Help regarding audio amplifier..

[sarang2502]

Hello forum members,

It would be great if someone helps me out,

I am having four speakers, 6 ohms and 8W each (Mercury).
I want to use them in amplifier circuit and play music through my PC/Laptop.
I have searched many circuits for it. But am totally confused about how much watt output circuit should I use.

Here are some which I found, please review it and let me know which is suitable, or if anyone has any other idea please suggest me.

Thanks in advance.
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#1:

This audio amplifier project is a class AB audio power amplifier using a TDA2003 module power amplifier. It is easy to construct and has only a few external components. The module is designed with short circuit and thermal protection. It can drive loads as low as 1.6 ohm and is capable of delivering over 10 watts from a 16 V DC power supply.

The power supply required for is 8 - 18V DC at 1 Amp or more. Maximum output power will only be obtained with a power supply of greater than 1A at 16V DC, and using 2 ohm speakers (or 2 by 4 ohm speakers in parallel). However approximately 4W RMS can be obtained with a 12V DC, 1A supply into a 4 ohm load.
The power supply should be well filtered to reduce mains hum, the on board capacitors alone are not adequate for this purpose but are necessary to ensure stability. Extra filtering is unnecessary if operating from a battery. If two boards are used for stereo, you will need to double the size of the power supply.


Audio Amplifier Circuit Diagram

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The major circuitry is contained in the amplifier module. C1 is the input coupling capacitor and blocks DC signal, so does C3 which is the output coupling capacitor, and C2 which blocks DC from the feed back loop to the differential input. R2 and R3 set the level of feed back. C4 and R4 provide a high frequency load for stability where loudspeaker inductive reactance may become excessive. C5 and C6 provide power supply decoupling or filtering.
There should be no problems with the stability of the circuit, however if you do, make sure the power supply filtering and leads are adequate. If necessary you might connect an RC compensation network between IC pins 2 and 4 as in the data sheet. Values for Cx of 22 - 33 nF and for Rx of 39 - 47 ohms, should be satisfactory whilst still maintaining satisfactory high frequency response.
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#2:

10W Audio Amplifier with Bass-boost
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High Quality, very simple design
No preamplifier required
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Circuit diagram:

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Parts:
P1_________________22K Log.Potentiometer (Dual-gang for stereo)
P2________________100K Log.Potentiometer (Dual-gang for stereo)
R1________________820R 1/4W Resistor
R2,R4,R8____________4K7 1/4W Resistors
R3________________500R 1/2W Trimmer Cermet
R5_________________82K 1/4W Resistor
R6,R7______________47K 1/4W Resistors
R9_________________10R 1/2W Resistor
R10__________________R22 4W Resistor (wirewound)

C1,C8_____________470nF 63V Polyester Capacitor
C2,C5_____________100µF 25V Electrolytic Capacitors
C3,C4_____________470µF 25V Electrolytic Capacitors
C6_________________47pF 63V Ceramic or Polystyrene Capacitor
C7_________________10nF 63V Polyester Capacitor
C9________________100nF 63V Polyester Capacitor

D1______________1N4148 75V 150mA Diode

IC1_____________NE5532 Low noise Dual Op-amp

Q1_______________BC547B 45V 100mA NPN Transistor
Q2_______________BC557B 45V 100mA PNP Transistor
Q3_______________TIP42A 60V 6A PNP Transistor
Q4_______________TIP41A 60V 6A NPN Transistor

J1__________________RCA audio input socket
Power supply parts:
R11_________________1K5 1/4W Resistor

C10,C11__________4700µF 25V Electrolytic Capacitors

D2________________100V 4A Diode bridge
D3________________5mm. Red LED

T1________________220V Primary, 12 + 12V Secondary 24-30VA Mains transformer

PL1_______________Male Mains plug

SW1_______________SPST Mains switch
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Comments:
This design is based on the 18 Watt Audio Amplifier, and was developed mainly to satisfy the requests of correspondents unable to locate the TLE2141C chip. It uses the widespread NE5532 Dual IC but, obviously, its power output will be comprised in the 9.5 - 11.5W range, as the supply rails cannot exceed ±18V.
As amplifiers of this kind are frequently used to drive small loudspeaker cabinets, the bass frequency range is rather sacrificed. Therefore a bass-boost control was inserted in the feedback loop of the amplifier, in order to overcome this problem without quality losses. The bass lift curve can reach a maximum of +16.4dB @ 50Hz. In any case, even when the bass control is rotated fully counterclockwise, the amplifier frequency response shows a gentle raising curve: +0.8dB @ 400Hz, +4.7dB @ 100Hz and +6dB @ 50Hz (referred to 1KHz).

Notes:
• Can be directly connected to CD players, tuners and tape recorders.
• Schematic shows left channel only, but C3, C4, IC1 and the power
supply are common to both channels.
• Numbers in parentheses show IC1 right channel pin connections.
• A log type for P2 will ensure a more linear regulation of bass-boost.
• Do not exceed 18 + 18V supply.
• Q3 and Q4 must be mounted on heatsink.
• D1 must be in thermal contact with Q1.
• Quiescent current (best measured with an Avo-meter in series with
Q3 Emitter) is not critical.
• Set the volume control to the minimum and R3 to its minimum
resistance.
• Power-on the circuit and adjust R3 to read a current drawing of
about 20 to 25mA.
• Wait about 15 minutes, watch if the current is varying and readjust
if necessary.
• A correct grounding is very important to eliminate hum and ground
loops. Connect to the same point the ground sides of J1, P1, C2, C3
&C4. Connect C9 to the output ground.
• Then connect separately the input and output grounds to the power
supply ground.
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#3:

18W Audio Amplifier
________________________________________
High Quality very simple unit
No need for a preamplifier
________________________________________
Circuit diagram:

**broken link removed**

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
Power supply parts:
R9______________2K2 1/4W Resistor

C7,C8________4700µF 25V Electrolytic Capacitors

D2_____________100V 4A Diode bridge
D3_____________5mm. Red LED

T1_____________220V Primary, 15 + 15V Secondary, 50VA Mains transformer

PL1____________Male Mains plug

SW1____________SPST Mains switch
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Notes:
• Can be directly connected to CD players, tuners and tape recorders.
• Do not exceed 23 + 23V supply.
• Q3 and Q4 must be mounted on heatsink.
• D1 must be in thermal contact with Q1.
• Quiescent current (best measured with an Avo-meter in series with Q3 Emitter) is not critical.
• Adjust R3 to read a current between 20 to 30 mA with no input signal.
• To facilitate quiescent current setting add R8 (optional).
• A correct grounding is very important to eliminate hum and ground loops. Connect to the same point the ground sides of J1, P1, C2, C3 & C4. Connect C6 to the output ground.
• Then connect separately the input and output grounds to the power supply ground.
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#4:

Description:

A 15 watt amplifier made using discrete components. Sergio designed this circuit for his Electronics Level II course.

Notes:

This amplifier uses a dual 20 Volt power supply and delivers 15 watts RMS into an 8 ohm load. Q1 operates in common emitter, the input signal being passed to the bias chain consisting of Q8, Q9, D6, D13 and D14. Q8 and Q9 provide a constant current through the bias chain to minimize distortion, the output stage formed by a discrete darlington pair (Q2,Q4) and (Q7,Q11). The last two transistors are power Transitors, specifically the 2N3055 and MJ2955. The 7.02K resistor, R16 was made using a series combination of a 4.7K, 680 Ohms, and two 820 Ohms. The 1.1K resistor, R3 was made using a 100 Ohms and a 1K resistor. You can use this circuit with any walkman or CD player since it is designed to take a standard 500mv RMS signal.

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#5:

You can use this powerfull amplifier
in any small audio project. It is very small (6.5 x 4.5 cm).It outputs 10W and uses a 9V battery.

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Componets List
R1 : 6 Ohm
R2 : 220 Ohm
R3 : nothing
R4 : 10 KOhm pontesiometer
C1 : 2200 uF / 25V
C2 : 470 uF / 16V
C3 : 470 nF / 63V
C4 : 100 nF
C5 : nothing
C6 : nothing
IC1 : TDA 2003
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#6:

8 Watt Audio Amp electronic circuit diagram

Here is the schematic for an 8 watt audio amp. This amp can be used as a simple booster, the heart of a more complicated amplifier or used as a guitar amp.

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Parts:

C1 - 10uf Electrolytic Capacitor
C2 - 470uf Electrolytic Capacitor
C3 - 0.1uF Disc Capacitor
C4 - 2000uf Electrolytic Capacitor 2200uF
R1 - 2.2 Ohm Resistor Anything Within 10%
R2 - 220 Ohm Resistor Anything Within 10%
IC1 -LM383 8 Watt Amp IC ECG1232

Notes:

1. IC1 MUST be installed on a heat sink.
2. C3 is for filtering and to prevent oscillation and should not be omitted.
3. The circuit can be built on a perf board, universal solder board or PC board, the PC board is preferred. I built the circuit on a perf board and had to add extra inductors, capacitors and resistors to prevent oscillation.
4. The circuit draws about 880 ma at 12 V.
5. By swapping the values of R1 and R3, you can turn this amplifier into a guitar amp with no preamp required.
6. If you can't find 2000uF, then replace C4 with a 2200uF unit.
7. If you add a 0.2uF capaciitor in series with a 1 ohm resistor to the output you can prevent oscillation of the circuit under certain conditions.
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[Externet]

Don't you have a plain stereo system at home?

 

[audioguru]

Most of those amplifiers do not make their rated output power:
1) Amp #1 makes 10W at clipping only if the load is 1.6 ohms (five 8 ohm speakers in parallel) and the supply is 16V. Then the power in each speaker is only 2W.
2) Amps #2 ands #3 have an output of 10W into 8 ohms but you would need one amplifier for each speaker.
3) The schematic for amp #4 has tiny little output transistors that will quickly over-heat and fail instead of the big power transistors in the text.
4) Amp #5 is a lie. It is missing the important parts shown on its datasheet. Its output power is only 0.8W (not 10W) into an 8 ohm speaker if its 9V battery is brand new.
5) Amp #6 uses an obsolete LM383 that has not been made for many years. with the 12V power supply shown, its output power is only 1.5W at clipping into 8 ohms, not 8W.

Aren't your 8W speakers extremely cheap or very small? A half-decent inexpensive speaker is rated at 60W.

 

[sarang2502]

Don't you have a plain stereo system at home?

I am having it, but i had a mercury 4.1 audio system with Woofer.. Now the woofer and amplifier circuit is crashed..
So the speakers are Useless.. May be i can use them, on back of each speaker it is written "6Ω 8W"...

 

[sarang2502]

Please review this circuit? Can it be used?

Details of speaker:
http://www.mercury-pc.com/product-detail.php?link=p-speaker&subtitle=Speaker&productid=129

I can use two speakers in parallel, for 6W on each channel... is it possible?



2X12 W HiFi Amplifier circuit

Description.

Here is the circuit of a 2X12 watt HiFi amplifier circuit using IC TDA 2616 from Phillips.A quiet simple and robust circuit using very less components.This makes the circuit ideal for a portable power amplifier.The circuit delivers 12 W power on 8 Ohm speaker for each channel at +/- 12 V dual supply.

The TDA2616 is a stereo power amplifier IC comes in a 9-lead single-in-line (SIL9)
plastic power package (SOT131). This IC is specially designed for mains
fed amplifier circuits, such as stereo radio,tape and television .The IC has good gain balance of both channels and Hi-fi in accordance with IEC 268 and DIN 45500 standards.Also the IC TDA 2616 has special inbuilt circuit for the suppression
of noise signals at the inputs, during switch-on and switch-off.This prevents click sounds during power on and power off.

Circuit Diagram with Parts List.

**broken link removed**



Notes.
All capacitors except C10 & C9 are ceramic.
All capacitors must be rated 50V.
Use a well regulated and filtered +/- 12 V dual power supply that is able to provide at least 2 A continuous current.

TDA 2616 Pin assignment & layout.
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[audioguru]

The Mercury company publish 3 different power ratings:
1) The zipped file owner's manual says 30W RMS and that the woofer is only 4" and the satellites are 3".
2) The first page of the sales sheet says 6 watts RMS per channel-Satellite and 24 Watts RMS Sub-woofer.
It also says a rediculous 1980 watts PMPO.
3) The specifications page says Sub-woofer: 15 Watts and Satellites: 9W each.

The Philips (NXP Semi) TDA2616 amplifier IC is not made anymore and has been withdrawn.
Its datasheet shows that its output was 6W per channel at clipping into 8 ohms with a plus and minus 12V supply. Its output was 10W per channel into 4 ohms. It might give 6W into each of your little 3" speakers when two speakers are in parallel for each channel.