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Manufacturer: Hem Sp. z o.o.
Price (when reviewed): 3295 USD (2795 EUR)

Contact: Al. Jerozolimskie 475
05-800 Pruszków ⸜ POLSKA



Provided for test by: Hem Sp. z o.o.


images by Ferrum, „High Fidelity”

No 242

July 1, 2024


FERRUM is a Polish audio brand owned by HEM, one of the most experienced companies in the industry, which has been designing and manufacturing equipment for MYTEK for 20 years. Ferrum's first product was the HYPSOS power supply. The second design was the OOR balanced headphone amplifier, the third was the ERCO DAC, and the next was the top-of-the-line DAC, the WANDLA model. It is now available in a GoldenSound version. We are testing it as THE FIRST MAGAZINE IN THE WORLD.

EXACTLY ONE YEAR AGO, in June 2023, HIGH FIDELITY featured the premiere test of Ferrum's Wandla DAC. This was the fourth product of this Polish brand, although the company behind it, HEM ELECTRONICS, is a veteran of the audio industry, as it was from the hands of its engineers that Mytek devices came out earlier. Ferrum, however, is a completely new opening for the company, and as time has shown, it is within this framework that it has been realizing itself to the fullest.

And exactly one year later, just after the Munich High End Show 2024, its new version, named GoldenSound, comes into our hands. Asked by me, Marcin says:

I would like to clarify one thing. Wandla GS Edition has exactly the same hardware as any other unit. Only the software differs from the classic version. In June, there will be a "conversion program" presented on our website that will allow you to install the GS software in any Wandla DAC, at a price of 595 euros.

As you can see, the main changes in modern digital devices are taking place at the software level. In the case of Ferrum, this is made possible by a programmable chip module called Heart. It was presented at High End Show 2022 and was intended to be offered to other manufacturers (report → HERE). On a small board with ST Electronics' ARM-series FGPA chip and Burr-Brown chip, it included a USB receiver, MQA decoder, digital input switcher, digital filters, etc.

The computational power of this circuit’s "heart" has been calculated in excess, so that additional functions and even improvements in the device's performance can be developed and introduced in the future. Using it, Ferrum has prepared a special version of the Wandla GoldenSound Edition DAC.


A few simple words…

R&D’s chief engineer

⸜ New features available in the GoldenSound version are displayed at the beginning of the queue in the "Audio" menu

THE HISTORY OF OUR COOPERATION with Cameron Oatley, known online as GoldenSound, began shortly after the launch of our Oor headphone amplifier. Cameron then received one of the first units for testing. He liked the amplifier very much, but during testing he detected some issues. He then contacted us and was impressed by the speed of our response, as well as our openness to comments. We solved those problems, of course, which made Oor an even better product.

Another device that Cameron really liked was our flagship Wandla DAC. That's when Cameron approached us with an idea for developing a signature GoldenSound version of the Wandla, which would include some small modifications and DSP algorithms. Interestingly, during our internal discussions there were very similar ideas floating around, so we readily agreed to his proposal. Cameron had an idea - we knew how to implement it.

⸜ Once you have accessed a function, all you have to do is turn it on - this can also be done using the remote control

The cooperation during the development of the new software went very smoothly, and after an initial discussion of what we wanted to do we prepared the first version, which we sent to Cameron for testing. The result was great from the beginning, although as a result of discussions we made a few more minor changes, which made the whole thing even better in the final product. Also, the Impact+ feature was added at a fairly late stage.

What we are very proud of is the impact of algorithms on sound quality, or rather.... lack thereof. Each of them changes something, and while they are not huge changes, none of them worsen performance in some other aspect, which is quite common in other DSP implementations. I remember a situation when we were testing speakers and they were lacking bass. So we used a digital parametric equalizer built into respectable software to boost the low frequencies. And indeed, there was more bass, but the stage and detail suffered. With our Impact+ algorithm, there is simply more bass and "perceptible dynamics," but the rest is left untouched.

⸜ A touch screen make the operation of the DAC even more convenient

What needs to be emphasized is that Cameron has a really excellent sense of taste in terms of the amount of changes the algorithm makes, and we could rely on him when it comes to choosing parameters. As a result, the changes to the sound are not exaggerated, which is something we all really wanted. PG



WE HAVE ALREADY TESTED THE BASIC VERSION OF THIS DEVICE, but it is necessary to repeat the most important information. Wandla is a digital-to-analog converter. It uses exactly the same chassis as previous devices from this company, that is quite a small one that measures 217.5 x 206.5 x 50 mm (W x H x D). Its housing is made of bent stainless steel powder-coated with black lacquer. On the side, however, an extremely distinctive element made of Corten or weathering steel has been added, in which the company's logo, which is essentially a symbol of iron, has been laser-cut, and illuminated with white light.

The Polish DAC offers as many as six digital inputs: AES/EBU, RCA, Toslink, two HDMI and USB. To one of the HDMI inputs, equipped with an ARC return channel, we'll connect a TV, and to the other, a file or CD transport, via the I2S protocol. This type of transport is offered by quite a few companies in the Far East, but you’ll find it also in PS Audio lineup. The USB input is unusual for this class of device, as it is a USB-C input. The DAC decodes PCM and DSD signals, and also offers an MQA decoder for all inputs:

• AES/EBU – PCM up to 192 kHz, 24 bits, DoP 64,
• Toslink – PCM up to 96 kHz, 24 bits,
• RCA – PCM up to 192 kHz, 24 bits, DoP 64,
• USB-C – PCM up to 768 kHz, 32 bits, DSD 256
• ARC – PCM up to 192 kHz, 24 bits,
• I2S – PCM up to 768 kHz, 32 bits, DSD 256 (PS Audio compatible).

In addition to digital inputs, there is also a stereo RCA analog input. The signal is sent out either through RCA or XLR jacks - the unit is fully balanced.

Operation of the DAC is extremely simple. The basis of the user interface is a large color touchscreen display. On it we can find information about the selected source, the type of digital signal and its parameters. And from the bargraph we will read the volume level. Because Wandla is not only a DAC, but it can also act as a preamplifier. Volume control can be performed in the digital domain - that's part of the ESS Sabre ES9038PRO chip used - or analog one, in an integrated resistor ladder. For volume control, there is a large volume knob or a nice metal remote control.

Wandla GoldenSound

ALREADY THE FIRST VERSION OF THE WANDLA DAC used Heart to introduce its own solutions. In addition to a number of filters offered by the ESS Sabre chip, Heart includes digital filters prepared in cooperation with Jussi Laako of Signalyst, best known for the HQPlayer software player. Over time, it became apparent that the available filters could be changed. Based on user feedback, Ferrum engineers selected the most popular ones and deleted the others. The idea was not to "muddy" the circuit’s operation with calculations that few people would use. In its place, more proprietary filters were added. The solution was called Dynamic Digital Filtering (DDF).

Several new features have been added to GoldenSound, as well as a system change. This version was developed with Cameron Oatley, who runs the YouTube channel of the same name; he is also referenced by the trumpet logo next to the new device name shown on the display (except for the display, both versions look exactly the same).

As we read in the company materials, HEM’s team decided to leave the circuit board unchanged, but completely omitted the MQA decoder this time to "get the best sound quality from the DSP engine". The changes include:

• higher digital headroom
• expanded stereo base, separately for speakers and headphones
• emulation of tubes in the circuit
• Impact+ function
• switchable maximum output voltage.

Two of them seem to be Ferrum's idea, namely headroom and output voltage, and they seem to come from studio equipment. Adjusting the output voltage, between 4 and 10 volts, allows the user to match it to a particular system. For example, in a system with a preamplifier, I would recommend the former value, and without a preamplifier, such as with a power amplifier or active speakers, the latter. As it reads:

It is possible due to a special hardware voltage divider that allows the user to select a lower output voltage and ensures compatibility with all amplifiers without the need for digital volume control or analog volume control elements in the signal path.

Bigger digital headroom is a much more interesting improvement. The idea is to give signals that are heavily compressed, on the threshold of digital overdrive, or even overdriven, a chance to be better converted to an analog signal. This type of signal is characteristic of modern, heavily compressed recordings, as well as aggressive remasters. The upper part of the signal envelope is flattened in them and this, however, can be remedied, to some extent. The digital signal level is lowered in the Polish DAC so that these maximum values are below 0 dB. This is a solution that changes the sound of the device, and is not just an add-on.

The other three features have been inspired by Cameron Oatley. In a video available on YouTube, the creator himself describes them, and it's worth spending the less than seven minutes to get a first-hand look at what they're all about (GoldenSound, Introducing the WANDLA GoldenSound Edition!, watch it → HERE).

As you can see, the changes made by these three features are relatively small. Oatley talks about it, but it was also confirmed by my listening. Marcin Hamerla, whom I asked about it, writes:

In general, our idea was that the changes should not be "straight to the face", but to be tasteful. We didn't mean the typical "DSP treatment" to "pull you out of your shoes", but actual improvements. And those, as you know, come from small, well-placed steps.

The strongest effect comes from the Impact+ function, the softest from the tube simulation, while it too can be heard well, but to enjoy it you need to have the right headphones. You can hear it well with, for example, HiFiMAN Susvara, but you won’t always hear it with lesser quality cans. Equally important is the choice of sound material.

One of the additions is "spatial" effect. It is supposed to improve the spatial experience by expanding the soundstage and by better separation between musical elements. It is supposed to be different from the usual solutions and avoid their drawbacks. The function has two modes: headphone and speaker, tailored for different applications. The tube mode was borrowed from sound processing programs. This mode intentionally introduces even-order harmonic distortion into the signal, similar to the distortion characteristic of a tube amplifier.

And finally there's the Impact+ feature, which the Ferrum chief mentioned. As the press materials read, it is designed for anyone who "likes a little more bass in their music". This feature uses a non-standard dual-band dynamic equalizer, which not only boosts the bass, but is also supposed to provide additional "punch" and subjectively higher dynamics.


˻ HOW WE LISTENED ˺ GoldenSound's Wandla DAC was tested in a HIGH FIDELITY reference system with both speakers and headphones. It was compared to the D/A section of the Ayon Audio CD-35 HF Edition SACD player, which also worked as a CD transport; in turn, the Lumin T3 file player worked as a file transport. The Ayon's digital output was connected to the DAC's RCA input via an RCA→RCA Acrolink Mexcel 7N-DA6100 II cable, and the file player's output was connected via a USB-B → USB-C QED Connect cable.

I had, in fact, two Wandla DACs at hand, an original version and the GoldenSound one. So I was able to compare their sound head-to-head. Both converters were powered by their respective power supplies, but plugged into a Nordost Qb8 strip, and this latter via a Harmonix X-DC350M2R Improved-Version cable to an Acoustic Revive strip. The DACs stood on the top shelf of a Finite Elemente Master Reference Pagode Edition Mk II rack on their feet.

In my system I use RCA cables, I also use a preamplifier. So the DAC was tested with the RCA output and with the output attenuator "bypass" enabled. It was connected to the Ayon Audio Spheris III preamplifier by Crystal Cable Absolute Dream cables. In the headphone system, the signal was sent to a Leben CS-600X amplifier, and this amplifier drove HiFiMAN HE-1000 v2 and Lime Ears Anima.


⸜ SHELLY MANNE & HIS MEN, Jazz from The Pacific Northwest (Live), Cellar | Reel To Reel Recordings/Tidal, FLAC 24/96 (2024).
⸜ GABRIELS, Angels and Queens, Parlophone | Atlas Artists/Tidal, FLAC MQA 16/44,1 (2023).
⸜ BEYONCÉ, Cowboy Carter, Parkwood Entertainment | Columbia/Tidal, FLAC 24/44,1
⸜ CARLOS RAFAEL RIVERA, Monsieur Spade (Original Sountrack), Lakeshore Records/Tidal, FLAC 24/44,1 (2024).
⸜ MADELEINE PEYROUX, Showman Dan, Membran/Tidal, SP, FLAC 24/96 (2024).

» You will find tracks used in the test on the TIDAL playlist → HERE


THE THING I WOULD LIKE TO SHARE WITH YOU already at this point is that on its own, without activating the new features, the new version of the Wandla DAC sounds better than the previous one. How is this possible? It seems that by changing the software, i.e. by deleting the MQA decoder - thus freeing the processor from additional work - and also by enlarging the overdrive interval, the digital signal is "treated" better, and the converter in the Ferrum has much better operating conditions.

On the one hand, these are not some huge differences, and I will understand if they seem too small in a given system. But on the other hand, if you had the opportunity to listen to them in your system for a longer period of time, after a while it may be difficult to return to the older version. And this is because this "new" sound is smoother and also deeper. The original DAC was fine in this regard, but I also knew that it was not as warm or as dense as with my Ayon Audio player or even the Lumin T3. And that's what you get with the new version from the start, without yet including the extras.

Wandla's sound deepened and filled out. And I heard it both with the monophonic recording Funny (Live), taken from SHELLY MANNE & HIS MEN's Jazz From The Pacific Northwest album, and with new realizations, such as the track Loyaity (feat. Ashley Sade) by GABRIELS, as released on the second disc of the Angels and Queens album. The former has a somewhat lighthearted feel, but also outstanding dynamics. The recording in question is from a concert at Seattle's The Penthouse club on September 15th 1966, and begins with an announcement. Both his voice and Mann's crew in the GoldenSound version sounded stronger, denser and more like in a club, rather than just "live". This recording had a thicker background, and the instruments had more weight.

It was even more interesting to listen to the second aforementioned track. It begins with beats in two channels of bass and vibraphone. Immediately afterwards, Jacob Lusk's unusually deep vocals enter, and after a while, on axis, Ashley Sade begins to sing, accompanied by a string section. Wandla's new version showed the differences between these elements - and they are really big - in a much better way. The low, saturated vocals of the leader, recorded with a very closely positioned microphone, and the distant voice of the female vocalist with a clipped bandwidth, shown as by tube-based old equipment, with a lot of noise, etc. This is obvious in both versions of the DAC, yet the new version sounded more believable.

After some time, once we understand the pattern of changes that are introduced in GoldenSound, we will find it hard to get past the fact that it's just a nicer sound. It wasn't bad at all before; Wandla is, after all, an excellent device. So also in the previous version, the cover of the Blackbird by The Beatles included on BEYONCÉ's latest album Cowboy Carter sounded great with it. It's a commercial recording, so with strong compression and multiple tracks. But it was with the latest version of the DAC and with all the effects turned on that it sounded more natural.

There was less "hoarseness" in the singer's voice, that is, an emphasized part that illuminates the vocal and makes it "present" in the mix. This is achieved by using various computer plug-ins and external devices, so-called Xciters. These are helpful tools, I reach for them myself, but one must be careful not to overdo it. Pop recordings usually go hard "forward" with it, because it gives a "kick" to the song, which performs better because of it when listening to it in the car or on inexpensive headphones. But in a good system - it tires listeners. Wandla with the new program showed this element in a deeper and smoother way, and thus better.

Against this backdrop, the convenience gained by adding a few new features may seem less exciting. After all, the new Ferrum DAC is better on its own. But the changes made possible by GoldenSound are cool and allow you to tune the sound of the device even more precisely.

IMPACT+ works gently, but indeed deepens the sound, especially at the very lowest part of the range. Vocals are stronger and bigger thanks to it, mainly through better three-dimensionality. I heard a positive change with both Shelly Mann's recording and Beyoncé's, so the effect is not dependent on the type of music. And when the sound has a very low extension, as in the track Sam Spade, taken from the Monsieur Spade soundtrack, composed by CARLOS RAFAEL RIVERA, it's even better. Everything then starts to gain momentum.

Equally subtle, but important in the long run, is the TUBE MODE function’s influence on the sound. In its case, however, acceptance of the changes will depend on the system and our taste. Adding distortion does add a warm tincture, but it also slightly blurs the contours of the sounds. The upper treble is warmer and withdrawn with it, and the attack is slightly softened. If the system plays too "forward", you may like it. The sound will then be a bit more substantial and lower. However, if the sound is well-balanced, then it may be better to leave this function in the "off" position.

The last of the proposed features, that is SPATIAL ENHANCEMENT, seems to me to be designed for headphone users. While listening to music through speakers I didn't notice any significant change. On the other hand, with headphones - aaa, it's a different story. It turns out to be one of the best systems for expanding the stereo base I've heard.

This function is not a simple crossfade circuit. Instead of mixing left and right channel signals together, instead of delaying them, etc., it does something I would expect from headphone listening. So it "notices" the panorama, i.e. adds weight to the edges of space. Again, the difference may not be large, but once heard, it is impossible to forget. With the function on, the sound is deeper, wider and more three-dimensional - which is exactly what it should be and what the makers of the DAC promised us. Without it, the sound is shallower and sort of duller.

With headphones, we also appreciate more the impact of the two earlier features, most notably Tube Mode. While listening through speakers in my system it didn't give me a clear "yes" or "no" answer, the headphones have already made it clear that this is a nice addition. MADELEINE PEYROUX's voice from the new song Showman Dan, itself very "tube-like" and listened to through a tube Leben amplifier after all, was more three-dimensional and more palpable. And even the heavily sampled, compressed Hot Dad by the CARR benefited, as the sound was less flat with it and not so - this is a surprise - distorted by maximum compression.


THE PRIMARY AND MOST IMPORTANT CHANGE that I hear in the sound of the Ferrum Wandla DAC in the GoldenSound version is the deepening of the sound and saturation of it. And this is a change independent of added features. For this alone, it will be worth to upgrade the software of the device, as mentioned by Marcin Hamerla at the beginning of the review. But the add-ons themselves are nice, too, especially Impact+, and with headphones also Spatial Enhancement. The tube simulation worked nicely when using headphones, while through the speakers it took some clarity out of the sound. Fortunately, each of these features can be turned off.

The bottom line is that this is still one of the most interesting DACs on the market today. It sounds in an open, resolving way, which in the new version is better supported by the lower part of the range. It already sounded in a very "analog" way in the basic version, but now it goes even more strongly in that direction. Additional features deepen this effect, and as a whole it gives the impression of listening to seemingly the same product, but yet different. A better one.

Technical specifications (according to the manufacturer)

Digital outputs:
• AES/EBU – PCM up to 192 kHz, 24 bits, DoP 64,
• Toslink – PCM up to 96 kHz, 24 bits,
• RCA – PCM up to 192 kHz, 24 bits, DoP 64,
• USB-C – PCM up to 768 kHz, 32 bits, DSD 256
• ARC – PCM up to 196 kHz, 24 bits,
• I2S – PCM up to 768 kHz, 32 bits, DSD 256 (PS Audio compatible).

Analog output: RCA
Analog input Vmax: 9.5 V RMS (2 – 3.5 V RMS recommended)
Analog input imp: 47 kΩ
Output level, 1 kHz):
• XLR – 5 or 10 V RMS
• RCA – 2 or 4 V RMS
Frequency response: 10 Hz – 200 kHz (+/- 0.1 dB)
• DAC -121 dB (0.00009%); THD+N: -115 dB (unweighted)
• analog in -123 dB (2 V RM)
Dynamics: 127 dB
Output impedance: XLR – 44 Ω | RCA – 22 Ω

Power consumption: 10 W (idle), 15 W (max)
Dimensions: 217.5 x 206.5 x 50 mm (W x H x D; knobs, feet, sockets excluded)
Weight: 1.8 kg

THIS TEST HAS BEEN DESIGNED ACCORDING TO THE GUIDELINES adopted by the Association of International Audiophile Publications, an international audio press association concerned with ethical and professional standards in our industry, of which HIGH FIDELITY is a founding member. More about the association and its constituent titles → HERE.


Reference system 2022

1) Loudspeakers: HARBETH M40.1 |REVIEW|
2) Line preamplifier: AYON AUDIO Spheris III Linestage |REVIEW|
3) Super Audio CD Player: AYON AUDIO CD-35 HF Edition No. 01/50 |REVIEW|
4) Stands (loudspeakers): ACOUSTIC REVIVE (custom) |ABOUT|
5) Power amplifier: SOULUTION 710
6) Loudspeaker filter: SPEC REAL-SOUND PROCESSOR RSP-AZ9EX (prototype) |REVIEW|
7) Hi-Fi rack: FINITE ELEMENTE Pagode Edition |ABOUT|


Analog interconnect SACD Player - Line preamplifier: SILTECH Triple Crown (1 m) |ABOUT|
Analog interconnect Line preamplifier - Power amplifier: ACOUSTIC REVIVE RCA-1.0 Absolute-FM (1 m) |REVIEW|
Speaker cable: SILTECH Triple Crown (2.5 m) |ABOUT|

AC Power

Power cable | Mains Power Distribution Block - SACD Player: SILTECH Triple Crown
Power (2 m) |ARTICLE|
Power cable | Mains Power Distribution Block - Line preamplifier - ACOUSTIC REVIVE
Power Reference Triple-C (2 m) |REVIEW|
Power cable | Mains Power Distribution Block - Power amplifier - ACROLINK Mexcel 7N-PC9500 |ARTICLE|
Power cable | Power Receptacle - Mains Power Distribution Block: ACROLINK Mexcel 7N-PC9500 (2 m) |ARTICLE|
Power Receptacle: Acoustic Revive RTP-4eu ULTIMATE |REVIEW|
Anti-vibration platform under Acoustic Revive RTP-4eu ULTIMATE: Asura QUALITY RECOVERY SYSTEM Level 1 |REVIEW|
Power Supply Conditioner: Acoustic Revive RPC-1 |REVIEW|
Power Supply Conditioner: Acoustic Revive RAS-14 Triple-C |REVIEW|
Passive filter EMI/RFI: VERICTUM Block |REVIEW|


Speaker stands: ACOUSTIC REVIVE (custom)
Hi-Fi rack: FINITE ELEMENTE Pagode Edition |ABOUT|
Anti-vibration platforms: ACOUSTIC REVIVE RAF-48H |ARTICLE|

  • HARMONIX TU-666M "BeauTone" MILLION MAESTRO 20th Anniversary Edition |REVIEW|


Phono preamplifier: Phono cartridges: Tonearm (12"): Reed 3P |REVIEW|

Clamp: PATHE WINGS Titanium PW-Ti 770 | Limited Edition

Record mats:


Headphone amplifier: AYON AUDIO HA-3 |REVIEW|

Headphones: Headphone Cables: Forza AudioWorks NOIR HYBRID HPC