Mullard 5-10
Encyclopedia
Electronic circuit
An electronic circuit is composed of individual electronic components, such as resistors, transistors, capacitors, inductors and diodes, connected by conductive wires or traces through which electric current can flow...
for a valve amplifier
Valve amplifier
A valve amplifier or tube amplifier is a type of electronic amplifier that makes use of vacuum tubes to increase the power and/or amplitude of a signal. Low to medium power valve amplifiers for frequencies below the microwaves were largely replaced by solid state amplifiers during the 1960s and...
designed by the British vacuum tube
Vacuum tube
In electronics, a vacuum tube, electron tube , or thermionic valve , reduced to simply "tube" or "valve" in everyday parlance, is a device that relies on the flow of electric current through a vacuum...
company, Mullard
Mullard
Mullard Limited was a British manufacturer of electronic components. The Mullard Radio Valve Co. Ltd. of Southfields, London, was founded in 1920 by Captain Stanley R. Mullard, who had previously designed valves for the Admiralty before becoming managing director of the Z Electric Lamp Co. The...
in 1954 at the Mullard Applications Research Laboratory (ARL) in Mitcham Surrey UK, part of the New Road factory complex, to take advantage of their particular products. The circuit was first published in Practical Wireless
Practical Wireless
Practical Wireless is a British radio and electronics magazine, now published monthly by PW Publishing of Broadstone, Dorset. The current editor is Rob Mannion....
magazine.
The amplifier featured five valves and an output of 10 watts - hence '5-10'. Of those valves, one was a full-wave-rectifier
Rectifier
A rectifier is an electrical device that converts alternating current , which periodically reverses direction, to direct current , which flows in only one direction. The process is known as rectification...
(an EZ80 or EZ81), one was a pre-amplifier pentode
Pentode
A pentode is an electronic device having five active electrodes. The term most commonly applies to a three-grid vacuum tube , which was invented by the Dutchman Bernhard D.H. Tellegen in 1926...
EF86
EF86
EF86 is a miniature high gain, low mu, pentode vacuum tube. It has 9 pins and connects to a B9A base.The EF86 was introduced in the late 1950s and were produced by Philips, Mullard, Telefunken, Valvo, and GEC among others...
and one a double-triode ECC83
12AX7
12AX7 is a miniature dual triode vacuum tube with high voltage gain. It was developed around 1946 by RCA engineers in Harrison, New Jersey, under developmental number A-4522. It was released for public sale under the 12AX7 identifier on September 15, 1947. The 12AX7 was originally intended as...
as phase-splitter. The power amplification was handled by a pair of EL84
EL84
The EL84 is a vacuum tube of the power pentode type. It has a 9 pin Noval base and is found mainly in the final output stages of amplification circuits, most commonly now in guitar amplifiers, but originally in radios and many other devices of the pre-transistor era.It was developed to eliminate...
working in push-pull
Electronic amplifier
An electronic amplifier is a device for increasing the power of a signal.It does this by taking energy from a power supply and controlling the output to match the input signal shape but with a larger amplitude...
configuration.
The frequency response
Frequency response
Frequency response is the quantitative measure of the output spectrum of a system or device in response to a stimulus, and is used to characterize the dynamics of the system. It is a measure of magnitude and phase of the output as a function of frequency, in comparison to the input...
of the circuit was from 40Hz to 20,000Hz with less than 0.2% THD
THD
THD may refer to:* That Handsome Devil, an American alternative rock band* Total harmonic distortion, a measure of the distortion of an audio signal* Total Hi Def , an optical disc format* Th.D. or D.Th...
.
In 1959 Mullard published its famous booklet "Mullard Circuits for Audio Amplifiers
Mullard Circuits for Audio Amplifiers
"Mullard Circuits for Audio Amplifiers" is a famous book by the Technical Services Department of Mullard Ltd, a British valve manufacturing company...
" covering a range of amplifier and pre-amplifier circuits using valves developed within the Receiving Valve Development Department at the New Road factory.
The circuit design of the Mullard 5-10, together with the recommended Partridge output transformers, was famous for its unique sound reproduction and many variations of this amplifier (including Mullard's own 20-watt version, the Mullard 5-20 using the EL34
EL34
The EL34 is a thermionic valve or vacuum tube of the power pentode type. It has an international octal base and is found mainly in the final output stages of audio amplification circuits and was designed to be suitable as a series regulator by virtue of its high permissible voltage between heater...
) were in widespread use until the very end of the valve era and may still be found in current production.