18W Class-B Audio Amplifier with Tone Controls

18W Class-B Audio Amplifier with Tone Controls

18W Class-B Audio Amplifier with Tone Controls

General Description for 18W Class-B Audio Amplifier with Tone Controls

The particular circuit configuration, allowed to push the NE5534 exceptional capacity of driving the output transistors near to its limits, enabling the whole amplifier to deliver relatively high power outputs without problems. Despite the complication added by the tone controls, the amplifier has an input sensitivity of 130mV RMS, allowing to connect directly to its input the most disparate audio sources without the need for a separate preamplifier. For this reason, it was possible to obtain 18W into an 8 Ohm load using a power supply voltage of +/- 20V. In order to satisfy repeated requests by correspondents, a medium power audio amplifier incorporating tone controls in the feedback path was finally designed.Total Harmonic Distortion figures are astonishingly low, much lower than comparable audio amplifiers using a single-IC audio amp. To avoid an excessive increase in parts-count, due to the addition of the tone controls, a simple amplifier circuitry was designed on the same guidelines of the successful 45 Watt Class B Amplifier, but using the excellent NE5534 IC instead of a discrete component op-amp to drive the output "dumper" transistors. An interesting feature of this amplifier is the absence of any kind of setup.

Parts for 18W Class-B Audio Amplifier with Tone Controls

P1______________50K  Log. Potentiometer (or 47K)
                     (twin concentric-spindle dual gang for stereo)
P2______________20K  Linear Potentiometer (or 22K)
                     (twin concentric-spindle dual gang for stereo)
P3_____________100K  Linear Potentiometer
                   (twin concentric-spindle dual gang for stereo)
R1_____________820R  1/4W Resistor
R2______________68R  1/4W Resistor
R3_______________1K8 1/4W Resistor
R4______________10K  1/4W Resistor
R5_______________1K  1/4W Resistor
R6,R7__________100R  1/4W Resistors
R8_____________330R  1/4W Resistor
R9______________47R  1/2W Resistor
C1_______________1µF  63V Polyester Capacitor
C2______________33pF  63V Polystyrene or Ceramic Capacitor
C3______________10nF  63V Polyester Capacitor
C4,C5____________1nF  63V Polyester Capacitors
C6_____________120nF  63V Polyester Capacitor
C7______________22nF  63V Polyester Capacitor
C8,C10_________220nF  63V Polyester Capacitors
C9______________22µF  25V Electrolytic Capacitor
C11,C12________220µF  25V Electrolytic Capacitors
IC1__________NE5534   Low noise Single Op-amp
Q1____________BD440   60V 4A PNP Transistor
Q2____________BD439   60V 4A NPN Transistor
J1______________RCA audio input socket

60W MosFet Audio Amplifier

High Quality, powerful unit: 90W into 4 Ohm load Also suited as guitar or bass amplifier

60W MosFet Audio Amplifier

60W MosFet Audio Amplifier Description

To celebrate the hundredth design posted to this website, and to fulfil the requests of many correspondents wanting an amplifier more powerful than the 25W MosFet, a 60 - 90W High Quality power amplifier design is presented here.

Circuit topology is about the same of the above mentioned amplifier, but the extremely rugged IRFP240 and IRFP9240 MosFet devices are used as the output pair, and well renowned high voltage Motorola's transistors are employed in the preceding stages.

The supply rails voltage was kept prudentially at the rather low value of + and - 40V. For those wishing to experiment, the supply rails voltage could be raised to + and - 50V maximum, allowing the amplifier to approach the 100W into 8 Ohm target: enjoy!

A matching, discrete components, Modular Preamplifier design is available here:Modular Audio Preamplifier.

Notes:

• In the original circuit, a three-diode string was wired in series to R10. Two of these diodes are now replaced by a red LED in order to achieve improved quiescent current stability over a larger temperature range. Thanks to David Edwards of LedeAudio for this suggestion.
• A small, U-shaped heatsink must be fitted to Q6 & Q7.
• Q8 & Q9 must be mounted on large heatsinks.
• Quiescent current can be measured by means of an Avo-meter wired in series to the positive supply rail and no input signal.
• Set the Trimmer R10 to its minimum resistance.
• Power-on the amplifier and adjust R10 to read a current drawing of about 120 - 130mA.
• Wait about 15 minutes, watch if the current is varying and readjust if necessary.
• The value suggested for C1 and C2 in the Power Supply Parts List is the minimum required for a mono amplifier. For optimum performance and in stereo configurations, this value should be increased: 10000µF is a good compromise.
• A correct grounding is very important to eliminate hum and ground loops. Connect to the same point the ground sides of R1, R3, C2, C3 and C4 and the ground input wire. Connect R7 and C7 to C11 to output ground. Then connect separately the input and output grounds to the power supply ground.

Parts:

R1______________47K   1/4W Resistor
R2_______________4K7  1/4W Resistor
R3______________22K   1/4W Resistor
R4_______________1K   1/4W Resistor
R5,R12,R13_____330R   1/4W Resistors
R6_______________1K5  1/4W Resistor
R7______________15K   1/4W Resistor
R8______________33K   1/4W Resistor
R9_____________150K   1/4W Resistor
R10____________500R   1/2W Trimmer Cermet
R11_____________39R   1/4W Resistor
R14,R15___________R33 2.5W Resistors
R16_____________10R   2.5W Resistor
R17_______________R22   5W Resistor (wirewound)

C1_____________470nF   63V Polyester Capacitor
C2_____________470pF   63V Polystyrene or ceramic Capacitor
C3______________47µF   63V Electrolytic Capacitor
C4,C8,C9,C11___100nF   63V Polyester Capacitors
C5______________10pF   63V Polystyrene or ceramic Capacitor
C6_______________1µF   63V Polyester Capacitor
C7,C10_________100µF   63V Electrolytic Capacitors

D1___________1N4002   100V 1A Diode
D2_____________5mm. Red LED

Q1,Q2,Q4_____MPSA43   200V 500mA NPN Transistors
Q3,Q5________BC546     65V 100mA NPN Transistors
Q6___________MJE340   200V 500mA NPN Transistor
Q7___________MJE350   200V 500mA PNP Transistor
Q8___________IRFP240  200V 20A N-Channel Hexfet Transistor
Q9___________IRFP9240 200V 12A P-Channel Hexfet Transistor

18W Class-B Audio Amplifier with Tone Controls

18W Class-B Audio Amplifier with Tone Controls

18W Class-B Audio Amplifier with Tone Controls

In order to satisfy repeated requests by correspondents, a medium power audio amplifier incorporating tone controls in the feedback path was finally designed.

To avoid an excessive increase in parts-count, due to the addition of the tone controls, a simple amplifier circuitry was designed on the same guidelines of the successful 45 Watt Class B Amplifier, but using the excellent NE5534 IC instead of a discrete component op-amp to drive the output "dumper" transistors.

The particular circuit configuration, allowed to push the NE5534 exceptional capacity of driving the output transistors near to its limits, enabling the whole amplifier to deliver relatively high power outputs without problems. For this reason, it was possible to obtain 18W into an 8 Ohm load using a power supply voltage of +/- 20V.

Despite the complication added by the tone controls, the amplifier has an input sensitivity of 130mV RMS, allowing to connect directly to its input the most disparate audio sources without the need for a separate preamplifier.

Total Harmonic Distortion figures are astonishingly low, much lower than comparable audio amplifiers using a single-IC audio amp.

An interesting feature of this amplifier is the absence of any kind of setup.

The power supply is straightforward. The parts values suggested are suited to power a stereo version of this design. For a mono amplifier a less powerful mains transformer can be used, having a 30V Center-tapped or 15 + 15V secondary winding, rated at about 24 to 30VA or 0.8-1A.

Notes:

Q1 and Q2 power transistors should be mounted on a finned heatsink of at least 100x50x25mm.

+ and - 22V is the absolute maximum permissible voltage supply for NE5534: please do not exceed this limit.

In the event you obtain a higher voltage from your power supply, you can consider the use of a regulated supply. Please see Simple, Efficient, Regulated Power Supply.

Parts:

P1______________50K  Log. Potentiometer (or 47K)
                     (twin concentric-spindle dual gang for stereo)
P2______________20K  Linear Potentiometer (or 22K)
                     (twin concentric-spindle dual gang for stereo)
P3_____________100K  Linear Potentiometer
                     (twin concentric-spindle dual gang for stereo)

R1_____________820R  1/4W Resistor
R2______________68R  1/4W Resistor
R3_______________1K8 1/4W Resistor
R4______________10K  1/4W Resistor
R5_______________1K  1/4W Resistor
R6,R7__________100R  1/4W Resistors
R8_____________330R  1/4W Resistor
R9______________47R  1/2W Resistor

C1_______________1µF  63V Polyester Capacitor
C2______________33pF  63V Polystyrene or Ceramic Capacitor
C3______________10nF  63V Polyester Capacitor
C4,C5____________1nF  63V Polyester Capacitors
C6_____________120nF  63V Polyester Capacitor
C7______________22nF  63V Polyester Capacitor
C8,C10_________220nF  63V Polyester Capacitors
C9______________22µF  25V Electrolytic Capacitor
C11,C12________220µF  25V Electrolytic Capacitors

IC1__________NE5534   Low noise Single Op-amp

Q1____________BD440   60V 4A PNP Transistor
Q2____________BD439   60V 4A NPN Transistor

J1______________RCA audio input socket

240W MOSFET Power Audio Amplifier

240W MOSFET Power Audio Amplifier

A high power audio amplifier circuit which can output up to 240W on a 4Ω speaker.
This mosfet amplifier is built with BUZ23 and uses a 40V symmetrical power supply. Connect the NTC close to the heatsinker.

MosFet 240W power amplifier schematic

240W MOSFET Power Audio Amplifier

Audio Amplifier Classroom Microphone System Circuit

This audio amplifier circuit is useful in classrooms to reduce the strain of lecturing ,if the surrounding environment is noisy. It uses the power amplifier IC LM380 that gives 2 watts output which is sufficient in a confined area. The amplifier is portable and the whole circuit and the battery can be enclosed in the Speaker box itself.

The circuit uses a preamplifier stage around NPN transistor BC 548 and a power amplifier around LM380.An external Collar MIC can be given to the input using an audio jack .The voice signals are amplified by T1 and fed to IC1 input through the volume control VR. Capacitor C3 reduce the undesirable howling from the speaker.

LM380 is the general purpose audio amplifier and its gain is internally fixed at 34 dB. Its output is short circuit proof with internal thermal limiting. The IC works between 5 to 22 volts DC and is dual in line version.

Classroom Microphone System Circuit Schematic

Audio Amplifier Classroom Microphone System Circuit

Assemble the classroom microphone system circuit on a common PCB. A 9 volt PP3 battery can be used to make the unit compact. If the amplifier is used for many hours, a 6 Volt 4.5 Ah rechargeable battery is a nice choice. If it is used, a charger input facility should be provided .Use a small good quality 8 Ohms speaker. If the output is not sufficient, use a high power amplifier IC circuit in the place of LM 380.

LM380 Pin connection

60W Bass Control Audio Power Amplifier Circuit diagram

Audio Power 60W Bass Control  Amplifier Circuit diagram 

60W Bass Control Audio Power Amplifier Circuit diagram

Audio Power 60W Bass Control  Amplifier Circuit description
This design adopts a well established circuit topology for the power amplifier, using a single-rail supply of about 60V and capacitor-coupling for the speaker(s). The advantages for a guitar amplifier are the very simple circuitry, even for comparatively high power outputs, and a certain built-in degree of loudspeaker protection, due to capacitor C8, preventing the voltage supply to be conveyed into loudspeakers in case of output transistors' failure.
The preamp is powered by the same 60V rails as the power amplifier, allowing to implement a two-transistors gain-block capable of delivering about 20V RMS output. This provides a very high input overload capability.

Audio Power 60W Bass Control  Amplifier Circuit Technical data:
Sensitivity:
70mV input for 40W 8 Ohm output
63mV input for 60W 4 Ohm output
Frequency response:
50Hz to 20KHz -0.5dB; -1.5dB @ 40Hz; -3.5dB @ 30Hz
Total harmonic distortion @ 1KHz and 8 Ohm load:
Below 0.1% up to 10W; 0.2% @ 30W
Total harmonic distortion @ 10KHz and 8 Ohm load:
Below 0.15% up to 10W; 0.3% @ 30W
Total harmonic distortion @ 1KHz and 4 Ohm load:
Below 0.18% up to 10W; 0.4% @ 60W
Total harmonic distortion @ 10KHz and 4 Ohm load:
Below 0.3% up to 10W; 0.6% @ 60W
Bass control:
Fully clockwise = +13.7dB @ 100Hz; -23dB @ 10KHz
Center position = -4.5dB @ 100Hz
Fully counterclockwise = -12.5dB @ 100Hz; +0.7dB @ 1KHz and 10KHz
Low-cut switch:
-1.5dB @ 300Hz; -2.5dB @ 200Hz; -4.4dB @ 100Hz; -10dB @ 50Hz

Notes:
The value listed for C8 is the minimum suggested value. A 3300µF capacitor or two 2200µF capacitors wired in parallel would be a better choice.
The Darlington transistor types listed could be too oversized for such a design. You can substitute them with MJ11014 (Q3) and MJ11013 (Q4) or TIP142 (Q3) and TIP147 (Q4).
T1 transformer can be also a 24 + 24V or 25 + 25V type (i.e. 48V or 50V center tapped). Obviously, the center-tap must be left unconnected.
SW1 switch inserts the Low-cut feature when open.
In all cases where Darlington transistors are used as the output devices it is essential that the sensing transistor (Q2) should be in as close thermal contact with the output transistors as possible. Therefore a TO126-case transistor type was chosen for easy bolting on the heatsink, very close to the output pair.
R9 must be trimmed in order to measure about half the voltage supply from the positive lead of C7 and ground. A better setting can be done using an oscilloscope, in order to obtain a symmetrical clipping of the output waveform at maximum output power.
To set quiescent current, remove temporarily the Fuse F1 and insert the probes of an Avo-meter in the two leads of the fuse holder.
Set the volume control to the minimum and Trimmer R3 to its minimum resistance.
Power-on the circuit and adjust R3 to read a current drawing of about 30 to 35mA.
Wait about 15 minutes, watch if the current is varying and readjust if necessary.

Audio Amplifier for Car Radio TDA7374B

Description:

The TDA7374B is a new technology class AB Audio Dual Bridge Power Amplifier in Multiwatt package designed for car radio applications. Thanks to the fully complementary PNP/NPN output configuration the high power performances of the TDA7374B are obtained without bootstrap capacitors.

Circuit diagram:

Audio Amplifier for Car Radio TDA7374B

Stereo 210 Watt Audio Amplifier

Circuit Diagam

Stereo 210 Watt Audio Amplifier

Baxandall Tone-Control Audio Amplifier

This circuit exploits the high slew rate, high input impedance, and high output-voltage capability of CA3140 BiMOS op amp. It also provides mid-band unity gain with standard linear potentiometers.

 Baxandall Tone-Control Audio Amplifier

90 W audio power amplifier based on transistor

Using only four transistors in the quasi-complementary amplifier configuration, this transistor power amplifier circuit can deliver 90W of power into 4 ohm loads and at low cost.

As shown in the transistor power amplifier circuit there are no expensive components in this circuit, except the power transformers and speakers. As shown in the diagram there are no expensive components in this circuit, except the power transformers and speakers. Input stage is formed by this two current driver directly raised a pair of transistors of the output stage. Transistor level end (2N3055) mounted on a heat sink to keep the lifetime of these devices. Supported by one source (of 80Vcc) at the output of the final stage, before the speaker, a capacitor is placed to block DC current, and just skip the audio signal. The power supply circuit 90 W audio power amplifier must be sufficient to provide current 1.5A per channel audio. Thus the power required to operate the stereo 3A and 6A is required for the four audio channels.

Read more at http://amplifiercircuit.net

90 W audio power amplifier based on transistor

18 Watt Audio Amplifier circuit diagram

18 Watt Audio Amplifier circuit diagram

Amplifier parts:
P1____22K Log. Potentiometer (Dual-gang for stereo)
R1___1K 1/4W Resistor
R2___4K7 1/4W Resistor
R3___100R 1/4W Resistor
R4___4K7 1/4W Resistor
R5___82K 1/4W Resistor
R6___10R 1/2W Resistor
R7___R22 4W Resistor (wirewound)
R8___1K 1/2W Trimmer Cermet (optional)
C1___470nF 63V Polyester Capacitor
C2,C5___100µF 3V Tantalum bead Capacitors
C3,C4___470µF 25V Electrolytic Capacitors
C6___100nF 63V Polyester Capacitor
D1___1N4148 75V 150mA Diode
IC1___TLE2141C Low noise, high voltage, high slew-rate Op-amp
Q1___BC182 50V 100mA NPN Transistor
Q2___BC212 50V 100mA PNP Transistor
Q3___TIP42A 60V 6A PNP Transistor
Q4___TIP41A 60V 6A NPN Transistor
J1___RCA audio input socket

7 tube 20 watt amplifier

This is a 7 tube 20 watt amplifier that must be used in conjunction with a pre amplifier having volume an tone controls. For this, I recommend this 6 tube pre-amp. With this amplifier you may use 6BQ5 output tubes. A 5U4-G rectifier is used so that the power supply will have plenty of pep to run the amp. This amplifier is basically a Magnovox amp visit page.

7 tube 20 watt amplifier

32W Stereo Audio Amplifier

32W Stereo Audio Amplifier

30 watt 4 Channel audio amplifier IC

Circuit diagram for TA8251AH:

30 watt 4 Channel audio amplifier IC

7.3W x 2CH audio amplifier ic

7.3W x 2CH audio amplifier ic

43 W BTL × 4-ch Audio Power IC

Overview:

The TB2904H (o) is 4-ch BTL audio amplifier for car audio applications.  This IC can generate higher power: POUT MAX = 43 W as it includes the pure complementary P-ch and N-ch DMOS output stage. It is designed to yield low distortion ratio for 4-ch BTL audio power amplifier, built-in standby function, muting function, and various kinds of protectors. 

Circuit Diagram:

Circuit diagram for  43 W BTL × 4-ch Audio Power IC

Datasheet for TB2904H: Download

14 W 4-Channel Audio Amplifier

The HA13151/HA13152 are high output and low distortion 4 ch BTL power IC designed for digital car audio. At 13.2 V to 4 W load, this power IC provides output power 14 W with 10% distortion.

Circuit Diagram:

14 W 4-Channel Audio Amplifier

Datasheet for HA13151: Download

4w audio amplifier

Circuit diagram:

4w audio amplifier

Datasheet for TDA1904: Download

2 x 80 W class-D audio amplifier

General Description:     

The TDA8927 is the switching power stage of a two-chip set for a high efficiency class-D audio power amplifier system. The system is split into two chips: 

• TDA8927J/ST/TH; a digital power stage in a DBS17P, RDBS17P or HSOP24 power package

• TDA8929T; the analog controller chip in a SO24 package.

     With this chip set a compact 2 × 80 W audio amplifier system can be built, operating with high efficiency and very low dissipation. No heatsink is required, or depending on supply voltage and load, a very small one. The system operates over a wide supply voltage range from ±15 up to ±30 V and consumes a very low quiescent current.

Circuit Diagram:

Circuit diagram for 2 x 80 W class-D audio amplifier

2x70W Audio Power Amplifier STK series

Overview

The STK412-000 series are class H audio power amplifier hybrid ICs that feature a built-in Shift power supply circuit. These ICs provide high efficiency audio power amplification by controlling (switching) the supply voltage supplied to the power transistors according to the detected level of the input audio signal.

Features

• Pin compatible IC series that covers power ratings from 50 W × 2 channels to 180 W × 2 channels at 0.7 or 0.8% THD, 20 Hz to 20 kHz. This allows the use of acommon PCB for all output classes.
• The pin arrangement is also unified with that of the three-channel STK413-000 series. This means that PCBs designed for three-channel models can also be used for two-channel models.
• Miniature package
• 50 W/ch to 120 W/ch (THD = 0.8%, f = 20 Hz to 20 kHz): 64 × 36.5× 8.5 mm*
• 150 W/ch to 180 W/ch (THD = 0.7%, f = 20 Hz to 20 kHz): 78 × 44× 9 mm*
• Not including the IC pins.
• Allowable load shorted time: 0.3 s

Circuit diagram

2x70W Audio Power Amplifier STK series