工业控制 | 能源技术 | 汽车电子 | 通信网络 | 安防监控 | 智能电网 | 移动手持 | 无线技术 | 家用电器 | 数字广播 | 消费电子 | 应用软件 | 其他方案

电路设计->音频电路图->其他音频电路图->带低音增强的立体声前置放大器电路 (Stereo Pream

带低音增强的立体声前置放大器电路 (Stereo Pream

发布人:fanxiaoxi 时间:2022-12-22 收藏

带低音增强的立体声前置放大器电路 (Stereo Preamplifier with Bass-boost)

gh Quality, simple design 20 to 30V supply

Parts:

P1_________________10K   Log.PotenTIometer (Dual-gang for stereo)
P2________________100K   Log.PotenTIometer (Dual-gang for stereo) (See Notes)

R1,R2_____________100K   1/4W Resistors
R3,R6______________15K   1/4W Resistors
R4_________________10K   1/4W Resistor
R5_________________22K   1/4W Resistor
R7__________________1K   1/4W Resistor
R8________________560R   1/4W Resistor

C1,C2,C5____________2΅2   63V ElectrolyTIc Capacitors
C3________________470΅F   35V ElectrolyTIc Capacitor
C4__________________1΅F   63V Polyester Capacitor
C6_________________47nF   63V Polyester Capacitor
C7_________________22΅F   25V Electrolytic Capacitor

IC1_______________TL072  Dual BIFET Op-Amp

SW1________________DPST  Switch (Optional, see Notes)

Comments:

This preamplifier was designed to cope with CD players, tuners, tape recorders etc., providing a gain of 4, in order to drive less sensitive power amplifiers. As modern Hi-Fi home equipment is frequently fitted with small loudspeaker cabinets, the bass frequency range is rather sacrificed. This circuit features also a bass-boost, in order to overcome this problem. You can use a variable resistor to set the bass-boost from 0 to a maximum of +16dB @ 30Hz. If a fixed, maximum boost value is needed, the variable resistor can be omitted and substituted by a switch.

Notes:

Schematic shows left channel only, but R1, R2, R3 and C1, C2, C3 are common to both channels.

For stereo operation P1, P2 (or SW1), R4, R5, R6, R7, R8 and C4, C5, C6, C7 must be doubled.

Numbers in parentheses show IC1 right channel pin connections.

A log type for P2 ensures a more linear regulation of bass-boost.

Needing a simple boost-in boost-out operation, P2 must be omitted and SW1 added as shown in the diagram.

For stereo operation SW1 must be a DPST type.

Please note that, using SW1, the boost is on when the switch is open, and off when the switch is closed.


Technical data (30V supply):

Gain @ 1KHz: 4

Max. input voltage @ 50Hz: 500mV RMS (280mV RMS @ 20V supply)
Max. input voltage @ 100Hz: 700mV RMS (460mV RMS @ 20V supply)

Max. output voltage: >8V RMS (>5V RMS @ 20V supply)

Max. bass-boost referred to 1KHz: 400Hz = +2dB; 200Hz = +5dB; 100Hz = +10dB; 50Hz = +14dB; 30Hz = +16dB

Total harmonic distortion @ 100Hz and 1V RMS output: 0.02%
Total harmonic distortion @ 1KHz and 1V RMS output: 0.006%
Total harmonic distortion @10KHz and 1V RMS output: 0.007%

Total harmonic distortion @ 100Hz and 5V RMS output: 0.02%
Total harmonic distortion @ 1KHz and 5V RMS output: 0.0013%
Total harmonic distortion @10KHz and 5V RMS output: 0.005%

Current drawing: 2mA


关键词: 前置放大器

评论

技术专区