…We’ll see if it gets to stay.

Used units of the Pass do surface on occasion, sometimes at the very outskirts of my financial reach, so perhaps it’s still an option. But buying second hand will make it very difficult to do a proper evaluation and I have no desire to buy anything blindly.

While my budget is insufficient for an integrated amp that does my speakers justice, I could cut the investment in half by just buying half the amp – I could get a separate power amp.  The problem, of course, is input selection and volume control. But if I can live with a huge bottleneck for a year or so, I could use my Allen & Heath Xone:42 DJ mixer as the preamp! Perhaps the bottleneck won’t even be that enormous – it’s one of the finer sounding mixers on the market, after all.

A benefit of the mixer-as-a-preamp approach is that by the time I’ve saved up (or acquired though forays into male prostitution)  enough money for a preamp, there might be more and better options of DAC/preamp combos than the Benchmark DAC1 PRE. Neither Esoteric nor Weiss built analog throughputs into their latest designs, so we’re probably a year or more away from proper competition in this category. With such a unit I could still get a two-box option by going with power amp and dac/pre instead of integrated and dac. Not counting the phono amp of course…

The downside of this is of course that I will have glorious speakers and a great power amp but mediocre sound for a year or more. Considering all the money and the effort that goes into this, which is about the lust for music in the end, it’s not a very attractive proposition. But neither is spending huge amounts of money on something that isn’t quite right.

On a whim (and after a beer or two), I listed my Lyngdorf TDAI 2200 amp for sale on Friday night. It got picked up by a new owner less than 48 hours later, so now I’m really in a hurry, but at least I’ve freed up some funds. The Stockholm Highend Fair is just a few days away, and hopefully I’ll find the amp of my dreams there, just like I found my speakers last year.

I think the deeper insight from all this is how much a consumer needs to know to make informed decisions. To confidently judge whether to spend money on a USB cable or dismiss it as placebo and a waste of money, the following needs to be understood:

• The fundamental difference between analogue and digital audio
• Pulse Code Modulation data structure, with bits and sample points
• How a clock pulse is used in D/A conversion
• The concept of jitter and its detrimental effect in the D/A stage
• Jitter supression using a Phase Locked Loop, or PLL
• Jitter supression using a memory buffer, and the inherent problems of buffer overflow or underrun
• The principles of packet data, with handshakes, tokens, data and status
• The difference between bulk and isochronous modes in USB
• How adaptive isochronous mode is fundamentally different from asynchronous isochronous mode
• Understanding the physical principles of electromagnetic interference, EMI, as it applies to cables

That’s just the basics for whether a USB cable can theoretically make a difference. No wonder the old hifi dinosaurs get it wrong.

A problem with integrateds is that you can’t upgrade single components. In my case it’s not just pre and power amplifiers that are in a single hull, but also DAC and DSP room correction. I can’t buy a new DAC since the amp has no analogue inputs, and with no analogue outputs other than speaker terminals, I can’t use it as a preamplifier either.

I actually can play vinyl still, but it’s cumbersome; My DJ Mixer also functions as a USB sound card. This means that it has built-in AD/DA. But to get that digital signal to the amp, I have to connect the USB to my Macbook Pro and then use it’s jitter-ridden optical output to the amp. Not only do I get USB and optical cables hanging like trip wires through the livingroom, but it also occupies my computer. On top of that, I don’t think the A/D of the mixer is quite top notch, regardless of how well its analogue parts perform. So to solve the most immediate problem which is that of vinyl playback, I’d need a proper A/D converter.

I’ve bought a Roland JP-8000 synthesizer, but I haven’t used it yet since I don’t have a sound card with MIDI. I could actually solve that as well as the ADC issue with a higher quality firewire sound interface, which I could also use for ripping vinyl to FLAC (Ican with the mixer too, but there’s that ADC quality concern…). But in order to make that investment really worthwhile, it should have a really good DAC section too. The RME Fireface 400 looks to be one of the finer products in the category (compared with cheaper options like still fairly potent TC Konnekt 24D) but considering how many things it does for the price, its digital circuitry is unlikely to stand even a sliver of a chance against something from Weiss or other single-purpose hardware. But those on the other hand are so expensive that I’d be better off putting that money towards an analogue amplifier, as the very point of the ADC route is to spend less money by getting to keep the Lyngdorf amp.

There is some middle ground however; The Metric Halo ULN2 is an external firewire interface just like the RME unit. At more than twice its price it’s still half of what I last saw the Weiss ADC list for, so it’s somewhat viable. The ULN2 has been getting a lot of attention in the computer audiophile circuit, where it’s used as a DAC. So I could then get an ADC to use with the Lyngdorf for now (and for vinyl ripping) as well as a good DAC for later when I upgrade the amp, and not immediately feel the need to upgrade again. So far so good, but of course there’s a drawback: It doesn’t have MIDI, so I’d still need a separate unit for music production. At it’s price, I would have needed all three legs to stand on to justify the purchase.

Even if I were to find the equivalent of a ULN2 with MIDI, I’d have to move it from the studio room to the livingroom each time I wanted to play vinyl. It would also mean that I couldn’t be making music in one room while my girlfriend plays vinyl in the other, so ultimately this path will not lead to a satisfactory solution. Perhaps if I found some sort of decent quality ADC for €100 or so, I could justify the purchase as a temporary fix. But it feels very uncomfortable pursuing a solution that is so short sighted and flawed. Back to the drawing board…

Having poured so much time and money into my speaker purchase, it would be wasteful to lower my standards and efforts for the other components. The required patience is in short supply however, as all my hifi investments from here on will have a smaller effect on the sound than the speaker upgrade brought. It’s tempting, then, to just go with what is affordable and sounds decent and get the whole thing over with. But where patience is scarce, ambition still soars high – I know myself too well to think I can find contentment with anything that isn’t thoroughly researched, auditioned and compared.

My main problem right now is that there’s a huge ever-branching delta of upgrade routes, and each one presents different problems in terms of equipment evaluation, system coherence, audio philosophies, financing and everything in between. In an effort to make the whole endeavour a little less intimidating, I’ll try to put the available paths into words. It’s all for my own benefit, but on the off chance that someone else finds it interesting, I’ll post it here.

But before I go all Freud on issues of amplifier technology and cables, lets look at what my starting point is. After buying the Focal Diablo Utopia speakers I immediately started looking at other components, and felt that a better DAC would provide a sizeable improvement. Many people don’t realize what a huge difference in sound there can be between CD players, and this has everything to do with the DAC. I was also painfully aware that my NAD C370 amplifier wasn’t the poster child of resolution and elegance, nor were my Technics 1210 turntables with their shitty stock tone arms and DJ cartridges. Last but not least, room acoustics is a huge factor in any audio system, so perhaps I should address that before everything else?

In the midst of this I came across a rather appealing deal on the Lyngdorf TDAI 2200 RoomPerfect amplifier. I won’t get into deeper technical details here, but it’s a digital amplifier, and hence has digital inputs. It also comes with a microphone and a DSP circuit that lets the amp adjust the sound based on room acoustics, speaker placement and listening position. As this solved the issue of DAC, amplifier and room acoustics (sort of) in a single unit that I could actually pay for, I bought it.

Without the RoomPerfect stuff, there was a small but noticable improvement in sound. The highs got a bit more texture and the sense of overall control improved. Calibrating the thing for the DSP correction gave some difference in the bass, but not by much and it was more different than it was better. If the units display is to be believed, my room and equipment needed only very minor adjustments, so as it turned out this feature wasn’t all that necessary. It was certainly no DarTZeel, but the overall sound was very nice, and honestly one I wouldn’t really be in any rush to throw more money at.

There is however a small problem with having only digital inputs, namely this:

I could no longer play vinyl, as the amplifier lacks analogue inputs. As you can see, that is quite a large amount of music now quarantined indefinitely. Running analogue signal to a digital amplifier is technically unappealing since it means an unnecessary A/D–D/A conversion, but right from the start I regarded the Lyngdorf as a temporary solution anyway. Upgrading the amp with analogue inputs is about €500, which isn’t cheap but at least somewhat agreeable. What is absolutely prepostrous however is that you can’t install the card yourself, and it has to be done at the Lyngdorf factory in Denmark. Better yet, it takes 5 weeks. There’s no fucking way I’d be out of music for a whole month, and the stupidity of this policy means I will absolutely refuse to take this route.

This is where I’m at now. I have a device that needs to be replaced with an amplifier (integrated or separates), DAC, and acoustic treatment for the room, and then I also need to improve the vinyl rig. Where to begin, how and for what cost is what I need to figure out.

I normally just write stuff here for my own enjoyment, as a way to flush my system of thoughts on a certain topic. But with digital audio I’ll see if I can fire up my inner philanthropist and start at the very beginning, going through things I’ve already known for 15 years. I think it will be an interesting challenge and it would make this series a lot more complete if I do. I will attempt to put everything in laymans terms, so even fundamentalist vinyl cavemen can follow my reasoning.

The first thing I need to define is what digital actually is, especially in terms of audio. To do that, you need to know how sound works, but I won’t regress into the basic physics here. So assuming that you’re familiar with the fundamental principles of waveforms (like the sine wave in the oscilloscope above), let’s look at how they are stored as data rather than as a groove in a vinyl or magnetism on a reel tape.

Imagine a chess board. It has 64 squares arranged in an 8×8 grid, denominated A-H along its X axis and 1-8 along the Y. In chess you cannot place your pieces on E4-and-a-half or anything like that; they have to obey the grid, so you’re either E4 or E5. This same type of rule exists with digital audio, in that a sine wave cannot be drawn as a smooth curve like in our analogue oscilloscope screen above. In fact, the image above has a faint square pattern on the screen, so imagine trying to approximate the sine wave by tracing the dark lines of this grid. This is how sound is stored as data; a series of coordinates with time along the X axis and amplitude along Y. The horizontal distance, or time, between these coordinates is constant. So that value is just a frequency rather than coordinate data for each point. This frequency is kept by a clock, and we’ll back to that later.

As you may guess, the finer grid you have, the closer you get to analogue sound. Inversely, a coarser resolution will reveal more of the unnatural sounding sideeffects of digital sound. There is no information of how the waveform is supposed to look between the points of data. There is simply no information there, so after each sample point the waveform is drawn straight ahead along the X axis until the frequency clock says it’s time for a new data point. Once there, the waveform is drawn straight up or down to get to the new coordinates. Because of this, the waveform isn’t drawn as a connect-the-dots chart, but with orthogonal angles:

The vertical axis, which denotes amplitude, is stored as a 16 bit value in CD audio. Now what the hell does that mean, you might ask. A bit in digital terms is a single one or zero, so at 1 bit you would have full amplitude or silence – 1 or 0, respectively. At two bits, you can have four combinations: 00, 01, 10, 11, essentially meaning you could have four different amplitudes in your waveform. So moving all the way up to 16 bits, there are 65384 possible combinations of amplitude. While it might be difficult to hear the difference in loudness between 47361 and 47362 in amplitude, there are other reasons to desire even higher bit depth.

So that’s the basics of CD audio, really – a clock-timed series of amplitudes stored as a 16-bit values. When converting something to digital, the strength of the electric signal in the microphone is measured at the rate of this clock, and stored as amplitude values. When playing it back from digital, the amplitude values are read at the pace of a new clock (hopefully indistinguishable from the recording one!) and a new electric signal is throttled according to these amplitudes. It’s a bit more complicated than that, but I’m sure you get the point.

Now that the basics are laid down, my next post will go through the ways in which these conversions, mainly focusing on digital to analogue, can get messed up and how to avoid these pitfalls.

A slight disclaimer: The above explanation of digital audio is for pulse-code modulation, or PCM for short. There is another, perhaps slightly less intuitive way of storing sound as data that is called Pulse-Width Modulation which is used on Super Audio CD’s under the name DSD. Since it’s trickier and far less common I won’t describe it further here.

First of all, I need to figure out where to aim my priorities next.

My current amplifier, while immensely powerful, is not the poster child of resolution and finesse. When I heard the darTZeel pre/power combo drive the Diablo’s big brother Scala Utopia it became very evident that these speakers can convey a lot more than what amplification a tenth of the darTZeel price is able to summon. In fact, my amplifier cost one fiftieth of the darTZeel combo…

Another step back in the signal chain, and we get to my Squeezebox Duet. The user friendliness of this system is of such a magnitude that I honestly don’t know how I put up with shifting CD’s before. A server-based music system is an absolute necessity for me now, and I can’t even imagine going back. However, it’s a rather cheap device. Considering the price of the Receiver, which is the bit that actually plays music, it’s amazing that it sounds as good as it does. The thing includes a wireless receiver & transmitter, wired network card, DAC and unbalanced RCA output stage, all for the price of a parking ticket or around 6-8 CD’s.

While I’m not an adherent of the Source First philosophy, I think my Return On Invest would be greatest if I gave my digital source attention before I move on to amplification. Thus, from here on my hi-fi posts will be about DAC research and other aspects of server-based music systems.

I do have a shitload of vinyl, but I’m ignoring that for now. An upgrade there might come before the digital source though, and when/if the day comes I’ll make sure to give it its due attention.

I arrived just 40 minutes before I started playing, since I had to get up at 6am on Saturday to catch the flight to Brussels and hence needed to get some sleep before playing. Then I also had to jump into a cab to go straight to the airport after my gig, so I didn’t get to socialize much. Thanks however go out to Arne for booking me, Joske and Sammy for their neverending hospitality and friendliness, Philip for the record (nice to finally meet!), Matthias for buying some vinyl from me and Billy (Cosmosis) for the nice handover and for being such a nice bloke.

What impressed me the most with the MBL 121 speakers was their stunning ability to illustrate the space of a recording. This makes them nearly unbeatable for classical, jazz, singer-songwriter and live recordings. Since I don’t listen to those types of music much, instead often drawn to “produced” sounds, this argument loses some of its weight in my case. Instead, their ability to provide an accurate and deeply satisfying soundstage from virtually anywhere in the room, including standing up, becomes their most compelling advantage. For social listening, this is tremendously valuable.

While the sweet spot of the MBL’s is essentially everywhere, the Focal Diablo’s laser precision are less forgiving. But once in that spot, are they ever rewarding. Sounds are given such body and texture that the tastebuds are triggered — I can literally sense the taste of vanilla and cream when Mari Boine sings “Goaskinviellja“, so smooth is her voice. Likewise, fizzing, distorted, black metal guitar resonance noise can trigger a taste sensation similar to that dry, astringent tongue sensation provided by an extremely hoppy beer. While I am mildly synaesthetic, i have never ever felt it this clearly with sound before. This almost supernatural effect aside, they still sound mindbogglingly controlled and tight, yet wide open and completely unstrained regardless of what madness is forced through them.

So in the end, love at first sight did prevail. The choice I had feared having to make blossomed into certainty. I made a pact with the devil and couldn’t be happier.

I am well aware that my purchase means I will have to run them with my existing electronics for some time to come, which means even though the sound is already fantastic, they will not be close to their full potential until the other components have been upgraded. I will do my best to scrape together enough money to upgrade one of my DJ turntables, get some acoustic room treatment in place and most of all put a proper DAC between Squeezebox and amp. In case I somehow manage to keep up my blogging pace, I intend to start a new series on Digital to Analogue Converter technology. It will serve both to help me learn more about the technology and also to sift through the market and try to find the holy grail of DAC’s. I might get a couple of more detailed listening impressions posted too…