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Mullard Circuits for Audio Amplifiers is a famous book by the Technical Services Department of Mullard Ltd, a British valve manufacturing company. First published in 1959 and then reprinted several times it contained a number of designs by Mullard engineers for high quality audio amplifiers, which were to be used by amateur constructors as well as by manufacturers as the basis for many ...
The increase in efficiency can allow a given vacuum tube to deliver more RF power than it could in class A or AB. For instance two 4CX250B tetrodes operating at 144 MHz can deliver 400 watts in class A, but when biased into class C they can deliver 1,000 watts without fear of overheating. Even more grid current will be needed.
The Doherty amplifier is a modified class B radio frequency amplifier invented by William H. Doherty of Bell Telephone Laboratories Inc in 1936. Whereas conventional class B amplifiers can clip on high input-signal levels, the Doherty power amplifier can accommodate signals with high peak-to-average power ratios by using two amplifier circuits within the one overall amplifier to accommodate ...
The 4-1000A is a relatively large glass tube with an overall height of 9.25 inches and a diameter of 5 inches. It is designed to operate with its plate (anode) at an orange-red color due to the "getter" being a zirconium compound on the anode structure which requires a great deal of heat to be effective.
An amplifier, electronic amplifier or (informally) amp is an electronic device that can increase the magnitude of a signal (a time-varying voltage or current). It is a two-port electronic circuit that uses electric power from a power supply to increase the amplitude (magnitude of the voltage or current) of a signal applied to its input ...
A pair of 833A's with adequate forced air cooling can deliver 1000 watts of CCS RF power operating as a class C amplifier plate modulated stage. A pair of tubes used in a class B modulator can deliver 1800 watts of "peak" AF power in ICAS service with speech, or 1600 watts in CCS service with music or high duty cycle operation. Two 833A's are ...
Even more rarely, higher powered SETs are produced commercially, usually using the 211 or 845 transmitting valves, which are able to deliver 20 watts, operating at 1000 V. Notable amplifiers in this class are those from Audio Note corporation (designed in Japan), including the "Ongaku", voted amplifier of the year during the late 1990s.
The key to understanding this efficiency without churning the actual numbers is that we have a 400-watt-capable amplifier but with the efficiency of a 100-watt amplifier. This is because the waveforms of music contain long periods under 100 watts and contain only brief bursts of up to 400 watts – in other words, the losses at 400 watts are ...