Review: Roksan Caspian M2
Roksan organises its electronics into several ranges of which the Caspian M2 range is half way, senior to the Kandy K2 and one step short of the Platinum series (which includes component pre and power amplifiers).
The Kandy and the M2 series are quite different internally, though surprisingly it is the Kandy amplifier which, on paper, is the more powerful of the two.
The M2 replaces the original Caspian range (which was launched the best part of 12 years ago) and the Caspian M1 series electronics, which underwent significant improvements internally.
The M2 is, in essence, a complete new model range and the CD player and amplifier are intended to leverage the performance of the company's mainstream electronics products upwards, while retaining a mainstream price.
Stylish pairing
Both the M2 components are unusual in the way they're presented. Although the fascia is an aluminium die-casting, the top panel is made from stainless steel, a harder material than aluminium and not easy to work with. But it has an excellent appearance and can be formed much thinner than aluminium.
It's structural properties mean it can be used to make a slimmer, smoother exterior, especially where it wraps around the base. It also gives the units a very distinctive and, we think, unusually attractive appearance.
Above all, the M2 is a well-turned out and arguably stylish pairing, though they are essentially classic stereo components with a bare minimum of flim-flam. They are presented well, with a contrasting black slab fascia and display windows, which are curved in characteristic Caspian style.
The rest of the structure is also well finished and typical of Roksan's great build. The M2 components are each supplied with an identical remote control, the design of which we haven't encountered elsewhere, though presumably it comes from a standard OEM supplier.
It is a full system remote, pre-programmed for both components in the Caspian and the Kandy ranges, but with enough buttons to control the amplifier and CD player, without needing to select the specific component. The unit also includes an impressively large, clear backlit LCD display.
The same handset will also control the matching tuner from each range.
Short-circuit protection
The updated M2 Caspians are simple looking, but internally sophisticated mid-market products, senior to (and more expensive than) the base level Kandy range.
Power output of this bipolar design is 85 watts per channel, which surprisingly is quite a bit less than the cheaper Kandy, which has a MOSFET output stage and is rated at 125 watts But the differences in output stage architecture make direct comparisons of this kind problematical. So what do you get for your money?
The amplifier has six inputs, including one for tape, plus a tape out and two pairs of preamplifier outputs, which allows the Roksan to drive one or two external power amplifiers – if more power is needed (one example would be a bi-amplified system).
One of the inputs is also available in an alternative balanced XLR connection, matching a similar output provision on the CD player.
There is also a power amplifier input too, though this needs to be activated internally. The internal design includes two mains transformers, a 350VA torroid for the high-power stages and a smaller 60VA torroid for the preamplifier. Both are described as ultra-low-noise, low-leakage designs.
A mains input filter is also included and output protection is provided by a thermostatically controlled cooling fan, short circuit protection and power supply failure detection. This cuts the output until the cause of the problem has been resolved (relays protect the output stage).
The various fan and protection circuits are more comprehensive than with the Kandy which, according to Roksan, is due to the fact that the amplifier has a very wide, open bandwidth and a correspondingly rapid rise time – which can trigger momentary high current flow. The Kandy appears to be a much slower circuit. And, in any case, MOSFETs are inherently self-limiting, at least to some extent.
Only the key features – source selection and volume, plus a mode switch and tape select are available on the front panel of the two M2 units. Other features can be accessed from the remote control.
The partnering CD player feature set corresponds almost exactly to what you would expect of a standard CD player. The display is of good quality and informative, though it is mounted below the disc loading tray, which means it is not necessarily readable if the player is positioned below the eye line and the drawer is open.
The front panel controls take care of the basics: track access, play, pause and stop and the quick-acting loading drawer. Around the rear are the usual single-edged outputs and the XLR balanced connectors to match the amplifier provision.
There are also no less than three digital outputs – a TOSLINK optical, S/PDIF electrical out and an AES/EBU balanced output via an XLR connector. A surfeit of riches!
A clear edge
The two M2 components don't appear to need extensive running in and in day to day use are fully on song within less than half an hour. Most of the listening was done using balanced interconnects. Latterly Roksan's own Pulse cables, which worked particularly well, easily outperforming a relatively low-end Nordost cable.
The CD player has particularly good timing and a more crisply defined and propulsive quality than some of the better known players in the same price territory. The same applies to the amplifier, which is sharp and on the button, almost as though it is balancing on the balls of of its feet, making some of the more prominent pretenders to the title of best disc player in its price class, however smooth and polished they may sound, seem a little slack.
In fact, there are no complaints about the M2 CD player. Yes, we missed the fact that it lacks SACD compatibility, but based purely on sound quality there is not usually a lot to choose between the two formats, except that the best hybrid SACDs sound just a little sweeter, more organic and less processed. But there are plenty of individual titles which contradict this, or that don't show a specific advantage in either direction.
Much the same can be said of the amplifier. Again, the M2 can sound a little rough around the edges, but its muscularity and drive gives it a clear edge over most competitors, most of the time.
It has solid stereo imagery and is even capable of the kind of subtlety that helps the ear interpret delicate, low-level ambient information as clues to depth imagery. Think of Mahler's off-stage band in several of his symphonies, or the kind of depth that helps create the sense that you are listening to a recording made in an identifiable acoustic of a particular size, which can often be sensed almost subliminally in live recordings.
The amp has the kind of punch and dynamics that you would expect of a grown-up model and even more than the CD player. Its excellent timing, for example, works really well with difficult and large scale material. It is also most effective at moderate or even fairly high volume levels, though it is not completely even in the way it treats music.
It is not the answer to all musical requirements and if it runs out of steam it can sound a little harsh and messy. But this is the exception. Selecting almost at random from discs that saw service during this test and which were not preselected for any compelling reason, the amplifier and CD combination worked really well with a recording of Britten's War Requiem (Rattle/CBSO), especially the male voices, Scott Walker's Tilt and some Alison Krauss and Union Station recordings.
All the above found the Roksan combination's sweet spot. Some recordings – an example being Jennifer Warnes The Well (SACD version) – seems to chime better with the (cheaper) Marantz KI Pearl Lite SACD player, as well as benefitting from the DSD recording.
Others, an example being Schoenberg's Gurrelieder (Esa-Pekka Salonen/Philharmonia) sounds slightly rougher around the edges through the Roksan as a DSD recording and as a Red Book CD, especially at the high volume levels that this music demands. But at reasonable levels within the compass of the amplifier, Roksan offers a bold, gripping and undeniably authoritative sound.
Persuasive and gripping
The M2s are very nearly the complete package, despite being a little uneven in their qualities and clearly not ideal for every disc it played. But this is a criticism that can be made of just about any comparable amplifier and disc player at this price level.
Other similar combinations (the Marantz Pearl Lites are obvious examples) are sometimes tidier, but often less successful at scaling the heights the Roksan was able to reach.
So, in conclusion, the M2s are often the more persuasive and gripping choice. The two components are also attractively designed and built, and their compact dimensions are a definite plus.
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Review: Audio-Technica AT2000T
Moving-coil cartridges are wonderful things, but they suffer from a disadvantage in their extremely low output, often less than 1mV peak, or one two-thousandth of what most CD players produce. Clearly, low-noise amplification is a must.
Because they have a low impedance, the self-noise of such cartridges is actually very low, but getting an amplifier to match or (ideally) better it is hard work.
It can be done with transistors or valves if you use enough of them, but it can often be more practical to use a transformer to provide some initial gain before active devices are called into play.
Challenging
A transformer, being passive, provides no power gain, but it can step up voltage (reducing current inversely) by enough to make low-noise active amplification much more efficient.
As a maker of cartridges, Audio Technica is well aware of the challenges and has designed the AT2000T transformer to step up the output of typical low-output moving coil designs.
Unlike some 'universal' transformers, it has no impedance selection, just a single input and output per channel, but it is claimed to match cartridges with impedance between two and 17 ohms, which in practice means the vast majority available on the market.
Its voltage gain of 24dB will boost the level sufficiently to feed a standard moving-magnet input.
Screwless
The transformers inside the case are small, under 40mm each way (actually by the standards of MC transformers that's quite big!) but the case is this size for a reason. Small-signal transformers are made of materials that are sensitive to mechanical shock and their electrical performance can be permanently affected by dropping them. They can also be mildly microphonic.
AT has taken the unusual step of fixing these transformers by surrounding them with soft plastic foam: no screws or other metal fasteners are used.
Around that is the case made of a high-permeability grade of magnetic material that provides effective magnetic screening – though you're still advised to keep the unit away from mains transformers and anything else that might generate hum fields.
Noise reduction
We happened to have an aged, but honest AT cartridge on hand, plus models from Denon, Goldring and Ortofon, plus various phono stages too, so we were able to try this transformer under a range of conditions.
It's impressively capable, and we mean it as a compliment that we were never really aware of its presence, except in one very valuable respect: it really does reduce the noise compared with even the best phono stages we could lay our hands on.
Transformers are not strictly noise-free because they have stray resistance and other factors which limit their performance, but this one approaches the ideal very closely.
As a result, it gets the most out of high-quality cartridges, making the replay system quieter than even the run-in groove on most LP pressings. The net difference while music plays may only be a couple of dB of signal-to-noise ratio gained, but subjectively that's well worthwhile in terms of extra resolution, veils lifted and so on.
Our Ortofon MC2000 (an oldie, but a goodie) sounds perhaps clearer than we've ever heard it, producing images of real solidity and stability, with a much better-defined acoustic around the performers than all-active amplification produced.
Sweet extension
Transformers are sometimes accused of compromising the frequency extremes, but even with slightly mismatched cartridges (impedance over 20 ohms) we couldn't hear any such effect.
Indeed, the unusually low noise makes the bass even clearer than ever, with a shade more weight to it but immaculate control and precision (the treble is very sweetly extended and open). There's no hint of coloration in the midrange: as with bass, the AT2000 makes things even purer here, simply because one's ear isn't trying to filter out quite so much noise and hash.
In the lab, we found bandwidth is superb and dead flat across the audio band plus, at least, an octave each end, while distortion is low at both high-and low-signal levels.
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Review: Roksan Radius 5.2
The Radius design has undergone so many changes over the years that practically no single part is left of the original, yet it is instantly recognisable as the same model.
In current guise, the Radius 5.2, it is an all-acrylic, semi-suspended turntable, with the familar Roksan 'egg' shape for the subchassis. Three compliant rubber mounts support the subchassis, while the motor is mounted compliantly in a housing which in turn is supported on the plinth.
The arm, included as standard, is the Nima unipivot. The subchassis shape is certainly visually attractive, but its original justification was to do with control of resonance.
Regular shapes tend to be more resonant than irregular and this one is sufficiently irregular to improve matters considerably compared to, say, a circle or rectangle.
The platter, of course, is unavoidably regular, but its acrylic material is in itself fairly 'dead', one of the reasons it has become so popular. It's supported on a new, close-tolerance main bearing and driven around its periphery by a silicone belt.
Compliant motor mounting is another Roksan speciality – that is, highly compliant, to the extent the motor very visibly wobbles as it starts up. It's not immediately obvious what the pros and cons of this are, though clearly it's likely to limit the amount of motor vibrations getting into the structure.
Similarly debatable, are the benefits of unipivot arms (of which the Nima is an example). It has a metal tube with a slightly decoupled counterweight mounted at the rear and an acrylic headshell at the front, all supported on a single needle bearing.
The slight downside of this is a very high pivot point, though low friction is an advantage. The arm lead is captive and is securely fastened to the plinth.
Sound quality
Roksan has always set great store by rhythm and pace and our listeners seemed to agree that these are particularly well handled by the Radius.
There was considerable praise for these, but if anything there was even more praise for bass definition, control, and detail. Possibly not what the Roksan stereotype would suggest – which is exactly why we're so fond of blind listening!
That said, it seems the tonal balance isn't entirely neutral across the board and one listener did point to a degree of coloration, most obvious with the piano recording, which interfered with his enjoyment. However, the others seemed much less bothered by that and were able to appreciate the fine information retrieval this deck is able to achieve.
Along with that it manages very good imaging, and was among the best at portraying both width and depth of an image.
In terms of timing, one of the listeners pointed out that the percussion in The Wall not only started, but also stopped, with notable precision when played on this deck. That makes for very persuasive rhythm all round, and the sound is indeed highly convincing in just about every genre.
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Review: Logitech Squeezebox Touch
The Squeezebox Touch is nothing less than an absolute bargain. There is truly little else to say about this incredibly easy to set-up and enjoy network player.
It crams a shed-load of technology into a 150mm by 110mm enclosure, which is just 10mm deep – albeit increasing to 40mm at its base to accommodate its connection sockets.
The player delivers internet radio along with music streamed from any computer(s) on your local network. It is wireless-capable, but we used it predominantly with a CAT5E Ethernet connection to enable it to access music reliably on a computer and NAS, running the free Squeexebox Server software, which runs on Windows, Mac and Linux operating systems.
We supplied it with rips from a £370 VortexBox Appliance 1TB NAS, which conveniently comes with Squeezebox Server already installed and configured – although putting it on a Windows PC is only a five-minute job.
Fully featured
You can connect the Touch to a regular hi-fi system through a pair of RCA analogue sockets, or through a DAC using the coaxial or optical output. Equally, you can connect it straight to a set of active loudspeakers in an appropriately compact office or study system.
While inspecting the back panel you will also notice a USB port, into which you can plug a memory stick or drive containing music you would like to play. There is also an SD-slot on the side of the player, in case you wish to play music stored on an SD card.
To use either of the sources one simply selects them in the on-screen (touch-screen) display. There is also a 3.5mm headphone jack outlet for late-night listening.
We prefer using the display to control the player rather than the remote handset, but this is mainly down to personal preference and familiarity. Either way, the interface is logical and responsive.
Touching the remote control increases the size of the display font, a feature our eyes particularly appreciated on the recently reviewed and considerably more expensive Arcam Solo Neo. There is no doubt that the Touch delivers a rewarding 'user experience', one that certainly belies the budget price of the unit.
Connecting to network audio is perhaps the feature that will be most attractive to the majority of buyers, but internet radio might prove more so to those of a not especially energetic disposition. We certainly enjoyed having Radio Paradise select music for us while we sat and relaxed.
A slick package
The question of build quality does not really arise with the Touch: it is little more than a circuit board and a touch-screen, with a handful of connections pinned to the rear of the plastic case. There are no mechanical components to fail or slip out of adjustment. Everything works as it should and the whole shebang looks sleek and shiny.
Its packaging is exemplary and Logitech even thoughtfully supplies a cloth for cleaning the screen. The favourable impression created by the slick packaging is reinforced when you flick through the user manual and discover just how easy it is to get the unit connected to your network and playing.
No elevator music
It truly seems churlish to criticise the Touch overall, when one looks at what one is getting for the price: streamed audio, internet radio, alarm clock functions and all for £260 or less.
The sound is not a million miles away from that of the Slim Devices Transporter I and that was comfortably over £1,000. It will now set you back around £1,799.
Sound quality obviously varies with the source material. High-resolution FLAC files naturally sound the best. They are understandably not as detailed as they are with the high-end Linn Klimax DS or the Naim HDX, but they sound vital and alive and do not sink to background or elevator music quality as one might expect.
At the other end of the performance spectrum, decent bit-rate internet radio still sounds plausible and entertaining, even if it is not a completely audiophile experience.
The sound offers an appreciable degree of subtlety: for example, it clearly reveals deft brush work on a hi-hat by a drummer behind a female vocal. This really is not the sort of polished performance one expects from a £250 streamer. It is extraordinarily assured, enjoyable, and highly authentic in musical terms.
Dynamically, the presentation seems slightly muted, but not to the degree that any listener is moved to complain. The unit has an embedded version of the server software, so that it can replay music from a USB hard disk with no external assistance.
The software enumerates a 160GB disk very quickly and replays tracks with the same ease that it reveals when playing from the Vortexbox appliance.
A stellar performer
The Squeezebox Touch thoroughly deserves to be a phenomenal success. It is a stellar performer and can hold its own against far more expensive competition. It strikes us as being the ideal office system: it sounds good; it looks good, it is a breeze to operate and it takes up negligible desk space.
Store your music on a convenient hard disk, install Squeezebox Server, add a pair of active loudspeakers and that is it: your music is totally sorted.
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T-Mobile G2: HTC Android 2.2 handset unveiled
T-Mobile has announced the arrival of the G2, its latest 'with Google' handset, which has been made by HTC.
Currently only available in the US, the T-Mobile G2 is the first smartphone specifically designed for T-Mobile's new HSPA+ network2, which means super speedy downloads using the US' 4G network.
This is the direct successor of the T-Mobile G1, which was the first Android phone on the market way back in October 2008.
The T-Mobile G2 has been given a large 3.7-inch screen which has a hinge design that opens to reveal a full QWERTY keyboard.
Android 2.2
It has been built on Android 2.2 and offers the usual seven customisable home screen panels, including a dedicated panel with one-click access to Google apps such as Android Market.
As it is 2.2, Flash player is enabled and the phone packs 4GB internal memory with pre-installed 8GB micro SD card, with support for up to 32GB of external memory.
There's also a 3.5mm jack and Swype pre-installed, which is a bit of a bonus.
Chip-wise, the T-Mobile G2 is powered by a Snapdragon MSM7230 which offers an 800 MHz CPU.
There's is also HD video shooting on board, with the G2 having a 720p HD video capabilities and a 5MP camera, complete with LED flash and autofocus.
The T-Mobile G2 has also been optimised with Google Voice, so you can shout orders at your phone and it should obey.
Current T-Mobile customers in the US will get exclusive access to preorder the G2 starting later this month.
There is no UK release date for the T-Mobile G2 just yet, but we will keep you posted as soon as we get further details.
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Video: Google Instant launches, pushes dynamic results
Google has unveiled its brand-new search engine this week, Google Instant.
Instead of waiting for you to press the search button, Google Instant brings you results in real-time, which change with each and every key stroke.
The result is the speediest search engine we have seen, which predicts what you are about to type.
"You don't really want search-as-you-type (no one wants search results for [bike h] in the process of searching for [bike helmets])," explained Marissa Mayer, VP Search Products & User Experience , in a blog post.
"You really want search-before-you-type – that is, you want results for the most likely search given what you have already typed."
Cache rules everything around me
In the blog post, Mayer explains the technology behind Instant Search, noting: "To bring Google Instant to life, we needed a host of new technologies including new caching systems, the ability to adaptively control the rate at which we show results pages and an optimisation of page-rendering JavaScript to help web browsers keep up with the rest of the system.
"In the end, we needed to produce a system that was able to scale while searching as fast as people can type and think – all while maintaining the relevance and simplicity people expect from Google."
On Twitter, Google CEO Eric Schmidt was so excited about the launch he hinted before the release: "We are already fast... fast is about to get faster."
Not everyone will see Google Instant straight away as this is a rolling launch. However, if you are in the France, Germany, Italy, Russia, Spain and the UK and sign into Google you should have it.
Google does not say whether it will become the core search engine experience for Chrome, Firefox, Safari and IE 8.
If you can't wait to see Google Instant, then point your browser to www.google.com/webhp?sclient=psy to try it out.
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ARM pushes smartphone processors up to 2.5GHz
ARM has announced the new Cortex A15 MPCore processor that it claims could see smartphones running at 2.5GHz speeds.
Tipped for use in the tablet, large-screen portable computers and home entertainment systems, as well as phones, ARM believes that this new core will help improve the next generation of gadgets.
It's claiming up to five times improved performance over today's smartphone processors without diminishing battery consumption, enabling functionality like 3D navigation, augmented reality, high speed internet connections and HD video recording – all from your mobile phone or tablet.
The Cortex A15 follows in the footsteps of ARM's successful Cortex A-Series, with a number of manufacturers using the Cortex A8 for high end smartphones, such as the Nokia N900.
Quantum leap
Samsung, ST Ericsson and Texas Instruments all helped shaped the functionality of the processor as they look to deliver more powerful chips:
"The market's demand for more functionality and connectivity with low power consumption requires ever more advanced processor, system and chip design," said Yiwan Wong, VP of SoC marketing, system LSI Division, Samsung Electronics.
"We believe this new Cortex-A15 MPCore processor core from ARM, with its quantum leap in processing capabilities, will successfully enable many next-generation electronic products and redefine the level of experience consumers will demand from their smartphones and mobile computing devices."
As an advanced lead partner and first licensee of the Cortex-A15 MPCore processor, we look forward to leveraging the Cortex-A15 core to deliver industry-leading processors that will provide the high performance demanded by the next generation of connected devices, all within a low power envelope," said Remi El-Ouazzane, vice president, OMAP platform business unit, TI.
"When pairing the Cortex-A15 MPCore processor with TI's SmartReflex 3 technology, future OMAP applications processors will yield a 60 percent reduction in power, enabling TI to continue delivering the industry's most energy-efficient, high-performing solutions."
The new ARM Cortex A15 is available for licensing from today, and in 32nm and 28nm manufacture, as well as future size specifications.
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How to use External Interrupts on an ATmega168
Daniel Garcia from Protostack has made a good tutorial describing the steps to Understand How to use External Interrupts on an ATmega168. It is nice to forget about manually coding to look for changes in state of inputs and other conditions within the microcontroller. Interrupts allow us to keep on doing real work while the system keep monitoring for changes.
“Microcontroller interrupts are just like that.
- The microcontroller is executing it’s main routine
- An event occurs, which raises an interrupt
- The Interrupt Service Routine (ISR) is run
- On termination of the ISR, the microcontroller returns to it’s main routine, at the point where it left off”
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