darTZeel CTH-8550 MKII integrated Amplifier-review!

The updated darTZeel CTH-8550 MKII integrated amplifier is intricately explored by Howard Milstein

As the adage goes “You can’t teach an old dog new tricks” To this I would personally and adamantly say, totally true! There is no doubt about it. However, in the case of this high-end audio hobby of ours, once in a while new tricks and surprises, can be learned (as this ‘old horse’ recently found out) as they can quite unexpectedly, be plowed down in front of your face. Indeed, sometimes they can be more startling than one may ever realize!

Many of us who review new audio equipment are in a privileged position. (Which I am overtly grateful for!). We are given the freedom to evaluate in a given time period some of the newest and foremost components available to audiophiles and music lovers. But, don’t be fooled – this is hard work; harder than anyone may realize!

Such was the case with my experience with the darTZeel CTH-8550 MKII  integrated amplifier. I was graciously allowed to unveil my ears to this integrated amplifier by distributor Jonathan Tinn of Blue Light Audio in Portland Oregon.

The designer of the darTZeel amplifiers, Mr.Hervé Delétraz is considered to be a man who is overtly passionate about musical reproduction. I now bring you some quotes and most intriguing ideas as stated by Mr. Deletraz:

“One of the things that I’m trying to push with my amplifiers is musicality. I don’t care about the price tag; if a specific audio component cannot convey music with its natural emotions, then it simply fails…… “When people ask me how I do make my components sound this way, it is always very difficult to answer. Simply because I do not know! And as I do not know, I generally say that I put a tiny bit of my soul in every machine. This is not ”not immodesty, but only the closest way I could describe my lifetime devotion into music reproduction.”

There might be lots of approaches to this, but few have so far succeeded”

Mr. Delétraz also suggests that his designs are quite independent of being Class-A, AB, D, or even tubes; believing that one of the main reasons a design has a particular sonic signature depends more on the designer himself than the operating class or technology being used. However, he does admit there are some basic differences, quite obviously, that cannot be denied.

Today, I would dare say that darTZeel amplifiers are somewhat renowned worldwide. As for the few uncompromising audiophiles that have heard this profound amplifier, many have come to recognize it as one of, if not the world’s best high-end amplifier currently being produced today. The unit is a conquering hero that produces a subjective sound quality that “gloats” in reproducing the dynamic range, detail, subtlety, and the most natural musical harmonics and sound fundamentals that may be contained within a great recording or “live feed” concert performance.

Not inconsequentially, Hervé Delétraz refers to his amplifiers as instruments. I must say quite adamantly that after having spent a month (that went by much too fast) listening to the CTH-8550 MKII integrated amplifier, I can completely understand why.

Essentially, I discovered that these attributes of the darTZeel CT-8550 MKII amplifier contain characteristics that bring a listener’s sonic perception to the most soaring comparable quality to many live, simply miked concert CD-r rips, or recorded CD’s, and streaming experiences I may have had when used with the appropriate system components in my listening room! This also applies to its analog vinyl phono reproduction capabilities as well. These are by no means, easy words to say, yet the feeling you get while listening to this amplifier do its work is always quite beguiling!

MKII UPDATES from the CT-8550

Some years back, when darTZeel developed and launched the CTH-8550 in 2008, it started to become one of the most acclaimed (if highly-priced) integrated amplifiers available to the most discriminating users. One could call it a true “analog military machine” as it combined the ultimate virtues of a preamplifier and a power amplifier, in a single housing. (darTZeel does make separate pre and power amplifiers as well – but at an even higher-priced combination. (See further down).

During the upgrade process about 10 years later, darTZeel thought, (as is customary with emphatic engineers), it appropriate to do a bit of modernization for this exquisite and best-selling amplifier. The designer, still thinking the CTH-8550 was close to perfection from a design point of view, reconsidered that rather than starting from scratch, it would be better to revisit this wonderful “instrument” (which is no understatement), and made a few of the following improvements. Rather than starting from scratch, they revisited this wonderful CLASS A/B, DUAL MONO integrated amplifier and systematically changed a few of its essentials. These are important changes, so read on:

1. A new folded sheet metal case of 2.5mm thick aluminum was exchanged instead of the original steel chassis. In today’s times, aluminum is much more suitable for the rejection of radio waves (RFI), such as those of cell phones or Wi-Fi. The phono stages are thus much less disturbed by RFI or radio broadcast.

2. The circuits of the MC phono inputs are of current source amplification topology, as was already the case on the CTH-8550 in 2008, (and this long before some manufacturers recently claim theirs to be the first). Now, an additional gain of 6 dB was added to better marry with cartridges whose output level is less than 0.3 mV. The result displays even more dynamics than before, with truly uncompromisingly blacker backgrounds.

3.The overall power supply has been improved to power the audio cards differently through dual rectifying circuits, thus further reducing external freeloading noise. Looking a bit more intricately, the CTH-8550 MKII was built with scrupulously matched, resistors, transistors, caps, circuit boards, and cabling which is controlled by its two separate toroidal power transformers; one enormously huge one takes care of the 8550’s output stages while the other, smaller one does the work for the pre-amp stage.
(I must not fail to mention that the revised CTH-8550 MKII has one of the most fantastic, solidly beautiful though maybe a bit gaudy, remote controls I have ever had the pleasure of using.).

The darTZeel engineers believe that comprehensively, the CTH-8550 MKII is quite a superior product as compared to the original CTH-8550 in terms of audio reproduction qualities and expect it to be produced at least through this coming decade. I cannot comment, never having had the pleasure of auditioning the CTH-8550 in my listening room. As such, the forthcoming evaluation began as a journey with some unexpected consequences!!

The rear panel represents an artisan’s approach to an efficient design. This includes seven standard inputs, (RCA and XLR, and, the Zeel 50 Ohm BNCs), truly excellent speaker terminals (4mm banana or spade), as well as RCA and darT outputs. A couple of USB ports, of compact but proficient size, rounds out its exemplary back panel.

Mr. Delétraz believes this should contribute to better sound reproduction in just about every department. Although the MK1 to MK2 upgrade is not currently available at the moment, darTZeel Audio might offer a partial upgrade in the very near future.


I will acknowledge that initially, it was a bit difficult to get my thoughts together for this review of the darTZeel CTH-8550 MKII integrated amplifier. Did you ever hook up a piece of equipment to your system, start to play it and then silently say to yourself, holy-sh_ t; – there is something out of the ordinary going on here? In this hobby, this type of occurrence is few and far between. In fact, after about a few days of listening to this unit, I came to realize that the darTZeel is virtually, a perfect amplifier!

The darTZeel produces music that is indescribably beautiful, exact, nimble, and subtle to the ears, dynamically extraordinary, and incredibly profound. It also is so filled with such musical “correctness’ that one can’t help to sit and listen to music with a feeling of such satisfaction as its sound permeates through your senses without barely…. any type of limitations!

Yes, the beautiful, expensive gold front panel, the metalwork, and the hefty build are a sight to behold, however, it is its eminently superlative reproduction of some of the finest program sources that never fails to thrill you in countless ways.

Massed strings, solo violins, voices, double basses, horns, and full orchestra–whatever the instruments or its tonality may demonstrate, the CTH-8550 MKII brings forth an overall sense of reality and pleasure of the recording venue- be it live and/or studio that never fails to make you just shake your head in wonderment and a bit of disbelief. I have only recently experienced this on a “few” such amplifiers!

Considering its outstanding, dual-mono power supplies and the innate amount of pure power this unit exhibits, the darTZeel CTH-8550 MKII yields nothing in the way it makes music emanate from your preferred loudspeakers into your listening room. This amplifier brings forth to the listener a level of emotion, low level to large scale dynamics tonality as well as the utmost musical precision and satisfaction that is rarely found in components today.

Operationally, you could not ask for a simpler, yet more highly sophisticated design in a solid-state class A/B amplifier. The darTZeel CTH-6550 MKII seems to make you forget about which source components, DAC, or cables you have connected to it. Should I dare say that if you are a tube enthusiast and have not heard this unit, it will ultimately make you forget about the “legendary” tube vs. solid-state debate once and for all!  It bridges all the conceived notions and gaps that may have once occupied your mind as such.

One need not constantly switch, compare and/or evaluate other products you may have on hand during the listening sessions. Indeed, I just sat for hours trying out old and newer program sources that kept on producing a sound that was stunning and barely short of amazing!

The CTH-8550 MKII stereo imaging was illuminating and quite revelatory, with incomparable stereo image locational effects locked into its dimensional space- and arguably, the best I have ever heard! The soundstage images never wavered- particularly the most critical central images…. hopefully, if your associated components are up to the job!

The program sources that were further employed and listed below were mostly live and studio-recorded classical, operatic, and acoustical pop that was engineered with a quality of reproduction that blatantly brought forth in each recording an unrelenting congruity of an artist and/or concert hall perspective, along with decadent ambiance depth, detail and a live natural tonality of instruments and their acoustics. There was barely anything that I played with this amplifier that failed to amaze me and satisfy my mindset as to the accuracy and beauty of the music is portrayed.

Almost every program source, be it analog or digital, expertly engineered or just finely recorded musical performances excelled in a way that makes the most ardent music lover just swim in an uncompromising display of musical delight. In this reviewers’ opinion, I can unquestionably make a good case in declaring the darTZeel one of the two or 3 greatest amplifiers on the planet.

Here are a sample of the program sources used for this evaluation:

Bernard HerrmannThe Bride Wore Black, OST revised audio *** Bernard Herrmann -McNeely – Fahrenheit 451- Man in grey flannel suit– Ghost and Mrs. Muir  *** Bernard Herrmann: Amazing Piano recording and film score suites with piano- Piano Hangover square/citizen Kane *** Handel: Water music – Nicholas Mcgegan *** Sinatra “In The Wee Small Hours” remastered vinyl *** Maria João Pires ~ MOZART PIANO CONCERTO # 17 / NHK Symphony MP3 ~ WAV container MY VIDEO UPLOAD *** Carlos Kleiber- Beethoven Symphonies 4 & 7 ~ PCM DVD RECORDING *** Paul Simon Graceland 25th anniversary edition *** Carlos Kleiber Beethoven – Berlin Philharmonic, Symphonies 5 & 7 ~ The Magnificent Seven/ Sederes/ ULTIMATE original re-recording~


Yes– and without basically any limitations, The CTH-8550 MKII permeates recorded music with all its atmospheric qualities. Its precision, inimitable sound beauty, detail, tonality, and pure refinement of reproduced sound make it a component that you will not fail to remember forever in your mind. Essentially, this type of performance removes the need to describe in any detail its sound within any particular area of the frequency spectrum!

Be that as it may, the darTZeel seems to bring forth a feeling that this is what the sound of reproduced music should always be like in your (decently)-tuned listening room. Of course, it goes without saying that equipment such as this should ideally be matched with the highest quality loudspeakers and associated equipment (see below) meticulously installed down to the smallest details.

The amplifier manages to establish a full-size surge of musical dynamism -that being the variation in loudness between notes being one of its most special virtues. It has a huge, 3 dimensional open sound while still maintaining the most absolute stereo locational effects of the program sources it displays. On the other hand, in some instances, it divulges those recordings that can be degenerately manipulative. (I cannot decline to mention this in many of my reviews because it is so blatantly obvious and self-evident). Nevertheless, this is an amplifier that can initiate and reproduce a remarkable scope of the music and sound that emanates before you.

Recognizing the above, the darTZeel in most cases will bring many audiophiles to a supreme state of musical heaven.! It simply is an amplifier that begs you to keep listening to the music of your choice, forgetting everything else going on, while only having to reach for another piece of source material to continue on the fantastic voyage.

It may be worth noting in more detail that darTZeel makes a separate pre and power amp of the CT-8550 MKII. I had mentioned in my previous review of the Naim Supernait 3 that in some instances, there is a supreme benefit to using an integrated amplifier of the highest quality as compared to separates from a particular manufacturer. However, (while not having auditioned the darTZeel separates), instances like this, contrary to most “Melophiles” thinking, could prove the former more true than previously thought.


In summation, and according to its designer, the CTH-8550 MKII is deemed a superior product as compared to the CTH-8550 in terms of its ultimate audio reproduction qualities, and so the stated goal by Mr. Hervé  Delétraz appears to have been achieved.

As all of us enthusiasts well know, high-performance audio is a hobby. Nothing more or less. Indeed, and as preached and shown here in the Sound Advocatemany manufacturers’ products offer outstandingly great-sounding components at budget-conscious prices or, contrarily, as in the case of the darTZeel CTH-8550 MKII, a product that could be out of the price range of even some of the most dedicated and determined audiophile and music enthusiasts. Many people often refer to the cost of the CT-8550 MKII which currently retails at about $32,000 (USD). Undoubtedly, this is quite a huge sum of money.

On the other hand, usually, (though not necessarily), better build quality and internal components used will add up to superior sound quality. These are typically the two basic things a consumer will receive when you spend more money on audio equipment. There are always going to be gems that perform better than their price suggests, but even then, there’s always going to be another manufacturer’s product that may infinitely surpass those, most likely for more money.

Most importantly, once you explore products that are above the mass production stage, the cost will rise exponentially as the production runs get smaller, and more boutique manufacturers start to emerge. For better or worse, the more expensive products tend to accentuate the personal preferences of a named designer, rather than objective scientific measurements.

Ultimately, because everyone’s economic circumstances are different, as is our disposable income, spending habits, and personal preferences, not everyone will be able to afford the darTZeel CT-8550 MKII integrated amplifier, yours truly, as a prime example!

However, based on this unit’s incredibly accurate, magnificently awe-inspiring, and outreaching musical integrity when played on my home system, not to mention its superlative build quality, I must say that I am completely intoxicated by it!!

Eventually, the question concerning the darTZeel CT-8550 MKII may not be “can you afford one– but sooner or later, when will you be able to purchase one?” I am still anxiously waiting!

Review Equipment used: Loudspeakers: Spendor SP1 ~ Audio Note UK AN/ED ~ Quad ESL-63 ~ Living Voice R25A anniversary loudspeakers Digital:Border Patrol DAC SE-i ~  Innuos Zenith Mk.3 server/streamer ~ Wyred4Sound 10th Anniversary DAC ~ Audio Note (UK) CD3.1x/2 ~ Analog : SOTA comet 5 and Dynavector high output moving coil cartridge.~ Amplification: PS Audio M1200 ~ Pass Labs XP-12/XA-30.8 amplifiers ~ Audio Note UK I-Zero integrated amplifier Cables / Conditioners: Inakustik AC-3500p power station & LS-4004 speaker cables, AC-2404 reference Air Power Cord ~ Silversmith Audio ‘Fidelium’ loudspeaker cables ~ Wireworld Silver Eclipse 8 bi-wired speaker cables ~ Wireworld Silver Eclipse 8 interconnects & Electra 7 power cords/ Audio Art 1 e” AC Power Cord.

darTZeel CTH-8550 MKII ~~ $32,000 USD.

Type: Dual mono integrated amplifier Power Output: 200 watts RMS (230 watts
peak) @ 8 ohms
330 watts RMS (360 watts peak) @ 4 ohms
Inputs: 4× RCA, 1× XLR, 2× Zeel BNC, 1× MM, 1× MC (phono inputs are optional)
Outputs: 1× RCA, 1× RCA (a record), 1× darT BNC, 1 pair speaker (4mm or spade)
Frequency Response: 3Hz–300 kHz THD: 1% from 7 Hz to 77 kHz
S/N: 115dB (A)
Dimensions: 170 × 440 × 335mm
Depth with handles – 415mm Weight: 28kg

USA distributor:

Jonathan Tinn
Blue Light Audio
(503) 868-0500

darTZeel Audio SA   https://dartzeel.com/

2 chemin Louis-Hubert
1213 Petit-Lancy / Geneva


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6 thoughts on “darTZeel CTH-8550 MKII integrated Amplifier-review!”

  1. You need to try a Kora TB400 that is less than half the price of the Dartzeel and sounds even better ! One of the best at any price !

    • Hi Rick:
      The Kora is not widely known here in North America (or anywhere for that matter) . Reading Mr.Lavorgna’s review of the 75 watt amp, it seems quite promising!
      I may contact the American distributor for a sample (kora-200).
      The DarTZeel is extraordinary but a bit overpriced. On the other hand, my upcoming review of the Pass XA 30.8 (and XP-12) at the moment is definitely meeting up to the DarTZeel in almost every way!!

  2. Só me resta ler essa belíssima análise desse super AMPLIFIER. Nem direito de sonhar eu tenho, mas fico feliz se alguém puder desfrutar de tal produto. Parabéns a todos envolvidos nesse projeto.

  3. (RE: darTZeel CTH-8550 MKII ‘Review’)

    Howard: A “review” of such any integrated-amplifier (let alone such a ridiculously priced one) must ultimately be compared to models from competing manufacturers. I suspect half of this models price is courtesy of its fanciful chassis/aesthetics. Without drawing comparisons -if nothing else but to serve as a reference- a review as this offers no value/insight for those considering such an expense. Lest we forget that $32/$40K (USD/CAD) can purchase a superb pre/linestage and power (mono) amplifer/s. In fact, if shopping wisely, one can pretty much purchase an entire system (source-cables-amp-to-speakers) for that kind of outlay.

    pete jasz

    • Hi Peter:
      Thanks for your fine comment. I originally intended to do as such. However,my last in house integrated was the supernait…..and at such an extraordinarily different price point, I decided to decline comparisons.
      However, I have 2 more integrated amplifiers on hand that I will be reviewing and indeed— there will be comparisons included with the darTZeel coming up. In fact, I will also include the Supernait 3 as well!
      Your comment is well taken!

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