Monarchy Audio SE-250 mono block amplifier H2O Audio Signature 100 stereo amplifier An Amplifier Comparison

An Amplifier Comparison: Monarchy Audio SE-250 mono block amplifier VS H2O Audio Signature 100 stereo amplifier

The following review is designed to simultaneously evaluate two components that use vastly different circuit to pologies. This is an effort to showcase their respective strengths, weaknesses and where they fit into the market. Please note that this article is not a shootout. There will be no winner at the end of the review.


H2O AUDIO Signature 100 stereo amplifier

Henry Ho, the man behind H2O Audio, first hit the scene a number of years ago with a small armament of bulletproof amplifiers built around the popular Bang and Olufsen ICE module. Despite the company’s small size, H2O quickly gained a small underground following that has remained strong, even during the period when the one-man operation lay mostly stagnant. Henry, now back into the saddle, is ready to kick start 2008 with his new amp; the Signature 100.

H2O AUDIO Signature 100 stereo amplifier review

Most affordable class D amplifiers use cheap switching power supplies, cheap parts, and come housed in a variety of cute boxes that weigh less than an electric pencil sharpener. The Signature 100 by sharp contrast – is a 50 pound true dual mono stereo amplifier that uses two 25 watt power supplies at the input stage, and two 500 watt toroidal transformers at the output stage. Housed in its aluminum casing are four massive capacitors that give you a whopping 200,000uf of capacitance per channel. That’s 400,000uf Total! Until now, you’d have to shell out a lot more cash to get this kind of horsepower.

Although Henry believes this build is necessary to gain all the benefits ICE has to offer, what initially lead him towards this topology was its capability of rendering accurate pitch definition, detail, resolution, control, and dynamics all without sacrificing that oh so open ended term; musicality. The Signature 100 was designed to embody all the sonic advantages from the B&O A250 ICE module while maintaining the benefits native to the circuit topology; exceptional power efficiency. This efficiency translates into cool operation that guarantees stable operation and a life span that extends well beyond most traditional amplifiers.

MONARCHY AUDIO SE 250 mono block amplifiers

Monarchy Audio, founded by Mr. Poon in 1979, brings nearly 30 years of industry experience to the table. Few know that Monarchy Audio initially started off as a distributor, importing Luxman kits from Osaka, Japan. Throughout the 1980’s, Monarchy Audio also exported goods to Asia, representing legendary companies such as Spica, Eminent Technology, Threshold, Sound Labs, and Now Hear This (NHT). It wasn’t until the early 90’s when Mr. Poon began to steer his company towards the manufacturing business. To get things kickstarted, Andrew Hefley, of Ampzilla fame, aided Mr. Poon in designing Monarchy Audio’s very first amplifier, the SE-100. The original SE-100 embodied the virtues that would later become the trademark sound of Monarchy Audio amplifiers; a warm and lush presentation that is akin to a good tube amplifier.

MONARCHY AUDIO SE 250 mono block amplifier part

The SE-250 mono block amplifiers were built to deliver serious muscle without giving up that tube love. To accomplish this, Mr. Poon developed a hybrid circuit which uses a single tube of the 6DJ8/6922/ECC88 variety at the input stage, and Hitachi mosfets at the output stage. The entire circuit is free of any feedback. Combined with a massive 850w toroidal transformer, Mr. Poon feels this topology gives his amplifiers exceptional dynamic range. To extract that last bit of warmth and blossom, the first 50 watts are biased for class A operation.

It is important to note that I never swapped tubes during my stint with the SE-250 mono blocks. I ended up sticking with the Jan Phillips 5814A that was installed in my review sample. This is not the stock tubs sold with the SE-250, which is usually a military grade 6DJ8 tube.

It is also important to note the price discrepancy between the two amplifiers. Even though a set of Monarchy SE-250’s retail for over twice the price of the H2O Signature 100, Monarchy Audio offers these amplifiers at a significantly discounted price when ordered direct. Give Monarchy Audio a call to get a quote. You’ll find that this comparison, although still a bit disproportionate, is fairly matched.

Specification Comparison

amplifiers inside

SpecsMSRP: H2O Signature 100$2000.00 USD Monarchy SE250$5000.00 USD
Warranty: 5 years 1 year-Transferable
Configuration: Dual mono stereo Mono block
Architecture: ICE power Hybrid tube/mosfet
RMS Current Delivery (into 8 ohms) 100wpc 250wpc
Maximum Power Consumption 110w 800w
Total Storage Capacitance: 400,000uf 32,800uf
Damping Factor (at 1 khz) 1600 100 – varied
Input Impedance: 100k ohms 100k Ohms
Input Sensitivity: 2V RMS 2.5V RMS
Unit Weight: 50lbs 45lbs each
Dimension: 13.5 x 6 x15 12.5 x5 x16

System Configuration

  • Room Size: 9ft D x 8ft D x 12ft L
  • Acoustic Treatment: Heavy wood furniture / GIK Acoustic 242 panels
  • Source: Arcam Diva 62 / E-MU 1212M
  • Pre Amplifier: Ayre K-5Xe / H2O FIRE
  • Speakers: Totem Acoustic Forest / Totem Acoustic Sttaf
  • Speaker Cables: Totem Acoustic Tres bi-wire
  • Interconnects: Totem Acoustic Sinew
  • Power Cables: Zu Cable Birth / Blue Circle BC-62

The Break Down

We’ve now arrived to the meat and potatoes of this comparison. In an effort this a painless read that is easy to understand, I’ve broken down the aspects of performance into specific categories. This should make the reading quick and informative.

Build / Ergonomics

H2O Signature 100: The H2O Signature looks like you’re a-typical power amplifier. It wasn’t designed to capture admiration from friends and family stopping by. It’s a plain, very heavy very sturdy machined aluminum box. In a few of the pictures you will see that my sample unit, en all black, has a solid top plate. Henry informed me that the production version will feature a much lighter vented top. The corners of the amplifier will also be rounded to give it more aesthetic appeal. In my opinion, it looks mucho better-o than my review sample.

amplifiers at room

Ergonomically speaking, I have just one major nitpick; the location of the power switch which is placed on the rear of the amp. Because of the Signature 100’s size, reaching around the back to switch the thing on/off gets a bit tiresome. In some rack configurations, this could be a deal killer. Further aggravating the situation is the requirement to shut the Signature 100 off before any other components in the chain whenever it’s time to power-down the system.

On the plus side; this amplifier runs stone cold even under high output levels. Ventilation is not a concern – saving you precious space and energy.

Monarchy SE-250: I was pleasantly surprised by just how well built and attractive the SE-250’s were. The slightly elevated horizontal heat sinks give the SE-250 a very sleek and modern look. This is accented by a hefty front panel, which is a machined 1” thick piece of aluminum. The front panel is lapped and polished by the same outfit that polished the Hubble telescope. A special coating is then applied on the surface, resulting in an incredibly smooth feel. Apparently, there are benefits to living near Silicone Valley. One thing’s for sure, I couldn’t keep my hands off of these amps when they were in the rig. Sooo smoooooth…

With a solid build and handsome look, the Monarchy SE-250’s were also very easy to operate. The power switch, which had a dim red glow when powered on, was located on the front panel for easy access. In fact, my only complaint has to do with the binding posts, which are unable to properly accommodate spade connections. As you’d expect from any amplifier that houses a tube and is biased for class A output – these things run HOT. The SE-250’s will need lots of ventilation for safe operation

General Character

H2O Signature 100: Summarizing the character of the Signature 100 can be done with a few simple words; delicate, powerful, dynamic, refined, and transparent. The Signature 100 represents a few firsts for me. It is the first affordable high power amplifier I’ve encountered that sounds as delicate and as resolute as a component that utilizes a short signal path. It is also one of the first transistor amplifiers I’ve come across that has managed to focus my attention away from those glass valve thingy’s. Unlike most amplifiers that impart an obvious flavor to every selection of the music, the H2O’s incredibly neutral presentation allows every component and recording to stand on their own merit.

H2O Signature 100

Monarchy SE-250: In direct contrast, the Monarchy SE-250 manifests a very rich, warm, and lush tone. These are high power amps with very distinct color. The SE-250 is not the most resolute amp on the market, nor does it sport the best coherency or definition at the frequency extremes. What it does do however, is create a very inviting sound that manages to fuse all the attributes audiophiles pine for in a high current package.

Sound Staging / Imaging

H2O Signature 100: One of the more salient attributes of the Signature 100 is its incredibly silent back-round. I feel it nearly matches the vaunted Red Wine Audio Signature 30 in this regard. A lack of back-round noise not only translates into exceptional detail, it also aids in giving all aspects of your music a greater sense of space along with very precise instrument/vocal placement across the soundstage. With the H2O in place, the soundstage projected well into the room that brought you much closer to the performance. There was nothing ‘mid-hall’ about it.

It is clear that the H2O amp was superior at projecting sound out into the room. Instruments jumped from the speakers when called upon to do so. Brass had bite. Drums slammed with gusto. Guitars pulsated with life. Not just a whiz-bang amp, the H2O also mastered the other end of the spectrum; producing a layered soundstage that gives the music insight in what reviewers call, the ‘lit from within’ effect. At no point did I ever feel any aspect of the soundstage to be blown out of proportion. It was never too wide, nor too forward. It was never too laid back or closed in. It simply reproduced whatever it was fed.

Monarchy SE-250: Although the SE-250 is unable to match the H2O’s ability to project into a room, it did not lag too far behind in terms of sound-stage width. The left/right channel separation was as good as I’ve heard from any conventional amplifier. The SE-250’s simply preferred take on a more laid-back approach – keeping the soundstage closer to the loudspeaker itself.

While not as clear or as distinct as the H2O, the Monarchy’s main asset is palpability. Vocals and acoustics were more convincing in terms of dimension and body. This was particularly noticeable when playing small jazz ensembles.

Detail / Resolution

H2O Signature 100: If detail and resolution are paramount to you, than the Signature 100 may be your huckleberry. This is not the kind of amp that ‘shouts’ subtle nuances to you. Instead, it renders detail that is so clear and natural that it’ll have you scratching your head wondering if some detail was ever meant to be subtle in the first place.

This is especially true when matched with the H2O “Fire” pre amplifier. The Signature 100 also passed my low-level listening tests with flying colors. Even at whisper-volumes, everything retained great presence and tone. From opera to rock and roll – I never had to turn up the volume to enjoy all the detail a disc had to offer. Sometimes though, you can have too much of a good thing. I found that the H2O made no effort to band aide poor recordings.

Monarchy SE-250: If I had auditioned the SE-250 without having heard the H2O Signature 100, I’d likely be riffing on about how much resolution is packed in this 250wpc powerhouse. Indeed, there is more than enough detail to keep most of us mere mortals, and even most audiophiles, pretty content.

Monarchy SE-250

In fact, there was never a time when I felt like I was missing any content. If I did, all I had to do was turn up the volume and it would all be there. What was there sounded very natural. Never once did I feel overloaded with resolution. This was very welcome for those long term listening sessions.


H2O Signature 100: What do you get when you take an efficient topology, a huge power supply, and a massive reservoir of capacitance and put them together? Incredible dynamic range – that’s what. Even though the H2O is rated at a common 100wpc, it is able to pound out dynamic shifts with a sense of effortlessness that make a few 200-300w amps I’ve ran sound like tinker-toys. This level of dynamic prowess brought on a whole new sense of scale and emotion to Tchaikovsky’s 1812 Overture, as played by Erich Kunzel and the Cincinnati Pops Orchestra. The same can be said for any type of music that benefits from muscle.

Monarchy SE-250: Far from being dynamically limited, the SE-250 was also very adept at handling large dynamic swings. Never once could I make these amps sound strained. However, despite having the 150watt advantage per channel, they still could not equal the H2O in terms of scale and force.

The Highs

H2O Signature 100: The H2O speaks precisely and clearly. There are no romantic over-tones that attach themselves to each note. Guitars zip and bite. Snares attack with instant sharpness and decay. Like most ICE powered units, the Signature 100 has a cool top end. Yet unlike most ICE powered units I’ve come across, it has a ‘liquid’ quality to the highs, something that I feel helps prevent the amp from living on the hyper-detail side of town. This quality is a welcome departure from what I’ve come to expect from ICE power. Long listening sessions were not only possible, they were also quite enjoyable.

Monarchy SE-250: The SE-250 has an ever so slightly rolled off top end, a character that I feel lends itself to a much wider variety of recordings. Although it does sacrifice a bit of extension and resolution, this slightly topped off treble lets you get back to enjoying a plethora of music out there that was never given the audiophile treatment during the recording and mixing process. While some discs are beyond help (think: Linkin Park’s, Meteora), the SE-250’s allowed me to sit back and enjoy a whole lot more music. These are the kind of amps that will have you cranking up the volume.

The Mids

H2O Signature 100: Open, clean and free of artifacts with excellent detail and separation – the H2O amp may have the most neutral midrange presentation I’ve encountered. That being said, it is important to note that no piece of hi-fi is truly neutral. The H2O’s tendency to project sound well into the room gives it a slightly forward character. Whatever the recording has to offer – that’s exactly what you get. It doesn’t get any more straightforward than that.

H2O Signature 100 and Monarchy SE-250

Monarchy SE-250: As you would expect from any component with a piece of glass in it, the mid-range is the SE-250’s greatest asset. Although it is not as clean and clear as the H2O, its blossom and rich tone gives the music a more palpable feel. Vocals are outright haunting. Acoustic instruments resonate throughout the room with a more natural sense of tone. This is the very first muscle amp I’ve encountered that has that oh so delicious midrange that is usually exclusive to smaller, pure valve components.

The Bass

H2O Signature 100: One of the biggest advantages of ICE power is its ability to deliver prestigious amounts of clean, controlled, and detailed bass. The Signature 100 exemplified this strength in spades; allowing bass to flow with effortless slam and extension. The amps grip on the woofers never allowed for any over-hang and lagged decay. Instead, it showcased the energy of the recording with first rate precision – reproducing complex bass lines with absolute ease.

Monarchy SE-250: Once again, the Monarchy takes on a different tact. True to character, the SE-250 sacrifices ultra precision and detail in favor for a richer, warmer perspective. Distinctly colored and notably slower than the H2O, the Monarchy’s pleasantly plump presentation helped to give the low end more heft and body. Appealing though as this character can be, this amp may not be the best choice for those who need something with an irongrip.


H2O Signature 100: Pardon my boldness, but I know of no muscle amplifier at this price point that offers this type of build quality, sophistication, neutrality, and top to bottom performance. The Signature 100 is a transparent amplifier that is chalk full of clarity, dynamics, air, and control – all wrapped up in a package that is unfailingly musical. I know of many products that aim to compete in this range. All I can say is; they’re going to have to try like hell to beat the Signature 100.

Monarchy SE-250: The Monarchy SE-250’s romantic flavor and delightful presentation made for many hours of enjoyable listening sessions. Once the music began to play, I found it pretty difficult to leave the comfort of my chair. This is not the amp for someone caught in the high resolution rat race. Instead, this is for the audiophile that is ready to settle down for the long haul. Considering what Mr. Poon actually sells these units for, they are an exceptional value. If you are an audiophile / music lover that wants that tube love in a high power package, these should be put on your short list. Highly recommended!


All too often, audiophiles get caught up in what stripes to wear, be it the tube versus solid state crowd, the ribbon versus dynamic cones and domes crowd, and so on. My time with the H2O Signature 100 and the Monarchy SE-250 further reinforced my own belief that not only can vastly different perspectives yield brilliant results, but that they can also have an equal appeal to the listener. During my time with the amps, I never found my preference to sway in one particular direction. What I ended up listening to was more influenced by my mood and the music that I wanted to hear. Both the H2O Signature 100 and the Monarchy SE-250 amps are exceptional products that give regular folk a real-world alternative. My hat goes off to both Henry Ho and Mr. Poon for creating two high performance products that are within reach of the common man. Take a bow gentlemen, you’ve earned it.

from affordableaudio,  By Sean Fowler