Low noise mixed headphone amplifier ----- Headphone Amplifier

Keywords: low noise mixed headphone amplifier Low noise mixed headphone amplifier It has a high-quality headset, directly connected to the sound source to listen to music, is the easiest way. But the standard sound source even when the maximum amplitude of the signal output is 0.755V, the power is only: u2 / r = 0.755V / 32Ω = 18mW, the satisfactory effect cannot be achieved. Therefore, an amplifier is required between the source and the headset. This hybrid headphone amplifier (circuit seeing) made by the author is a high input low output impedance amplifying circuit with a tube 12au7 cathode follower and Dulinton tube BC517 emitter. The high input impedance characteristics of V1 make T3 input impedances are not affected by the pre-pre-stage volume potentiometer or signal source change, keeping audio output frequency response. T3 and T1, T2 constitute a constant current source A single-ended power amplifier circuit, R5 sets the constant current source operating current to 27mA. Due to the V1 screen works in 12V low voltage, the screen is weak, and T3 selects the current high gain Dawndon Tube. C2 is a radio frequency filter capacitor. R2, the R4 partial pressure circuit holds the V1 gate on the 1/2 supply voltage. C1, R1 constitute a signal input circuit, where R1 is a gate input voltage matching resistor, and it is not too small to select the capacitance of C1. T5, R7, C5 constitute a capacitance multiplier filter circuit, which is that the circuit impedance is low, the energy consumption is small, and the filter output is smooth and stable, and the V1 screen and the T3 collector provide a DC operating voltage of the stainless background. In addition, when the power is turned on, the power supply is charged to C5, T5 delay is turned on, so that the V1 filament is gradually heated. T4 is used to partition the interference signal generated by the filament circuit to extract the audio amplifier, and the T4 on-resistance is only 0.16 Ω. Author: Lin Xinxiong

Our other product:

Professional lightning protection system for Tower	Professional FM Radio Station Equipment Package	FMUSER FU-1000C 1000W FM Transmitter With USB Audio Input Interface
FMUSER 200W FM Radio Broadcasting Package	Hotel IPTV Solution	FMUSER FSN-1000T V5.0 1KW FM Radio Broadcast Transmitter