Several of you have asked me to expand this little mini series on tubes and transistors by one day to help understand bias, what it means and how it works.  Understand that this is actually a bigger subject than I can comfortably cover in a small daily post but I’ll do my best – and to do this let’s design a single ended amplifier together – right here in this post.

Remember in our understanding of the different types of devices we have two: voltage devices (tubes and FET’s) that are always on and we have to turn them off – and current devices (bipolar transistors) that are always off and we have to do the opposite.  With this understanding in mind we can now easily appreciate that each of these devices can be used in one of two ways: as either a switch (on/off) or an amplifier (moving between the two extremes of on/off).  To make a tube or FET a switch we need to simply turn it all the way off or let it go back to all the way on – and then the opposite for the bipolar transistor.  Just as a side note – in the late 1940′s early computers used vacuum tubes as electronic switches requiring huge rooms and building full of them to perform even simple calculations.  The term “bugs”, associated with computer program glitches, is rumored to have come from this era as the glowing tubes attracted moths to the light that wreaked havoc in the systems.

To make an amplifier we need to stay away from using the device as a switch – we never want to reach the two extremes of always on or always off if music is going to come out of our device without distortion (the always on state is called clipping).  This means we need to use the device in its in between state, and we want to begin our journey right in the middle.

So, let’s design our little amplifier using a single device – in this case we’ll choose a JFET and design a single ended amplifier.  To do this we need a few elements: a battery and 4 resistors.  We want a gain of 10 for our amplifier – meaning if we put 1 volt on the input we will get 10 volts on the output.  This is easy.  Remembering our device has 3 nodes: the signal input (gate) and the 2 battery inputs (drain and source) we place a resistor on the drain and connect it to the + of our battery and another resistor on the source and the – of the battery.  We make sure the + resistor is 10 times bigger than the – resistor (this sets our gain).  We’re almost ready to amplify our signal.

On the input side (gate in a FET, grid in a tube and base in a transistor) we want to make sure the device sits right in the middle of the battery voltage – this is important because we want our musical signal to have room to move – and move somewhere away from the two extremes (always on or always off).  This process is called biasing the amplifier.

Let’s imagine we have a 30 volt battery – we want our device to therefore rest at half of that or 15 volts.  In a FET, tube or transistor this is really easy, we simply use two more resistors on the input that have a ratio such that we get 1.5 volts at their meeting point.  One goes to the – of the battery and the other to the + and when our little amplifier sees this, it produces 15 (1.5 x 10) volts on the output.  Bingo, we have an amplifier.  The output of this amplifier is taken at the junction of the + resistor and the drain.

Now, when you put our phono cartridge on the input, the tiny voltage is amplified and we get a 10 times larger signal on the output which makes music!

Sorry this was so technical and it’s the last one that will be – promise.  Tomorrow we wrap up the series with some comments about how all this ties together.

Let me leave you with one interesting notion, that of field effect.  Remember that in a tube or FET there is no physical connection between the input and the output – everything is controlled through a mysterious “field” that goes through the air and magically turns the device off or somewhere in between on and off?  How the heck is that possible and is there an example of this in real everyday life?

Sure – and this is one I delight in leaving people with because it gets your brain spinning.  Picture yourself driving in your car down a busy city street.  Suddenly, the light ahead turns yellow and you slow down.  The light turns red and you stop and wait.  The light turns green and you go.  Sound familiar?  This is the same exact way a field works – only this time the field is working on you.  In the traffic example a change in small particles called photons has this effect and in our transistor the particles are called electrons.  In both cases there’s no apparent physical connection or touching yet control happens perfectly.

Now you know you’re no different than an amplifier.  Just make sure you sit in the middle and don’t go running any red lights.

We’ll wrap up the series tomorrow.

For example, one might consider a tube preamplifier as the ultimate amplification device in terms of musicality but the fact is that preamplifier has many problems including microphonics (the propensity of a device to act like a microphone and reproduce what the speakers are playing), tube sonics going downhill with every hour you use it, noise, etc.  Or, perhaps you’ve found the perfect solid state preamplifier but long for a bit more of that tube warmth or low level detail and attention to the wonderful openness tubes possess.

I hope the one thing I was able to get across in this series is that as designers we have choices.  We can first learn all there is to know about the what and why each of these device types reacts the way they do, then use the advantages of both in our design.

As another example I mentioned that a voltage device always makes for a better input than a current amplifying device – but that’s not always true.  Nelson Pass, for example, has shown that if you take a simply bipolar transistor and run it at high voltage in a single ended mode, just like a tube, it sounds extremely musical and you get the best of both worlds.  There are always penalties, of course, heat and restrictions that may not be acceptable can be part and parcel to such an approach.

On the other hand, a careful examination of each device’s strengths and weakness coupled with intelligent design implementation can result in absolutely wonderful and musically satisfying high-end equipment.  Unfortunately most designers seem afraid to mix and match – maybe because they don’t really know all this, perhaps they just want a cleanly executed design specific to their genre or perhaps it’s just easier to throw a chip amplifier into the design and call it good (lazy).

I can remember when Audio Research first introduced a sold state voltage regulator in their tube preamplifier – the howls from tube lovers the world over smacked of heretical thinking and they wondered if Audio Research had finally gone over to the dark side of solid state.  Actually, they had taken a bold move to use the right device in the right application.

When designers display the courage to step outside the tried and true norms people have come to expect, magic can happen in high-end audio gear.

Tomorrow the I answer a few questions about biasing and the following day, the last in the series.

Many of us have also heard that tubes produce a warmer sound due to the fact they have even harmonics and transistors are harsher and colder producing only odd harmonics.  While it’s perhaps true that even harmonics (a simple doubling of the frequency) may sound more welcome that odd harmonics (times three) in the broadest sense it isn’t actually the device that is responsible for the focus on harmonics it’s the way it is used.

Most tube preamplifiers are single ended amplifiers while most solid state designs are not.  This has a lot to do with how each sound – not because it’s a tube or a transistor but how it is used.

In a single ended design there is one amplifying device covering the entire musical signal while in a push pull or complimentary design there are two: one for one half of the signal and the other the remaining half.  The simple fact that second order harmonics are louder than third order harmonics in most any device dominates the single ended approach while push pull and complimentary designs cancel these distortions by the very nature of their operation.  What this means is that any device, tube or transistor, will display the same basic character with respect to odd or even harmonic distortions depending on how it is used.  The fact that tubes more typically are used single ended than most transistors is the reason the audio “facts” have evolved about the warmth of tubes vs. transistors.  Fact is, in practical applications it’s mostly true!

Designers of both tubes and transistors can make choices and tradeoffs to achieve their goals.  For example, one of the tradeoffs of tubes is they have relatively high output impedance and are not easily capable of driving a loudspeaker directly – where the opposite is true for transistors.  This is the reason most tube power amplifiers have large output transformers and transistor amplifiers do not.  The transformer “fixes” the tube output issue but, of course, has many drawbacks sonically.  Some designers have gone to great lengths to fix this problem by designing what’s called OTL or output transformerless amplifiers.  While not ideal it does show that where there’s a will there’s a way.

The point I’d like to get across in today’s post is that much of what we relate to as “common knowledge” between the differences of tubes and transistors has as much to do with how they are implemented as the devices themsleves.  Some of it is a Catch 22 – where the implementation differences are necessitated by the limitations and advantages of each device type – but much of it is simply a pure choice by the designer.

Tomorrow we get to discover a bit of the best of both worlds.

What I have to share hopefully will be interesting to both the uninformed as well as those knowledgable in everything electronic except how to make something sound good.  There are many fine electrical engineers that can make excellent amplification devices but they won’t necessarily be high-end and they’ll not likely produce musically satisfying results.

Remember in our earlier discussions I mentioned there are two types of transistors: the standard Bipolar Junction transistor (BJT) and the Junction Field Effect Transistor (JFET).  The former acts like everything we associate with a transistor and the latter more like a tube.  It is to this difference that I want to address today’s post.

In a typical BJT used in 99.9% of all solid state amplification devices such as preamps, power amps and DACS, there is a physical connection between our three nodes – the input, output and power connection.  A change in one will be reflected in the other three – which means that our phono cartridge we’re using as a source is not isolated from changes we make in our amplifying device – something not good for sonics.  Again, just to keep the feathers from being ruffled too much – yes there are tricks and methods to reduce these effects – but natively and without these modifications what I have mentioned is true.

In a tube or JFET this is not the case.  The input is basically immune from any changes to the other two nodes in this type of device and the physical connection does not exist – instead a field is generated that impedes the flow of voltage in the device.  We refer to these types of devices as voltage amplifiers and the BJT as a current amplifier.  Voltage amplifiers are always on and the input merely turns them off – referred to as “pinching” the voltage – where current amplifiers are the opposite and considered more like a pump.

In fact, a good way to view these two types of effects would use a water analogy.  In a BJT current device picture a hand pump for water.  If you want the water to flow, start moving the handle of the pump up and down and you force water to flow.  In a voltage device, picture the water already flowing in a hose and then pinch or squeeze the hose to restrict that flow.

What’s the big deal between these two types of devices?  Simply put when used as an input to a source like a phono cartridge, CD player, or even a power amplifier the current amplifiers don’t handle micro dynamics and low level details anywhere near as well as the voltage amplifying devices do – because they don’t naturally respond to these low level signals having a certain amount of current required to get them moving at all.

I know, I know, there are many fine examples of this not being true, ways of biasing that overcome these obstacles and tons of technical reasons to argue the point – but in case after case tube and transistor input circuits almost always outperform their current amplification counterparts in these two critical areas of music.  I have numerous examples of our designs at PS over the years where we simply replaced the input bipolar transistor with a JFET and a whole new world of musicality opened up.  The hard edge of the upper harmonics and low level detail associated for so long with transistors is gone and in its place a musicality from both the lowest level details to the highest is achieved that is rare amongst amplification devices.

What we can conclude from all this is that when it comes to tubes vs. solid state used as a connection between a source and the internals of the amplifier, designers are much better off to place a voltage amplifying device on the input (tube or JFET) rather than a current amplifying device.  The lack of a physical connection seems rather important to achieving the musicality anyone reading these posts would most likely want to hear.

Tomorrow I was going to cover transconductance (how a voltage amp works) vs. Gain (how a bipolar transistor works) but some of you have written asking me to focus a bit more on the sonic differences between the two and focus more on how they are implemented.

Tubes and transistors are only partially linear devices – which means they will not always faithfully reproduce a larger version of the input signal on their outputs.

In our example yesterday we placed a phono cartridge on the base (input) of a transistor and connected a loudspeaker to the output of the transistor.  This works as an amplifying device but at the quietest and the loudest extremes of the phono cartridge’s output the transistor (as well as the tube) don’t produce an exact but larger replica of the input.  Only signals that fall somewhat in the middle loudness region are handled with perfection.  Now, granted this is a major over simplification for those of you amongst our readers that already understand this, so please bear with me.  The thrust of this argument is what’s important to our understanding.

Take a look at the following picture which shows a “typical” linearity curve.  What this is showing is signal out for a constant rising signal in.  Starting left to right, we are seeing an increased output voltage – with the quietest signal on the left and the loudest signal on the right.  If I included a picture of the input signal you’d note that would be a simple straight line going from the lower left corner to the upper right corner.  A perfect output curve would be the same – whatever I put in, I get out – just larger.

You can see that only a portion of the middle signal is linear – output perfectly matches input.  Now, don’t panic because as circuit designers we have many ways to “linearize” this response curve which include different biasing schemes, feedback methods etc.

What’s important to this discussion is that from a high-end perspective we would like a perfect device because the fewer tricks and schemes we employ to achieve a linear response from one extreme to another the better, cleaner and more open our musical presentation will be to a given piece of equipment.

There are no perfect devices – but remember in yesterday’s post we mentioned that tubes run at much higher voltages than most transistors in a typical amplifying circuit?  Think about the curve in the graph on this post which is showing the output voltage of a device.  It should be obvious that the greater the voltage the greater the linear region.

Let’s imagine that the graph represents 10 volts and the linear region is about 50%.  That means that even on a good day you get a 5 volt linear region to play with – not a lot from a designer’s standpoint.  Now imagine that the same graph represented 100 volts which is a 10X increase – which gives us 50 volts of linear region!  This is huge and more than we would ever need as designers.

From a sonic standpoint we hear image and apparent micro and macro compression as we get near the edges of our linear region and the ear picks these cues up immediately and recognizes something has changed.  This is one of the primary reasons why most tube circuits sound so open, effortless and compression free at the quietest and the loudest extremes of the musical presentation.  Think of this as a car analogy – if you have an oversized V8 engine in a small car, chances are good you won’t notice any difference in performance from the slowest speeds to the fastest speeds.  Change the engine out for a tiny 4-banger and your acceleration and top end speeds are compromised as the tiny engine struggles to do its best.

So while neither tubes nor transistors are true linear devices, the one with the highest voltage wins when it comes to an open and effortless soundstage with perfect micro and macro dynamics.

Notice that I didn’t pick out tubes as the winner in this closing statement – just that used without a lot of knowledge to these effects, a pedestrian solid state audio designer (vs. a pedestrian tube audio designer) will always lose the sonic battle – hence, most tube designs sound more open and effortless than most solid state designs.

However, once armed with this knowledge we can have the freedom to express ourselves with either discipline – so as solid state designers we can choose our working voltages to take advantage of this knowledge.  For example, in most every PS Audio amplification device we have always run two to three times the typical voltage used by other designers for this very reason.  Others have done the same – but it is NOT common practice.

Tomorrow let’s focus on one other difference between tubes and bipolar transistors, fields vs. solid connections.

Let’s start with what the two have in common: they both are linear amplification devices and they both have three nodes to control them.  Linear amplification means that when you place a small signal (voltage and current – like that of a phono cartridge) on their input, they will make a larger and more powerful replica of the input.  The three nodes we have to remember are that each device type has one node that goes to the “-” of a battery, another goes to the “+” of a battery and the third – the middle one – is used as an input for the small signal you want to convert to a bigger signal across the other two nodes.  Actually there are numerous other schemes using these 3 nodes to amplify but those are beyond the scope of this short primer.

Next let’s understand there are two types of transistors: junction and field effect.  Bipolar junction transistors (BJT) are what most of us would think of when we picture a transistor.  This transistor fits all the classic models and is used in the majority of today’s amplification devices and early computers.  The field effect transistor (FET), on the other hand, acts very much like a tube.  This is the device the very first researchers described but could never figure out how to make until much later than the junction transistor came into use.  Some high-end amplification devices and most computers use FETs today.  PS Audio, for example, uses FETs in all of our audio amplification products to get a bit of the warmth associated with tubes – Nelson Pass is also a big advocate of the FET.

Skipping some of the obvious physical differences between tiny solid state devices (transistors) and larger glowing glass envelopes sometimes called “fire bottles” (tubes), let’s get to a couple of significant differences that will help us understand how these two classes of devices sound differently in high-end audio amplification applications.

Perhaps the single biggest difference between transistors (both BJT and FET) and tubes is the voltage they operate at.  Tubes operate at very high voltages, typically on the order of ten times higher, while transistors operate at relatively low voltages.  There are, of course, exceptions to these broad views – there are both low voltage and high voltage devices in both classes – but I don’t believe they are relevant to this post since 99% of high-end audio products use these choices in their classic architecture.

The second biggest difference is two fold: the BJT amplifies current and is always off, the tube and FET amplifies voltage and are always on.

How these two main differences in devices are managed and the results of using the devices in high-end audio is a topic for tomorrow’s post: High voltage and linearity.

See you then.

I promised yesterday to tell you more about the crystals that people were using for radios and how years later those mysterious crystals would again play a major role in everything we do today.  Here we go.

Around the turn of the century experimenters discovered that certain types of natural crystals would act like a radio receiver for the new fangled Marconi wireless radio signals.  No one understood why they worked, they just did.  What’s was cool about these crystals was they required no power to operate – no battery, no AC, nothing.  All you needed to make a crystal radio was some wire, a crystal and a set of tiny headphones and with a little luck and fooling around you could get in on the new radio era.

Soon commercial versions of the crystal radios became available and within 20 years of their introduction there were millions of crystal radio sets around the world enjoying the new commercial radio broadcasts of the day.  What killed the crystal radio was the new Audion tube receiver we learned about yesterday.

So we have two interesting paths: the crystal radio path that started in about 1902 and ran its course through about 1920 and the Audion and later Triode tube radios that started about the same time but didn’t begin their decline until the 1950′s when the transistor was first introduced.  Coincidently the transistor’s popularity and subsequent public awareness came about because a fledgeling upstart company, Texas Instruments, needed a mass market appeal product that used the new transistor with enough volume so they could lower manufacturing costs.  That turned out to be the transistor radio which also gave another fledgeling upstart company its birth when Akio Morita and Masaru Ibuka decided to take a chance on the new device and start a company called Sony.

These disparate yet related paths started with the mysterious crystal that no one understood.  Experimenters had known for years that if you placed a tiny whisker of wire on the surface of a crystal, connected the wire and ground through a coil of wire, you could receive radio signals.  The crudest implementation of this weird phenomena required users to carefully place the whisker on just the right spot on the crystal to get the loudest sound through the headphones.  These were known as “cat whisker” receivers and sometimes took hours and hours of experimenting to find just the right spot on the crystal.

Enter three physicists: John Bardeen, Walter Brattain and William Shockley.  Bardeen and Brattain were traditional physicists who worked for the new Bell laboratories and had been charged with trying to figure out a way to get rid of the vacuum tube in the telephone system.  Vacuum tubes, by the late 1940′s were used through the phone system as amplifiers and mechanical relays were used as switches.  The nationwide phone system worked – barely – but making long distance calls was something of an ordeal employing thousands of inefficient vacuum tubes and failing relays.

Bardeen and Brattain were intrigued with crystals and were focusing their research on trying to figure out how they worked and if it might be possible to use them as a replacement for vacuum tubes.  They had figured out by this time that the reason crystals worked as radio receivers was their curious ability to pass current only in one direction.  Radio signals, which are AC, need to be turned into DC so you can operate a headphone.  By passing the radio signal through a crystal you cut off half of the AC and what remains is a type of moving DC that goes back and fourth to the music on the radio wave.  The two researchers were trying to see if they could get more controlled results using the cat whisker and control more current than what naturally occurred in these crystals.

William Shockley was what we might have called a hippie had this history been written in the 1960′s.  By all accounts a wild and crazy guy, completely full of himself in every respect and went to work at Bell Labs with an idea that also involved crystals.  Instead of using the cat whisker to physically touch the crystal, Shockley wanted to make a grid of metal (remember the vacuum tube grid from yesterday?) and induce a current “in the air” that could control the crystal without any physical contact.  He made numerous attempts at this, all of which failed during this phase of the research.  Unknown to Shockley at the time physicist Julius Edgar Lilienfeld and later Oskar Heil (yes, of the Heil Air Motion transformer loudspeaker fame from ESS) had already patented such a device called a Field Effect Transistor (FET) although they never actually made anything that worked.

Bell Labs put the three physicists together in a team headed by Shockley (much to the horror of the other two) and they plowed through several years of work which culminated in the discovery of the solid state diode and soon after the first transistor.  Shockley tried to nab credit for the invention and was first to submit it as a field effect device – only to then discover the older patents.  Panicked and discouraged Shockley went  home and in a stroke of pure genius, figured out what is known today as the junction transistor consisting of three elements (just like the vacuum tube), the base, the emitter and the collector.  You’ll recall that in the vacuum tube we had the grid, the anode and the cathode – which loosely translates to the same thing in the transistor.

In 1956 Bardeen, Brattain and Shockley were awarded the Nobel prize for their discovery of the point contact transistor and I can safely suggest the world has and will never be the same.  If you want to enjoy some terrific reading on the subject by a writer far more gifted than I read Crystal Fire the birth of the information age by Michael Riordan – a great storyteller.

The transistor can be thought of like the tube with its two current flowing elements (anode and cathode in a tube – emitter and collector in a transistor) and the middle “grid” or “base” that is controlling the flow (like a valve) of the current – only, unlike the vacuum tube, the transistor is always off (remember the tube is always on).

To picture a transistor working we take a battery with one end the + and the other end the -.  Place the + end of the battery on the transistor’s collector and the – on the transistors emitter.  When you do this in a transistor, nothing happens – no current flows through the battery because the transistor is always off.  If the same model were used to explain the tube, current would flow immediately because the tube is always on.

If you take a little bit of the + voltage and apply it to the base of the transistor, a current starts to flow between the emitter and the collector.  If we again attach a phono cartridge between the – of the battery and the base of the transistor, then when you play a record on the turntable the small voltage generated by the phono cartridge will make a big voltage flow between the emitter and the collector – should you have your loudspeaker attached at that point you will get music.

Tomorrow: The fundamental differences between tubes and transistors

You may have heard the term “Audion” as there is a UK manufacturer using the name to build tube electronics as well a popular MAC MP3 player software leveraging the name as well.  The true origins of the name refer to the first tube amplifier invented by Lee De Forest in 1907.  Until the invention of the Audion there was no such thing as an electronic amplifier.  De Forest’s invention was not an audio amplifier but rather a radio amplifier – but it started something big for audio.

In the early 1900′s radio, then known as “wireless”, was listened to on crystal radios – basically a piece of crystal with a tiny wire touching the crystal surface and both crystal and wire connected to a set of headphones.  De Forest was looking for a way around using crystals – playing with heating a gas to mimic the action of the crystal – a well known but unexplained phenomena at the time.  To take advantage of the heated gas’s tendency to conduct electricity, he captured some of the gas in a glass envelope called a tube.  Around the glass tube he wrapped some wire and to that wire he attached a set of headphones – he heard radio.

In later experiments he discovered that if he placed a small piece of wire inside the glass tube, formed in a grid pattern, the radio reception was improved.  He now had a wire at each end of the glass tube and one in the middle.  De Forest had stumbled onto what is known as a Triode: meaning it has 3 parts.

While DeForest’s triode worked better than any crystal radio receiver of the time it was not a linear audio amplifier – it was a non-linear radio receiver.  DeForest had incorrectly determined that the glass tube had to be filled with gas in order to work – which was the entire basis of his thought.  In fact, so convinced was he of this fact the patent he took out specified the gas requirement and the name “Audion” came two words: Audio and Ion (as in ionized gas).    Turns out he was dead wrong.

It wasn’t until 1912 that Irving Langmuir of General Electric figured out the Audion could become a linear audio amplifier by removing all the gas DeForest had so adamantly demanded be included.  Once the gas and the air had been removed from the glass tube what was left, of course, was a whole lot of nothing called a vacuum and to this day, most of the world refers to this type of amplification device as a “Vacuum Tube”.  Our UK friends refer to it as a valve, which I’ll explain next.

A triode vacuum tube is the most common of all tubes, even today.  If you listen to tubes in your high-end system, chances are quite high you’re listening to a triode.  Triode means three and the three elements in a triode are:

• The cathode
• The Anode
• The Grid

Picture these three elements as simply pieces of conductive metal with wires attached to them (the wires terminating at the tube’s socket where the pins are).  The three elements are housed in a glass “bottle” and all the air has been removed from the bottle.

The cathode, also known as the heater, has power applied to it so it heats up.  This causes a couple of things to happen: electrons start to boil off the metal in large numbers and it glows.  This glow is what you see when the tube lights up and starts to work and it’s also responsible for much of the heat a tube produces.  Think of this as the generator or transmitter.

The anode is the receiver of the electrons that the cathode is generating.  If the designer places a positive voltage to this anode from a power supply all those streaming electrons boiling off the heater will be attracted to the higher voltage of the plate and we get a current flowing.  In fact, a vacuum tube is always on producing maximum current all the time.  The challenge is to turn off the tube – but I jump ahead.  Hang in there.

If you want to make an audio amplifier you need a current flowing (which we now have) and then you want to selectively turn that current up and down (selectively off) in synch with a musical signal – so you get more current when the signal is louder and less current when the signal is quieter.  To do this, you need some sort of valve.  Notice how cleverly I inserted the “Valve” reference here.  That’s my tip of the hat to the Brits.

The Grid is the valve.  Think of the grid as a piece of metal that looks like a fly swatter.  All those boiling electrons go through the holes in the grid.  If you apply a voltage to the grid that is the opposite or lower than what you have on the plate, the electrons can’t pass through the grid to the plate anymore.

What’s cool about this setup is you only need a very small amount of voltage going in the opposite direction to stop the electrons from  flowing: thus a little change in voltage on the grid results in a huge change in the plate.  Voila – the very definition of an amplifier is a little voltage producing a very large voltage (or current).

So now imagine the output of a phono cartridge – it’s really tiny.  Place that tiny voltage and put it on the grid of a vacuum tube.  Now take a big power supply and place that on the plate of a vacuum tube.  At the output of the tube, place a speaker or headphone between the plate and ground.  When you play a record, the tiny voltage from the phono cartridge makes a big change in the current passing through the loudspeaker and sound comes out when the loudspeaker starts to move back and  forth in perfect synch to what’s on the record grooves.

Houston, we have music.

Remember back to the beginning of this article where Lee DeForest was trying to invent something that did not use a crystal for a radio?  Tomorrow we’ll find out how that left turn away from crystals set us back 50 years and how those crystals had to wait their turn to spark an entirely new type of device called a transistor.

Tomorrow From crystal radios to supercomputers.

First let me suggest that there can be no debate about the fact circuits built using one or the other sound differently.  But the question many of you are perhaps interested in is why?  What makes these two amplification devices different, what types of techniques can be employed to maximize the sound quality of both and then answer the question of why I have been a lifetime fan of tubes and yet always designed with solid state.

Because I like to keep these posts short and this is a big subject, hopefully one worth exploring for you, I will break the posts up in small daily doses.  Here’s the subjects we’ll cover, one per day.

• The Audion
• From crystal radios to supercomputers
• The fundamental differences between tubes and transistors
• High voltage and linearity
• Solid state vs. fields
• Odd or even
• How we get the best of both worlds
• Why I design with solid state exclusively

I realize some of this sounds technical.  It is.  I won’t bore you or overwhelm you with technical trivia in this mini series.  I promise it’ll be kept simple and understandable.

If we’re lucky, maybe even enjoyable.  Till tomorrow.

“The answer seems obvious … Do No Harm … meaning that the inevitable compromises required by anyone not so small-minded that they think they can make a perfect product, must be chosen such that that they do not harm the very reason we listen to music.

From one perspective, adding a “tube buffer stage” certainly is causing change, but that change, and presumed reduction is information, might also be a compromise which reduces harm caused elsewhere in the mic-to-ear chain more than it reduces the correct information. This might mean filtering what happened upstream, or reducing downstream misbehavior by damping the ingredients which might provoke that misbehavior … the way a high filter used to be so extremely necessary on a CD input circa 1980′s, especially in solid state electronics.

In order to run a long HDMI cable, way past the original intentions of HDMI LLC, the first level of attack is to passively sculpt the signal, actually reduce it, so that the data can be better recognized (of course you know all this stuff). The next level is also to sculpt/reduce the amplitude, but with a finer chisel … unfortunately the active chips which do this seriously destroy sound quality, but that’s not so bad if one is only feeding a projector.

My point is that less can be more.”