Calyx Femti Amplifier

The Calyx Femti is a dimunitive power amplifier that is a visual match for the 24/192 DAC. It's aluminium unibody chassis is finished in black with an artistic rendition of a G and F clef engraved on the top cover.

The rear panel is quite cramped and includes two pairs of high quality binding posts, a set of single ended inputs and a rotary selector switch to operate the Femti as a normal stereo power amplifier, a dual output mono amplifier (for a biwired speaker), and a bridged mode mono amplifier. Very much like the Femto DAC, the power switch for the Femti is discreetly located on the side (right hand side vs. left hand side for the Femto). An IEC outlet permits use of after-market power cords.

The Femti delivers 125 watts per channel into 4 ohm loads (and presumably half of that into 8 ohm loads), and 500 watts in bridged mode operation. A tricolour LED indicates normal operation, short circuit, and overload conditions. Not much information is provided about the technology used in the Femti, but I would not be surprised that this amplifier is powered by a B&O ICEPower module - I recall seeing the three LED indicators in a technical manual for ICEPower modules.

A close-up view of the offending binding posts - spade users beware

Ergonomically, I dislike two things about the Femti. The first are the binding posts which are shrouded. A downward facing slot allows insertion of spades from the bottom, but this is generally impossible with large gauge or stiff speaker cables. Eventually, I had to either evaluate the Femti with its chassis all the way at the rear edge of the rack (to allow the cables to trail downwards), or with the Femti elevated by tall footers to provide necessary clearance for the cables. This could have been easily solved by having the slots face upwards.

The second issue I have is the rotary selector switch. This can be easily rotated by accident (especially when you are busy trying to manipulate cabling at the rear), and could damage the amplifier if this is done while the amplifier is in operation. A recessed switch would have been more appropriate.

This unit is on dealer loan and I was quite worried about its initial performance. It was passed to me with about 50-75 hours under its belt. While it was pleasing, it also had a laidback and smooth character which tended to obscure low level detail.

I ran it continuously for an additional 48 hours, powering my KEF LS50 speakers with a burn-in signal. The chassis became slightly warm after extended use, and could probably be left powered, for long periods of time.

I paired the Femti with my Conrad Johnson ET-3SE or Sun Audio SVC-500 tube preamps, or drove it directly from my Antelope Zodiac Gold DAC. The Antelope has a relay controlled resistor network to adjust output levels. I was pleasantly surprised to hear the Femti essentially take on the character of its upstream partnering equipments. Both the Conrad Johnson and Sun Audio offered a fuller and more liquid perspective, while I felt that the Zodiac Gold connected directly to the Femti, offered the highest degree of resolution.

The Femti proved to be quite sensitive to power cords too. Pairing the Femti with an Oyaide Tunami terminated with Oyaide P/C-046 plugs resulted in a rather flat and bland presentation. A switch to a Nanotec Golden Strada 305 terminated with Oyaide P/C-004 was pleasing, but harmonically too sweet and polished. The Femti was eventually matched with an Acrolink 6N-4030 terminated with Furutech FI-28(R) connectors.

The Femti was very comfortable driving my Focal Diablo Utopia and KEF LS50 speakers. However, the match with my Thiel CS2.7 was less than ideal, with a noticeably strain and loss of control at louder volumes. I would keep the pairing to more sympathetic loads.

Detractors of Class D amplifiers should listen to the Femti. Tested blind, I doubt that they would even be able to correctly identify the Femti as a Class D amplifier.

Sonically, the Femti is quite neutral. It avoids the one-note bass I have heard from some early ICEPower models, while retaining excellent bass control. My LS50 especially appreciated the tightness and extension afforded by the Femti.

Midrange is smooth with a slight hint of creamy richness. Female vocalists are portrayed with a richer and less sibilant presentation. This slightly laidback quality provided for fatigue free listening, and a tendency to flatter poorer recordings. However, on the downside, some low level detail such as the texture and vibrato from singers such as Kit Chan is not as prominent.

The top end is extended and well-behaved. Percussion instruments are crisp and clear, with good strike and decay from cymbal strikes.

The Femti projects a wide soundstage, with above average depth.

Compared to my Conrad Johnson duo, the Femti did not project as deep a soundstage, nor render acoustic space as well. However, the Femti had the edge over my glassware in bass control, background blackness, and instrument separation.

To sum it up, the Femti is a competent performer in a compact package. Much of its performance depends on how you will handle volume control duties. I think this leaves the Femti in a rather awkward position. Much of its competition are able to offer at the Femti's price point, similar functionality and volume control in one package. However, I still think the Femti is worth a listen provided you are able to accept it's ergonomic short comings, and carefully plan your system.

A word of thanks to Audio Basic for their loan of the review unit.

Audio Basic

1 Coleman Street
#04-27, The Adelphi
Singapore 179803
Tel : +65 6338 3245
E-mail : audiobasic_sg@yahoo.com.sg

Calyx Femto DAC

Introduction

The Calyx Femto is the latest DAC from Digital & Analogue, the wonderful Korean company that brought us the 24/192 DAC and the Coffee DAC and headamp.

I loved my 24/192 DAC, but wished it had more inputs. The Femto is obviously the answer to that and much more. Based on the ESS Sabre 9018 DAC chip, the Femto is a full sized component  with all the inputs that you could ask for.

At a price multiple of the 24/192, the Femto has to deliver much more to earn its share of the Audiophile wallet.

Features

The Femto is a massively chunky and heavy unit. You need to personally lift it to feel its 18.5 kg weight and massive solid aluminum panels. Somehow, pictures do not convey the true size of the unit - it is much bigger than it looks. Measure your rack space carefully before purchasing !

Of particular interest are its feet, which are lined with cork, and its power button, which is discreetly located on the left hand side of the unit. I seldom switch off my digital equipment, and relocating the power button from the front panel leaves the fascia of the Femto looking clean, sleek and uncluttered.

The Femto is beautiful, elegant and sophisticated in a very understated way. With matching beauty and brains, my Femto would be ideal marriage material if she were human (I’ve decided my Femto is female).

Lest I forget, the matching remote control is also finished from solid aluminum, and has sufficient weight to cause serious damage to intruders. I wonder sometimes whether Calyx has some secret deal with an aluminium mining company and/or a CNC factory, because they are certainly liberal in their use of material.

As suggested by its name, the Femto’s main feature is its super accurate clock that has its accuracy measured in femtoseconds. A femtosecond is one quadrillionth, or one millionth of one billionth of a second. Mathematics was never my forte, so I will leave you to ponder exactly how miniscule that is.

Instead of a single Sabre 9018 chip as used in the 24/192, the Femto uses twin 9018 chips. The Femto also gains two onboard linear power supplies that separately power the digital and analogue sections of the Femto. In comparison, the 24/192 relies on either the 5V supply from the source’s USB bus (never a good idea!), or a switched mode wall wart. Calyx must have realised that, since the 24/192 now ships with an in-house designed linear power supply as standard.

The Femto has enough digital inputs to cater for almost every need. Twin inputs are provided for coaxial ,optical and AES/EBU, while a sole BNC input is also provided. Computer audiophiles are taken care off by a single USB input which accepts signals up to 24/192 resolution and sampling rate.

The front panel buttons manipulate a digital volume control, phase inversion and digital filter settings (which actually sets the low pass filter at 50, 60 or 70 kHz - 50 kHz was used throughout my listening sessions).

On the output side, both single ended and balanced outputs are provided.

The front display thoughtfully displays all relevant information, such as the input selected, sampling rate (a very important and often overlooked function), volume and polarity.

First Impressions

Unboxing the Femto was a pleasure. The double boxed packaging and accompanying foam lining are sturdy enough to withstand serious punishment and can be re-used a number of times without too much issue.

The manual is a bit sparse though, with no explanation of the digital filter settings, as well as obvious errors, such as reference to installing drivers on the supplied CD-ROM (which could not be found after some frantic searching). In any event, Mac users do not need to install any.

The Femto needs plenty of run-in. Out of the box, it sounded decent enough, although a bit lacking in bass authority. On the top end, it also sounded a bit dry.

Detailed Impressions

After about 100 hours under its belt, the Femto was put through its paces. Both its USB and BNC inputs were used, with the computer audio source being a 2011 Mac Mini (with 8 GB of RAM) running Pure Music 1.84. Traditional disc spinning duties were tasked to my Cary CD-500. The Cary’s upsampling feature is sent through its digital output, so this feature was disabled to eliminate unnecessary variables.

I noticed that the 24/192 truly shines through its USB input, with its coaxial input a distant second. In respect of the Femto, this is still the case, although the gap in performance is less. No need to make excuses for SPDIF performance here.

Coming from the 24/192, the differences are immediately discernible. After extended listening, and time for the brain and ears to become comfortable and process the information, it is obvious that the Femto is not a case of a DAC cut from the same cloth of its sibling, but is altogether a different animal.

The first thing that grabs you is the precision of soundstage, and the acoustic reverberation surrounding each instrument and voice. The depth and height of the soundstage are exceptional. The Femto excels in both microdetail and dynamics. Its focus and grip are never lost, and the finest touches are clearly discernible even during busy mixes.

The tonal balance of the Femto would be best described as slightly sweet, with a solid bass foundation. It can also be said to be “brilliant” sounding, with a certain shine and airiness in the upper frequencies. I would not consider it to be bright, but the Femto would never be described as dull sounding ! Subjectively, the Femto gives the impression of having no constraints at either end of the frequency spectrum, with an open and unforced quality.

Low frequencies are well controlled and extended. In terms of slam, the Femto shows you its pedigree compared to the 24/192 with more authority, bloom and warmth in the bass. 

In conveying the human voice, the Femto continues in the family mould, with both detail and the right amount of sweetness and warmth.

In my system, the high frequencies were incredibly extended, and the combination with the inverted beryllium dome tweeter in my Focal speakers were clean and free from strain and harshness.

I believe that any further comparisons between the 24/192 and the Femto would be meaningless. The 24/192 should not be treated as a Femto-lite at a lower price. Both units are in totally different classes, and a side-by-side audition should not be made between the two, unless you are willing to commit to the budget required for the Femto.

The Femto, despite its sheer amount of micro detail, cleverly sounds natural at all times and is fatigue free. I felt that it was able to put recordings in their best light, and not be constrained by the quality of the recording. That being said, it is by no means veiled – give it a well recorded high resolution file, and it simply shines !

I like to listen to jazz , classical music and vocal works. The Femto is especially suited for my music taste. Two artists that I am particular fond of, are Patricia Barber and the late Eva Cassidy.

Patricia Barber's performance of Santana's Black Magic Woman (from her album - Companion) is electrifying and hair raising. The intricacy of the drum and electric guitar work, especially the solo parts are laid out with great transparency and energy. Eva Cassidy's recording of her live performance at the Blues Alley is one of my favourite albums and never fails to move me emotionally.I am happy to report that the Femto sounds incredible with both, from a technical and artistic viewpoint. 

As clichéd as it may sound, the Femto allowed me to rediscover my music collection. Simply put, the Femto makes recordings sound real and lifelike. The immediately emotional response is not about the usual hi-fi superlatives, but more the feeling of being at the recording venue, immersed in the music.

Conclusion

I was somewhat apprehensive that the move from the 24/192 to the Femto would bring only marginal improvements. After all, we are all familiar with the law of diminishing returns – and the 24/192 already brings so much to the table. A short session at the dealer with a side-by-side comparison was sufficient for me to take the plunge.

It was a pleasant surprise, that the Femto would bring such a substantial improvement to my system. I would generally be hesitant to describe a product of this price as a bargain, but the Femto truly is one.

So far, in my hi-fi journey, I’ve had two breakthrough moments. 

The first was my acquisition of my Focal Micro Utopia Be – it changed my idea of the limits of dynamic driver performance, especially in respect of its tweeter performance. 

The second was the basic room treatment done to my listening room – it made me realize the strong influence of the room, and its importance relative to the equipment sitting in the rack. 

You may put down the Femto as my third  – an elevation of source quality to unimagined heights.

I cannot speak of how the Femto compares to other high-end players in the digital space, but do check out the Femto if you are looking in that price range.

Calyx Coffee DAC and Headamp

Good things come in small packages ! Well this does not always hold true for audio equipment, but nevertheless, the Calyx Coffee is really diminutive and cute as a button to boot.

The Calyx sports the current in-thing for DAC chips, the ESS Sabre. At the Calyx’s asking price, you obviously luck out if you were hoping to get the Reference Sabre chip. Instead, you get the ES9023 which sports two D/A convertors (vs. the eight found in the Reference chip). Like the rest of the Sabre chips, the ES9023 also boasts technology such as Hyperstream Architecture and Time Domain Jitter Eliminator (the complex technical details of which overwhelm my feeble mind).

Interestingly, the ES9023 chip includes a 2VRMS driver which would presumably allow a designer to skip the op-amp stage and use the ES9023 as a single chip solution.

On the bright side, your hard-earned money gets you a 24/96khz capable DAC with asynchronous USB connection, and a fairly competent headphone amplifier. The most obvious target market for the Calyx would be in a computer based head-fi or desktop set up. Given its small size and portability, it is also the perfect traveling companion, and was in fact the reason I purchased one. Pack in a nice pair of earphones with your notebook and the Coffee, and suddenly your work trips do not seem so lonely after all.

Dressed in a shade of a rather weak looking cup of Java, the Calyx is a simple bar shaped device. On one end, you will find its single USB input, and on the other, a pair of RCA outputs, and a 3.5 mm headphone jack.

The top of the unit is adorned with a single neat row of small gold buttons, that can control the source computer, with the ability to control play, skip and volume control (including mute). Stick on rubber feet are provided, so no worries about marring the beautiful surface of the Calyx. No cables of any form are provided, which is fine with me. Most freebie cables end up in the dustbin anyway. The Calyx draws its power from the computer’s USB port and there is no option to power it from an external 5V power supply.

Shaking the unit results in an alarming rattling sound. I was worried that something was broken inside, but the dealer assured me that it was just the buttons. True enough, the rattling stops if you apply a bit of pressure on them. Other than that, build quality is excellent. There are no screws or joints on the top and sides of the unit, so the Calyx is presumably milled from a single aluminum block. The bottom plate is screwed on though, making the enclosure of the Coffee a two piece assembly.

Installation was straight forward and hooking up the Calyx to my computers running Windows XP and Mac OS/X Lion were hassle free. No drivers were required and the Calyx was immediately recognized. Everything worked as expected, including the operation of the buttons to control the volume, etc. The steps were a bit coarse though, and I ended up using the slider bar on Windows to control the volume of the Calyx.

The Calyx Coffee has enough juice to drive most ear or head-phones on the market. It certainly had no problem driving either my 250 ohm Beyer DT-880 or my Audeze LCD-2. With the latter, volume is almost maxed out, so LCD-2 users who listen very loud may want to look elsewhere. Sound quality is good, well above average and far better than you expect for its price.

Hooking up the Calyx to my main hi-fi system, I questioned the sanity of using cables (Acrolink 7N-D5000 RCA and LAT International USB 2) which were more than 8 times the cost of the Calyx. I then awaited for the David vs. Goliath moment. After a few minutes, it was obvious that my Audio-gd DAC 19 was in no danger of being outclassed by the Calyx. The Audio-gd is close to 4x the cost of the Calyx, so no surprises there.

The Calyx has what I consider to be the typical Sabre house sound - slightly laidback and hyper-detailed. Sabre chips do not have the incisive leading edge emphasis of more analytical chips, but instead presents its sonic picture in a natural way. The details are all there, but are not presented with the stark contrast and leading edge emphasis of some of its competitors.

Bass is firm and slightly full. However, it lacks slam and extension. Bass freaks will definitely not be satisfied. You could say that the Calyx is slightly bass shy but the overall quality of its limited bass is quite high.

Midrange is one of the Calyx’s stronger points with a smooth and natural human voice. The usual suspects of sibilant tracks are quite well behaved and it is unlikely that this DAC will come across as cold or harsh. Listening to Eva Cassidy's album, “Live at the Blues Alley”, you get a sense that the Calyx chooses to honey coat things. The usual sibilance and slightly piercing quality of Eva sounds very nice on the Calyx – a bit too nice to be true.

High frequencies are clean and fast, and the sense of acoustic space is well conveyed. Nevertheless, treble extension could be better and is easily bettered by more expensive equipment.

Imaging is good, but soundstaging is slightly flat, with a reduced perception of width and depth in recordings. This is very noticeable as a loss of presence and air on Janos Starker's recordings of Bach's Suite for Solo Cello. Instruments and voices are also placed further back than my usual gear, with slightly smaller image sizes.

The Calyx is also not the most dynamic DAC out there. Rock and metal lack some energy and rawness. Faster music sometimes comes across as being a bit too polite.

Detail wise, the Calyx is definitely a significant upgrade over a stock computer soundcard or chip. However, some level of microdetail is lost, which is apparent when compared to the Audio-gd.

Two things I would have liked to see would be support for a RCA digital input, and support for 88.2 khz sampling rate. The first omission is forgivable since the Calyx is clearly not intended for primary use in home systems. However, the second omission is less so. The lack of 88.2 khz sampling support deprives native decoding of some source material out there (admittedly quite rare), as well as 2x up-sampling of red book material. My personal experience with red book up-sampling, is that it sounds more natural up-sampled to 88.2 khz compared to sample rate conversion at non integer multiples, e.g. 96 khz. I know what many will say, the big brother Calyx DAC is the answer to my wish-list.

In summary, the Calyx is a great upgrade for computer audio users. It is very competitively priced and competent. I am very impressed with the Calyx Coffee and recommend it highly for a portable computer based setup, and even more so, if primary listening is being done through head or ear phones. If using inefficient or difficult to drive headphones, I would advise you to try before you buy.

For home rigs, the Calyx is a less convincing proposition. While it is adequately suited for budget rigs, spending a bit more would definitely pay more dividends in the long run. Then again, for the money, you certainly could do a lot worse.

The weaknesses of the Calyx Coffee should be viewed in context of its affordable price. When used without reference to better (and much more expensive) equipment, the Coffee is musical, offers a useful upgrade in resolution and is pleasing to the ear. It gets a lot of things right, with good tone, especially for those with a musical diet tuned more towards jazz, vocal recordings and chamber music. It is only when you do direct comparisons to other gear, that you realise what is missing. Throw in its head amp stage, and you realise the excellent value proposition presented by the Calyx.

Postscript - Calyx Coffee users should try pairing their units with the ifi iUSB power supply. This provides a significant boost to the performance of the Coffee.

Brief audition of the Usher BE-718 DMD with Calyx DAC and integrated amplifier

I am quite familiar with the original Usher BE-718 which uses a Beryllium alloy tweeter. The BE-718 and the X-718 that preceded it stirred up quite a lot of controversy, from its close resemblance to a certain other renowned manufacturer, to the Beryllium content (or lack thereof) of its tweeter dome.


Controversy notwithstanding, the BE-718 sounded great and I would have walked home with a pair if my amplifier had the power to drive it. Audio Basic had no issues driving it with their solid state amplifiers, but a quick hook up to a 30 watt per channel EL-34 push pull amplifier proved that these speakers really thrive on power.

Fast forwarding to the BE-718 DMD, I believe that the speaker is internally identical to the BE-718, with identical crossover points etc. Worldwide, dealers are offering the DMD tweeters to BE-718 owners as a drop-in upgrade. Local users should be aware that the domestic version is not the same as the U.S. version which sports a tweaked crossover with upgraded capacitors and internal wiring.

Driven by the Calyx DAC and integrated amplifier (100 watts per channel into 8 ohms), the BE-718 DMD sounds quite different from its Beryllium predecessor, primarily in the resolution of air and detail. The Beryllium tweeter is already quite extended and resolving, and the DMD tweeter is a further step in this direction.

Are either tweeters bright ? That depends on what you are coming from. I think they are fine and subjectively sound less bright than the Beryllium tweeters on my Focal Micro Utopia BE. Of course, a tweeter does not maketh the speaker.

On the low frequency front, the Usher has a fair amount of grunt and good low bass given its cabinet size. Bass lines are agile enough and the amount of bass should be just right for a standard Singapore sized HDB bedroom (3x4 meters).

Going up to the midrange, vocals are smooth although slightly dry. The upper midrange has a slight hardness to it and brass instruments seem more prominent compared to other speakers.

The high frequencies are the true star of this speaker, with speed, resolution and air that are truly impressive for the asking price of these speakers.

Subjectively, the Focal is a better speaker. It has more bass authority, a better midrange, and more resolving high frequencies. It also throws a bigger soundstage and can resolve front to back layering better than the Usher. The Focal also happens to be much more expensive than the Usher.

At its present promotion price, I think the Usher is an excellent buy (contact X-audio or Audio Basic directly for prices). Is it worth it for original BE-718 owners to upgrade to the DMD tweeter ? I think that it is a far more difficult proposition. The cost of the DMD tweeters as sold locally is substantial. Although the DMD tweeters sound better to my ears, I would not put that much a premium to it to justify the cost.

Last but not least, credit also goes to the Calyx duo. The Calyx DAC (24/192) offers world class resolution at affordable prices, while the Calyx integrated amp never ran out of steam, even at rather uncomfortable volume levels. The Calyx integrated amp also has a built-in DAC and USB input (24/96 only). Add a Mac Mini, Calyx integrated amp and the Usher, and you have a very nice system for around S$ 6,000. Now where were systems like this when I started out in hi-fi 20 years ago ?