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Typical push–pull audio tube power amplifier, matched to loudspeaker with an impedance-matching transformer. Audio amplifiers typically do not match impedances, but provide an output impedance that is lower than the load impedance (such as < 0.1 ohm in typical semiconductor amplifiers), for improved speaker damping.
The amplifier damping factor, which is the ratio of the nominal load impedance (driver voice coil) to amplifier output impedance, is adequate in either case for well-designed solid state amplifiers. Tube amplifiers have sufficiently higher output impedances that they normally included multi-tap output transformers to better match to the driver ...
Because of their inability to drive low impedance loads directly, valve audio amplifiers must employ output transformers to step down the impedance to match the loudspeakers. Output transformers are not perfect devices and will always introduce some odd harmonic distortion and amplitude variation with frequency to the output signal.
A speaker L pad is a special configuration of rheostats used to control volume while maintaining a constant load impedance on the output of the audio amplifier. [1] It consists of a parallel and a series rheostat connected in an "L" configuration.
Only the magnitude of the loudspeaker impedance is used, and the power amplifier output impedance is assumed to be totally resistive. Comparison of damping factors for a solid state amplifier (Luxman L-509u) and a tube amplifier (Rogue Atlas) In typical solid state and tube amplifiers, the damping factor varies as a function of frequency.
This is called impedance matching or a matched connection. In this case, Z S = Z L, DF = 1/1 = 1 . The actual output impedance for most devices is not the same as the rated output impedance. A power amplifier may have a rated impedance of 8 ohms, but the actual output impedance will vary depending on circuit conditions.
Constant-voltage speaker systems are also commonly referred to as 25-, 70-, 70.7-, 100 or 210-volt speaker systems; distributed speaker systems; or high-impedance speaker systems. In Canada and the US, they are most commonly referred to as 70-volt speakers. In Europe, the 100 V system is the most widespread, with amplifier and speaker products ...
In electronics, a common-gate amplifier is one of three basic single-stage field-effect transistor (FET) amplifier topologies, typically used as a current buffer or voltage amplifier. In this circuit, the source terminal of the transistor serves as the input, the drain is the output, and the gate is connected to some DC biasing voltage (i.e. an ...