Wiring Diagram

No setup is required: if correct values are used for resistors R3 to R7, LED D1 will illuminate at 0dB input (0.775V RMS), LED D2 at +5dB input (1.378V RMS) and LED D3 at +10dB (2.451V RMS).

The circuit was optimized for low current consumption as it was intended for battery operation. To achieve this, the best arrangement has proven to be the one using two different op-amp types for IC1 and IC2. In fact the LM393 IC was not operating satisfactorily as dot-mode LED driver, whereas the LM324 was unable to charge C2 in the linear way, as expected. Therefore, the final circuit is some op-amp wasting, but the small added cost will be quickly compensated by battery savings.

This amplifier circuit is suitable for home power audio devices. The STK082 amplifier specifications might lead you to believe that it can use supply voltages of up to ±43V. but I don't recommend anything greater than ±25V if 8 ohm loads are expected, although ±30V will be fine if you can provide good heatsinking.

Subwoofer controller is quite simple, an input buffer provides phase switching and ensures that the input impedance of the source does not affect the filter performance, and this is nowfollowed by a 12dB/octave high pass filter. The phase reverse switch is used so that the sub can be properly phased to the rest of the system. If the mid-bass disappears as you advance the level of control, then the phase is wrong, so just switch to the opposite position.Contribute a better translation

The board has only one input, so if you plan to use a normal stereo feed supplying a single P48 board, you'll need to sum the two stereo outputs. This is easily accomplished by using a pair of resistors - the value should be between 2.2k and 4.7k. If this is done, replace R1 with either a 100 ohm resistor or a wire link.

VR1 is used to change the gain of the second integrator. The level through the controller can be set to make sure that there is no distortion - there can be a huge amount of gain at low frequencies, and if the gain is too high, distortion is assured!

The high-pass filter is designed as a peaking type, and gives a response that is almost perfect down to 20Hz. The lowest frequency can be tailored by changing C1, C2, C3 and C4. As shown, the response peaks at 18Hz, but you can use 68nF to increase this to 27Hz, or 47nF for 39Hz. See Table 1 for the full range of values.

AUDIO TONE CONTROL 2 TRANSISTOR CIRCUIT SCHEMATIC DIAGRAM

Audio tone control circuit based transistors on these provides a maximum cut and boost of around 10dB at 10K and 50Hz.
audio tone control 2 transistorSkema rangkaian audio tone control 2 transistor


The first BC109C transistor is acting as a buffer. It provides the circuit with a high input impedance, around 250k has a voltage gain of slightly less than unity. As the Baxendall tone control circuit is a passive design, all audio frequencies are attenuated. The position of the controls and reactance of the capacitors alters the audio response. The last transistor provides a slight boost of about 3x. The output is designed to feed an amplifier with input impedance of 10k to 250k. Both tone controls should be linear type Potentiometers.


quick Data Transistor BC109C

Low current max. 100 mA
Low voltage max. 45 V
Collector-base voltage open emitter 30 V
Collector-emitter voltage open base - 20 V
Peak collector current - 200 mA
total power dissipation Tamb £ 25 °C - 300 mW
DC current gain (hFE ) IC = 2 mA; VCE = 5 V 200 - 800
transition frequency IC = 10 mA; VCE = 5 V; f = 100 MHz 100 - MHz

AUDIO LIMITER BERBASIS OP-AMP CIRCUIT SCHEMATIC DIAGRAM

This audio peak limiter employs a FET as a variable resistance to attenuate the input signal according to a control voltage (CV). It offers unusually good performance with low cost and component count. A TL072 dual opamp (U1) provides the circuit gain and full wave peak detection.


Audio Limiter Berbasis Op-AmpSkema Rangkaian Audio Limiter Berbasis Op-Amp


If desired, a LED VU meter may be used here instead, and with proper calibration will give a good indication of the peak attenuation at any time. This option will require some experimentation from the constructor, and further details are up to the individual to work out.

The 4.7K resistor and 1uF capacitor (R14 and C5) determine the attack time, which is about 5ms as shown. R12 and C5 determine the release or recovery time, and as shown this is approximately 1 second.

R11, C3 C4 and R13 form the distortion cancelling circuit, and as can be seen, the control voltage impedance is very low compared to the distortion cancellation impedance, so the circuit's attack time is not compromised. The values of resistance and capacitance have been optimised for the least distortion across the audio band, at 0.3% THD typical for frequencies above around 500 Hz, at 1.65V RMS output level. Below 500 Hz, the distortion rises gently with decreasing frequency, but also falls with lower voltages. Distortion is negligible at any voltage level below the limiting threshold.

8WATT AUDIO AMPLIFIER TDA2030 CIRCUIT SCHEMATIC DIAGRAM

This is a circuit of 8-watt audio amplifier IC TDA2030-based mono. When you use 4 ohm speakers then you get 14 watts output power, and around 8 watts if you use 8 ohm loudspeaker.

Although the TDA2030 is capable of delivering 20 watts of audio power, I deliberately reduced the output to about 8 watts to 10 watts drive speakers. This is more than adequate for a smaller room. Input sensitivity is 200mV. Higher input levels naturally will give greater output, but no distortion should be heard. The gain is set by the 47k and 1.5k resistors. The TDA2030 IC is affordable and makes a good replacement amplifier for low to medium audio power systems. Incidentally, it is speaker efficiency that determines how "loud" the sound is. Speaker efficiency or sound pressure level (SPL) is usually quoted in dB / meter. A speaker with an SPL of 97dB / m will sound louder than a speaker with an SPL of 95dB / m.

Absolute Maximum Ratings IC TDA2030

Supply voltage ± 18 (36) V
Input voltage Vs
Differential input voltage ± 15 V
Output peak current (internally limited) 3.5 A
Power dissipation at Tcase = 90°C 20 W
Tj Stoprage and junction temperature -40 to 150 °C

LED INDICATOR AUDIO AMPLIFIER CIRCUIT SCHEMATIC DIAGRAM

This circuit, connected to the loudspeaker output of an audio amplifier, will indicate the instantaneous output power delivered to the loudspeaker(s) by means of six LEDs illuminating one after another by voltage values increasing little by little, providing the visual impression of a luminous bar or column, increasing and decreasing in height following the increase and decrease of the signal’s level.

Notes:

    * The output power indicated by each LED must be doubled when 4 Ohms loads are driven.
    * The circuit can be adapted to suit less powerful amplifiers by reducing the number of LEDs and related voltage dividers.