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

45 Watt Class B Amplifier

45 Watt Class B Amplifier Description

45W into 8 Ohm - 69W into 4 Ohm Easy to build - No setup required

45 Watt Class B Amplifier

45 Watt Class B Amplifier Description

The main design targets for this amplifier were as follows:

• Output power in the 40 - 70W range
• Simple circuitry
• Easy to locate, low cost components
• Rugged performance
• No setup

These goals were achieved by using a discrete-components op-amp driving a BJT complementary common-emitter output stage into Class B operation. In this way, for small output currents, the output transistors are turned off, and the op-amp provides all of the output current. At higher output currents, the power transistors conduct, and the contribution of the op-amp is limited to approximately 0.7/R11. The quiescent current of the op-amp biases the external transistors, and hence greatly reduces the range of crossover.

The idea sprang up from a letter published on Wireless World, December 1982, page 65 written by N. M. Allinson, then at the University of Keele, Staffordshire.
In this letter, op-amp ICs were intended as drivers but, as supply voltages up to +/- 35V are required for an amplifier of about 50W, the use of an op-amp made of discrete-components was then considered and the choice proved rewarding.

The discrete-components op-amp is based on a Douglas Self design. Nevertheless, his circuit featured quite obviously a Class A output stage. As for proper operation of this amplifier a Class B output stage op-amp is required, the original circuit was modified accordingly.

Using a mains transformer with a secondary winding rated at the common value of 25 + 25V (or 24 + 24V) and 100/120VA power, two amplifiers can be driven at 45W and 69W output power into 8 and 4 Ohms respectively, with very low distortion (less than 0.01% @ 1kHz and 20W into 8 Ohms).

This simple, straightforward but rugged circuit, though intended for any high quality audio application and, above all, to complete the recently started series of articles forming the Modular Preamplifier Control Center, is also well suited to make a very good Guitar or Bass amplifier. Enjoy!
Notes:
2N3055 and MJ2955 transistors were listed for Q8 and Q9 as the preferred types, but many different output transistors can be used satisfactorily: TIP3055/TIP2955, TIP35/TIP36, MJ802/MJ4502 amongst others.
Discrete op-amp output transistors Q6 and Q7 do not require any heatsink as their cases remain at ambient temperature. Power transistors Q8 and Q9 should be mounted on a black, finned heatsink as usual.

Parts:

R1______________18K  1/4W Resistor
R2_______________3K9 1/4W Resistor
R3,R6____________1K  1/4W Resistors
R4_______________2K2 1/4W Resistor
R5______________15K  1/4W Resistor
R7______________22K  1/4W Resistor
R8_____________330R  1/4W Resistor
R9,R10__________10R  1/4W Resistors
R11,R12_________47R  1/4W Resistors
R13_____________10R    1W Resistor


C1_______________1µF  63V Polyester Capacitor
C2_____________470pF  63V Polystyrene or Ceramic Capacitor
C3______________47µF  25V Electrolytic Capacitor
C4______________15pF  63V Polystyrene or Ceramic Capacitor
C5_____________220nF 100V Polyester Capacitor
C6_____________100nF  63V Polyester Capacitor

D1,D2,D3,D4___1N4148  75V 150mA Diodes

Q1,Q2________BC560C   45V 100mA Low noise High gain PNP Transistors
Q3,Q4________BC556    65V 100mA PNP Transistors
Q5___________BC546    65V 100mA NPN Transistor
Q6___________BD139    80V 1.5A NPN Transistor
Q7___________BD140    80V 1.5A PNP Transistor
Q8__________MJ2955    60V 15A PNP Transistor
Q9__________2N3055    60V 15A NPN Transistor

24 W BTL or 2 x 12 W stereo car radio power amplifier

General Description:

The TDA1515BQ is a monolithic integrated class-B output amplifier in a 13-lead single in-line (SIL) plastic power package. The device is primarily developed for car radio applications, and also to drive low-impedance loads (down to 1,6 Ω). At a supply voltage VP = 14,4 V, an output power of 24 W can be delivered into a 4 Ω BTL (Bridge Tied Load), or, when used as stereo amplifier, it delivers 2 × 12 W into 2 Ω or 2 × 7 W into 4 Ω. 

Features:

• flexibility in use − mono BTL as well as stereo
• high output power
• low offset voltage at the output (important for BTL)
• large usable gain variation
• very good ripple rejection
• internal limited bandwidth for high frequencies
• low stand-by current possibility (typ. 1 µA), to simplify required switches; TTL drive possible
• low number and small sized external components
• high reliability.
• he following currently required protections are incorporated in the circuit. These protections also have positive influence
• on reliability in the applications.
• load dump protection
• a.c. and d.c. short-circuit safe to ground up to VP = 18 V
• thermal protection
• speaker protection in bridge configuration
• SOAR protection
• outputs short-circuit safe to ground in BTL
• reverse polarity safe.

Circuit Diagram:

Circuit diagram for 24 W BTL or 2 x 12 W stereo car radio power amplifier

Datasheet for TDA1515BQ

10 + 10W Stereo Amplifier for car radio

General Description:

The TDA2004A is a class B dual audio power amplifier in MULTIWATT package specifically designedforcar radioapplications; stereoamplifiersare easily designed using this device that provides a high current capability (up to 3.5 A) and that can drive very low impedance loads (down to 1.6Ω ).

Circuit diagram:

Circuit diagram for 10 + 10W Stereo Amplifier for car radio

Datasheet for TDA2004A: Download

4x12W car radio power amplifier

FEATURES:

Requires very few external components

High output power

Fixed gain

Diagnostic facility (distortion, short-circuit and temperature detection)

Good ripple rejection

Mode select switch (operating, mute and stand-by)

Load dump protection

AC and DC short-circuit safe to ground and to VP

Low power dissipation in any short-circuit condition

Thermally protected

Reverse polarity safe

Electrostatic discharge protection

No switch-on/switch-off plop

Flexible leads

Low thermal resistance

Identical inputs.

GENERAL DESCRIPTION:

The TDA8562Q is an integrated class-B output amplifier in a 17-lead single-in-line (SIL) power package. It contains 4 × 12 W single-ended amplifiers.

Circuit Diagram:

4x12W car radio power amplifier

2 × 40 W/2 Ω stereo BTL car radio power amplifier

General description:

The TDA8566 is an integrated class-B output amplifier which is available in several packages. TDA8566TH is contained in a 20-lead small outline plastic package. The TDA8566TH1 is a 24-lead small outline plastic package which is pin compatible with the I2C-bus controlled amplifier TDA1566TH for one board layout. TDA8566Q is a 17-pinDIL-bent-SIL package. The device contains 2 amplifiers in a Bridge-Tied Load (BTL) configuration. The output power is 2 × 25 W in a 4 Ω load or 2 × 40 W in a 2 Ω load. It has a differential input stage and 2 diagnostic outputs. The device is primarily developed for car radio applications.

Features:

Differential inputs

Very high Common Mode Rejection Ratio (CMRR)

High common mode input signal handling

Requires very few external components

High output power

4 Ω and 2 Ω load driving capability

Low offset voltage at output

Fixed gain

Diagnostic facility (distortion, short-circuit and temperature pre-warning)

Good ripple rejection

Mode select switch (operating, mute and standby)

Load dump protection

Short-circuit proof to ground, to VP and across the load

Low power dissipation in any short-circuit condition

Thermally protected

Reverse polarity safe

Protected against electrostatic discharge

No switch-on/switch-off plops

Low thermal resistance

TDA8566TH1 is pin compatible with TDA1566TH

Circuit Diagram:

2 × 40 W/2 Ω stereo BTL car radio power amplifier 

4 x 13 W single-ended power amplifiers

FEATURES

Requires very few external components

High output power

Fixed gain

Diagnostic facility (distortion, short-circuit and temperature detection)

Good ripple rejection

Mode select switch (operating, mute and standby)

AC and DC short-circuit safe to ground and to VP

Low power dissipation in any short-circuit condition

Thermally protected

Reverse polarity safe

Electrostatic discharge protection

No switch-on/switch-off plop

Flexible leads

Low thermal resistance

Identical inputs.

GENERAL DESCRIPTION

The TDA8511J is an integrated class-B output amplifier in a 17-lead DIL-bent-SIL power package. It contains 4 × 13 W single-ended amplifiers.

Circuit Diagram:

4 x 13 W single-ended power amplifiers

TDA1557Q 2 x 22w car radio power amplifier

FEATURES

Requires very few external components

High output power

Low offset voltage at output

Fixed gain

Good ripple rejection

Mute/stand-by switch

Load dump protection

AC and DC short-circuit-safe to ground and VP

Thermally protected

Reverse polarity safe

Capability to handle high energy on outputs (VP = 0)

Protected against electrostatic discharge

No switch-on/switch-off plop

Flexible leads

Low thermal resistance.

GENERAL DESCRIPTION

The TDA1557Q is a monolithic integrated class-B output amplifier in a 13-lead single-in-line (SIL) plastic power package. The device contains 2 × 22 W amplifiers in BTL configuration and has been primarily developed for car radio applications.

Circuit Diagram

Circuit diagram for TDA1557Q 2 x 22w car radio power amplifier