While an electric guitarist would be able to play at a small club with a watt amplifier, a bass player performing in the same venue would probably need an amplifier with or more watts. It provides an easy way to write programs that compile and execute on data-parallel hardware, such as graphics cards GPUs. Some of these arrangements include only the fronts of speaker cabinets mounted on a large frame. Some are made of MDF or particle board —especially in low-budget models. These large PA systems and movie theatre sound systems were very large and very expensive, and so they could not be used by most touring musicians.
The cone speaker, widely used in s-era amp cabinets, was not offered for sale until The first amplifiers and speakers could only be powered with large batteries, which made them heavy and hard to carry around. When engineers developed the first AC mains -powered amplifiers, they were soon used to make musical instruments louder.
Engineers invented the first loud, powerful amplifier and speaker systems for public address systems and movie theaters. These large PA systems and movie theatre sound systems were very large and very expensive, and so they could not be used by most touring musicians. After , smaller, portable AC mains-powered PA systems that could be plugged into a regular wall socket "quickly became popular with musicians"; indeed, " These early amps had a "single volume control and one or two input jacks, field coil speakers" and thin wooden cabinets; remarkably, these early amps did not have tone controls or even an on-off switch.
In , the Stromberg-Voisinet firm was the first company to sell an electric stringed instrument and amplifier package. However, musicians found that the amps had an "unsatisfactory tone and volume, [and] dependability problems", so the product did not sell well. Even though the Stromberg-Voisinet amp did not sell well, it still launched a new idea: In , Vega electrics launched a portable banjo amplifier.
In , Electro String Instruments and amplifier this is not the same company as Stromberg Electro Instruments introduced a guitar amp with "high output" and a "string driven magnetic pickup".
Electro set out the standard template for combo amps: In , Vivi-Tone amp set-ups were used for live performances and radio shows. In , Rickenbacker launched a similar combo amp that added metal corner protectors to keep the corners in good condition during transportation. In , Dobro released an electric guitar and amp package. In , Audio-Vox was founded by Paul Tutmarc , the inventor of the first electric bass Tutmarc's instrument did not achieve market success until Leo Fender 's launched the Precision Bass.
In , Vega sold a pickup and amplifier set for musicians to use with existing guitars. Volu-Tone used "high voltage current" to sense the string vibration, a potentially dangerous approach that did not become popular. In Dobro released a guitar amp with a vacuum tube rectifier and two power tubes.
By , Dobro and National began selling combo amps for Hawaiian guitar. In , Gibson had developed prototype combo amps, but never them. The first electric instrument amplifiers were not intended for electric guitars, but were portable PA systems. These appeared in the early s when the introduction of electrolytic capacitors and rectifier tubes enabled economical built-in power supplies that could plug into wall sockets. Previously, amplifiers required heavy multiple battery packs.
People used these amplifiers to amplify acoustic guitar , but electronic amplification of guitar first became widely poplular in the s and s craze for Hawaiian music , which extensively used amplified lap steel guitars. In the s, the earliest combo amplifiers had no tone controls.
The first tone controls were simple, mainly providing treble adjustment. The limited controls, the early loudspeakers , and the low amplifier power typically 15 watts or less prior to the mids gave poor high treble and bass output.
Some models also provided effects such as an electronic tremolo unit. In confusion over nomenclature, Fender labeled early amplifier tremolo as "vibrato" and called the vibrato arm of the Stratocaster guitar a "tremolo bar" see vibrato unit , electric guitar , and tremolo.
Some later amplifier models included an onboard spring reverb effect, one of the first being the Ampeg Reverberocket amp. In the s, several guitarists experimented with producing distortion by deliberately overdriving amplifiers. Distortion became more popular from the mids, when The Kinks guitarist Dave Davies produced distortion effects by connecting the already distorted output of one amplifier into the input of another.
Later, most guitar amps were provided with preamplifier distortion controls, and "fuzz boxes" and other effects units were engineered to safely and reliably produce these sounds. In the s, overdrive and distortion has become an integral part of many styles of electric guitar playing, ranging from blues rock to heavy metal and hardcore punk.
Guitar combo amplifiers were at first used with bass guitars and electric pianos , but these instruments produce a wider frequency range and need a full-range speaker system.
Much more amplifier power is required to reproduce low-frequency sound, especially at high volume. Reproducing low frequencies also requires a suitable woofer or subwoofer speaker and enclosure , with bass cabinets often being larger in size than a cabinet for mid-range or high-range sounds. As well, the open-back cabinets used on many electric guitar amps, while effective for electric guitar, do not have good bass reproduction. Woofer enclosures must be larger and more sturdily built than cabinets for mid-range or high-frequency tweeter speakers.
As such, in the s, when Ampeg introduced bass amplifier and speaker systems, bass guitarists began to use them. Similarly, Hammond organ players used a specialized keyboard combo amplifier, the Leslie speaker cabinet, which contains a woofer for the low frequencies and a horn for the high frequencies.
The Leslie horns rotate and a baffle around the woofer rotates as well, producing a rich tremolo and chorus effect. Typically, guitar amplifiers have two amplifying circuit stages and in addition frequently have tone-shaping electric circuits, which usually include at least bass and treble controls, which function similarly to the equivalent controls on a home hi-fi system.
More expensive amplifiers typically have more controls for other frequency ranges, such as one or two "midrange" controls and a "presence" control for high frequencies. Some guitar amplifiers have a graphic equalizer , which uses vertical faders to control multiple frequency bands. Some more expensive bass amps have a parametric equalizer , which enables precise control of tone. The first amplifier stage is a preamplifier.
It amplifies the audio signal to a level that can drive the power stage. The preamplifier also changes the tone of the signal; high preamp settings add overdrive. The power amplifier produces a high current signal to drive a loudspeaker and produce sound. Tone stages may also provide electronic effects—such as equalization , compression, distortion, chorus , or reverb. Amplifiers may use vacuum tubes called valves in Britain , solid-state transistor devices, or both.
The two common guitar amplifier configurations are: A wide range of speaker configurations are available in guitar cabinets—from cabinets with a single speaker e. Guitar amplifiers vary widely in price and quality. Other companies produce expensive custom-made amplifiers for professional musicians, which can cost hundreds or even thousands of dollars USD. Most combo amplifiers have a carrying handle, and many combo amplifiers and cabinets have metal or plastic-reinforced corners to protect the amp during transportation.
Control knobs and buttons are typically on the front of the cabinet or chassis, though in some cases, the knobs are on a recessed panel at the back of the top of the amplifier. The most basic amps only have a few knobs, which typically control volume, bass and treble. More expensive amps may have a number of knobs that control pre-amp volume or "gain" , distortion or overdrive, volume, bass, mid and treble, and reverb.
Some older amps and their re-issued versions have a knob that controls a vibrato or tremolo effect. Some amps have an XLR jack for a microphone, either for the guitar amp to be used for singing in effect as a mini- PA system , or, for acoustic guitar, to mix a mic signal with a pickup signal. The vast majority of guitar amps can only be powered by AC mains power plugging into a wall outlet ; however, a small number of practice amps designed for buskers also have battery power so they can be used for street performances.
A combo amp contains the amplifier and one or more speakers in a single cabinet. In a "head and speaker cabinet" configuration, the amplifier and speaker each have their own cabinet.
The amplifier head may drive one or more speaker cabinets. In the s, guitarists played through public address amplifiers, but by the s, this was uncommon. A rare exception in the s was grunge guitarist Kurt Cobain , who used four watt PA amplifiers in his early guitar set-up.
Some guitar amps have an XLR input so that a microphone can be plugged in for singing. Guitar amps that include a mic input are in effect small, portable PA systems. Some amps, typically bass amps, have an XLR connector to provide a balanced output from the preamp section to go into a PA system or recording input.
Instrument amplifiers are available in a wide range of price, quality, and performance levels. Some are designed for beginners, such as small, low-wattage practice amps , which typically have a single 8" speaker and about 10 watts, or smaller "combo" amps with relatively low wattage 15 to 20 watts and a single 10" speaker. Mid- to large-size "combo" amps with 30 to 50 watts and one 12" speaker or four 10" speakers are best for high-volume situations, such as band rehearsals and onstage performances.
Some guitar amps are strongly associated with specific instruments or genres, such as the Marshall amps, which are widely used in heavy metal music. Vacuum tubes called "valves" in British English were by far the dominant active electronic components in most instrument amplifier applications until the s, when solid-state semiconductors transistors started taking over.
Transistor amplifiers are less expensive to build and maintain, reduce the weight and heat of an amplifier, and tend to be more reliable and more shock-resistant. Tubes are fragile and they must be replaced and maintained periodically. As well, serious problems with the tubes can render an amplifier inoperable until the issue is resolved. In the s, high-end tube instrument amplifiers along with a small number of hi-fi power amplifiers used by audiophiles and high-end studio microphone preamplifiers survive as the few exceptions, because of their perceived sound quality.
Tube enthusiasts believe that tube amps produce a "warmer" sound and a more natural "overdrive" sound. Typically, tube amps use one or more dual triodes in the preamplifier section to provide sufficient voltage gain to offset tone control losses and drive the power amplifier section. While tube technology is, in many ways, outdated, tube amps remain popular since many guitarists prefer their sound. Most inexpensive and mid-priced guitar amplifiers are based on transistor or semiconductor solid-state circuits.
Solid-state amplifiers are cheaper to produce and more reliable, and they are usually much lighter than tube amplifiers. High-end solid-state amplifiers are less common, since many professional guitarists favor vacuum tubes.
Only a few solid-state amps have enduring attraction, such as the Roland Jazz Chorus. A hybrid amplifier involves one of two combinations of tube and solid-state amplification. It may have a tube power amp fed by a solid-state pre-amp circuit, as in most of the original MusicMan amplifiers. Alternatively, a tube preamplifier can feed a solid-state output stage, as in models from Kustom , Hartke, SWR and Vox. This approach dispenses with the need for an output transformer and easily achieves modern power levels.
Microprocessor technology allows the use of digital onboard effects in guitar amps to create numerous different sounds and tones that simulate the sound of a range of tube amplifiers and different sized speaker cabinets, all using the same amplifier and speaker.
These are known as modeling amplifiers , and can be programmed with simulated characteristic tones of different existing amplifier models and speaker cabinets—even microphone type or placement , or dialed in to the user's taste. Many amps of this type are also programmable by way of USB connection to a home computer or laptop. The use of "full range, flat response" FRFR amplification systems by electric guitarists has received an extra impetus from modeling amplifiers.
Before widespread availability of modeling, guitarists did not commonly plug electric guitars straight into PA systems or powered speakers , because most genres relied on the tonal coloration of a regular guitar amplifier setup—from the preamplifier , equalization filters, power amp , guitar speakers , and cabinet design.
The FRFR approach assumes the tone is shaped by sound processors in the signal chain before the amplifier and speaker stage, so it strives to not add further coloration. Acoustic amplifiers are intended for acoustic guitars and other acoustic instruments, especially for the way these instruments are used in relatively quiet genres such as folk and bluegrass. They are similar to keyboard amplifiers, in that they have a relatively flat frequency response with minimal coloration.
To produce this relatively "clean" sound, these amplifiers often have powerful amplifiers providing up to watts RMS , to provide additional " Headroom " and prevent unwanted distortion. Since an watt amplifier built with standard Class AB technology is heavy, some acoustic amplifier manufacturers use lightweight Class D amplifiers , which are also called "switching amplifiers. Acoustic amplifiers produce an uncolored, "acoustic" sound when used with acoustic instruments with built-in transducer pickups or microphones.
The amplifiers often come with a simple mixer, so that the signals from a pickup and condenser microphone can be blended. Since the early s, it has become increasingly common for acoustic amplifiers to provide a range of digital effects, such as reverb and compression.
So do you see any other solution or potential problems??? Tim, The title is correct. I do not see a contraction. If it helps, I think it is likely that this is what is causing the original problem.
A more readable way of accomplishing the same escaping might be this We do not create this. We get it from external systems. If your upstream data source is shipping XML-encoded HTML and you're expecting plain text, then the difference in expectations is the problem. We are reading the XML and converting it to plain text for another process. We do not want any escaping in the text we are converting. The code now does NOT do double parsing and I do not think that it should.
Both encodings are technically valid, but you need to determine which of you is following the data specification. I did not think that we would have to do double parsing. That just sounds wrong. I am not expecting plain text but XML. So then every XML document we need requires double parsing? Sign up or log in Sign up using Google.
We get a lot of xml data from various sources. The utf is 8. We notice that some have what appears to be double encoding of the &. && within the tag for A & B comes in as. The AMP Project is an open-source initiative aiming to make the web better for all. The project enables the creation of websites and ads that are consistently fast, beautiful and high-performing across devices and distribution platforms. Learn about AMP or Start Building. AMP is an open-source library that provides a straightforward way to create web pages that are compelling, smooth, and load near instantaneously for users. AMP pages are just web pages that you can link to and are controlled by you. AMP builds on your existing skill sets and frameworks to .