Class S power amplifier 02

A practical circuit of Class S power amplifier (the other channel is the same), lcl is the pre-voltage amplifier, and the high-speed
operational amplifier LF'353 is used. IC 2 is the current drive amplifier, and the operational amplifier is NE5532. The power consumption of NE5532 can reach 800mW. , it
is most suitable to be used as power drive here. Rl～R8. R9～R16 can
use 0.15～0.3fl/2W 5% accuracy resistors, or 8
1/4W, 1.2fl～2.2C1 resistors with 5% accuracy can be used in parallel
instead In fact, the accuracy can reach Within l". IC3 is used as a clipping indication circuit
. When the signal amplitude is too large and clipping occurs, IC 3 drives VD3
to flash to indicate. The effective power of the undistorted sine wave of this amplifier
is 30W×2 on a 4n load and 8fl load. It is 16W×2; the voltage gain
is 24dB. If you need to increase the gain, you can increase R39 and R42; the input
sensitivity is 750mV (or 2V); this power amplifier is a pure DC
amplifier with a frequency response of O~sokHz ; The input impedance is
27kn, add a 47kfl potentiometer to adjust the volume. This amplifier
does not require a large radiator area. In order to facilitate production and save costs
, it is recommended to use the shell as a heat dissipation carrier. The amplifier tube is welded on the back and
Bend it outward and use an iron strip with two
tapped holes of 3mm diameter. You can open
two Press the iron strip against the pipe and use The screws pass through
the bottom plate to press the tube against the bottom plate (the rear plate is also acceptable), so that
the open heat fin of the power amplifier tube is close to the casing and coated with thermal conductive silicone grease, because the heat sink
is generally connected to the tube collector plate. , so the insulation between the mica sheet and
the shell should be added, and the iron bars must not be pressed on the heat sink of the tube. If the impedance of the dubbing box is 8n, the power of the transformer should
be greater than 40W. If it is 4fl, the filter capacitor will not be larger than 60W. Less than 4700plF×2. R5 1. R52.C9.clo,
no installation holes are left on the printed board, and the effect is better if it is directly welded on the crimping post 6