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Headphone amplifier + headphones

Erzetich Audio

Manufacturer: ERZETICH AUDIO
Price (in Poland):

Erzetich Audio | Blaž Erzetič s. p.
Voglarji 21 | SI-5252 Trnovo pri Gorici | Slovenia


Provided for test by: ERZETICH AUDIO

The ERZETICH AUDIO was founded in 2012 and specializes in designing headphone amplifiers, and lately also two models of headphones were added to the lineup. The owner is Blaž Erzetič. He studied electronics, but also worked as a designer, illustrator and photographer. He lectured at two Slovenian universities: the University of Arts and the University of Natural Sciences, and as a musician he released four albums. This time we review his top headphone system: DEIMOS amplifier and PHOBOS headphones.

he Deimos headphone amplifier and Phobos headphones are to top products of the Slovenian company ERZETICH AUDIO. They are complementary products despite the fact that Deimos was launched in 2014 – it debuted during High End Show in Munich – and the Phobos is a new addition to the lineup, the latter was actually developed with one goal in mind: to complement the top headphone system by this brand.

Deimos was a result of a reflection on the amplifier that we talked about in February 2013, meaning a relatively inexpensive, small model called Perfidus. Blaž Erzetič, the owner and main designer, calls this project POS, or "Perfidus on Steroids". In turn, the Phobos headphones are to some extent an extension of the Mania. Both designs look almost identical, however, they feature different types of membranes - Mania are dynamic headphones, and Phobos are magnetostatic ones.

Blaž Erzetič
Owner, designer

Blaž Erzetič during the Audio Video • Prague 2017, then with other brand’s headphones

"After making an amplifier called Perfidus I wanted to make a bigger one - even more detailed, but at the same time more balanced sound-wise. And I needed a name which is even more evil. Deimos sounded nice, since it was, in Greek mythology, a god of terror. At the same time Deimos had a twin brother Phobos, personification of fear. I knew at the very start that this amplifier will be coupled with something else, just not sure what with. After experimenting with headphones, I've seen that the model with the planar magnetic drivers was a great match, so I thought that this should be the right brother for Deimos - the Phobos."


Deimos is a really "big boy". This device looks like a mid-size integrated amplifier. The influence on such perception has a very large volume knob and an interesting, inclined body. If we take a look inside, it turns out that the power supply is larger than in many integrated amplifiers - there are three toroidal transformers, one for the control logic circuit and two for each amplifier channels, as well as a multitude of filtering capacitors with a total capacity of 43,000 μF .

Its front was made of artificially aged wood, which in small quantities could be found in some of this manufacturer’s amplifiers, but which only truly shines in his headphones. An unusual way of indicating the volume level caught my eye. The basic one is a small hollow in the knob. But next to it, there is a row of white LEDs. While turning the knob we can hear a quiet clicking inside - apparently a discrete attenuator, featuring a resistor ladder switched in relays - and we can also see a LED after LED lighting up, from left to right.

This is a high power amplifier whose output - unbalanced (unfortunately) - can be adapted to the headphones of user’s choice by changing the gain. The second switch allows user to select an active source - it's a balanced circuit, so we have XLR and RCA inputs. And there is also a switch that turns on the power. The figure in the instruction manual shows that there is another switch on the back panel, which disconnects ground from the housing, but it was not there in the tested unit. The explanation may be that for the test I received the first working unit of Deimos, which belongs to Blaž and possibly the switch was added later.

The Deimos amplification stage is based on integrated circuits in the input section and transistors in the output. This is a dual-mono Class A design. In the input there is a resistor-based attenuator with 64 steps controlled by digital logic circuit - the latter is powered using a separate power supply. As it reads in company materials, the amplifier is to be characterized by "natural, wide sound with a quick attack". The buyer receives a 5-year warranty for his unit.


From the start the Phobos headphones were designed as a partner for the Deimos amplifier - one of the headlines on the manufacturer's website says it directly: "Long lost brother of Deimos". And because the headphone amplifier in question is a typical product of this manufacturer and it is not cheap, the headphones designed for it had to be special. So Blaž reached for the technique, which for several years has been at the forefront of the pack, the magnetostatic diaphragms.

What does it mean magnetostatic? | We write about them regularly, because almost all important brands today have at least some models in their lineups. Magnetostatic designs are also called orthodynamic or planar ones. Their design is similar to what we know from Magneplanar magnetostatic loudspeakers. Normally headphones feature conical or domed shape membranes, powered by magnets - a design almost identical to the one of dynamic loudspeakers.

The magnetostatic headphones feature a large, flat membrane with a conductive path sprayed on it; the diaphragm is stretched in a magnetic field created by permanent magnets, also known as stators. The magnets must have a shape that does not disturb the air flow. However, their impact can not be completely eliminated, so it is important how a given company manages to find an optimal shape for them. For example, the main upgrades in Audeze's lineup consist precisely of the improvements of their profiling.

Most such designs utilize magnets on both sides of the coil, which guarantees an even magnetic field strength in both directions of the diaphragm movement (e.g. Audeze headphones). The problem is, however, that the diaphragm on the ear’s inside is to some extent shaded by the magnetic system. In order to eliminate this issue some companies - for example HiFiMAN - decided to place magnets on one side only. In turn, the disadvantages of such a solution are: the need to use stronger magnets, as well as the asymmetric propagation of air on both sides, and thus, the formation of distortions.


The first magnetostatic headphones were designed by Rank Radio International Ltd, under the direction of Oliver Hille. They carried the company's name Isodynamic, and users called them ID1. They were introduced to the market in 1972 and cost about 20 British pounds, which was quite reasonable. A year later they received the prestigious Design Council Award.

Although they sounded great and looked equally good, they had a serious - for those times - issue: very low efficiency. At 120 ohms they needed a dozen or so watts to show what they could do. As it turned out, the market was not prepared for it, and although similar attempts were made along the way - like the aforementioned Yamaha designs or more modern Fostex TR50RP - such products have never gained much popularity.

The name "isodynamic" did not survive. You could probably hear a different name: "orthodynamic". Its roots are Greek words "orthos" ("right", "proper", "correct", "compatible") and "dynamikós" ("possessing strength"). The name "orthodynamic" was created in 1976 by the Yamaha and was the marketing name of specific headphones. With time, however, it migrated and today it defines a whole group of products.

It’s a similar story to that of Xerox, whose name now means a photocopying machine, Velcro, or Tannoy, which in the UK is used for public address (PA) systems.

Other term rarely used is still the "isodynamics" ("equal strength"). The next term used for HiFiMAN, Audeze, Oppo and other headphones is: "planar". "Planar" means "flat". And it is probably the best description of this type of design included the reviewed model. Each of these terms tries to describe their design.

The Phobos is a planar design. The membrane was purchased from one of the specialists, but Blaž does not disclose which one. We only know that it is a construction with magnets on both sides of the membrane. Their mechanical design is identical to the Mania model. These are over-the-ear headphones, an open design, with a separate element that keeps the headphones on the head and a headband. Their cups are made by hand from aged wood, and the back is covered with a metal plate with slits cut into it.

One plugs the mini-XLRs connectors from the lower side. These are exactly the same as used by Audeze. They are delivered with a two-meter long, shielded cable made of silver-plated copper wires, terminated with a 6.3 mm jack plug. It is not particularly flexible, so one might considering replacing it with some higher quality, more comfortable to use after-market cable - I use cables from a Polish company Forza AudioWorks Noir HPC Mk2.

The mechanical design of the Erzetich Audio headphones is symmetrical, so it does not matter where the front and back are, which is the left channel and which is the right one - we make the choice by connecting the cable one way or the other. They are quite heavy, but also quite comfortable to wear.

The Deimos headphone amplifier and the Phobos headphones were mainly assessed as a system with the Ayon Audio CD-35 Hf Edition SACD source, via the unbalanced RCA output. Separate sessions, however, I spent listening with the Lumïn T player as a source via the XLR output. The amplifier was compared to our two reference amplifiers - Ayon Audio HE-3 (tube) and Bakoon HPA-21 (solid-state, battery powered). In turn, the headphones were compared to three other models: HiFiMAN HE-1000 v2 (magnetostatic), AKG K701 and Sennheiser HD800 (both dynamic); HiFiMAN and Sennheiser utilized Forza AudioWorks cables. The amplifier was powered using the Acoustic Revive Absolute-Power Cord.

ERZETICH AUDIO in „High Fidelity”
  • TEST: Erzetich Audio MANIA (+ headphone amplifier BACILLUS) | headphones
  • TEST: Erzetich Audio PERFIDUS | headphone amplifier

  • Recordings used for the test (a selec- tion)

    • Al Jarreau, All I Got, GRP ‎065 082-2/SUDL 003630, Test Press SACD/CD (2002)
    • Chet Baker, Baker’s Holiday, Verve Records B0003279-16/SUHD 009960, Test Press SACD (1965/2004)
    • Fisz Emade, Dwa ognie, ART2 Music/Tidal, FLAC 16/44,1, SP (2019)
    • Kortez, Mój dom, Jazzboy/Tidal, FLAC 16/44,1 (2017)
    • Kraftwerk, 3-D The Catalogue, KlingKlang | Parlophone 95873424, 7 x CD (2017)
    • Megadeth, Countdown to Extinction, Capitol/Mobile Fidelity Sound Lab, UDCD 765, gold-CD (1992/2006)
    • Neu!, Neu! ‘75, Brain Records/P-Vine Records PCD-93529, CD (1975/2012).
    • Rain Tree Crow, Rain Tree Crow, Virgin/Virgin Japan VJCP-688775, „80’s Paper Sleeve Series”, CD (1991/2008)
    • Rival Sons, Feral Roots, Low Country Sound | Elektra/Tidal, FLAC 16/44,1 (2019)
    • Steely Dan, Gaucho, MCA Record 0602498605103/SUSS 003100, Test Press SACD/CD (1980/2003)

    | Deimos

    There is this expectation, that the more expensive products of a given company will sound like its cheaper devices, only "more". Such expectations are valid. Big manufacturers of consumer electronics design whole lines of products from the beginning to the end, using some solution or circuit as a base for all of them, and later developing them towards an even better sound in more expensive models, or trying to keep as much of the original sound as possible despite price reduction for cheaper models.

    The more expensive models utilize more and more advanced circuits, better components, more robust mechanical construction, richer functionality and, as a result, they offer a better performance. Most often they include some of aforementioned improvements, very rarely all of them at once. But once accepted assumptions (restrictions) are applied throughout the whole series. Such homogeneity is crucial for them, because only then the "series" as such makes sense.

    However, this is not an ironclad rule, that is, not always a lineup forms a series. What can be easily traced by listening to Perfidus and Deimos amps. The tested headphone amplifier does not sound like - for example - Perfidus and Bacillius - and in turn the tested headphones sound to a great extent like the Mania model. It represent this Slovenian company’s completely different approach to the topic.

    Deimos delivers an open, incredibly even open sound This applies to various aspects of its performance - from tone (of course), through space (also clear), to energy distribution (which is not so obvious). This device shows the band’s extremes in a precise, well differentiated, powerful way. Even the Bakoon HPA-21, an amplifier with extremely transparent sound, does not show them in such an authoritative and clear way. Ayon Audio HE-3 plays equally strong at the bottom, extends equally low, but its top is smoother, slightly rolled off at the very top. Deimos presents both of them in an unbelievably honest way, that is pure and clear.

    It is not about excessive use of a "contour". Not even for a moment did I feel that the extremes of the band are emphasized, but rather that Deimos finally showed them in all their extent, that it had no problems with bass extension, with delivering enough power, or with the subtlety of trebles, ie with resolution. Listening to it using dynamic headphones, warm ones, warmer than HiFiMANs - that is, Sennheisers HD800 and AKG K701 - confirmed it quickly.

    Both these models had a lower center of gravity than HE-1000 V2, but generally sounded - paradoxically! - lighter. They could not reproduce bass tones in such a precise and authoritative way as the planar headphones did. In turn their tops were still nice, pure (maybe the purest these cans ever presented), but they were clearly in the back, because the most important part of the band was the midrange.

    But Deimos does not really „promote” this part of the range. It simply let all the headphones I paired it with, to sound in their own way, gave them a voice, so to speak. Yes, it modified the whole presentation in its own way, but these were modifications covered by the "voice" of specific headphones. Amplifier developed by Blaž Erzetič's does not emphasize midrange, it's not the case, in which it is a complete opposite of the Bacillus model. It distributes sound energy to the entire band, giving each sub-range equal dose of it.

    So I am talking about a very neutral and - let me emphasize - open sound. Do not expect, however, that the amplifier will deliver a velvety sound, or that it will show a large volume of vocals and instruments from the middle of the band projected on the listening axis. It will rather withdraw them, it will align their size with what is comes form the sides. I must admit that I wished for some more saturation of the midrange and its lowering. However, it was, of course, a projection of my own expectations, not an issue with Deimos.

    It, in addition to the good tonal balance, guarantees a unique space presentation. It does not even need special recording for it, such as binaural recording of a piano by Zenph or live Kraftwerk recording from the 3-D processed using the Dolby Headphone. Regular tracks played from Tidal were enough to present its abilities in this regards, as, for example, from a very good, new album by Rival Sons or songs from Drake's album. There was a very low bass (Drake) and spatial guitar (Rival Sons). Such space requires a slight emphasizes in the upper midrange and lower treble area, which the reviewed amplifier delivered.

    | Phobos

    Deimos and Perfidus are two different, in my opinion, amplifiers, although they share the same technical solutions. In turn, Phobos and Mania are headphones cut from the same "piece" of cloth, and yet their designs are fundamentally different. And some claim that audio is predictable or boring!

    The top Erzetich Audio headphones have a characteristic tonal balance - characteristic for this company’s products. If we associate the planar membranes with a bright sound, then we need to think it over again - that's how electrostatic headphones sometimes sound like, but the magnetostatic ones rarely do. It is quite the opposite, some of such cans sound warm, present a rolled off treble, let it be Audeze with their LCD-3 model, or Oppo with PM-3. Phobos is another example of this type.

    Their sound is focused around the lower midrange and upper bass. This is where the most is happening, and that's where the tonal gravity of these cans draws our attention. The top is always present, but rather like in tube amplifiers based on EL34 - it complements the midrange, it acts as sort of a spice for the „main course”. One of the consequences of such a type of presentation is that it gets calmer. We sit comfortably with them - and the surprising (for the size) comfort they provide also helps - in a chair, we close our eyes and let the music lead us wherever it wants. And it does not matter if we listen to Kortez from the Mój dom, Fisz Emade duet from the Dwa ognie single, introducing the Radar album, or even to the powerful guitars of the Rival Sons.

    I think that we are dealing here with an opposite situation to that with the amplifier. Namely, there is a powerful midrange, and the extremes are slightly hidden behind. But although it is like I say, it is not forced, but very natural. You have to know, however, that it is performance far away from the so-called "correctness". Apart from the powerful lower midrange/upper bass area, there is a lot of the whole midrange too. Its upper part is calmed down and smoothed. With highly compressed recordings like those from the Depeche Mode Fragile Tension / Hole To Feed maxi-single, it makes the sound a bit harder, more "square".


    The top Erzetich Audio products clearly have their "own" sonic signature which is more obvious with the headphones. The Deimos amplifier sounds fast and direct and offers enormous dynamics. It is open and neutral. This is probably the most transparent product of this company, although even here one can notice a desire to slightly ease the attack, to deliver everything in a pleasant way.

    The Phobos headphones are much more distinctive. Although they feature a planar design, they sound warm, low, with a rolled off treble (at least they create such an impression). Their presentation is focused primarily on the middle of the band, in which they resemble the cheaper Mania model. They are more resolving and faster, but at the same time a bit less tonally balanced.

    Both, the amplifier and headphones are so characteristic that you can fall in love with them from the very first moment or equally fast decide: "never again!". Let me encourage you to listen to it yourself - with this amplifier and headphones you will also get a small piece of a great man, Blaž Erzetič.

    Technical specification (according to the manufacturer)

    | Deimos
    Headphone impedance: 8-600 Ω 
    Frequency range: 4 Hz-40 kHz (-1 dB) 
    Power consumption: 15 W
    Dimensions (W x H x D): 320 x 125 x 330 mm
    Weight: 6.4 kg

    | Phobos
    Nominal impedance: 45 Ω
    Driver: planar magnetic
    Design: open
    Weight: 690 g


    Reference system 2018

    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