Valve sound is the sound either from a valve amplifier or a specially designed transistor amplifier. It is described by some audiophiles to be a richer, warmer sound than that from transistor counterparts. Some musicians also prefer the distortion characteristics of tubes over transistors for instrument (usually guitar) amplification. An audiophile, most generally, is a lover of sound or music, but the word is more commonly used about someone who cares about hi-fi playback of sound recordings, rather than live performances. ... Assorted transistors The transistor is a solid state semiconductor device that can be used for amplification, switching, voltage stabilization, signal modulation and many other functions. ... A musician is a person who plays or composes music. ... A distortion is the alteration of the original shape (or other characteristic) of an object, image, sound, waveform or other form of information or representation. ... Photo of transistor types (tape measure marked in centimeters) Transistor in the SMD form factor The transistor is a solid state semiconductor device used for amplification and switching. ...

The term "Valve sound" is used in two main areas that are sometimes confused:

• In sound reproduction systems (stereos) where accuracy to the sound of the original recording is usually the goal.
• In guitar amplifiers, where audible distortion is usually the goal.

Valves are claimed by some to sound better in both situations, though the criteria are vastly different. Sound reproduction is the electrical or mechanical re-creation and/or amplification of sound, often as music. ... In popular usage, stereo generally to dual-channel sound recording and sound reproduction – sound that contains data for more than one speaker simultaneously. ... This page is about amplifiers for musical instruments. ... A distortion is the alteration of the original shape (or other characteristic) of an object, image, sound, waveform or other form of information or representation. ...

History

Before the introduction of transistors in the late 1940s, all amplifiers used tubes. Since then, solid state (transistorized) amplification has become commonplace due to its size, price, and portability. However, tube amplifiers, especially single-ended triode (SET) models, have retained a loyal following amongst some audiophiles, with modern units from companies commanding very high prices. // Events and trends World War II was a truly global conflict with many facets: immense human suffering, fierce indoctrination, and the use of new, extremely devastating weapons such as the atomic bomb. ... For the British rock band of the same name, see Amplifier (band) An amplifier can be considered to be any device that uses a small amount of energy to control a source of a larger amount of energy, although the term today usually refers to an electronic amplifier. ... In electronics, solid state circuits are those that do not contain vacuum tubes. ... There are two methods by which logic signals are transmitted over a cable. ... Simplified diagram of a triode. ...

Audible differences

Many audiophiles prefer the sound of tubes over transistors but the actual audible differences in sound have proven difficult to define. What most valve enthusiasts will agree on is that valves "sound better" than transistors, and audiophiles claim that there is indeed an audible difference. However, it appears that no results from scientifically conducted listening tests are available to confirm or deny the audiophile claims. Audio can mean: sound that can be heard electronics or other signals of frequencies audible to humans (about 20--20,000 Hz) broadcasting or reception of sound high-fidelity sound reproduction sound recording and reproduction in general I hear in Latin This is a disambiguation page — a navigational aid which...

'Texture'

The problem is explaining these sound differences in words, as few words exist to describe the characteristics of sounds. Audiophiles use words like 'creamy' and 'crunchy' to describe tube harmonic distortion, which are words to describe texture. They state that tube amps sound much 'warmer' and 'creamier' than solid-states.

Improved bass

Some claim that the bass response is more extended and smoother with valve amplifiers.

Harmonic content and distortion

A widely-used argument claims that valves produce only even-numbered harmonics, while solid state amplifiers produce only odd-numbered harmonics. It has been claimed that even-numbered harmonics are "more musical", since they all correspond to named notes in the western musical scale, while only some of the odd harmonics do. However this argument is highly suspect, as any even harmonic can be viewed as merely an odd harmonic transposed up by one or more octaves, so the odd and even sets of harmonics contain the same proportion of named notes. (See Mathematics of musical scales) The total harmonic distortion, or THD, of a signal is a measurement of the harmonic distortion present and is defined as the ratio of the sum of the powers of all harmonic components to the power of the fundamental. ... In electronics, solid state circuits are those that do not contain vacuum tubes. ... In music, a scale is a set of musical notes that provides material for part or all of a musical work. ... A musical scale is a discrete set of pitches used in making or describing music. ...

In fact, the harmonics produced by a non-linear device depend on the topology and symmetry of the amplifier; not the type of device used. An amplifier with a symmetric (odd symmetry) transfer characteristic, like a solid state push-pull op-amp, produces only odd harmonics. An amplifier with an asymmetric transfer characteristic, like a class A valve amplifier, produces both even and odd harmonics.^{[1][2] [3]} As valves are often run in class A, and semiconductor amplifiers are often push-pull, the types of distortion are incorrectly associated with the devices instead of the topology. To do: 20th century mathematics chaos theory, fractals Lyapunov stability and non-linear control systems non-linear video editing See also: Aleksandr Mikhailovich Lyapunov Dynamical system External links http://www. ... In mathematics, even functions and odd functions are functions which satisfy particular symmetry relations, with respect to taking additive inverses. ... A push-pull output is a type of electronic circuit that can drive either a positive or a negative current into a load. ... An operational amplifier or op-amp is an electronic circuit module (normally built as an integrated circuit, but occasionally with discrete transistors or vacuum tubes) which has a non-inverting input (+), an inverting input (-) and one output. ... Class A can mean either: Class A amplifier, a category of electronic amplifier Class A network, a type of Internet Protocol address In English law Class A drugs are those which have the highest criminal penalties under the various Misuse of Drugs Acts. ...

In order to produce only even harmonics, the device needs a transfer characteristic with even symmetry. A simple example is a solid state full-wave rectifier. Note that the fundamental, which is an odd-numbered harmonic, would not be reproduced at all. (The lowest frequency produced by a full-wave rectifier is double the original; or the second harmonic.) The production of only even harmonics is obviously not desirable in audio reproduction systems, though it is used in guitar distortion. AC, half-wave and full wave rectified signals A rectifier is an electrical device, comprising one or more semiconductive devices (such as diodes) arranged for converting alternating current to continuous current. ... The fundamental tone often referred to simply as the fundamental, is the lowest frequency in a harmonic series. ...

Additionally, this simplification fails to note that harmonic distortion only occurs when a single sine wave is input. For more complex signals (any other form of audio), the frequency components produced by non-linear distortion are not harmonics, but more complex intermodulation products. In trigonometry, an ideal sine wave is a waveform whose graph is identical to the generalized sine function y = Asin[ω(x − α)] + C, where A is the amplitude, ω is the angular frequency (2π/P where P is the wavelength), α is the phase shift, and C is the... An intermodulation product is the product of two signals mixed in a nonlinear device, such as a nonlinear amplifier It is usually f1+f2, f1-f2, 2f1-f2, 2f2-f1, 3f1-2f2, 3f2-2f1, and more sums and differences of the two frequencies and their harmonics. ...

In audio reproduction systems, the types of harmonics produced should be irrelevant, since proper amplifier design can reduce all harmonics to inaudibility, and they should never see overload conditions. It is, of course, possible that the greater amount of distortion in class A valve amplifiers is the actual reason for the perceptually "improved" sound, even if it is degradation from an engineering standpoint. Overload can refer to: Electrical overload, a situation where an electrical machine or system is subjected to a greater load than it was designed for. ...

Measurement differences

Attempts to measure the difference between them produce confusing results. Testing for distortion, frequency response, and noise at normal signal levels and assuming linear operation of the test amplifier, no truly significant differences exist. Frequency response is the measure of any systems response to frequency, but is usually used in connection with electronic amplifiers and similar systems, particularly in relation to audio signals. ...

Under severe overload by signal transients (30% THD) however, tube and transistor amplifiers measure differently. Overload can refer to: Electrical overload, a situation where an electrical machine or system is subjected to a greater load than it was designed for. ... Transient means passing with time. ... THD means total harmonic distortion. ...

Valve and transistor amplifier designs compared

There has been considerable debate over the characteristics of valves versus bipolar junction transistors. Some 'audiophiles' have argued that the quadratic transconductance of tubes compared with the exponential transconductance of transistors is an important factor. This has not been proven. The schematic symbols for PNP- and NPN- type BJTs. ... f(x) = x2 - x - 2 In mathematics, a quadratic function is a polynomial function of the form , where a is nonzero. ... Transconductance, also known as mutual conductance, is a property of certain electronic components. ... The term exponential may refer to any of several topics in mathematics: Exponential distribution Exponential function Exponential growth, exponential decay Exponential time Matrix exponential Exponential map (in differential geometry) All relate in some fashion to exponents. ...

Some audiophiles say that devices are not as important as circuit topology, since MOSFETs exhibit a transfer characteristic similar to tubes but fail to reproduce valve sound in modern amplifiers. Triodes and MOSFETs have certain similarities in their transfer characteristics, whereas later forms of the valve, the tetrode and pentode have quite different characteristics that are in some ways similar to the transistor. There are many kinds of circuit An electric circuit interconnects electrical elements or electronic elements together usually to perform some useful function. ... Topology (Greek topos, place and logos, study) is a branch of mathematics concerned with spatial properties preserved under bicontinuous deformation (stretching without tearing or gluing); these are the topological invariants. ... Example of a MOSFET The metal oxide semiconductor field-effect transistor (MOSFET), is by far the most common field-effect transistor in both digital and analog circuits. ... Simplified diagram of a triode. ... Example of a MOSFET The metal oxide semiconductor field-effect transistor (MOSFET), is by far the most common field-effect transistor in both digital and analog circuits. ... A tetrode is a two-grid vacuum tube. ... In electronics, a vacuum tube (American English) or (thermionic) valve (British English) is a device generally used to amplify a signal. ...

Soft clipping

An important aspect of tube sound is the soft clipping characteristic of tubes. A tube amplifier will reproduce a wave relatively linearly to a point, and as the signal moves beyond the linear range of the tube (into overload), it distorts the signal with a smooth curve instead of a sudden sharp-edged cutoff. The harmonics added to the signal are of lower energy with soft clipping than hard clipping, though the type of harmonics will be the same for both; dependent on symmetry. However, soft clipping is not exclusive to valves; see section "Intentional creation of distortion" below. Clipping is one form of distortion that occurs when an amplifier is overdriven, which happens when it attempts to increase voltage or current beyond its limits. ... A wave is a disturbance that propagates through space, often transferring energy. ... The word linear comes from the Latin word linearis, which means created by lines. ... Overload can refer to: Electrical overload, a situation where an electrical machine or system is subjected to a greater load than it was designed for. ... In everyday speech, to distort something is to force it out of its natural shape. ... In acoustics and telecommunication, the harmonic of a wave is a component frequency of the signal that is an integral multiple of the fundamental frequency. ... Valve sound is the sound either from a valve amplifier or a specially designed transistor amplifier. ...

Circuit design may also play an important role in the tube sound; tube circuits are often less complex and laid out differently. It is argued that simplicity is usually best, as the length and complexity can change the inductance and capacitance of a circuit. Of course a more complex circuit can cancel out these effects with other components. Inductance (or electric inductance) is a measure of the amount of magnetic flux produced for a given electric current. ... // Definition Capacitance is a measure of the amount of electric charge stored (or separated) for a given electric potential. ...

Bandwidth

Early valve amplifiers often had only limited bandwidth, in part due to passive component technology available at the time, notably resistor - capacitor-coupled stages and output transformers. Tube stages were usually capacitively coupled, reducing low frequency response. Tubes could not directly drive speakers, so output transformers were used which further reduced both high and low frequency response. Bandwidth is a measure of frequency range, measured in hertz, of a function of a frequency variable. ... Resistor symbols (US and Japan) Resistor symbols (Europe, IEC) A pack of resistors A resistor is a two-terminal electrical or electronic component that resists an electric current by producing a voltage drop between its terminals in accordance with Ohms law. ... A capacitor is a device that stores energy in the electric field created between a pair of conductors on which electric charges of equal magnitude, but opposite sign, have been placed. ... Three-phase pole-mounted step-down transformer. ... A capacitor is a device that stores energy in the electric field created between a pair of conductors on which electric charges of equal magnitude, but opposite sign, have been placed. ...

Gain

Audio valves typically have only modest gain. This makes it possible to design very simple valve circuits that rely on this inherent open-loop linearity and have little, or indeed no, negative feedback, and thus have very simple distortion spectra. An open-loop controller does not use feedback to control states or outputs of a dynamic system. ... Negative feedback is the process of feeding back to the input a part of a systems output, so as to reverse the direction of change of the output. ...

Negative feedback

Tube amplifiers could not, and did not need to, use as much negative feedback (NFB) as transistor amplifiers due to the large phase shifts caused by the output transformers and their lower stage gains. Negative feedback is the process of feeding back to the input a part of a systems output, so as to reverse the direction of change of the output. ...

Power supplies

Early tube amplifiers usually used unregulated power supplies. This was due to the high cost associated with high-quality high-voltage power supplies. The typical anode supply was simply a rectifier and a filter capacitor. When the tube amplifier was operated at high volume, the power supply voltage would dip, reducing power output and causing signal modulation. This dipping effect is known as "sag" which may be preferable to some guitarists. A power supply unit (sometimes abbreviated power supply or PSU) is a device that supplies electrical power to a device or group of devices. ... International safety symbol Caution, risk of electric shock (ISO 3864), colloquially known as high voltage symbol. ... Diagram of a zinc anode in a Daniells cell. ... AC, half-wave and full wave rectified signals A rectifier is an electrical device, comprising one or more semiconductive devices (such as diodes) or vacuum tubes arranged for converting alternating current to direct current. ... The term filter may refer to: A device to separate mixtures. ... A capacitor is a device that stores energy in the electric field created between a pair of conductors on which electric charges of equal magnitude, but opposite sign, have been placed. ... A power supply (sometimes known as a power supply unit or PSU) is a device or system that supplies electrical or other types of energy to an output load or group of loads. ... International danger high voltage symbol. ... Modulation is the process of varying a carrier signal, typically a sinusoidal signal, in order to use that signal to convey information. ... This article or section does not cite its references or sources. ...

In contrast, modern amplifiers often use high-quality, well-regulated power supplies. The output voltage remains constant, even at the peak of the amplifier rating. For this reason, the power supply is near ideal and does not affect the sound.

Push-Pull Amplifiers

A Class A push-pull amplifier produces exceptionally low distortion for any given level of applied feedback, and also cancels the flux in the transformer cores, so this topology is seen by some as the ultimate "engineering" approach to the tube hi-fi amplifier for use with normal speakers. Output powers of 10W is possible using standard tubes, and up to 25W using "reasonable" extreme tubes. Class A can mean either: Class A amplifier, a category of electronic amplifier Class A network, a type of Internet Protocol address In English law Class A drugs are those which have the highest criminal penalties under the various Misuse of Drugs Acts. ... A single GWR autocoach capable of push-pull operation. ... A distortion is the alteration of the original shape (or other characteristic) of an object, image, sound, waveform or other form of information or representation. ... Feedback is (generally) information about actions. ... In the various subfields of physics, there exist two common usages of the term flux, both with rigorous mathematical frameworks. ... Three-phase pole-mounted step-down transformer. ... A loudspeaker is a device which converts an electrical signal into sound. ...

The majority of commercial HiFi amplifier designs are Class AB, in order to deliver greater power and efficiency, typically 12 - 25 watts upwards. Such designs will invariably use at least some NFB. High Fidelity is also the title of a book by Nick Hornby and a film directed by Stephen Frears, based upon Hornbys book. ... Class A amplifiers tend to have very low distortion when used with small signals, and are very inefficient Class B amplifiers tend to be efficient but suffer from high distortion when used with small signals. ... Electric power is the amount of work done by an electric current in a unit time. ... // Definition The efficiency of an entity (a device, component, or system) in electronics and electrical engineering is defined as useful power output divided by the total electrical power consumed (a fractional expression). ...

Class AB push pull topology is nearly universally used in tube amps for electric guitar applications. Whereas audiophile amps are primarily concerned with avoiding distortion, a guitar amp embraces it. When driven to their respective limits, tubes and transistors distort quite differently. Tubes clip more softly than transistors, allowing higher levels of distortion (which is sometimes desired by the guitarist) whilst still being able to distinguish the harmonies of a chord. This is because the soft profile of the tube amplifier's distortion means that the intermodulation products of the distortion are generally more closely related to the harmonies of the chord. An intermodulation product is the product of two signals mixed in a nonlinear device, such as a nonlinear amplifier It is usually f1+f2, f1-f2, 2f1-f2, 2f2-f1, 3f1-2f2, 3f2-2f1, and more sums and differences of the two frequencies and their harmonics. ...

Single-Ended Triode (SET) Amplifiers

SET amplifiers typically measure very badly - they have low output power, are inefficient, have poor damping factors and high measured distortions. The damping factor in an electrical circuit gives the ratio of the impedances of two electronic devices, the load impedance (input impedance) and the source impedance (output impedance). ...

The triode, despite being the oldest signal amplification device, also has the most linear transfer characteristic, and thus requires little or no negative feedback for acceptable distortion performance. NFB is used in most post 1950s amplifiers and although it usually reduces the measured distortion level, it results in an unpleasant combination of harmonics to some ears. Simplified diagram of a triode. ... Negative feedback is the process of feeding back to the input a part of a systems output, so as to reverse the direction of change of the output. ... The examples and perspective in this article or section may not represent a worldwide view. ...

Some audiophiles say that measured sound performance is a very bad indicator of real world sound performance. In the 70s, designers started producing transistor amps with higher open loop gain to support a greater value of negative feedback. These amps produced near perfect measured results but in the opinion of some listeners sounded cold, dull and clinical. In the years since this fashion has reverted to giving much greater attention to making an amplifier which has modest gain but good open loop linearity, and then deploying this with only minimal levels of NFB. Centuries: 1st century BC - 1st century - 2nd century Decades: 20s - 30s - 40s - 50s - 60s - 70s - 80s - 90s - 100s - 110s - 120s 70 71 72 73 74 75 76 77 78 79 Note: Sometimes the 70s is used as shorthand for the 1970s, the 1870s, or other such decades in other centuries... An open-loop controller does not use feedback to control states or outputs of a dynamic system. ... Negative feedback is the process of feeding back to the input a part of a systems output, so as to reverse the direction of change of the output. ...

Despite their linearity, SETs do distort. SETs have a unique distortion pattern: a simple and monotonically decaying series of harmonics, dominated by modest levels of second harmonic distortion, which is like adding the same tone one octave higher. The added tone is usually lower, at about 5% or less in a no feedback amp. Some say that this "distortion" can actually enhance the music, making it sound somewhat richer, as if a quiet chord is being played in the background. It is a form of distortion. Whether is considered bad distortion depends on personal taste. In acoustics and telecommunication, the harmonic of a wave is a component frequency of the signal that is an integer multiple of the fundamental frequency. ... In music, an octave (sometimes abbreviated 8ve or 8va) is the interval between one musical note and another with half or double the frequency. ...

SETs usually only produce about 5 to 10 watts or less; the most expensive amp in existence, the $350,000.00 Wavac SH-883 monoblock SETs only produce about 150 watts. Large amounts of power are not necessary in amplifiers, as only a few watts are required to drive most audiophile speakers to a SPL of nearly 100 dB at 1 m. Their low power also makes them ideal for use as preamps. Watts may refer to: Plural form of Watt, a measure of electrical power Watts and Co. ...

Intentional creation of distortion

Valve sound from transistor amplifiers

Some individual characteristics of the tube sound, such as the waveshaping on overdrive, are straightforward to produce in a transistor circuit or digital filter. For more complete simulations, engineers have been successful in developing transistor amplifiers that produce a sound quality very similar to the tube sound. Usually this involves using a circuit topology similar to that used in tube amplifiers. The term Distortion synthesis refers to a group of sound synthesis techniques which modify existing sounds to produce more complex sounds (or timbres), usually by using non-linear circuits or mathematics. ... An FIR filter In electronics, a digital filter is any electronic filter that works by performing digital math operations on an intermediate form of a signal. ...

In 1982, Tom Scholz, a graduate from MIT and a member of Boston introduced the Rockman, which used bipolar transistors, but achieved a distorted sound adopted by many well known musicians. Advanced digital signal processing offers the possibility to simulate valve sound. Computer algorithms are currently available that transform digital sound from a CD or other digital source into a distorted digital sound signal. Needless to say, this lacks the nostalgia of using tube gear. Donald Thomas Tom Scholz is the primary songwriter, musician and founding member of the Massachusetts-based rock band Boston. ... The Rockman is a headphone guitar amplifier. ... Digital signal processing (DSP) is the study of signals in a digital representation and the processing methods of these signals. ... A Lego RCX Computer is an example of an embedded computer used to control mechanical devices. ... Flowcharts are often used to represent algorithms. ... CD may stand for: Compact Disc Canadian Forces Decoration Cash Dispenser (at least used in Japan) CD LPMud Driver Centrum-Demokraterne (Centre Democrats of Denmark) Certificate of Deposit České Dráhy (Czech Railways) Chad (NATO country code) Chalmers Datorförening (computer club of the Chalmers University of Technology) a 1960s... A digital system is one that uses discrete numbers, especially binary numbers, or non-numeric symbols such as letters or icons, for input, processing, transmission, storage, or display, rather than a continuous spectrum of values (an analog system). ...

Transistor sound from valve amplifiers

Using modern passive components, and modern sources, whether digital or analogue, and wide band loudspeakers, it is possible to have valve amplifiers with the characteristic wide bandwidth and "fast" sound of modern transistor amplifiers, including using push pull circuits, class AB, and feedback. Some enthusiasts have built amplifiers using transistors and MOSFETS that operate in class A, including single ended, and these often have the "valve sound". Passive has several meanings: In grammar it describes a grammatical voice. ... An electronic component is a basic electronic building block packaged in a discrete form with two or more connecting leads or metallic pads. ... A digital system is one that uses discrete numbers, especially binary numbers, or non-numeric symbols such as letters or icons, for input, processing, transmission, storage, or display, rather than a continuous spectrum of values (an analog system). ... Closeup of a loudspeaker driver Wall-mounted loudspeaker. ...

Tube/transistor hybrid amplifiers

Tubes are often still used to impart a distortion characteristic that most people find audibly pleasant to solid state amplifiers, such as Musical Fidelity's use of Nuvistors, tiny triode tubes, to control large bi-polar transistors in their NuVista 300 power amp. Musical Fidelity is a low volume producer of high-end audio) equipment. ... The nuvistor is a type of vacuum tube announced by RCA in 1959. ...

Alternatively, one may use a light bulb in the feedback loop of an infinite gain multiple feedback (IGMF) circuit. The sluggish response of the light bulb's resistance (which varies according to temperature) can thus be used to moderate the sound and attain a valve-like "soft limiting" of the output. The light bulb is one of the most significant inventions in the history of the human race, illuminating the darkness of the evening and bringing light indoors at all times in order focus on the task at hand. ... Conductance can refer to: Electrical conductance, the reciprocal of electrical resistance. ... Temperature is also the name of a song by Sean Paul. ...

Valve sound enthusiasts

Several enthusiasts consider that "pure" valve amplifiers should not use anything except valves as active devices. Others, in contrast, will use valves for the audio circuit, but will accept the use of semiconductor gain devices in the power supply or as constant current sources, etc. Other schisms concern the use of triodes vs. tetrodes and pentodes, and the use of directly heated valves vs. indirectly heated valves. An ideal current source, I, driving a resistor, R, and creating a voltage V A current source is an electrical or electronic device that delivers or absorbs electric current. ... The word schism (IPA: or ), from the Greek σχισμα, schisma (from σχιζω, schizo, to split), means a division or a split, usually in an organization. ... Simplified diagram of a triode. ... A tetrode is a two-grid vacuum tube. ... In electronics, a vacuum tube (American English) or (thermionic) valve (British English) is a device generally used to amplify a signal. ...

Many of the explanations relate to the circuit topologies pioneered using valves, and traditionally associated with them ever since, regardless of whether they are built using valves today, notably the single ended directly heated triode amplifier circuit, which operates in class A and often has no negative feedback; this topology is a classic source of the valve sound. Simplified diagram of a triode. ... This topic has already been covered in electronic amplifier. ... Negative feedback is the process of feeding back to the input a part of a systems output, so as to reverse the direction of change of the output. ...

See also

• Physics of music
• Audiophile
• Audio system measurements
• Power chord
• British Valve Association

Sound waves Variations in air pressure against the ear drum, and the subsequent physical and neurological processing and interpretation, give rise to the experience called sound. Most sound that people recognize as musical is dominated by periodic or regular vibrations rather than non-periodic ones (called a definite pitch), and... Audiophile, from Latin audio hear and Greek φιλειν (philein) love, is a word used to describe a person dedicated to achieving high fidelity in the recording and playback of music. ... The designer of a system for sound reproduction needs to be able to measure the systems performance in a number of areas. ... In music, a power chord is, in the broadest sense, a chord that remains euphonious when distorted by amplification. ... Please wikify (format) this article as suggested in the Guide to layout and the Manual of Style. ...

References

1. ^ Ask the Doctors: Tube vs. Solid-State Harmonics — Universal Audio Webzine
2. ^ Volume cranked up in amp debate — Electronic Engineering Times
3. ^ W. Bussey and R. Haigler (1981). "Tubes versus transistors in electric guitar amplifiers". IEEE International Conference on Acoustics, Speech, and Signal Processing, Volume 6 p. 800–803.

External links

• Stereophile: Scientists vs. Audiophiles
• "The Cool Sound of Tubes" by Eric Barbour
• Tubes vs. Transistors: Is There An Audible Difference?
• PDF Tubes vs. Transistors in Electric Guitar Amps
• Tubes vs. Transistors: Feature Comparison
• Why Tubes?
• Tubes Sound Emulator VST