Around the fall of 2019, I took a drive north to Deja Vu Audio located in a suburb of DC to take a look at their inventory of Harbeth loudspeakers. Unbeknown to me at the time, Deja Vu is a dealer for the Synthesis brand of audio products, a company based in Morrovalle, Italy. While I saw and heard many fine products at the Deja Vu store, my strongest memory is of my encounter with the Synthesis amps Vu was using at the time to drive both Harbeths and Audio Note speakers in his various demo rooms. I was very pleasantly surprised by what I heard that day, and I made a mental note to track down a Synthesis amp to bring home and try in my system.

Synthesis was founded in the late 1990s by Luigi Lorenzon. Specializing in tube amplification, the company is known for its hand-built audio components that aim to blend modern technology with the classic warmth associated with tube amplifiers. Synthesis products, including amplifiers, preamplifiers, and integrated systems, are crafted with a focus on achieving fidelity and emotion in music reproduction. Here’s a link to the Synthesis website.

Synthesis Roma Integrated amp

Synthesis Roma Integrated amp – Image Courtesy of Synthesis at

It took three years, but I finally achieved my goal of acquiring a Synthesis amp – the Action A100 Titan integrated. While I always try hard to support dealers, my approach to sustaining both my hobby and this website makes it challenging to pay full retail prices for products. To fuel my enthusiasm for experiencing new gear and creating content for this website, I strategically acquire equipment by exploring used items on platforms like USAudiomart or Audiogon, occasionally checking Craigslist, and frequently taking advantage of dealer trade-in inventory. The latter method is how I came to possess the Synthesis Titan.

I bought the A100 Titan from Tim at Carytown Sound in Richmond, a nice one-owner example, complete with remote and manual but sans box. Handling the unit wasn’t easy with its bulky shape, 88 lb mass, and uneven weight distribution. As I’m awaiting spinal surgery at the year’s end I’m not supposed to lift anything heavier than an empty paper bag, but needs dictate and exceptions must be made. So I wrestled the amp onto a temporary platform sitting between the speakers in my main rig and set about improvising some longer cables to run between the Holo Audio May KTE DAC and the new integrated amp. I’m setup primarily for a separate pre/power arrangement running XLRs between the preamp located off to the side of my listening room and monoblock power amps located between the speakers. So I have long cable runs, but they’re of the balanced variety and not RCAs. For now, I’m having to use Cardas adapters until I can source a couple of long RCA runs, hopefully from Bob at Iconoclast, as they make the best audio cables I’ve owned.

Now, the Synthesis A100 Titan actually has an inbuilt DAC, but at the time of writing this, I haven’t gotten around to trying it. I wouldn’t expect it to outperform the Holo Audio May that I use as my reference (December edit – now the dCS Rossini Player / Master Clock), but I will eventually get around to trying it and I’ll include comments in my final review.

Synthesis Action A100Titan 100W Integrated Stereo Tube Amplifier review

Synthesis Action A100 Titan Integrated Amplifier Specs and Features

  • Power Output:
    • The A100 Titan provides a minimum of 200 watts (100W per channel), power output from 8, KT66’s in Ultra-Linear (UL) – push/pull operation.
  • Custom Output Transformer:
    • The A100 Titan, like its larger counterpart, features a newly designed custom output transformer resulting in a rich sound stage with an authority that belies its 100W.
  • Features:
    • USB & S/PDIF Input:
      • Onboard 24Bit 192KHz Wolfson DAC is included.
    • DC Powered Tube Heater:
      • All input tubes have DC stabilized heater circuits to reduce hum noise to a near in-audible minimum.
    • Output Transformer:
      • The output transformer uses Hi-Grade Iron-Silicon for superb frequency reproduction & bandwidth. The newly designed custom output transformer unique to the A100 Titan achieves highly delicate & precise sound reproduction faithful to the original recording.
    • Mechanical Chassis Construction:
      • The power supply & output transformers are held by an extremely rigid “H” structure that keeps the unit free from unwanted vibrations, further helping to reduce unwanted vibration energy getting to the tubes.
    • Remote Control:
      • Featuring a CNC machined case with a soft button design, perfectly matching the aesthetics for the “ACTION” series.
    • Feet:
      • Four CNC machined aluminum feet with an insert of natural rubber. The depth & form of these rubber feet are calculated to minimize vibrations of the amplifier in isolation from its surroundings.
    • Binding Posts:
      • Gold-plated professional binding posts for a continued oxidization-free connection that further improves sound refinement.
    • Sockets:
      • Gold-plated ceramic sockets for a continued oxidization-free connection that further improves sound refinement.
    • Components:
      • Components for the A100 Titan have been selected with great care throughout. Only the best available components are considered, and all must undergo an exhaustive analysis of their sonic influence prior to final selection.
  • POWER STAGE (1 CH.) 4 X KT66
  • INPUT STAGE (1 CH.) 1 X 12AX7/ECC83
  • DRIVER STAGE (1 CH.) 1 X 12BH7
  • INPUT IMPEDANCE 50KOhm / 75 Ohm (S/PDIF)
  • OUTPUT TAP 6 Ohm
  • CONFIGURATION Push-Pull Ultra linear 43% tap
  • POWER OUTPUT (1 CH., THD < 1%) 100W RMS @ 6 Ohm
  • FREQUENCY RESPONSE from 20Hz to 20KHz ± 0.5dB
  • DISTORTION 1% @ 1KHz (Max Power)
  • S/N RATIO >90dB “A” weighted
  • INPUTS 4 line inputs / 1 S/PDIF input / 1 USB input
  • D/A CONVERTER – 2 X WM8740, dual mono configuration, 192KHz oversampling
  • S/PDIF FORMAT – PCM 32-192KHz, 16-24 bit
  • USB INTERFACE – PCM 16bit 48KHz, standard audio device, no driver required
  • OUTPUTS – Pre out (variable level)
  • BIAS SETTING – Manual adjustment, independent for each power tube
  • DIMENSIONS (W,D,H) – 410x503x235mm
  • WEIGHT – 40Kg
  • LINE POWER – 117, 230, 245 Vac 50/60 Hz (see rear label)

It’s great to have comprehensive specs and the above are courtesy of the Synthesis web page here.

Synthesis Action A100 tube integrated amp review

There are several different integrated amp models in the Synthesis range and 3 in the Action series. The three Action amplifiers share a consistent design, featuring a full-width heavy-duty metal chassis. The front is dominated by a sizable central volume dial, breaking up a silver strip housing the model name and power button on one side, while the other side accommodates status lights and buttons for inputs. Atop this structure, a removable vented cage conceals and safeguards the tube complement of 8 KT66s and the 2+2 input/driver tubes.

On the rear panel, you’ll find four line inputs and a (variable) pre-out which is handy for subwoofers, along with S/PDIF and USB ports. The analog connections are exclusively unbalanced RCAs, as Synthesis only supports balanced sources on its Metropolis hardware and Roma pre/power system. Each input is labeled with nomenclature also replicated on the front panel input switches.

The Synthesis A100 Titan’s SPDIF/coaxial connection supports PCM files up to 192kHz/24-bit, while the USB input is limited to 44.1/48kHz/16-bit. The A100 Titan employs a Wolfson WM8740 DAC chip. Those invested in computer audio-based file servers or streaming devices optimized for USB might be disappointed to see the USB limited to 44.1/48/16 bit, which is a little archaic by today’s standards. My take on the DAC feature is that it’s very much convenience-based and present only to help new users of the amp get their system up and running quickly with minimum fuss. Those of us more heavily invested in our systems will likely use external DACs with enhanced feature lists and likely superior sound quality. The A100 Titan justifies the best possible equipment pairings, as I’ll get to in a moment.

Synthesis A100 tube integrated amp review


Sound Quality – Classic Or Modern Tube Sound?

Classic. Without a shadow of a doubt, I can confidently affirm that the overarching sonic character of this Synthesis amplifier is deeply entrenched in the classic tube amp style synonymous with the CJ sound of the 80s. My recollection takes me back to three years ago when I first encountered two distinct models of Synthesis Integrated amps at Deja Vu Audio. It was precisely this characteristic that intrigued me the most, and fueled my desire to explore more from the brand. You see, I’m of the opinion that if you want a tube amp, then buy an amp that sounds like a bloody tube amp! I get that products are measured against benchmarks like neutrality and transparency, but that’s not what tubes are all about – or shouldn’t be, IMHO. If I’m putting up with the cost and hassles of tube ownership then it’s because I want something that solid-state amps cannot give me – I want that classic tube sound. I want a big, bold, lush, warm, and full-sounding musical presentation that excels through the midrange and particularly so on vocals. I don’t want a wishy-washy thin sound that claims ‘neutrality’ ahead of musical enjoyment. I know, I can sense you shifting uncomfortably in your seat and reaching for your copy of ‘How To Be A Card Carrying Audiophile‘.

Get with the program folks – listening to music on tube amplifiers versus solid-state amplifiers should present a unique sonic experience, with its own set of virtues peculiar to tubes. Tube amps voiced in the classic way deliver a warm and smooth sound and contribute to a richer, more textured audio experience. The harmonics produced by tubes add a natural, euphonic quality to the music, enhancing the overall listening enjoyment. (This analog warmth is often attributed to the way tubes handle distortion, providing a more forgiving and pleasing character to the sound.)

Synthesis Action A100Titan 100W Integrated Stereo Tube Amplifier review

So yes, the Synthesis A100 Titan proudly embraces its identity as a tube amp. Flicking through my arsenal of customary test tracks, which efficiently provide 98% of the information I seek about a product’s sound in just 25% of the time, it’s quickly evident that this amplifier produces a substantial, expansive, and layered soundstage, with holographic images that come with a delightful richness in tone and with ample color saturation, showcasing the distinctive qualities that only tube amps can offer.

Of course, I wouldn’t praise the performance of a tube amp unless it excelled in the crucial midrange, and the A100 Titan certainly does. When listening to Margo Timmins, the lead vocalist of the Canadian alternative country and folk rock band Cowboy Junkies, her ethereal vocals on the opening track of Trinity Sessions evoke a spine-tingling presence, as if she were standing right there in the room before my eyes.

Duke Ellington’s ‘Blues in Orbit’ takes on a distinctive sound, revealing the tube amplifier’s impact on the tonality of the instruments. In the title track, JimmyEllington-Blues-in-Orbit Hamilton blows the soulful intro to “Three J’s Blues,” on tenor sax, leading to a conversation created between Ellington’s piano and the sax where the A100 Titan adds a slightly warm resonance to the sax and a weightier presence to the piano, enhancing the overall textures of both.

Moving through the album, the A100 Titan’s influence becomes apparent in tracks like “Villes Ville Is the Place, Man,” where it handles the dynamic interplay of instruments with precision. The bracing, beat-driven jaunt of this composition, featuring solos by Ray Nance, Harry Carney, and Johnny Hodges on trumpet, baritone sax, and alto, respectively, reflects the tube amp’s ability to preserve the authenticity of each instrument’s sound while adding just a sprinkle of its own warm character. Yes, I’m talking here about tube colorations, and the Synthesis A100 Titan is guilty as charged. But in its defense, it uses only a gentle touch to add a subtle layer of warmth to Ellington’s classic jazz masterpiece, highlighting the brilliance of each instrument and spotlighting timbre and tonality in a fairly truthful but extremely pleasing way.

The A100’s bass is a little on the tubby side, but natural to the acoustic unamplified instrument’s true tone and timbre. It’s also quite full and powerful in the low end, it isn’t rolled off as is often the unfortunate consequence of running tubes into a 4-ohm demanding speaker like my ProAc D40R. The top-end is a little reticent. I sense it doesn’t quite peel back the layers of the onion in quite the same way as my Hybrid Veloce Saetta monoblocks. There isn’t quite the same degree of air and sparkle on the top end, and I sense that the shimmer of cymbals and some of the spatial cues from an acoustic venue are a little less present in the soundscape than they can be. But being a little less forward on the top end isn’t uncommon for a push-pull tube amp design and I find its presentation overall to be very pleasing and non-fatiguing and I’m rarely conscious of there being anything much actually missing up top.

So overall, I really do like this beast of an integrated amp. Its big, bold, and warm-side-of-neutral presentation is exactly the kick I want from my tube cocktail and I can forgive the minor sin of omission on the detail front, where my Veloce amps do have it beat.

A fantastic buy at around $11K new and an even better buy on the used market if you have the good fortune of finding one.

CAH – 11/23

Additional Notes 19/2/2024:

I mentioned in the above a mid-review switch away from the Holo Audio May KTE DAC to a new dCS Rossini DAC/Player with the Master Clock. Most of my dCS Rossini Player / DAC / Master Clocknotes used in the above review were made before adding the Rossini to my system, hence little was said about the Rossini with Synthesis A100 Titan Combo. So let’s fix that:

Some of you might think my system to be a little lop-sided, running the rather expensive Rossini DAC/Player/Clock into a relatively inexpensive integrated amp. The only way to prove or disprove that assertion would be to use the Synthesis Titan and then switch to something far more expensive (like my resident pre/power combo from Veloce Audio, retailing around $36K when new), to see if the Synthesis amp is somehow ‘withholding’ some of the potential from the Rossini. I haven’t been able to do that yet, due to having had surgery 2023 year-end which has left me unable to lift anything heavy for a while. What I can say, unequivocally, is that the Rossini Player/DAC/Clock and Synthesis A100 Titan sound absolutely wonderful, and a significant step up from the Synthesis Titan with Holo Audio May DAC combo.

The Holo Audio May is an excellent DAC that has a rich and layered sound – almost tube-like in its presentation when run in NOS mode. But it has a warmth to its sound, a little midrange coloration, and a little top-end reticence that becomes more noticeable when the unit is paired with a tube amp. Add to this my ProAc D40R speakers, which run a little on the warmer side of neutral, and the three components when coupled together deliver a level of warmth that might be too much for some. Switching to the Rossini, which I would describe loosely as ‘dead neutral’, and the coupling together of the three components unveils a real synergy to the sound. Gone is any notion that the Synthesis might be a little reticent on the top end and guilty of obfuscating some detail.

I’ll post an update when I’m able to switch in the Veloce amps to do a more indepth comparison with the Synthesis amp. But at this stage, my respect for the A100 Titan has only increased and I stand by a wholehearted recommendation of this excellent integrated amp from Italy.

System Used For This Review: