edge. The Weiss managed to strike a perfect balance - with a detailed and grain-free midrange and good highs without sounding bright or strident.  

Readers to this point would be wondering what made the Weiss special compared to competition? In my view, the DAC204 was able to convey a superior sense of dimensionality and realism - with clear illumination of the acoustic space around each voice and instrument in the recording. I associate this particular quality with high-end DACs which is high praise indeed for the Weiss. 

The subtly warm tone and lack of harshness allowed for many hours of fatigue-free listening. Despite the professional audio heritage, the Weiss struck me as a musical device - I spent most of my time enjoying the music instead of trying to dissect the recording. 

Swapping out of the Plixir for the stock power supply greatly diminished the performance of the Weiss. Apart from losing impact and power in the low-frequency region, the drop in resolution and separation was obvious. 

Conclusion

Sonically compelling with the Plixir power supply, the Weiss offers great flexibility in a small format. The price with upgraded power supply is well justified if you require the functionality of the INT204 board - Recommended.

I would like to thank Sound Affairs Pte Ltd for arranging this review. 

Weiss DAC204 D/A Convertor

Price - S$ 3,996 (with stock power supply), $5,000.40 (with Plixir Elite BDC and Statement DC cable)

Sound Affairs Pte Ltd

110 Lorong 23 Geylang

#06-03 Victory Centre

Singapore 388410

http://mysoundaffairs.com

 

Grimm MU1 Music Player

Grimm MU1 Review

Grimm Audio was founded in 2004 and is based in Eindhoven, The Netherlands. Helmed by Eelco Grimm and Guido Tent, Grimm is well-known in professional audio circles.

Grimm claims that the MU1 is the ultimate digital musical source. That's certainly a bold claim - let's see whether the MU1 performs as claimed.

Description

Underneath the hood, the MU1 runs its software on a Linux-based Intel i3 computer board and an in-house designed FPGA board which runs format and sample rate conversion. An ultra-low jitter clock (<0.6 ps RMS (>10 Hz)) completes the picture. Hey, it’s a Grimm and you wouldn’t expect anything less would you?

At the moment, the MU1 is a Roon-based solution that acts as both Roon Core and Roon End-Point. There are plans to offer a DLNA solution in the future though. Tidal and Qobuz support are available through the Roon app, but Spotify Connect is not supported. 

The MU1 is available with internal music storage of up to 8TB. Otherwise, you can use network storage or an external drive connected to the twin USB 3.0 ports on the MU1.

Three digital inputs (AES, coaxial and Toslink) are provided which allows the MU1 to process external data streams, allowing other digital sources to enjoy the goodness of the MU1.

The FPGA upsamples the data stream to either 2x or 4x of the sampling rate before being sent to the two AES or single coaxial digital outputs. A fourth digital output via an RJ45 port serves as a proprietary connection for the Grimm LS1 speaker. The digital outputs may also be configured for 6-channel output for surround sound use. No preamplifier ? No issue – there is a digital volume control on hand too. As there is no way to attenuate DSD streams, conversion to PCM is required to make use of the volume control.  

Setting Up

Hook up the MU1 to your network via its LAN port (wireless connection is not available), switch on the power, and you are ready to go. The difficulty factor depends on how familiar you are with Roon. As a long-time Roon user, setup was straightforward. The well-written manual is comprehensive, and I spent less than an hour setting up the MU1 and loading my test tracks into the internal drive. The unit connected to the internet and prompted an upgrade to its firmware. Grimm has worked hard in the past to upgrade the performance of the MU1, so you can expect steady improvements in performance over time.

Operation

The giant wheel on top of the unit controls the MU1. With a combination of short/long presses and turning the wheel, you can access the various menu options. Most users would navigate their library and operate playback through the Roon App, whether running on their mobile phones or a tablet.

The sampling rate conversion can be switched to “Original”, “2FS Oversampling” or “4FS Oversampling”. If “2FS Oversampling” is selected, files at 44.1 and 48 kHz sampling rate will be upsampled at 2FS, while 88.2 and 96 kHz sampling rate files will be played at their native sampling rate. In the case of files over the targeted oversampling rate, they will be downsampled (e.g. 8FS and DSD material). The MU1 also supports DoP in case the user prefers to play DSD files natively on their DAC.

The USB port can also be enabled to output data, but I found it sounded inferior to the AES and SPDIF outputs when paired with my Totaldac D1-Six DAC. 

Programmable remote-control operation is possible if an external IR receiver is connected to the 3.5mm jack provided on the rear of the unit. As I did not have an IR receiver on hand, this function was not tested.

Sound Quality

The MU1 is simply the finest quality Roon playback I have heard bar none. The tone is a fluid, almost analog-like quality with powerful dynamics and extended highs. My Roon ROCK (Roon Optimized Core Kit) server runs on an Intel i7-based NUC fitted into a fan-less Akasa Turing chassis for fully passive cooling. The MU1 ran rings around my home rig, to the point that the performance gap between the two was simply unbridgeable.

One very important caveat is that the performance lead of the MU1 depends on your source material and how you employ upsampling (or not). The lead narrows considerably if you are playing  DSD natively, or PCM files without upsampling. I am personally not a big fan of upsampling, but the MU1 does this in a way that improves sound quality so significantly in terms of separation and detail that you will just leave the upsampling enabled permanently.  

If you are a DSD fan and your DAC does not support DoP, operation will also be cumbersome. You will need to change your Roon settings to output the digital stream via the USB port, which then leaves you without upsampling. You could connect up your DAC via the SPDIF or AES output, and toggle between the two signal paths, but the routine will quickly become old. The other alternative would be to stick to the SPDIF or AES output, and convert all DSD streams to PCM – something bound to offend a DSD purist!

Coming back to the sonics, there is a certain rightness to the MU1. Bass is very tight and powerful, and piano notes have a rich solidity and realism that fills the room. The midrange is on the warmer side of things, and vocals have a warmth and richness that is creamy and inviting. This is coupled with very extended and clear high frequencies that reveals plenty of detail and air. Counter-balanced with the hefty low-end and warm midrange, you end up with a tone that is not bright at all, yet highly detailed and easy to listen to. This is not a product that plays the neutrality card, but instead takes the path of connecting emotionally with the listener. 

The way the MU1 produces music is very special - music is highly energetic, yet natural and non-fatiguing. Your brain instantly registers that the MU1 is a rare and outstanding product that stands out from the crowd. 

Closing Thoughts

This is a niche product. If you dislike Roon or want ruler-flat neutrality, you should look at something else. Some audiophiles would balk at the price-tag of the MU1 and insist that this is an overpriced computer server build. An audition should quickly sort that out. I know of several experienced audiophiles and reviewers that purchased the MU1 after experiencing what it brings to their system. Although the outcome would be Grimm for my bank account, I definitely want one! Highly Recommended.

Grimm MU1 Music Player

Price - S$16,000 (excluding GST and with 4TB SSD internal storage)

Grimm products are available from :-

Sound Affairs Pte Ltd

110 Lorong 23 Geylang #06-03
Victory Centre
Singapore 388410

http://www.mysoundaffairs.com/

Topping D90 MQA DAC

Introduction

Topping is well known for their low-cost audio electronics, ranging from amplifiers to DACs and headamps. They have become increasingly upmarket and their top-of-the-line DAC, the D90 was released last year. 

The buzz around the D90 was centered around the decoding chip used, the Asahi Kasei AK4499. The DAC chip alone does not maketh the final output. The quality of the power supplies and the output stage play a part too, not to mention the implementation of the digital receiver, clocks etc. 

The AK4499 is Asahi Kasei’s premium offering in their Velvet Sound range. It is described as a 4 channel switched resistor DAC with top-notch measurements like a dynamic range of 137 db (stereo) and THD+N of -124 db. 

Description

The D90 MQA DAC is an update of the D90 DAC with MQA decoding and a change of the USB chip from the XMOS XU208 to the XU216. The rest of the features list of the D90 MQA reads like any premium DAC, including fully balanced outputs, DSD 512 decoding, I2S input and dual Accusilicon Femto clocks. The best feature is left for last - a retail price comfortably below USD 1,000 (USD 799.99) !

In a nod to modern conveniences, the D90 MQA includes a Bluetooth receiver, with support for Bluetooth 5.0 and LDAC/AAC/S-BC/APTX/APTX LL/APTXHD protocol. In other words, you can stream 24 bit / 96 kHz music with the right source. If you believe that a receiver and antenna is the work of the hi-fi devil, you can disable the function from the front panel. 

The rear panel has all the usual inputs, including Toslink and AES. I2S input is in the form of a HDMI socket, and the pin settings can be configured to maximise compatibility with your source. 

Both single ended and balanced outputs are provided. The RCA jacks are spaced quite close, so be careful if you have cables with very large RCA plugs. 

Easy access to the voltage selector at the bottom of the unit.

Looking at Topping’s internal pictures, a single power transformer is used in the linear power supply (the mains voltage is easily switchable by the user), with lots of goodies like Nichicon FW power supply capacitors, TI OPA1612 chips for I/V conversion, and healthy voltage regulation (including 6 independent regulated power supplies). Bear in mind that all this is packed in an enclosure that is small and light enough to be held in the palm of your hand. The Topping's external dimensions are 22.2 cm x 16 cm x 4.5 cm (W x D x H), and the unit weighs 1.4 kg.

The Topping is a fully balanced design, with two outputs from the AKM4499 DAC chip paralleled to achieve better performance. The AK4118 receiver chip supports up to 24 bit / 192 kHz sampling rates through the Optical, Coaxial and AES digital inputs. USB and I2S inputs support up to 768 kHz sampling rate, as well as DSD 64 - DSD512. USB decoding is handled by an XMOS XU216 chip, which contains two xCORE tiles with up to 2000 MIPS processing power (double that of the XU208). You may also choose to have simultaneous output from both the RCA and XLR analog outputs, or only have one output active.

The digital volume control can be operated in 0.5 db steps, which permits you to skip a separate pre-amplifier if required. The Topping also has a choice of six FIR digital filters for PCM and two settings for DSD.  A plastic remote control is also provided with close to full functionality. The remaining functions can be accessed by pressing the left button and switching on the unit. 

I liked the front OLED panel, which uses large fonts that can be seen across the room. All necessary information is displayed, including the active input and output(s), sampling rate, volume and whether the stream decoded is PCM, DSD and MQA processed. The brightness of the display can be controlled, but not switched off entirely - take note if you are an audiophile bat.

Build quality is impressive and the look and feel of the Topping far exceeds my expectations, especially at its price level.  

MQA - A Primer

MQA, or Master Quality Authenticated is a process that was established by Meridian Audio, the well-known British hi-fi company. MQA allows high-resolution audio to be packed into a compact data stream. It also digitally fingerprints files so that you can be assured that your file has not been tampered with in any way.  

MQA files are backward compatible with any equipment capable of playing back red-book CDs or digital files, and can be encoded on popular files formats like WAV, FLAC or ALAC. In a process that is termed as "Audio-Origami", the high-resolution signal is folded into either a 44.1 kHz or 48 kHz sampled format depending on the sampling rate of the original file. Lossy compression is then applied to the ultra-sonic frequency range (which has little amounts of energy). The most practical benefit to this is reduced data bandwith required if you are streaming (e.g. from Tidal), and much smaller file size.

MQA is also able to do digital compensation to the encoded signal based on the recording equipment. If your DAC has a full MQA decoder, there is also further compensation for the playback device.

The first level decoding (MQA Core Decoder) of the signal enables the signal to be unfolded into a high resolution stream (MQA Core Stream) of either 88.2 kHz or 96 kHz. You may use Roon, or any other compatible software decoder to extract the MQA Core Stream. 

The Topping is a full MQA decoder which will perform the full unfolding, authentication of the stream, and apply file and DAC specific compensation to achieve the highest possible sound quality. To be clear, no software decoder is required for full MQA decoders, and MQA encoded files can be played from any source. In my case, the files were streamed from my Melco N1/ZH2 NAS and TIDAL. For users that do not own a DAC with MQA decoding, a software decoder upstream will at least allow them to enjoy high-resolution audio, but without the final unfolding to either 172.4 kHz or 196 kHz sampling, nor DAC compensation.    
I high recommend watching this video on "The Hans Beekhuyzen Channel" which explains how MQA works. 

Sound Quality

In comparison to their upmarket relatives, my experience is that budget to mid-range DACs generally lag behind in microdetail retrieval, low frequency authority and dimensionality. They do deliver most of the goods, but that fraction left on the table is what motivates audiophiles to open their wallets.

Serious listening was done after a week of burn-in and experimenting with the different inputs (I'll come back to that later).

The Topping delivers very good sound quality with excellent detail retrieval. It has tight bass which is delivered with punch when required. Midrange reproduction is good with a sweet tonality that is comfortable to listen to. High frequencies are extended too, with a sparkle and decay that is able to recreate a spacious and convincing portrayal of the acoustic space of the recording. Its star quality to me is staging and imaging, which is done with very good depth, width, and space around voices and instruments.

I would describe the Topping as tonally close to neutral with a touch of warmth. The staging and vocals have a laidback character to it, while transients are clear but with a soft edge to it. If you like your music to have a crisp snap and edge, you are probably not going to like the Topping. 

The Topping likes to play nice, and the softer presentation does flatter poor recordings, especially bright and harsh ones. I actually find this to be a desirable character, considering that the Topping will most likely be used with other affordable equipment, which may have weaknesses and flaws best not laid bare for all to see.    

I also did some listening tests to sample MQA files available from 2L. I preferred the MQA encoded files of both the original high-resolution recording, and the CD quality file. I was not sure about the merits of MQA prior to this, but consider me sold.   

As good as the Topping may be, it is not going to dent the sales of high-end DACs. While it does embarrass a lot of the competition, as well as many mid-range DACs, the Topping is unable to match the best out there in detail retrieval, dynamics and other audiophile niceties that the enthusiast seeks. To be clear, I am very comfortable recommending the Topping for the price, and even if your budget is a multiple or two of that. However, don't rush out to sell your flagship DAC in favour of the Topping !

A Word About Inputs

I have a general preference for using SPDIF over USB inputs, relying on an outboard USB / SPDIF bridge as I find it delivers better sound quality. In the case of the Topping, the USB input was superior, with SPDIF sounding a bit more gray and vague. I use a Weiss INT204 bridge, powered with an Uptone JS-2 power supply. It was a surprise then that the much simpler (and cheaper) route sounded better.

I also tried connecting my Melco N1/ZH2 NAS to the I2S input of the Topping using a Singxer SU-1 USB / SPDIF bridge. Despite careful study of the pinouts of the Topping, and appropriate setting of the DIP switches on the Singxer, I was unable to get any sound although the appropriate sampling rate was displayed on the Topping. 

The Bluetooth connection actually works quite well, and I was very comfortable using my Samsung Galaxy S10+ phone to stream music from Tidal to the Topping. The quality is more than decent and the slight loss in quality is more than acceptable. 

Most of my listening was done using the USB input.

Glitches

While switching from non-MQA to MQA encoded files, there was a brief, but loud burst of static through my system. The Topping locked-up on the two occasions that it happened, and the unit had to be powered down and restarted before everything was back to normal. I was not able to recreate this again, and I am unsure whether the problem lies with the Topping, or the rest of the equipment in the chain. Do leave a comment on this post if you have had similar experiences with your Topping.

Conclusion

The Topping D90 MQA is an excellent way to get your feet wet in the MQA pool for a modest outlay. I am pleasantly surprised at the very high quality delivered for the price and this is definitely an outstanding value-for-money product - Best Buy. 

P.S. The Topping was a personal purchase by me at full retail price. 

Second Opinion (From TC)

Description

I was pleasantly surprised when i received the package from Eric. It comes in a large black cardboard box with the words "TOPPING" on top. The DAC is snuggly fit in between the thick foam compartments and it would survive any kind of rough handling during shipment. The DAC is the most light weight and smallest that i have come across in this hobby with the Calyx 24/192 coming in second place in terms of size but on the other hand very heavy due to the casing.

Being conditioned that bigger and heavier equipment means more good stuff are packed inside, frankly when i lifted the Topping i thought "is it really as good as what all the reviews say ?" With the D90 placed on top of the Oppo 205, i hooked it up and started playing songs using the Cambridge Audio CXC as a CD transport. I sent a photo to Eric and promptly got a reply back that the DAC looks like it's floating! I looked closely and realised that it's front is being lifted up due to the heavy power cord it's connected to. I removed the Oppo 205 from the rack and placed the DAC back on the rack space this time ensuring that the DAC is fully resting on the rack shelf and powered it on. Wow! the sound is lifted up by a few notches right away! Important tip to note. Though the Dac is small and lightweight, it's still sensitive to placement and deserves a good spot in your rack and try not to stack it on top of other equipment to get the maximum potential out of it.


Sound

True to the AKM "Velvet Sound", the DAC does sound very refined and smooth without any rough edges. Music flows like a water stream and you can just sit back and let the DAC perform its magic. 

Be patient and let the DAC warm up at least 30 minutes and you will be rewarded with spades of details and layering. Bass is tight, in control and not excessive. It's not a forward sounding and grips you in the seat type of sound but i would say the character is an even handed with a deep soundstage. As i keep listening to the DAC, fluidity, naturalness and musical comes to my mind.  

Just for the fun of it, I have tried to tweak the sound with the cloned Ceraball footers but find that it tipped the high frequencies too much and wasn't to my liking. Overall, the presentation is still neutral with just a tinge of warmth.


Other comments- despite its small size and light weight, resist the temptation to stack it on top of other equipment to save space. It's sensitive to placement and deserves a proper spot on your rack. Warm up is critical and give it at least 30 mins to let the music soar!RCA cable users might face problem with the tight spacing between the connectors

At this price point, it's a very good performance DAC with a myriad of connectivity options and is even able to handle MQA.

The D90 is highly sensitive to the source equipment that it pairs up with. Compared to the Cambridge Audio CXC, the sound quality coming out from the Mac mini is still very good but just a tad softer and rounded. Layering and micro details are not as transparent but overall
it's still highly enjoyable if you are not out to "dissect" the music. The bass attack is strong and big. I think a dedicated streamer will do more justice to the D90.

I was unable to to turn on the Bluetooth until i sought help from Eric who informed me of the magic menu that will appear when you press the standby button together with the power switch behind the DAC. So for anxious users like me who just like to jump headon to test the DAC without reading the instruction manual, please take note. The Bluetooth function is highly interesting and all you need is your mobile phone. Detecting the D90 on the mobile phone is a breeze and it brings with it a myriad of music sources at your disposal. You could
stream Tidal, Spotify, music files on your mobile and even local radio stations. 

Music quality is slightly below using mac mini but it ups the fun and convenience factor. All you need is a mobile phone, D90, a power amp and you are good to go. Just think of the space that can be saved with a simple setup like this. I have tried out the connectivity distance and i could achieve about 10 metres before I experienced sound dropouts streaming FLAC files. That's quite good already if you like to move around your house multi-tasking doing chores while you listen to music to keep the boredom away.

Final words

The D90 impressed me greatly with its small form factor, multi-functionality and very good sound quality for its price. It banished the common thinking that for good sound quality, the equipment must be big and chock full of components inside. If i could reverse my audiophile
journey a few years back and not be "burdened" with so much equipment, I would get this in a heartbeat. 

Just maybe, if your girlfriends and spouses (Note from Eric - I advise only having one girlfriend or spouse at a time please !) can see how small this D90 is, they will surely "approve" the indulgence in this hobby right away !