Author Archives: Tim

Upgrading a PC to SSD (Crucial MX200)

The trigger for me was Visual Studio 2015 – a large software installation – which I managed to break by installing some beta software. I couldn’t fix it easily, and knew I would have to uninstall it completely and then reinstall, which takes ages.

One thing that speeds up this kind of thing is to use an SSD instead of a hard drive. I already use SSD on my laptop, but my PC had two 1TB WD Black hard drives in a RAID configuration.

I ordered a 1TB Crucial MX200 SSD. While I could have managed with a smaller one, the larger size is worth it for me if only for the convenience of not having to spend time uninstalling stuff and reorganising my existing drive to free up enough space to downsize.

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This 2.5″ SSD drive comes with a spacer and a code for downloading Acronis True Image. I did so, and used it to clone the existing drive. It took several hours but worked perfectly.

This PC is nearly four years old and based on an Intel Core i5. It has recently been upgraded to Windows 10. I am more than happy with the performance of the SSD. Here are the figures from CrystalDiskMark:

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Here are the results from my old 1TB WD Black RAID:

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There are not many upgrades that will get you such a dramatic performance improvement, and for me it made reinstalling Visual Studio 2015 substantially less painful.

I no longer have RAID on the C drive. The SSD according to Crucial [PDF] has an MTTF of 1.5 million hours (170 years or so) and “endurance” of 320TBW, equivalent to 175GB per day for five years. The implication is that after 320TB has been written, the drive will sill work but will be read-only. I don’t take much notice of such claims, but I can accept that today’s SSDs are more reliable than hard drives. If it fails though, I doubt that any data can be coaxed out of it, as you can often do with a hard drive. Even with RAID though you still need a backup strategy, so I will now be relying on that.

Hard drives are still useful for storing lots of stuff in a NAS (Network Attached Storage) but I can’t see myself using them again as the primary drive in a PC or laptop.

Hands On: Xbox One Game Streaming to Windows 10

Xbox One Game Streaming has been switched on for all Windows 10 users and I gave it a quick try.

You need the latest Xbox app of course, as well as a wired Xbox controller (I used a 360 controller). Turn your Xbox on, run the app, make sure you are signed in with a Microsoft account that also has a profile on the console, and hit the Connect button near bottom left.

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Once connected, click Test streaming to verify that you have enough bandwidth, or Stream to start streaming.

I tried Dark Souls 2. It worked pretty well, except that the screen (which is dark anyway for this particular game) was even darker over the streamed connection. With the in-game option set to maximum brightness it was playable. I did not notice any lag though there was an occasional stutter; this is over wireless though and a wired connection would be better.

While you are streaming, all the action displays on the TV connected to the console itself as well as on your PC.

Streaming only works full screen. If you are streaming and press the Windows key you get an odd effect where streaming continues in the background but the Start menu displays.

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If you then run another application, the streaming pauses, but you can resume later. Or sometimes the Xbox app seems to quit. It seems best not to switch apps while streaming.

I noticed that trying to start streaming when the console is on standby does not work; you cannot wake it up. That is a shame.

Otherwise, it all works as you would expect. Although it is not as good as gaming in say the living room with what is probably your biggest screen, this is a nice feature for when that room is in use and you want to sneak off and play a game.

How to overcome “A required drive partition is missing” in Windows 8.1 reset

Here is the scenario: an HP all-in-one PC gets a virus and as a precaution the owner wishes to reinstall Windows.

The recovery drive on the PC is intact, but attempting to use the Windows 8.1 troubleshooting tools to “Reset your PC” (in effect reinstalling Windows) raises the error “A required drive partition is missing”.

This seems to be a common scenario in cases where the PC was supplied with Windows 8 and upgraded to Windows 8.1. The problem seems to be that Windows 8.1 makes some changes to the drive partitions that make it incompatible with the Windows 8.0 recovery partition.

Here is the workaround I used:

1. In Windows 8.1, make a recovery drive. To do this, first connect a USB drive that you are happy to have wiped. It will need a capacity of around 16GB or more. Then run Control Panel, search for “recovery”, and choose Create a recovery drive.

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2. When creating the recovery drive, make sure the option to include the recovery partition is checked. This will copy the recovery partition from the PC to the USB drive.

3. When you are done, you will be able to boot from the USB drive. You could choose the Reset option from there, however you will still get the error. First, go to Troubleshooting and Advanced and select the command prompt. When the command prompt opens, type:

diskpart

Now type:

list disk

You will see two disks (or more) listed, one for the USB boot device, and the others the disk(s) in the PC. Select the internal boot drive. It is normally obvious from the sizes which is which. Select it by typing:

select disk n

where n is the number of the drive as shown by list disk.

WARNING: the next step will delete all data on the selected drive. If in doubt, back out and make a backup of the drive before proceeding. If something goes wrong, your PC will no longer be bootable and you will need recovery media from the manufacturer, or to buy a new copy of Windows.

Once you are happy that it is safe to delete everything from the drive, type:

clean

or

clean all

The first command does a quick removal of the partition table from the drive but does not zero the data; it will be invisible but possibly recoverable using data recovery tools. The second command zeroes all the data and takes much longer (several hours), but it is more secure, if for example you want to sell or transfer the PC.

Once this is done,reboot the PC using the USB recovery drive. Select troubleshooting, then Reset your PC. This time it will work and you will be back in Windows 8.0.

Note: This scenario is common enough that it seems to be a flaw in the Windows 8.x recovery tools. I do not understand why Microsoft has so little regard for its users attempting to recover Windows (and usually highly stressed) that it has not fixed this problem.

Note 2: What if you cannot boot into Windows 8.1 to make the recovery drive? I have not tried it, but in theory it should be possible to create a recovery drive on another PC and copy the recovery drive to it.

DatAshur encrypted drives: protect your data but be sure to back it up too

The iStorage DataAshur USB flash drive is a neat way to encrypt your data. Lost USB storage devices are a common cause of data theft anxiety: in most cases the finder won’t care about your data but you can never be certain.

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The DatAshur is simple to operate but highly secure, presuming it meets the advertised specification. All data written to the drive is automatically encrypted with 256-bit AES CBC (Advanced Encryption Standard with Cipher Block Chaining) and meets the US FIPS 140-2 standard. The encryption is transparent to the operating system, since decryption is built into the device and enabled by entering a PIN of 7 to 15 digits.

Note that a snag with this arrangement is that if your PC is compromised a hacker might be able to read the data while the drive is connected. If you are really anxious you could get round this by working offline, or perhaps using Microsoft’s clever Windows to Go (WTG) technology where you boot from a USB device and work in isolation from the host operating system. Unfortunately DatAshur does not support WTG (as far as I know) but there are alternatives which do, or you could boot into WTG and then insert your DatAshur device.

Normally you enter the PIN to unlock the drive before connecting it to a PC or Mac. This does mean that the DatAshur requires a battery, and a rechargeable battery is built in. However if the battery is exhausted you can still get your data back by recharging the device (it charges whenever it is plugged into a USB port).

OK, so what happens if a bad guy gets your device and enters PINs repeatedly until the right one is found? This will not work (unless you chose 1234567 or something like that) since after 10 failed tries the device resets, deleting all your data.

You should avoid, then, the following scenario. You give your DatAshur drive to your friend to show it off. “I’ve just updated all my expenses on this and there is no way you’ll be able to get at the data”. Friend fiddles for a bit. “Indeed,and neither can you”.

Here then is the security dilemma: the better the security, the more you risk losing access to your own data.

The DatAshur does have an additional feature which mitigates the risk of forgetting the PIN. You can actually set two PINs, a user PIN and an admin PIN. The admin PIN could be retained by a security department at work, or kept in some other safe place. This still will not rescue you though if more than 10 attempts are made.

What this means is that data you cannot afford to lose must be backed up as well as encrypted, with all the complexity that backup involves (must be off-site and secure).

Still, if you understand the implications this is a neat solution, provided you do not need to use those pesky mobile devices that lack USB ports.

The product tested has a capacity from 4GB to 32GB and has a smart, strong metal case. The plastic personal edition runs from 8GB to 32GB and is less robust. An SSD model offers from 30GB to 240GB, and larger desktop units support SSD or hard drive storage from 64GB to 6TB, with USB 3.0 for fast data transfer.

Prices range from around £30 inc VAT for an 8GB Personal USB stick, to £39.50 for the 4GB professional device reviewed here, up to £470 for the monster 6TB drive or £691 for a USB 3.0 external SSD (prices taken from a popular online retailer). The cost strikes me as reasonable for well-made secure storage.

More information on DatAshur is here.

On Bitcoin and the future of digital currency

Last week I attended the Pioneers Festival in Vienna. One of the topics was Bitcoin, a peer-to-peer digital currency based on cryptography and distributed transaction records. The number of Bitcoin is limited to about 21 million, of which over 14 million have already been “mined”. The word mining is somewhat deceptive; miners do not discover bitcoin exactly, rather they are rewarded for solving hard mathematical problems that confirm the validity of a block of Bitcoin transactions. The system provides for a decreasing number of Bitcoin to be generated until 2140, following which miners will be rewarded by transaction fees; at least, that is the idea as I understand it.

Bitcoin is interesting on multiple levels: mathematical, political, financial and practical. The currency has real value, but this tends to be volatile; it is widely enough accepted to be useful, but not enough that you can be sure of its future. There are intense debates even within the Bitcoin community about what should happen to it technically (forks are under discussion) and the extent to which it is safe from manipulation. There is a strong incentive to get in early on any Bitcoin alternative since it would be so profitable.

At Pioneers Bitcoin evangelist Roger Ver spoke and gave away $125 worth of the currency during his talk; he also gave me $5.00 when I spoke to him later. He describes himself as a Bitcoin investor, meaning one who invests in Bitcoin initiatives as well as hoarding the currency itself. That Ver predicts a bright future for Bitcoin is as surprising as the sun rising; his world depends on it.

Ver is also a libertarian who did jail time for selling explosives on eBay and renounced his US citizenship; you can read his own account of the incident here, where he adds:

Currently, I am working full time to make the world a better, less violent place by promoting the use of Bitcoin. Bitcoin totally strips away the State’s control over money. It takes away the vast majority of its power to tax, regulate, or control the economy in any way. If you care about liberty, the nonaggression principle, or economic freedom in general you should do everything you can to use Bitcoin as often as possible in your daily life.

The implication is that if you believe that taxation and regulation are not entirely evil you may be wary of Bitcoin, either because of worries over its use by criminals (it is commonly requested for the payment of ransoms by the purveyors of ransomware like Cryptolocker, for example), or through concerns that regulators, banks and governments may try to make it an illegal currency if its usage grows, or try to find ways of regulating it that remove its advantages.

Another possibility is that Bitcoin will be replaced by some other digital currency and lose most of its value.

Nevertheless, the ability to send digital cash to another person anywhere on the internet without involving a bank or a currency exchange is a powerful and disruptive concept.

Bitcoin in practice

What about the practical aspect of Bitcoin? If you want to try it out you can take a look here. There are several problems confronting the ordinary person who wants to get started, including which Bitcoin wallet (a means of holding Bitcoin) to choose and how to acquire some currency. Lack of regulation means that you either have to trust a web entity to hold your Bitcoin for you – perhaps losing it if the site gets hacked – or hold it yourself, which requires good backups and strong security since your own computer might get hacked and your Bitcoin stolen. Alternatively you can maintain low balances so that not much is lost if the worst happens.

Once you get set up though, Bitcoin is useful. Using Bitcoin, you can make payments with either zero or very low fees either for sender or recipient. Payments are non-reversible by design. Bitcoin is ideal for micropayments, and some companies prefer it for that reason. At Pioneers I met Parkt, which runs a scheme enabling one or more retailers to pay for your parking if you shop at their stores. They like Bitcoin because it is cheaper for them.

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Bitcoin is also good for international payments since it is internet-based. There are some win-win scenarios, like the ability to purchase Amazon gift vouchers at a discount, said to be around 20%. The way this works, I was told, is that some workers for Amazon’s Mechanical Turk service (perform tasks for payment into your Amazon account) have difficulty converting their Amazon balance into cash. They can buy Amazon gift vouchers though, and sell them at a discount for Bitcoin.

How is Bitcoin doing? Its value has been stable since the beginning of the year, but it has fallen in value substantially since its peak in November 2013. Here is the chart for the past year:

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At this point, all you can say for sure is that the future of Bitcoin will be interesting to observe.

Cloud storage sums: how does the cost compare to backing up to your own drives?

Google now offers Cloud Storage Nearline (CSN) at $0.01 per GB per month.

Let’s say you have 1TB of data to store. That will cost $10 per month to store. Getting the data there is free if you have unlimited broadband, but getting it all back out (in the event of a disaster) costs $0.12 per GB ie $120.

A 1TB external drive is around £45 or $58 (quick prices from Amazon for USB 3.0 drives). CSN is not an alternative to local storage, but a backup; you will still have something like network attached storage preferably with RAID resilience to actually use the data day to day. The 1TB external drive would be your additional and preferably off-site backup. For the $120 per annum that CSN will cost you can buy two or three of these.

The advantage of the CSN solution is that it is off-site without the hassle of managing off-site drives and probably more secure (cloud hack risks vs chances of leaving a backup drive in a bus or taxi, or having it nabbed from a car, say). Your 1TB drive could go clunk, whereas Google will manage resilience.

If you consider the possibilities for automation, a cloud-based backup is more amenable to this, unless you have the luxury of a connection to some other office or datacentre.

Still, even at these low prices you are paying a premium versus a DIY solution. And let’s not forget performance; anyone still on ADSL or other asymmetric connections will struggle with large uploads (typically 1-2 Mb/s) while USB 3.0 is pretty fast (typically up to 100 Mb/s though theoretically it could be much faster). If you have the misfortune to have data that changes frequently – and a difficult case is the VHDs (Virtual Hard Drives) that back Virtual Machines – then cloud backup becomes difficult.

The Watch

I am in San Francisco so naturally I looked into the Apple Store to see the Watch.

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The poor old Apple Store is stuck behind a crane and a lot of fencing but there was still a good crowd there.

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There are watches behind glass, watches you can play with that are firmly attached to the counter, and watches in drawers which you can try on under the guidance of a rep, but which are disabled (the buttons do nothing).

A few observations.

It is a lot of fun. I found it easy to navigate using the main menu (a heap of icons, as you would expect), and zooming/tapping to explore.

There are two physical buttons, the crown and a pushbutton. The pushbutton only does two things (I was told by the rep), one press for the contacts app, press and hold for Apple Pay. Can you configure this? Apparently not.

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The crown is a  select button if you push it, zoom (or something app-specific) if you spin it, and Siri if you press and hold.

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Most of the features are things you can already do with a smartphone, excepting the fitness sensors of course, but this is on your wrist and therefore handier.

Maps is useful; it might be worth it just for that.

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Note that the watch is largely a remote for an iPhone. If you don’t have an iPhone (or it is out of charge) it is not much use. The rep thought it would still tell the time but wasn’t sure.

I tried on a couple of models, one the Sports with a cheapish strap ($400; the base model is $349), and another with a stainless steel band ($700). Both were comfortable and I was especially taken with the stainless steel edition.

There are plenty of things about the gadget that are annoying. The need for daily recharging is one, the dependence on an iPhone is another. However it is elegant and delightful so I imagine all will be forgiven, among the Apple community at least.

How do I buy one? Online only, I was told, and delivery maybe in July.

Quick thoughts on Surface 3 from a long-term Surface user

I’ve been using a Surface as my usual travel PC for a while now – mostly Surface Pro (the first iteration) but also Surface RT and Surface 2. Microsoft has announced Surface 3 – is that a good buy?

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Note: this is not a review of Surface 3. I intend to review it but have yet to get my hands on one.

First, a quick note on how I have got on with Surface to date. I love the compact size of the devices and the fact that I can do all my work on them. I find full-size laptops unbearably bulky now – though slim ultrabooks or small netbooks still have some appeal.

The main annoyances with my Surface Pro are the small SSD size (I have the 128GB model) and a few technical difficulties, mainly that the keyboard cover (currently the Power Cover) plays up from time to time. Sometimes it stops responding, or I get oddities like the mouse pointer going wild or keys that auto-repeat for no reason. Detaching and re-attaching the keyboard usually fixes it. Given that this is Microsoft hardware, drives and OS, I regard these bugs as disappointing.

Surface power handling is not very good. The Surface is meant to be running all the time but sleeps so that touching power turns it on or off almost instantly. That’s the idea, but sometimes it fails to sleep and I discover that it has been heating up my bag and that the battery is nearly flat. To overcome this, and to save battery, I often shut it right down or use hibernate. Hibernate is a good option – fairly quick resume, no battery usage – except that about every third resume it crashes. So I tend to do a full shutdown.

I find the power button just a little unpredictable. In other words, sometimes I press it and nothing happens. I have to try several times, or press and hold. It could be the contact or it could be something else – I don’t think it is the contact since often it works fine.

The power cover has stopped charging, after 10 months of use. It is under warranty so I plan to get it replaced, but again, disappointing considering the high cost ($199).

A few grumbles then, but I still like the device for is portability and capability. Surface Pro 2 seemed to be better that the first in every way. Surface Pro 3 I had for a week on loan; I liked it, and could see that the pen works really well although in general pens are not for me; but for me the size is a bit too big and it felt more like an ultrabook than a tablet.

What about Surface 3 then? The trade-off here is that you get better value thanks to a smaller size (good) and lower performance (bad), with an Atom processor – Intel’s low power range aimed at mobile computing – instead of the more powerful Core range. Here are some key stats, Surface 3 vs Surface Pro 3:

  Surface 3 Surface Pro 3
Display 10.8″ 12″
Weight (without cover) 622g 800g
Storage 64GB or 128GB 64GB-512GB
Processor Intel Atom x7 Intel Core i3, i5 or i7
RAM 2GB or 4GB 4GB or 8GB
Pen Available separately Included
Cameras 8MP rear, 3.5MP front 5.0MP rear, 5.0MP front

What about battery life? Microsoft quotes Surface Pro 3 as “up to 9 hours of web browsing” and Surface 3 as “up to 10 hours of video playback”. That is a double win for Surface 3, since video playback is more demanding. Anandtech measured Surface Pro 3 as 7.6 hrs light use and 3.45 hrs heavy use; the Surface 3 will fare better.

How much do you save? A snag with the Surface is that you have to buy a keyboard cover to get the best out of it, and annoyingly the cover for the Surface 3 is different from those for Surface, Surface 2 and Surface Pro, so you can’t reuse your old one.

A quick look then at what I would be paying for the Surface 3 vs Surface Pro 3 in a configuration that makes sense for me. With Surface 3, I would max out the RAM and storage, because both are rather minimal, so the cost looks like this:

Surface 3 with 4GB RAM and 128GB storage: $599
Keyboard cover: $129
Total: $728.99

Surface Pro 3 with 8GB RAM, 265GB storage, Intel Core i5, pen: $1299
Keyboard cover: $129.00
Total: $1428.99

In other words, Surface 3 is around half the price.

Will I buy a Surface 3? It does look tempting. It is a bit less powerful than my current Surface Pro and perhaps not too good with Visual Studio, but fine for Office and most general-purpose applications. Battery life looks good, but the 128GB storage limitation is annoying; you can mitigate this with an SD card, say another 128GB for around $100, but I would rather have a 256GB SSD to start with.

However, there is strong competition. An iPad Air, I have discovered, makes an excellent travel companion, especially now that Office is available, provided you have a good keyboard case such as one from Logitech; you could get an iPad Air 2 with 64GB storage and a keyboard for slightly less than a Surface 3.

The iPad comparison deserves some reflection. The iPad does have annoyances, things like lack of direct access to the file system and non-expandable storage (no USB). However I have never encountered foibles like power management not working, and as a tablet it is a better design (not just because there are abundant apps).

It is also worth noting that there is more choice in Windows tablets and convertibles than there was when Surface was first released. Some are poorly designed, but ranges like those from Asus and Lenovo are worth checking out. In a sense this is “job done” since one of the reasons for Microsoft doing Surface was to kick-start some innovation in Windows hardware.

I hope to get some hands-on with Surface 3 in the next few weeks and will of course report back.

Devialet’s Phantom audio system on show in Barcelona

I was glad to see and hear the French Devialet Phantom system at the Mobile Focus event in Barcelona, just before Mobile World Congress, having missed the company’s recent presentation in London.

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The Phantom is a device that looks like a giant eyeball, and is essentially an active mono wireless DAC and speaker. There are two models, the Phantom which delivers up to 99dB at 1 metre and costs €1690, and the Silver Phantom which delivers up to 105 dB at 1 metre and costs €1990. There is an optional Dialog unit at €299 which is a wi-fi router that creates a private network for the Phantom as well as supporting a guest network designed for music sharing. A Dialog can also control up to 24 Phantoms and is necessary for multi-channel; obviously for stereo you need at least two. An app called Spark runs on iOS, Android or Windows (not Windows Phone) and handles playlists as well as visualising music.

Each Phantom has a midrange unit, a treble unit, and two woofers. It measures 253 x 255 x 343mm and weighs 11 kg.

My encounter with Phantom did not get off to a good start. I am allergic to misleading jargon, and the pitch the Davialet representative made to me was confusing to say the least. “Digital chops up the sound,” he told me; but with hybrid technology Devialet was able to reproduce the purity of analogue sound. I observed that every DAC in the world is able to decode digital formats to analogue sound, and we had some difficulty progressing to what exactly is different about Devialet’s approach.

The case for the Phantom is not helped by the over-the-top language in the brochure, which modestly claims “the best sound in the world” and under a heading “IN TECHNICAL TERMS” promises Zero distortion, Zero background noise and Zero  impedance.

The system was playing Hotel California by the Eagles when I was there. I know the sound of this album well and it sounded boomy and unpleasant, though it is difficult to get good sound on a stand in a busy exhibition so I make generous allowance for that.

I did get a copy of a white paper which offers a bit more information. There are several technologies involved.

The first is what Devialet called ADH (Analog/Digital Hybrid). This combines class A amplification with the efficiency of class D. The way Devialet puts it is that several class D amplifiers act as slaves to the class A amplifier, so that the class D amplifiers provide the power while the class A amplifer the control.

A Texas Instruments PCM179x DAC is positioned next to the amplifier to minimise any loss between the two.

Next comes SAM (Speaker Active Matching) which processes the audio to compensate for the characteristics of the drive units. This “takes place ahead of the DAC and power amplifier section” according to the paper, so you could think of it as a kind of digital pre-amplifier. SAM has “a mathematical model of the complete drive unit, accounting for the electrical, mechanical and acoustical behaviour.”

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A third feature has the name HBI (Heart Bass Implosion). This tackles the tricky problem of reproducing deep bass with a small enclosure. The idea is to use a sealed box design for high efficiency at the lowest frequencies, a driver with long 26mm excursion (the difference between the foremost and backmost position of the driver) in order to move more air, and to use two symmetric drivers to cancel mechanical vibrations.

This does result in high maximum air pressure inside the enclosure, up to 174dB SPL according to Devialet’s paper. Most drivers collapsed in this environment, so Devialiet designed its own woofer.

Finally Devialet’s engineers figured that a sphere is the ideal shape for producing sound without “diffraction loss”.

The result, according to the specs, is 16Hz to 25kHz +- 2dB, and 20Hz to 20kHz +- 0.5dB which is impressive for a speaker system.

The problem with such measurements is that they typically taken in an anechoic chamber whereas actual listening rooms have all sorts of resonances that result in a much less accurate sound.

Does Devialet’s Phantom system sound as good as a more traditional system at its price level? That is the question which interests me; if I get an opportunity to try it out I will be sure to report back.

Playing native DSD with Raspberry Pi 2 and Volumio

There are many intriguing debates within the world of audio, and one which has long interested me concerns DSD (Direct Stream Digital). This is an alternative technology for converting and recovering sound from digital storage. The more common PCM (Pulse Code Modulation) works by sampling sound at very short intervals and recording its volume. By contrast DSD records the difference between one sample and the next, sampling at an even greater frequency to compensate for the fact that it only captures a single bit of data in each sample (ie on or off). For example the standard used by CD is:

16-bit precision, 44.1 kHz sampling rate

and by SACD (a DSD format):

1-bit precision, 2.8224 MHz sampling rate

The SACD was introduced by Philips and Sony in 1999 as an upgrade to CD, since it is a higher resolution format cable of a dynamic range of 120 dB and frequency response up to 100 kHz. It was an effort, like the PCM-based DVD Audio, to convince the public that the CD is not good enough for the best quality sound.

SACD was largely unsuccessful, mainly because there was not really any dissatisfaction with CD quality among the general public, and even some experts argue that CD quality already exceeds what is required to be good enough for human hearing.

That said, SACD was popular in the niche audiophile community , more so than DVD Audio. Some listeners feel that SACD and DSD results in a more natural sound, and believe that PCM has some inherent harshness, even at higher-than-CD resolution. Enthusiasts say that DSD stands for “Doesn’t sound digital”. For this reason, there is a regular stream of new SACD releases even today, and DSD downloads are also available from sites like Native DSD Music and Blue Coast Records. Some DSD downloads are at higher resolution than SACD – Double-rate or Quad-Rate.

The resurgence of DSD has been accompanied by increasing availability of DSD DACs (Digital to Analogue Converters). While these tend to be more expensive than PCM-only DACs, prices have come down and a quick eBay search will find one from under £100.

There are several complications in the DSD vs PCM debate. While DSD is a reasonable format for storing digital audio, it is poor for processing audio, so many SACDs or DSD downloads have been converted to and from PCM at some point in their production history. If PCM really introduces harshness, it is presumably too late by the time it gets to DSD. That said, it is possible to find some examples that are captured straight to DSD; this can work well for live recording.

Another complication is that some consumer audio equipment converts DSD to PCM internally, to enable features like bass management.

Is there any value in pure DSD? I wanted to try it, preferably with DSD files rather than simply with SACD, since this is much easier for experimenting with different formats and conversions as well as enabling Double DSD and higher. Unfortunately SACD is rather hard to rip, though there is a way if you have the right early model of Sony PlayStation 3.

The first step was to get a DSD-capable DAC. I picked the Teac 301 which is a high quality design at a reasonable price. But how to get DSD to the DAC? Most DSD DACs support a feature called DSD over PCM (DoP), which conveys the DSD signal in a PCM-format wrapper. DoP is not a conversion to and from PCM, it merely looks like PCM for better compatibility with existing playback software.

Next, I used a Raspberry Pi 2 supplied by Element14 (cost around £25.00) and installed Volumio, a pre-built version of Linux which includes an audio streamer and web-based user interface. You download Volumio as a single file which you burn onto a micro SD card using a utility such as Win32DiskImager. Then you plug the card into the Pi, connect to a home network via Ethernet and to a DAC via USB, and power on.

After a minute or two I could connect to Volumio using a web browser.

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My music is stored mostly in FLAC format but with a few DSD files in Sony’s DSF (Digital Storage Facility) format, and located on a Synology NAS (Network Attached Storage). In Volumio’s menu I went to Library and mounted the network share containing the media. Next, I tried to play some music. PCM worked, but not DSD. I changed the playback settings to enable DoP:

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Success: My DSD files play perfectly:

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If you squint at this image you will see that the 5.6 MHz light is illuminated, indicating that the DAC is processing Double DSD.

It sounds lovely, but is it any better than the more convenient PCM format? I am sceptical, but intend to try some experiments, using a forthcoming audio show to find some willing listeners.

That aside, I am impressed with the capability of the Raspberry Pi for enabling a simple and cost-effective means of playing DSD over the network, although with the assistance of an external DAC. It plays PCM formats too of course, and with Volumio is easily controlled using a mobile device, thanks to the touch-friendly web UI.