Class a amplifiers sound quality analysis
In static, a power amplifier and b power amplifier connected to pure resistive load, the test will be about the indicators, and even class a larger thermal noise.But the actual application, it is the true load (dynamic load), mini wireless speakers, and the impedance of the different frequency when the mini wireless speaker is different also, at this time of electroacoustic index will be inferior to pure resistive load indicators, transient distortion is produced.Due to the existence of the negative feedback and will feedback to the former level, this kind of distortion is key to the speaker system transient quality type design, uninterrupted by effective damping (control), and the higher the voltage build-up rate of the signal, the distortion more serious.For hifi mini wireless speaker (Such as:NSP-0001), it is important to the quality of the speaker system inertia can by amplifier is effective damping (control).
B damping of the power amplifier can not effectively control the mini wireless speaker, for
any output only one arm and a half weeks at work, or pushing or holding, but it
can't work at the same time, so it's a single direction of damping, namely
whether the positive half cycle or negative half cycle, he only propelled the
mini wireless speaker work motivation, and does not produce control a pull back, to
comprehensive damping,
drive current must promptly reversing, here's the problem.
Input square wave, for example, may work when input signal wave are more
complicated, for instance, when the signal goes up, the mini wireless speaker can go to work
according to the signal waveform, but when the signal suddenly stops, the
mini wireless speaker is due to the effect of inertia of the quality, does not stop, this
time the voice coil is conducting A counter electromotive force generated arm
and as output tube, and in the original globe B arm is conduction, and the counter
electromotive force and inspired by negative feedback back to the top level has
been enlarged to B arm output tube conduction, complete B power amplifier this
special damping, because the process to zero, A moment lost free oscillation
damping.Conduction change as the process finished, B arm, originally A arm of
the conduction is the partial delivery pipe resumed conduction, and experience
A zero damping moment to regain lost damping.So b damping of the power
amplifier at any moment is of single direction, the mini wireless speaker of damping is
accomplished by running a zero phase, having a distortion in almost all the
time.
Class a amplifiers plus or minus two arms are conducting, to the damping
coefficient of both sides, in the sudden high voltage rises, voice coil
according to the waveform to action, the signal stops, the electric potential
by the conduction of the complete pathway B arm, inertia is damping, cannot
produce free oscillation, the potential can establish, class a amplifier the
omnidirectional damping, forcing the vibration of the mini wireless speaker always based on
waveform to vibration signal.Class a amplifier mini wireless speakers whether under the
condition of different signal voltage will not make a transient distortion, can
control the omni-directional damping, drive current commutation in time, so as
to achieve the perfect sound quality.NSP-0004 a crystal mini wireless speaker is a good example of this amp sound
quality pure, high don't distortion bass heavy powerful mix, can put the
perfect sound performance paragraphs audio freely.