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Topic: Valve amplifier

Related Topics

Class AB amplifier

Class A amplifier

Thermionic valve

Vacuum tube

Triode

	NationMaster - Encyclopedia: Valve amplifier
		Valve stages thus need to be coupled using some component able to totally block and withstand several hundred volts, typically a capacitor, occasionally a coupling transformer, adding phase shifts and possibly coloration to the signal.
		Valves remain in widespread use in Guitar and High end audio amplifiers due to the sound quality they produce, but are largely obsolete for most other applications, mainly due to the cost effectiveness advantages of the transistor.
		In later oscilloscopes, a type of amplifier using a series of tubes connected at equal distances along transmission lines, known as a distributed amplifier was employed to amplify very high frequency vertical signals before application to the display tube.
	www.nationmaster.com /encyclopedia/Valve-amplifier (3437 words)

	Marshall Amps :: The Secret Life Of Valves
		When replacing power valves with different manufacturers valves you must replace all power valves with the same make and the amplifier must be then re-biased to suit the new valves.
		If when power valves are removed there is a burn mark on the valve base, the valve base must be replaced and the speaker lead and speaker cabinet being used must be serviced.
		The valve line-up in a 100 watt amplifier is shown in pairs - 2 on the left (1 and 2) and 2 on the right (3 and 4).
	www.marshallamps.com /resources/secret_life_of_valves/top_tips.asp (574 words)

	Valve Amplifier Review
		After all, there are lethal voltages inside valve amplifiers, well beyond mains levels, and it could be all too easy to make a mistake while fault-finding a home-constructed amp, and reap the dangerous consequences.
		I like the EL34 Valve Amplifier a lot, and despite its slightly crude looks and the limited input socketry I could probably live with it as the heart of a simple system of CD player, tuner, amplifier and speakers.
		But I suspect the appeal of this amplifier will be governed as much by prejudice and common beliefs about the relative merits of solid-state and valve amplification as it will by the real-world needs of multisource systems, and the greater convenience offered by price competitive designs with their record/listen selectors, remote controls and so on.
	www.affordablevalvecompany.com /el34gram.htm (1773 words)

	AVA - Fet Valve 350Ex Amplifier
		We have spent the past two years analyzing amplifier performance and the Fet Valve Ultra 350 and Ultra 550 are the result of our engineering and listening evaluations.
		The Fet Valve amplifiers are our highest expression of hybrid design, blending the best of vacuum tube and solid state technologies.
		This stunning amplifier is for those demanding musical reproduction that is not reproduction at all, but is best described as a ticket to the performance.
	www.avahifi.com /root/equipment/amplifier/fetvalve_350ex.htm (573 words)

	PowerPedia:Amplifier - PESWiki (Site not responding. Last check: )
		The relationship of the input to the output of an amplifier — usually expressed as a function of the input frequency — is called the transfer function of the amplifier, and the magnitude of the transfer function is termed the gain.
		Amplifiers are commonly classified by the conduction angle (sometimes known as 'angle of flow') of the input signal through the amplifying device; see electronic amplifier.
		Valve amplifiers are widely, but not always correctly, associated with the valve sound.
	peswiki.com /index.php/PowerPedia:Amplifier (2142 words)

	Valve based audio - audiotools.com.
		Thermionic valves, vacuum tubes, lamps or whatever they are called were you live are as fashionable in audio equipment today as rows of blinking led's were in the early 80's, and partly for the same reason, both shine rather nicely esp. if you turn down the lights.
		While this company did manufacture valve based audio in the 80's they have not done so for quite some time but they decided to celebrate their 25th anniversary in November 2003 by introducing a new valve based integrated amplifier that they call the V 10.
		Has one of the more interesting ranges of valve kit's out there, but at the same lime one of the most expensive as well, all their models are low power units and most models are integrated but there are power amps there as well.
	audiotools.com /valve.html (2984 words)

	New To Guitars - TheGuitarSite.com, TGS Gear Mall, guitars
		The main objection to these early amplifiers was their harshness and limited dynamic range, caused almost entirely by the super clean sound and wide frequency response up to their maximum output, after which the onset of clipping occurred quite abruptly and harshly.
		There was much debate at the time that valve amplifiers produced overdrive with primarily even harmonics (musically related to the fundamental and therefore desirable), while transistor amplifiers produced odd harmonics which do not have a musical relationship to the note(s) played.
		Valve amplifiers use an output transformer which results in the lower order harmonics being predominant in the early phases of overdrive, giving the characteristic smooth overdrive.
	www.theguitarsite.com /new/primer_ampvalve.asp (1707 words)

	ESP Amplifier Basics - How Audio Amps Work (Part 1)
		In the beginning the vacuum tube was the only way to amplify, and valves (or "tubes") survive to this day, with a dedicated following of "believers" who are convinced that the development of the transistor (or indeed, any semiconductor) was fundamentally a bad idea.
		Because valves have a relatively low voltage gain, it is common to bypass the cathode resistor with a capacitor to defeat the local feedback and extract as much gain as possible, as is shown in Figure 1.1.
		Cathode followers are very unusual in the valve amplifier, and it is more common to use a "push-pull" output stage, generally using a transformer to match the high voltage and relatively high impedance of the output valves to the impedance of the speaker.
	sound.westhost.com /amp-basics1.htm (3111 words)

	Croft Series 5 Power amplifier
		This is a budget audiophile valve amplifier from Glenn Croft, who is better known for his Futterman-inspired OTL amps and his cigar-box valve preamps from the 80's.
		The only weak point of the valve amplifier was a slight lack of dynamics at higher volumes - I guessed that this was a consequence of the largish demonstration room, and reckoning it ought't be a problem in my living room at home made the decision to buy one.
		To my surprise, despite the similar serial numbers, I noticed that each amplifier had different values for the the coupling capacitors, though the major hardware such as the transformers seemed to be identical.
	www.soton.ac.uk /~apm3/diyaudio/Croft5.html (1022 words)

	Valve Amplifiers
		This is used in valved amplifiers to match the valves (which demand a high impedance load) to the loudspeaker, which is a low impedance device.
		Valves are inherently high impedance devices, and the effects of back-EMF from the speaker are therefore far less likely to achieve significant penetration at sufficient level to degrade performance.
		In our experience, a top valved amp gives a sweeter, smoother result than a top transistorised amp, but this is a generalisation and we have heard at least one transistorised amplifier, currently being developed by A~~, a local manufacturer, which seems to have none of the audible deficiencies of either type.
	sound.westhost.com /hfr_be.htm (2498 words)

	450 watt amplifier design
		Because of the high RF currents circulating in the amplifiers, especially in the output combiner, it is imperative that the correct (or equivalent) fixed and tuning capacitors are used.
		The input to the amplifier is via a chassis mounting BNC socket at one end of the housing, while the output is taken via a N-type socket mounted at the other end.
		All of the amplifier ancilliary circuitry is be built into a separate cabinet which is connected to the amplifier by a short umbilical cable.
	www.uksmg.org /amp.htm (1714 words)

	Light Valve Amplifier
		Light Valve Amplifier (LVA) is a term used to describe a specific type of light valve developed by Hughes-JVC (Image Light Amplifier (ILA)).
		The light from the addressing display shines onto an array of photo-sensors which output an electric voltage varying in intensity to the brightness of the light which falls on them: the brighter the light, the higher the voltage.
		The light valve now holds a duplicate of the source image and a very bright lamp can be used to project the image in the same way as in a normal light valve projector.
	www.meko.co.uk /lightvalveamp.shtml (279 words)

	Bluetone Amplifers: Virtual Valve Technology (Site not responding. Last check: )
		Much of the character of early valve amplifiers is attributable to the relatively low, and non linear, gain of the valves themselves and the inherent requirement to AC couple the separate stages.
		Without feedback the amplifiers were as non linear as their internal valve characteristics; giving rise to harmonic distortion figures of typically 2 or 3%.
		As each amplifier stage goes into overload the bias for it’s FET is disturbed causing audio compression and low frequency anomalies which continue for several seconds after a loud passage has been amplified.
	members.aol.com /bluetoneamps/vvt.html (1748 words)

	Silicon Chip Online - Publisher's Letter
		That concept will probably turn off more than half of the valve amplifier aficionados, since they have swallowed the nonsense from some hifi magazines that all feedback is anathema.
		Secondly, the amplifier will need to be very quiet, in order not to audibly degrade the signals from compact disc and DVD players.
		So that’s the broad concept, with no circuit details, no potential valve list for people to salivate over and nothing else to look forward to other than it would be a "valve" amplifier rather than a "soul-less solid-state design.
	www.siliconchip.com.au /cms/A_108021/printArticle.html (520 words)

	Valve Amplifiers
		The Integre is a medium power stereo amplifier, with a line-level input stage allowing the connection of three sources.
		A voltage amplifier input stage is directly coupled to a cathode-coupled phase inverter.
		The Mini valve integrated amplifier is a low power stereo amplifier, that offers the enticing sound of valves, at a lower cost.
	www.lyrita-audio.com /valve_amplifiers.htm (205 words)

	HI-FI WORLD - OLDE WORLDE - LEAK STEREO 20 VALVE AMPLIFIER
		The later models are finished in a Charcoal grey and date from roughly the same period in the mid-1960s as the Garrard 401.
		As the amplifier ages, old EL84 valves pass more current than the 48mA specified and coupling capacitors ëleakí electrically with age, which means the output valves will pull even more current.
		With the three-watt resistor fitted and the amplifier operating normally (ie, capacitors and valves in good condition), this resistor dissipates two-and-a-half watts and therefore runs pretty hot.
	www.hi-fiworld.co.uk /hfw/oldeworldehtml/leakstereo20.html (1119 words)

	Valve Amplifier Repair by Greg Cooney of Indefatigable Audio
		Valve Amplifier Repair by Greg Cooney of Indefatigable Audio
		A range of services and options for the impeccable professional repair, total restoration, pimping or modification to all valve based audio equipment including all power amps, mono blocks, pre-amps, tuners and guitar amps.
		Optional pimping can include adding leds to bottom of valve sockets to illuminate glass, antiquing, custom paint and/or air-brushing, chrome or gold plating, wooden accents etc. I source and supply all parts required and will even arrange courier or personal pickup and delivery of your 'baby'.
	www.valveaudio.co.nz /index.html (228 words)

	Valve Amplifier - Customers Reviews of Models EL34
		All was going according to plan during the demo session when salesman suggested that I give a listen to this rather odd looking valve amplifier from Kent.
		Musical Fidelity X-A1 MOST transistor amplifiers sound horrible because of the LARGE amounts of "crossover distortion" at LOW level, when you are trying to hear the dying echo in a concert hall.
		The EL34 unlike many amplifiers does not immediately grab your attention by over emphasising on a particular part of the audible spectrum or by having a hard upfront sound.
	www.affordablevalvecompany.com /el34cust.htm (2968 words)

	Marshall Amplifier
		The Marshall Vintage Modern 2466 Tube Amp Head is an all-valve amplifier with a choice of two dynamic ranges selectable by footswitch.
		The Marshall Vintage Modern 2266C 50 Watt 2 x 12 is an all-valve single channel amplifier with a choice of two dynamic ranges selectable by footswitch.
		The Marshall Vintage Modern 2266 50 Watt Head is an all-valve single channel amplifier with a choice of two dynamic ranges selectable by footswitch.
	www.amplifierbuyer.com /marshall-amplifier.htm (174 words)

	HiFi Hacks » Blog Archive » Refurbishing Valve Amplifiers (Site not responding. Last check: )
		This may be true of the modern valve amplifier, however refurbishing an old valve amplifier is an easy way to experiment with the sound of valve amps without making the major investment of buying a new one.
		There was a period in the 80’s where it was generally accepted that transistor based amplifiers were superior to their valve based counterparts in most every way, and as a consequence valve amplifiers were being sold cheap or even thrown away.
		The valves to spot are the final stage output valves; once you know these you will have an idea as to the power of the amplifier.
	www.hifihacks.com /?p=12 (1765 words)

	electrohydraulic valve controls, connector amplifier for proportional valves, proportional plug, electro-hydraulic ...
		The economy version of the Connector Amplifier simplifies control of proportional solenoids by supplying a current proportional to an input control (4-20 mA).
		Operating the amplifier with a supply voltage lower than the solenoid rated voltage may result in reduced maximum current output.
		Ensure the brown rubber base gasket is in place, providing a seal between the amplifier and the plug on the valve.
	www.axiomatic.com /valve-amplifier-ec4.html (868 words)

	Valve Audio - Integrated amplifiers, Pre-amplifier / Power Amplifier combos, Dual Mono block Power Amplifiers, Valve ... (Site not responding. Last check: )
		Designed to meet the need for a high power integrated hybrid amplifier, the Predator provides state of the art signal processing using classic cathode follower and plate-loaded techniques with absolute minimal local feedback.
		Still utilizing only one triode, in this execution of this plucky little amplifier, the valve is plate loaded directly by a DUAL pair of mosfets per channel.
		Some manufacturers like Valve Audio and a few others try to keep it simple by keeping active signal processing paths as short and uncomplicated as possible, preserving as much of the original signal character and timbre as possible.
	www.valveaudio.co.za (611 words)

	Powell's Books - Valve Amplifiers 3RD Edition by Morgan Jones
		Morgan Jones' Valve Amplifiers has been widely recognised as the most complete guide to valve amplifier design, modification, analysis, construction and maintenance written for over 30 years.
		As such it is unique in presenting the essentials of 'hollow-state' electronics and valve amp design for engineers and enthusiasts in the familiar context of current best practice in electronic design, using only currently available components.
		Morgan Jones' Valve Amplifiers has been widely recognized as the most complete guide to valve amplifier design, modification, analysis, construction and maintenance written for over 30 years.
	www.powells.com /biblio/4-0750656948-0 (626 words)

	Some thoughts about singleended Valve Amplifiers
		The harmonic spectrum of a correctly operated pentode voltage amplifier is further of a spectrum very different to that of a triode and integrates such with that of a directly heated triode that the resulting harmonic spectrum is essentially "ideal".
		In Class AB Push-Pull Amplifiers the AC flowing through the Supply as soon as the Amplifier leaves it’s Class A operation is identical to that on an singleended Amplifier, but the current draw is very substantially signallevel dependent.
		In an singleended valve amplifier it is however possible to overdrive the Amplifier with brief peaks by as much as 10db before the distortion becomes audible.
	www.fortunecity.com /rivendell/xentar/1179/theory/seamptheory/SEAmplifiertheory.html (7677 words)

	Earmax, the reference high end single-ended valve headphone amplifier
		To be featured, alongside all the other headphone amplifiers, especially all those which have been appearing out of the woodwork, to try to challenge the King for his crown, and to have been adjudged as the best of the lot, is extremely gratifying:
		Valve replacement in the standard unit should be from specially sourced defunct stock, direct from the Audiophile Club, otherwise the output valves are likely to cause an unacceptable amout of distortion.
		Valve replacement in the Pro unit is with ECC 88 output valves and a central ECC 81 input valve, high quality matched valves being available from the Audiophile Club.
	www.audiophileclub.co.uk /earmax.html (670 words)

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