Components of an Audio System

• High-End Audio
• Beginning
• High-end?
• Components
• Starting
• Lingo

A stereo system consists of a number of components. I'll try to say what these are here, and make a few general comments about how high-end versions of such components differ from the typical consumer models.

Speakers

Everyone knows what speakers are. Their job is to convert the electrical signal coming from the amplifier into acoustic energy. There are many different sorts of designs of speakers, because there are so many different ways to accomplish this task, and different sorts of speakers have different strengths and weaknesses. Here, perhaps more than anywhere else, individual preference is what decides what is "good": The trade-offs that have to be made in actually producing a speaker, at any price point, are numerous; different designers will make different choices, which may or may not match your own personal inclinations.

One thing which should be said about high-end speakers is that they are often small, and can sound a bit lean in the bass, especially at the lower price points. There are two simple reasons for this.

1. Most widely available consumer speakers have a lot less deep bass than they seem to have: What they have is lots of mid-bass; it is easy to be fooled into thinking one is actually hearing really deep bass when all one is hearing is lots of inarticulate booming. High-end speakers do not play that game: They reproduce what they can and don't attempt to hide their failings by skewing their frequency response. (At least, they shouldn't: If they do, then by my definition, they are not truly 'high-end'.)
2. Making a speaker which does have really deep bass, without making that bass ludicrously muddy, is an expensive proposition. Physics tells us, for reasons I do not entirely understand, that how deep a speaker's bass is, to a significant extent, is a function of how big the speaker is (unless one is willing to pay an enormous penalty in efficiency, i.e., require huge amounts of power to produce reasonable volume). But one gets tight, solid bass only if the cabinet is non-resonant, well-braced and made of relatively rigid materials. The larger the cabinet, the harder, and more expensive, that is to pull off. So most high-end designers of lower-cost speakers make this compromise: They build small, rigid cabinets, sacrificing really deep bass for tightness, and putting the money they would have spent on a big box into drivers that will produce a musical midrange and smooth treble. That, after all, is where most of the musical information is. You can't hide bad midrange.

Of course, the quality of the drivers themselves (the woofer, tweeter, mid-range, and such) is also important: There have been many advances in driver-technology in recent years, and good drivers can be expensive to build. Another factor is the nature and quality of the crossover, which is a bit of electronics which directs the correct parts of the signal to the different drivers (sending the bass to the woofer, the high frequencies to the tweeter, and so forth). Since the signal itself is passing through these electronics, it is important to use high-quality parts, built to tight tolerances; and here too the designer can incur significant expense.

Amplifiers

A standard receiver is actually two or three or four components in one. It might contain a tuner, which is what you use to listen to the radio. It definitely contains a pre-amplifier, which accepts the signal from your other components, allows you to select among them, lets you set the volume, and provides some degree of (mostly current) amplification; and it contains a power amplifier, which accepts the signal from the pre-amplifier and produces the signal that actually drives the speakers. If the receiver has a phono input (few do nowadays), then it also contains a phono pre-amplifier, which accepts the very low-level signal from the turntable, applies RIAA correction, and then amplifies it to a level suitable for the main pre-amplifier to handle.¹

Power Amplifiers

First, then, the power amplifier. Its job, as said, is to produce the signal that will actually drive the speakers. There are lots of ways to do this: Tubes vs transistors marks the first, and most obvious, division. But I'll not go into that here. Be advised, however, that there are many very good tube amps available nowadays, of all sorts of different kinds, and that many listeners find the sound of a good tube amp irresistable. (But watch out for cheap tube amps. You get what you pay for, and a tube that goes bad will often take a speaker with it.)

One often hears a lot of talk about watts: Perhaps one of the things that most surprises people when they start to encounter high-end gear is that the amplifiers aren't 5000 watt monoliths. One of my very favorite high-end amps, for example, is the Pass Aleph 3, a tiny little box that produces 30 watts per channel. There are some very expensive high-end amps that produce less than ten watts, in fact. (These sorts of amps generally require extremely efficient speakers.)

Now, there are two major differences between high-end and consumer amps. First, high-end amps are actually designed to drive speakers, not just to produce impressive measurements on the test bench. Watts don't matter very much. What is much more important is the amount of current an amplfier is capable of delivering, given the requirements of the speaker, and how much control the amplifier has over the load it is driving. (The speaker itself is fighting the amplifier all the time: It's a resistive, and sometimes reactive, load.) A good high-end amp will typically deliver a great deal more current than a consumer one, providing it with much more control over the behavior of the speaker (and a greater ability to react properly to variations in the impedence presented by the speaker). And even waiving that point, 50W is usually more than sufficient to drive a moderately efficient pair of speakers to decibel levels that your neighbors would not appreciate. (For many years, I had a Pass Aleph 5, which produced 60W into an 8 ohm load. My speakers, Thiel CS 1.5s or 1.6s, were not insanely efficient. Yet it produced more than enough volume in my room.)

In a high-end power amplifier, much of the cost is actually absorbed by the power supply, that is, by what provides the raw current to the circuitry. This raw current is crucial. It is by modulating this current that the amplifier does its job, so every anomaly present in the current delivered by the supply is there in the output. (Think of the amplifier as trying to project the path of a small and varying (AC) signal onto that of the large, flat (i.e., DC) signal. Every effort is made to produce a clean, steady flow of raw current: That means taking special care to filter out unwanted contaminants from the AC line, which will otherwise find their way into the signal sent to the speakers; to keep additional contaminants from being introduced; and to prevent the sudden draw which a musical transient causes from causing a drag on the power supply and interfering with its ability to provide the raw current.

In fact, for these reasons, in any high-end component, much of the cost is in the power supply.

Pre-amplifiers

The pre-amplifier is the 'control center': It accepts inputs from source components, allows you to choose among them, and allows you to set the volume. Typically, it provides some amplification (usually current amplification), so the signal will be strong enough to drive the power amplifier (and the cables on the way).

High-end pre-amplifiers are often minimalist, compared with (the relevant part of) what one used to find in so-called rack systems (or a car audio system). For example, there are usually no tone controls (bass, treble, and assorted buttons). This is consistent with the Audiophile Ideal: Tone controls provide one with only the grossest ability to shape the sound; if one is interested in accurate reproduction, it is not a good idea gratuitously to alter the overall frequency response of the system. More importantly, tone controls insert otherwise unnecessary components into the signal path: This tends to result in the introduction of colorations, even when the controls are set to 'flat'.

There are, again, many sorts of pre-amplifiers: Tube and transistor, and even so-called hybrid models, which contain both. There are also so-called 'passive' pre-amplifiers (something of an oxymoron), which provide for source selection and volume control, but provide no amplification of the signal at all. In the right system, such passive pre-amps can be wonderful: They really do get out of the way. But in many cases, the amplification a conventional pre-amp provides just is needed for the power amplifier to be properly driven (especially if you want to use long cables between these components). A compromise here is a "buffer", such as the First Watt B1, which you can actually build yourself, if you can solder at all. (And it is not very hard to learn how to solder. I did, and I had no relevant training or experience.) Only a lot of experimentation can tell you what will work in your system, but there are general guidelines which a good sales person can explain.

Phono Pre-amplifiers

A phono pre-amp takes the very low-level signal from a phono cartridge (the 'needle'), applies RIAA correction (records are cut with the bass lowered in level and the treble boosted), and amplifies the signal to a level that the pre-amp can handle (line level). A good phono pre-amp is essential if one is going to get good reproduction from vinyl: The signal is so low in level when it emerges from the cartridge (around 5 millivolts, maximum, and often much lower) that very special care needs to be taken with it; tiny errors, which might be inaudible in other cases, can be disastrous here. The quality of the power supply is critical.

Phono-preamps are often just boxes: There are no visible controls; many of them don't even have on-off switches. But there are some controls it is useful to have, and different pre-amps provide one with different levels of flexibility.

First of all, it can be very useful to be able to set the gain on such a unit: Different cartridges have different levels of output and need different amounts of gain to produce a listenable signal. For example, many phono pre-amps allow one to choose between moving magnet and moving coil gain. Generally speaking, moving coil cartridges have much lower outputs than moving magnets, by a factor of ten or even fifty (though, as always, there are exceptions). A pre-amp that does not allow this choice almost always will restrict you to moving magnets, which are not usually as good.²

Second, cartridges often respond in different ways to 'loading', that is, to the input impedence (and even capacitance) of the pre-amp. It is nice to be able to experiment with this: I found, for example, that one of my old cartridges, a Sumiko Blue Point Special, sounded its most lush when run into 100 ohms; although that cost me something by way of gain, the BPS had a high-enough output that it didn't matter, in the end; one can often compensate for that by setting the pre-amp to a higher gain, anyway. (One needs to be a bit careful with this, though, as the higher-gain settings can introduce noise.)

Integrated Amplifiers

An integrated amplifier combines all of the above parts into one box (possibly excepting the phono pre-amp). There are sonic costs associated with this integration, largely deriving from the fact that the sort of power supply a pre-amp needs is quite different from the sort of power supply a power amp needs, and due to potential corruption of the signal in one section by what is going on in the other. That said, however, compromises must always be made and, especially at the lower price-points, integrated amps can make a great deal of sense.

Those looking to get into high-end audio might well consider an integrated first. It is well to be aware, however, that doing so can make one's upgrade path more difficult: One will have to buy a separate pre-amp and power amp at once, when (or if) one decides to upgrade one's system. Unless, that is, one buys an integrated which has a pre-out jack on the back, allowing the integrated to be used as a pre-amp, driving a separate power amp. Many of the low-cost integrateds made by high-end companies do come with this sort of feature. I myself took just this route some years ago, with an NAD 3225.

Source Components

CD Players and Assorted Accoutrements

The main source component of many audio systems when I first wrote these notes was the CD player or equivalent.³ A CD player in fact consisted of (at least) three parts: A transport, which spins the disc and delivers the bits; a digital-analogue converter, or DAC, which converts the bits into an analogue signal; and an analogue amplifier, which produces the current needed to drive the pre-amp. The last two, of course, go together more so than do the first two: The DAC is pretty useless unless there is enough power in it to get the signal to the pre-amp.

Some high-end audio companies abandoned the concept of the 'single box' CD player in favor of separate transports and DACs, connected by a digital link. After a while, though, that strategy has fell into disfavor: The process of getting the digital signal from the transport to the DAC itself introduced certain sorts of digital artifacts (mostly jitter, as it is known), which, even in relatively small amounts, can be musically disastrous. That led many designers to abandon the concept of separate transports and DACs and to return to the production of single-box units.

Before all that got sorted out, however, there was another revolution.

Music Servers and Such

Nowadays, it's obvious that CDs are dinosaurs. Most of us get most of our music online, through digital downloads or streaming. But before I go any further, let me say this: You cannot get true high-end performance from mp3, m4a, or any other "lossy" format, and I don't care how high the bitrate is. These sorts of compression throw away the very details high-end componments work so hard to reproduce, so if you just want to listen to mp3, then you're wasting your money on high-end audio.

Of course there are also lossless forms of compression, such as FLAC. These are perfectly acceptable. You can rip CDs to FLAC, and you can nowadays download FLACs directly from the web. My favorite band, Umphreys McGee, offers soundboard recordings of every show as FLACs, and so do many other bands. Tidal, Qobuz, and similar sites offer CD-quality streaming, or even higher-quality streaming (e.g., 192kHz and 24 bits, on Qobuz). And various other sites, such as HDtracks offers hi-rez FLAC downloads of a lot of great albums. You can't get everything that way, but you can get more and more every day.

How will we play the FLACs we ripped or downloaded or are streaming? The simplest way is to use a so-called USB DAC that you just plug into your computer. There are a lot of really good ones, such as the Benchmark DAC-1 USB. It's ridiculously good, and used versions (as of this writing) for around $500. You can get excellent USB DACs for much less, too. E.g., you can get some really good Schiit from these folks. In my own reference system, I use a Logitech Transporter. You can build similar devices quite cheaply nowadays, using so-called single-board computers, such as the Raspberry Pi, and using free software from people like Max2Play. But, honestly, there are so many options here, and more every day, that anything I write now will shortly be out of date. So, if you want to explore this kind of thing, drop me a note.

DACs, Again

The rise of music servers made DACs relevant again. A DAC, or digital-analogue converter, does precisely what its name says: It takes a digital signal and converts it to an analogue one, which you can actually listen to.⁴ Of course, there are many ways to do this, and DACs exist at many price points. My own experience lately is that, in some respects, we have reached near perfection with DACs, at around $1500, at least where CD-standard, 44.1/16 material is concerned. DACs that are at all comparable in price sound more or less the same to me now with such material (though better output stages can of course make a difference). And you can get outstanding sound for a lot less, e.g., from Schiit Audio.

Turntables and Assorted Accoutrements

Many people are surprised to hear that there are people who still listen to records (though there seems to be a revival amongst the youth). Indeed, some of us still think that a nice, clean record, played on a well-set-up, high-quality 'record player' sounds much, much better than even the best-produced digital recordings. This is particularly true as regards older recordings. For all the work that went into it, the 50th anniversary CD of Miles Davis's Kind of Blue (or the Beatles' Sgt Peppers) was made from tapes that were nearly fifty years old. The state of the tapes at the point simply can not be what it was in 1959 (or 1967), and the quality of the digital media reflects that. But even with current recordings, I hear major differences between digital and analog versions: The sound of a record is simply much more musical than that of a CD or download. To my ear, a guitar usually sounds more like a guitar when reproduced by vinyl; cymbals, in particular, sound much more realistic. Even more dramatic differences accompany the spatial aspects of a recording. High resolution digital is a lot better, and it can be very close to analog, but I'm not sure it's there yet.

What is usually called a 'turntable' (or, if you're really old school, a 'record player') consists of three parts: The turntable proper, whose job it is to spin the record, at the prescribed speed; a tonearm, which carries the cartridge, and whose job it is to hold the cartridge as steady as possible over the groove of the record; and the cartridge itself, which contains the stylus, or needle, and the electronics which convert the mechanical energy, created by the groove of the record, into an electrical signal, which can be sent to the phono pre-amp.

All of these parts are crucial. It is easy to think that the most important part is the cartridge: After all, that's where the sound is coming from. But many people think that the cartridge is the least important part. Not, of course, that it doesn't need to be good: It does; your 'table is not going to sound any better than your cartridge. But the cartridge can not do its job unless it is held precisely over the groove; it can not do its job if the tonearm is transmitting or storing up resonant energy. And it can not do its job if the 'table itself is transmitting all kinds of vibrations to the stylus, through the record itself, or through the tonearm. Moreover, many of the most annoying colorations one hears in poor turntables are actually caused by very slight fluctuations in the speed at which the record is being played. (Such minor variations can make a piano sound harsh and 'brassy', for example.) One Audiophile mantra is: Nothing is unimportant. Nowhere is that more true than with turntables.

Not only is 'table itself important, but so is how it is set-up, in particular, how the cartridge is set-up. One can not simply screw a cartridge onto a tonearm and expect to get good sound: The cartridge has to be aligned properly, so that the stylus meets the groove at the right sort of angle. This can not be done visually: The tolerances are much too small for that to be possible; it can only be done with the right sort of equipment. If you are buying a turbtable from a dealer, you can get them to set it up for you: But you will probably want to have some kind of system for yourself which will allow you to check, and reset, the alignment from time to time. There are a number of inexpensive 'protractors' which will allow you to do this. (These are not what you used back in elementary school.) And it is also worth having at least an inexpensive stylus-pressure gauge (these can be had for as little as $15), to check the tracking force of the cartridge. The little numbers on the counterweight are rarely very accurate (when they're there at all).

Unfortunately, there is one aspect of alignment that really can not be set once and left: This is the vertical tracking angle or VTA. Perhaps I'll add some thoughts about VTA later or elsewhere. For now, I'll just mention it.

A good turntable can, fortunately, be had for not much money: Such companies as Rega make solid 'tables for less than $500. And there are now several good 'tables that cost even less. But the best deal is a used table: One can get a truly terrific used VPI HW-19 Jr, say, for less than $500, with an arm, though it may take some searching to find one. Try audiogon.com.

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