Power Amp-TDA 7294

Welcome back to Free Circuit dot com again,Today ,I would like to present a small audio amplifier circuit with TDA7294.

You can follow by PCB thus as my post.

The described circuit uses two TDA7294 for use in stereo (2 x 80 watts) and bridge mode (1x 180 watts), configure this setting only four drivers.

To facilitate the installation of each fuel. The performance is a kind of symmetry with a simple bridge rectifier 6A, and two large electrolytic capacitors, which 10000μF 22000μF/50v. This power supply for two modules. The processor is recommended 22-0-22 to 28-0-28 / 5 A, depending on the quality of the transformer is at least 6 amps is recommended.

Parts Layout PCB

Amp TDA7294 PCB

The TDA7294 is a monolithic integrated circuit in MULTIWATT15 package for use as audio class AB amplifier in Hi-Fi field applications (stereo, powered speakers, car, high-end TV) is provided. Many thanks to the wide range of voltage and current capacity he is able to offer the highest property taxes in both 4Ω and 8Ω, to offer even in the presence of poor supply regulation, with the rejection of high-voltage power supply. The built-in mute with delay sounds easier to avoid the remote mode off.

Mosfet Amplifier K1058 circuit

Welcome back to Free circuit dot com,We would like to present audio amplifier circuit as this amplifier consists of two completely separate mono amp for each channel has its own power supply, so zero inter-channel crosstalk, a common phenomenon in amplifiers, the same diet. 0 – - 40VAC at 640VA To the full power any 40VAC transformer should be evaluated to obtain. Unlike many designs, referring to the capacitors to supply the current peaks, I prefer the raw power available from the transformer, have resulting in faster transients.

Mosfet 200W Class A PCB

Although RAS-300 specifications moderate, if they immediately hear the huge reserves of power available and not cause of fear that something, this would give a very loud while driving amplifiers. You hear nothing but the truth without distortion at any level, and I guarantee you that this amp the best qualities of the connected devices reveal.

Mosfet 200W Class A Parts Assembly

Differential Amplifier circuit

Welcome back to free circuit dot com,today i have true balanced input differential amplifier circuit  , So far we have only used one terminal of the operational amplifier inputs on the amplifier or the “reversal” or “non-inverting” input to a single input signal to the other input connected to the mass increase. But we can also receive signals from both inputs at once to produce another common form of op-amp circuit called a differential amplifier.

   Basically, as we saw in the first tutorial on operational amplifiers, the amplifiers are all “difference amplifier” because of their input configuration. But by connecting a voltage signal proportional to an input signal and another on the other input of the resulting output voltage to the “difference” between the two input signals V1 and V2. Differential amplifier then the difference between two voltages, this type of circuit strengthened doing a subtractor, as opposed to stating amplifier input or the amounts that the input voltages. This type of operational amplifier circuit is commonly known as a differential amplifier configuration is shown below:

Open – Close No Tub. The offset circuit including output fast.
I was stepping into ICs using C instead of applying all the columns in my hi-end audio equipment.  Voltage +-15V.
Small PCB 12.6X6.3 cm. Print zoom – Zoom in itself.

Power supply for amplifier 100W circuit

Wecome back to free circuit dot com,today we have power supply for your audio amplifier with 100 W V-MOSFET.
The proposed power amplifier for 100W V-MOSFET is what appears in the above figure. It has separated supply for the various stages of supply, output stage, stage driver, power amplifier and phase protection. Anyone who wants can remove parts or add a power supply for each channel, separating completely the channels between them. Attention should be given to ground loops. For anyone who does not use the preamp circuit and protection can suppress the corresponding winding.

Out Voltages For Power Supply
+V1=+60V -V1=-60V
+V2=+12V -V2=-12V
+V3=+65V -V3=-65V

Electronic Parts List
C1….4=15000uF 100V
C5-8=2200uF 25V
C15=33nF 630V

IC1=7812
IC2=7912
C6-9=100nF 100V
C7-10=47uF 25V
C11….14=2200uF 100V
BR1=Bridge 250V 25A
BR2=Bridge 250V 3A
BR3=Bridge 250V 3A
T1=220V / 2X43V AC – 250VA
/2X15V AC – 20VA
/2X46V AC – 40VA
S1= 2X2 switch 250V/10A
F1=Fuse 2A slow

Mic mixer circuit

Welcome back to Free circuit dot com again,today we have still audio circuit for your build .
The circuit is a basic 3 input mic mixer circuit with the popular opamp 741 ICs.
Two 741s are used here.U1, U2 are used as preamplifiers.
They produce a gain of around 40 dB to the individual input signals.
The U1 is wired as a summing amplifier to add the signals from three preamplifiers.
IC2 also gives a gain of around 5decibel to the final output signal.
Total gain of the system is around 45 dB.

Electronic Part List

 R1, R2, R3  1K 1/4W Resistor 
R4, R5, R6 10K Logarithmic Pot 
R7  1Meg 1/4W Resistor 
R8, R10  10K 1/4W Resistor 
R9, R11  100K Linear Pot 
C1, C2, C5, C6 0.1uF Ceramic Disc Capacitor 
C3, C4   22nF Ceramic Disc Capacitor 
U1, U2    741 Op Amp 
J1, J2, J3    Input Jacks Of Your Choice 

Note
R9 and R11 control bass and treble, respectively and R1-R3 are level controls.

because the circuit draws such low current, we using  2 X 9V batteries  that can be used for a power supply.

You should be build the mixer in a metal case will cut down on noise.

Power amp 400W IRFP448 Circuit

Amplifier circuit today,We would like to show you for the MOSFET 400 watt amplifier is amplifier on my kW shares the same circuit and basic PCB layout.
  The only real difference is the number of output devices to the device.
  We have using The IRFP448 design while the MOSFET amplifier 14 O / P devices.
  These amplifiers can be used for virtually any application that requires high performance, low use Noise, distortion and excellent sound quality. Examples would be subwoofer amplifier should FOH stage
  Amplifiers, surround a canal a very powerful sound amplifier, etc.
  The 400W MOSFET-amplifier has four key stages of amplification. We are looking to start any   Phase appropriate detail.

The bias and buffer stage
  As the name suggests All Q ,C and ZD the Bias and buffer phases. Its main goal is to provide a stable MOSFET Gates  and offset voltage and the voltage buffer amplifier stage of the High Resource capacity. What would have without the phase response and the effect
  Slew rate is indeed very bad. The flip side of the coin is not the extra step
  Introduction of an additional dominant pole in the amplifier feedback loop.

400W MOSFET PCB

Power amp 400W IRFP448 PCB

and We have the electronic components layout thus as below

Power amp 400W IRFP448 PCB Layout

We have to continue in power circuit PCB and components layout

Power for Amplifier 400W IRFP448 Mesfet PCB

400W Power IRFP448 Mesfet PCB Layout

  
  The final stage of the Current Gain Stage
  Also to what the name suggests this stage converts the voltage developed in the VAS
  and provides all the amps required to drive at 8 or 4 ohms. 2-ohm loads are possible
  for several minutes at a time. In fact, I have tested more than 1600 1kW amplifier
  Watts RMS at 2 ohms. But that would not be recommended as a long-term exposure at all.
  If it is higher than the figures of the STI-amp.
  Power to the AV amplifier 800
  The components of the power for this amplifier are as follows, and are favored
  A channel or a power module alone.
  1 toroidal transformer with a rating of 1kVA. Primary windings are made to fit

Magnet MA200 Amplifier Circuit

MAXNET power amplifier in my country is the brand. The audio player known to everyone.
 I used to own a MA-200, when eight years ago, 100 +100 W sound like very smooth.
If the Yellow Tang C Beenic change any of the grades there is still a good bit better sound no less.
 Also works good, but late, as amended Modify bit.
 Budget $ 150 transformers out of order from Magnet only.

I have all device list both power amplifier and power supply.

Power Amplifier Side                                  

Capacitor                                          

47uF35V        Electrolyte            5     Ea. 
1uF50V          Electrolyte            2     Ea. 
0.1uF63V      Polycabornate          20   Ea. 

390pF100V   Polystyrene                 1    Ea.
100pF100V    Polystyrene                2    Ea.
220uF16V       Electrolyte            1    Ea.   
5.6pF50V        ceramic                      1    Ea.
7pF50V        ceramic                      1    Ea.
100uF50V       Electrolyte            2    Ea.

MAXNET MA200 Power supply circuit

Semiconductor devices

1N4148           2   Ea.
J1- RCA     1   Ea.
10  Ohm watt per trun R
BC 546      2   Ea.
BC 556       2   Ea.
BC 550     2   Ea.
BC 560  2   Ea.
2SB649AC  3   Ea.
2SD669AC     3   Ea.
BD 139       1   Ea.
MJ15003       2   Ea.
MJ15004     2   Ea.

Maxnet MA200 PCB

Resistor 1/2 W 1%

220K    2   Ea.         33K       1     Ea.          120     6    Ea.         3.3K     1    Ea. 
33K      1   Ea.         4.7K      5     Ea.          330     3    Ea.         39         1    Ea.
3K        1   Ea.         47K       1     Ea.          30K    1    Ea.         56         1    Ea.
18K      1   Ea.         8.2K      1     Ea.          100     1    Ea.         10         1    Ea.
1K        8   Ea.         1.5K      3     Ea.          10K                        10/2      1   Ea.  
  

220K    2   Ea.         33K       1     Ea.          120     6    Ea.         3.3K     1    Ea.  

33K      1   Ea.         4.7K      5     Ea.          330     3    Ea.         39         1    Ea.

3K        1   Ea.         47K       1     Ea.          30K    1    Ea.         56         1    Ea.

18K      1   Ea.         8.2K      1     Ea.          100     1    Ea.         10         1    Ea.

 1K        8   Ea.         1.5K      3     Ea.          10K                        10/2      1   Ea.   

100W amplifier circuit with MJ15003,MJ15004

I’m going to continue present the amplifier circuit.
Per the circuit today,I use this circuit for 10 years. It’s like a horse who never gave up fighting against any situation Nanjing.
Now he can rest a Srsom to get used to it faithfully Eseietid said.
Spec of OCL with MJ15003, 15004 4 pairs on each side.

Merit
Tolerance (if not all Stainless City).
Symptoms are easy to fix a few.
Sound .. Chris for novice operators.

Flaw
If the circuit to lose the trans router will lose out because of power flow with all speakers.
Working at high temperature. Power consumption is quite normal most of the design.

For the size of the current transformer .

Not less than 3 amps when using a full 8 ohm speakers.
Not less than 6 amps at full use 4 ohm speakers.

Thus as below show you the PCB completely and componence setting.

100W Amplifier PCB with MJ15003,MJ15004

50 watts Amplifier circuit

Amplifier circuit today! ,I got the circuit from japan forum which have good detail both circuit diagram ,PCB,part assembly,layout and show case in completed set that you can make with this information for 50 Watts Power Amplifier.

could you read specification thus as below.

Performance
Output Power 50 watts into 8Ω 70 watts into 4Ω
Music Power 77 watts into 8Ω ;105 watts into 4Ω
Frequency response -1dB at 14Hz and 70kHz (at 1W- see Fig.1)
Input sensitivity 0.875V for 50Ω into 8Ω
Harmonic distortion <.05% from 20Hz to 20kHz; typically <.003%
Signal-to-Noise Ratio -114dB unweighted (22Hz to 22kHz); -119dB A-weighted, both with respect to 50W into 8Ω
Damping factor >140dB at 100Hz & 1kHz, with respect to 8Ω and without PTC thermistor
Protection fuses plus “Polyswitch” PTC thermistor .

50 watts Amplifier PCB

50 watts Amplifier componence layout

50 watts amplifer real assembly

50 watts power supply

Power supply wiring

Subwoofer filter Circuit

PCB SubWoofer filter

Subwoofer filter Assembly

High volt genarator circuit

The simple circuit described here is capable of generating up to 2.1 kilovolts or more from a current source with low voltage flyback (LOPT) transformer to recover from a B / W or color TV or computer monitor. Typical output with a 12 VDC 2 A power supply or batteries will be 12,000 V. Maximum output current at full voltage is typically on the order of 1 to 2 mA. Higher currents are available, but decreases the output voltage. A 2 kV, more than 10 mA may be possible depending on your particular flyback transformer input voltage and current.
As you can see the diagram below, does not get much easier than this!

CAUTION: Read the document: “Safety Guidelines for High Voltage and / or equipment for power line” and shoot the circuit!
Read in its entirety!

flyback obtain solutions with high voltage secondary winding. primary may be left intact if it is known to be in good condition – not short-circuited. A flyback removed due to failure can be used if the primary were to fail and the primary turns can be removed without damaging the HV secondary or losing the secondary connection back! Flyback fail in both directions (primary and secondary).

CAUTION:  Locate the return of the winding tension. It can be a different color yarn winding low voltage or the output of the flyback portion of the plate in a different place. You can not use an ohmmeter to locate the return of power Fast-forward if the return to a high-voltage multiplier or HV rectifier diodes rectifiers decline is far greater than the battery voltage used in your meter. However, a connection with a liquidation infinite resistance to all other terminals may be the HV return. The flyback HV rectifier or multiplier without a return can be easily identified by measuring the resistance between the HV output and all other terminals. The high voltage winding has a resistance of 100s-1000 ohms than a single dose of digits or less for all other windings.

Wind 10 turn center tapped winding drive and 4 turn centertapped feedback winding using # 16-20 gauge wire. Make sure that both halves of each coil are wound in the same direction. Log centertap in each case on the settlement – not a show cycle. A good insulation with duct tape.

Vcc should typically be in the range 12-24 volts in a couple of amps. oscillating circuit is scheduled for about a Vcc of 5 V or more. If you do not get the high voltage, reverse the connections to the transistor bases. heat sink is recommended for the transistor. Be aware of the capabilities of your return (B / W monitor up to 15 KV, color up to 30 KV). You risk destroying the secondary windings and / or HV rectifier if you get carried away. Running this on 24 volts will probably cause an internal arc-over in a small flyback, then start again with more caution and a new flyback.

Actual production depends on the turnover of the flyback you have.

For a typical small B / W TV, monochrome screen or a video terminal, you should be able to get around 12,000 volts with 12 VDC.
I built one from a dead Mac-Plus flyback from which I removed the coils (dead) primary.

With a large color television or color monitor flyback, 30,000 V or more will be made possible with 24 VDC.

The operating frequency is in KHz to 10 KHz range depending seconds of VDC, the load and the specific flyback.

You can experiment with the speed, resistance values, etc. to optimize operation and power for your needs.

WARNING: Contact with the output will be painful, but probably not particularly dangerous due to small (few mA) current availability.
HOWEVER, if you add a high voltage capacitor for charge storage, do not even think of approaching the HV!

Pre-Amp Tube Circuit

Preamp Part List
R1-7=1Mohm
R12-13=100ohm
C9=4.7uF 250V*
R2=100Kohm 1W
C1=220nF 250V*
U1=ECC82
R3-8=1Kohm 1W
C2=220pF ceramic or mylar U2=ECC81
R4=1.2Kohm 1W
C3=2.2uF 350V*
RV1=2X100Kohm log.
R5-11=5.6Kohm 2W
C4=1000uF 16V
RV2=2X100Kohm lin.
R6=100Kohm
C5-6=2X50uF 450V
RL1….6=Relay 12V 2X2 [1A] 
R9=22Kohm
C7=1uF 250V* 
R10=100Kohm
C8=220nF 630V *polypropylene or MKT

Power supply Circuit

Power suply
IC1-2=LM317*
R1=2.2Kohm 5W
R2-4=100Kohm 2W
R3=680ohm  5W
R5-6=220ohm
R7=470ohm  1W
C8-13=10uF 16V
C1=33nF 630V
C2…..5=2X50uF >350V
C6=4700uF 25V
C7-9=100nF 100V
IC3=7812  [1A]
C10-15-19-20=47uF 25V
T1=230Vac / 200V 0.15A
C16=470uF 25V
T2=230Vac / 12V 3A
C17-18=100nF 100V
F1=0.2A slow
BR1=4 X 1N5408
BR2=4 X 1N5408
BR3=4 X 1N4007
F2=0.1A fast
TR1-2=4.7Kohm trimmer
S1= Switch 2X2 10Aac
RL7=12Vdc Relay 2X2 10A
D1…..7=1N4007 EMI RF Filter 230Vac/6A
D8=12V 0.5W zener * with heatsink

Input Selector - Delay Drive Circuit

Input Selector – Delay Drive
R1…..5=1.2Kohm
R6-8=1Mohm
R7-9=10Kohm
R10-11=1.2Kohm
C1=100nF 100V
C2=10uF 25V
C3=22uF 25V
Q1-2=BD679
IC1=4081
D1……5=3mm Red
D6……9=1N4148
D10-11=3mm Green LED
LED S2=SEL 1X6 step
S3=1X2 mini switch

25w amplifier circuit

Here is the circuit diagram of an amplifier of 25 W of power in 2009 TR. BC559 provides two channels of each rating, 12.5 watts into 4 ohms, both channels are load.Here bridge to a single channel out put weight will receive 25 W.

TR BC559 also has built in features such as short-circuit protection, thermal protection, overload protection, etc., with very low components.The external factors, the most interesting things I see on this chip is not necessary dual power.

 Notes

Do not connect more than 24 V BC559

 If 5 amperes bridge is not made available to one with four 5 A diodes.
Fit a suitable heat sink size BC559

If you operate the circuit without heat sink.
To connect the volume control in connection with a 10K pot
All capacitors are in this neighborhood has done more than 25 V.
Capacitors with a + sign must be maintained and electrolytic capacitors are usually positive.Other exception ceramic.If us that there is no data in the circuit or shares list.This law applies to all circuits on this site.

100W MOSFET CIRCUIT

Circuit description: 
The 100-watt amplifier, basic research has been developed, which builds and (relatively) easily one a reasonable price. Has performed better (read: musical quality) than the standard STK module amplifiers are produced by using practicable and in any stereo receiver mass market today. When I built this thing, it was because I needed a 100 WPC amp and I wanted to spend the money. So I designed around all the parts I had in store.
The level design is more or less, and I’m sure there are no commercial units are similar. Knowlwdge For me, it is not an exact copy of the economic entity, nor I am aware that patents on Topology. For manufacturers to experience improved a lot and I know that improvements can be made but the idea was easy to hold and be able to do Anyone can do circuit of the United Nations and has the patience to do a sloppy job.
The input stage is a win is lf351 op amp, most of the open sky, as it stabilizes the dc voltage at rest. This then feeds a phase crossing, the swing voltage (-), Rail reference.

 The slope of the stage is an improvement Darlington High Linearity frerqency with. 2SC2344 the same collector has a large capacity Rather basic tension on. The MPSA42 demonstrate with a Low-Z and has a C (OB) PF few that is submerged by an effective CAP 33pF pole-splitting. And the stage) 2SA1011 the active load (current source, which provided an approximately 20 mA. The current scene is limited by a 2N3094 approximately 70 mA in worst case.
The result is a complete with outputs in Darlington complementary parallel. You could even though they cover, with one, if only 8 ohms easy to get to load the disk use is not recommended this. The use of machines in parallel increases the ability to drive reactive load (such as a significant current during the voltage waveform crosses zero and provides a high voltage and high curent through the transistor at a time) from L ‘ amp draw Can a High damping factor reduces and the maximum power transistor PROVIDE Peaks (remember, the profit on a drop of power transistors as the current increases).
       Compensation and poly case and a zero. The op-amp pole and the pole generated by the CAP 33pF, and the resistance of 470 ohms MPSA42 bias control. (the part of 33pF can benefit multiplied.) PF The capacitor 22 provides for compensation of lead and feedback will ADOTTAT from production tranconductance Rather than the production itself. It was in this way, the phase introduced by the output transistors, the feedback is not high frequency for the visa. This closed loop intorduces politicians, high-frequency limits. The two capacitors compensation must be type-1-creamic (NPO) mica or silver – with zero coefficients voltage signal.
          Amplifier Project was to be a 2-channel + / – 55 volt unregulated Run furniture, making up to + / – 48 volts at full load. It uses a 40-0-40 volt, 5 amp toroidal transformer, a rectifier bridge, 10,000 UF and filter covers per page. When using a standard EI transformer, a 6-amp rated units used. With this power, which produces 100 watts continuous, both channels driven into 8 ohms of resistance, without clipping. DB headroom and dynamic medium, and the United Nations. For more space, download voltages up to + / – 62 volt circuits may be used without modification.
Among other things, is the pattern in Postscript.
RESTRICTIONS:
           Without changes, the amplifier 4 ohm speaker systems are currently driving is no limit. The limit of a short circuit around a 4.5 A peak current, conventional speaker loads are discussed. (E ‘course at a higher peak current of the output swing approaches the rail.) If you perform either of these high-end speakers with the minimum means of impedance uncle, or that the stay is for REAGENT The range of most audio frequency (0.5 + J3.2 ohms) you might have a better amplifier than this. If the highest yield Motorola power transistors are used, the operation of a 2 ohm resistive load without any problems (), except for heat.
‘ve Never seen a slew-induced distortion on this amp with a CD of the band-limited (22 kHz) signal. I suppose fans of real high-end pieces can beat mixed with a TTL square wave signal with a pilot tone of a pick-19KHz stereo and Crank It Up will ensure that there is spectrum Spinges around, but who listens ?
Possible changes: (What power if I mo ‘?)
            The output transistors are Toshiba (Young 2SD424/2SB554) can not shoud USE superior supply voltages with a volt + / -60. If you intend to promote more use in parallel, or use the pairs 250 watt Motorola (MJ15024/MJ15025). A very low impedance should be increased, the slope of phase distortion in a drive with more than a basis for the release of Darlington Generating or add another gain stage current. Higher-beta (s faster) power transistors with reactive load is not worth a crap. Non-FT High When you replace sections is certified to have a fair distribution of the second chance.
              NE5532 op-amp can be used in input phase. If more than used the way for the + / -15 volt shunt regulator (symmetric ins UCCISE Bessel filter, etc.), the fall of 2.7K resistors Reduce might, for example, to maintain regulation 1.8K ohms. 2.7K resistors, but also can add up to 4 lf351 the type of op-amp regulator (Ho-hum balanced inputs 347 for a quad setup, in fine, DJ UN to prevent).
Recommendations of construction:
            The equalizer output and thermal transistor (2SC1567) to be mounted on a common heat sink – a unit measuring 5 centimeters high, with a rib 8 inches wide by 1.25 fins should do well for a channel. (You can see if pleasant) side of the case from them. Most applications do not require refrigeration normal than that. 2SC1567 And the reason for the Project for the bias regulator output was chosen because it is completely isolated – the version is more ECG mounting options. TO-3 outputs for the hardware is always convenient and easy to use.
The driver transistor amplifiers and voltage (2SC3344/2SA1011 couples) all require that, as a heat sink. Individual TO-220 heat sink is sufficient for the council – to dispel the tension of about 1.4 watt amplifiers. A common piece of 1 / 8 inch thick 1 cm x 4in. Aluminum angle will be long enough for all 4 on every channel, but be aware that they must be designed to take advantage of natural ventilation, must be and the transistor insualted.
Reasons attributable to keep separate from others, and a point. If this fails, the distortion high (5% or so), or are even vibration.
The bias output stage must be set to below about 25 milli ampere transistor output. This requires a value some time to stabilize, by You need more than an hour or so check during initial setup. Measure, measure the voltage across the emitter resistor and using Ohm’s law. This way you can participate in current output transistors in parallel at the same time to change and see if it was a serious discrepancy. Parties With the data of the same code, should not be turned off by more than 10%, after heated. Distortion power amplifier can amount used, but it takes more care to fix it. If you raise a quiescent current of more than 50 milli amperes per page, the value of the emitter resistors.
Initial Checkout:
Something just do not connect! Apparently a mistake, insignificant, can put your house on fire! (In addition to the blow out is worth 30 dollars in a microsecond transistors.) A variac will work in theory, but can the amplifier BOLT on the rail, if the offer is inadequate. I suggest using an Ballast Resistance – a 60-100-watt bulb in series with the AC power cord. Otti is a bright flash when you tap the application, it must be (almost) as the supply load current to reach its nominal value down. Amplifier and then typically work at low volume. If the amp draws too much power for any reason, the bulb shines, increase the resistance, and to limit the power to the circuit. In general, it is either a mis-wire (using DMM) Oscillation O (pointing to an area or RF power) of the metro. When the lamp is dim-dim-Bright-Light … And then the amplifier and marginally stable layout grounding should be reviewed. The values of the capacitors of adequate compensation should be, if they are not significant changes in the state. Mine is stable, as it is.
Further information:
The circuit is in PostScript, it should be printed Situation In soloist. Emitters of the transistors are designated by an “E”. I was too lazy by arrows on the symbols of transistors – and I use it in this way more than a year.
Find a particular problem? MCM (1-800-543-4330) has all the transistors. The total cost for a stereo version is to be between $ 150 S $ 250, a second type of operations of the case it could to find the transformer, and the heat sink. If you pay for ‘list’ of all to have, probably cost about $ 1,000 to build.
The information will HERIN is no guarantee, no warranty expressed or implied. Do not stand aside for the accuracy of the data is the author of technical information or the use of such false or assumed.
The equipment described in this article was designed, built and tested on my personal time with my personal resources.

electric power controller circuit

The equipment which can be controlled The equipment which works by the resistance. Such as the the tungsten-filament lamp, the soldering iron and so on. The equipment which is using the AC series motor(with the brush). Such as the drill, the electric fan, the cleaner and so on. The equipment which can not do the control The fluorescence light. The synchronous motor(using the capacitor) As for the synchronous motor, the number of rotations is decided by the frequency of the alternating current. So, basically, it isn’t possible to control with the circuit this time. However, the torque(power to turn) of the motor declines when the electric current which flows through the synchronous motor decreases. With it, the revolution can be slowed down. In this case, with the load which is applied to the axis of the motor, the number of rotations isn’t constant. The electric power which can be controlled is decided by the permission value of the electric current which can pour into the TRIAC. I used the TRIAC which can apply the 12-A electric current to the circuit this time. In the calculation, in case of AC 100V, a maximum of 1200 W can be controlled but in the actual use, about 700 W or 800 W are safe.

The following shows the basic measurement results …

60W audio power amplifier circuit

Reduced the value of the Class A-based resistance to 560 ohms **
Increased the value of the bootstrap capacitor 100uF
Decreased Stabilization 100pF caps on (she was formerly 220pF)
Added the output inductance and damping resistance (see News)
** It is conceivable that with a few transistors, the value of 560 ohms is not correct. If this is detected, you should “optimize” this resistance to at least maintain DC offset. If you really wanted, you could even with a 2k trimpot (), and set it for at least DC offset. It is best to wait until the first temperature stable, but it will not change much anyway.

Apart from these changes, the amplifier is loaded with highly original and provide a + /-35V (voltage), as indicated at 70W into 8 ohms give completely satisfied. In his life, many of the above mods have done, because I never had the schedule when I needed him to find, as often as it went, like me! It is an evidence of the fair amplifier that can handle all types of resistor and capacitor replacements are made, and it still works well.

The noise and distortion figures are a bit pessimistic – there is so little distortion at 1V (20V or for that matter) that my major problems for the disruption, has a readable measurement. The oscilloscope output shows that most of what I see is noise – the integration of the production (my scope is that it is not) to eliminate the noise shows very little at all.

120 W audio power amplifier

This is Super Bridge 120W Power Amplifier by IC BDX67B for you as the amplifier circuit using the integrated circuit. Can not be circumvented, because this circuit wattage 120W delivers approximately 2 ohms.

View circuit and PCB where the circuit will think an important equipment used to be.

Must use the power that fits around the +40 V and-40V when the current 4Amp.

Besides the need for a heat sink with a format suitable IC BDX67B and Q1-Q4 BC556A, BC548 to the track all to see. Build easy penalty not paint anything. Ask a fun friend Power Amp Super Bridge 120W by BDX65B you sir.

230 W MOSFET Audio Amplifer Circuit

Here is simple LED-power audio amplifier circuit with MOSFET amplifier TL071C and 2 may be up to 45 W into 8 ohms.

For MOSFET IRFP240 and IRFP9240 are used safety with device can now be these modification.

The scheme is at the request SILICONIX and the voltage change of 2 serial resistances from suppliers operating voltage amplifier driver was inserted.

MOSFET must be mounted on at least one condenser 1K / W.

Amplifier efficiency is 70%, the reduction in the frequency distortion in more than 0.2% at 20 Hz at 8 ohms and 10W.

With a supply voltage in the range of + – 30V, can supply audio amplifier MOSFET 45W into 8 ohms and 70W into 4 ohms.

Remember that the sound amplifier is short, so all you can check the radio button is protected, whether the speaker is connected.

Electronic project contains the essential elements for building a HiFi Amp module using the LM1875 chip.

This project contains the essential elements needed to build an amplifier module for high fidelity with the National Semiconductor LM1875 IC. With the addition of a handful of parts and an adequate supply, this module provides 25W RMS into 8 ohms @ 1% THD.

PCB dimensions are a tiny 53 x 50mm (2.1 “x 2″). Heatsink, power transformer, speaker and cables are not included. (CPS50)
 

This project contains the essential elements needed to build an amplifier module for high fidelity with the National Semiconductor LM1875 IC. With the addition of a handful of parts and an adequate supply, this module provides 25W RMS into 8 ohms @ 1% THD.

25 Watt HiFi audio Amplifier Circuit

The project is built on a single side PCB. Protel Schematic & Autotrax were used in conception.

25 Watt LM1875 Implementation of components containing PCBs
Data to be provided to you:

Heat sink with a thermal resistance of 1.4 C / W or higher. Use the washing of silicon impregnated in the event of attack on the chip.
Speaker 8 ohm adequate power
Suitable cables.
Solder the power cables and audio directly on the pad provided on the PCB.

25Watt Hifi Amplifier PCB

The chip can be used with two agreements that provide single and dual power. We decided to use the dual fuel version. Version only offering that require the use of electrolytic capacitors 63V, thus increasing the cost and overall size of the module.

The input signal is coupled with R1 and C1 for the non-inverting input (pin 1) of the integrated circuit. Closed-loop gain of the amplifier is set at 19 by resistors (180K) and (10K). and C (22uF) in 3dB frequency point 7Hz.

The output appears on pin 4 of IC and drives a speaker directly. Speakers can produce long enough capacity to drive the amplifiers in the VHF oscillation. Resistance R6 (1W) and capacitor C4 (0.22UF) to help prevent this. They are linked through the production and the form of a Zobel network, which provides high frequency stability when driving capacitive loads.

The power supply integrated circuit is connected via 2A fuse for protection against external shorts to ground. Provide additional decoupling capacitors Supply Board.

The module is powered by a dual + / – 25V supply. These guides are provided by a separate power supply board. Consists of four diodes (1N5401) connected as a rectifier bridge and four electrolytic capacitors (2200uF) to soften wrinkles.

The power transformer used to power the module should be assessed at 60VA with a center-operated 35V secondary winding. A 30V transformer secondary winding can also be used, but the lower output DC would lead to reduced power.

If you want to run two modules in a stereo amplifier, you can use a common food. In this case, the RANSFORMER should be valued at 80VA.

Test

Before the switch, verify that all parts are inserted in the correct positions. Make sure that the electrolytic capacitors are in the right direction. Connect the power leads with a multimeter (set to read amps) in series with the positive rail. Do not connect a speaker or an audio input yet.

Turn on and check the current stabilizes at 50-70mA. There will be a brief charges that Suge main filter capacitor. You must have installed the radiator, otherwise the overload protection circuit to reduce the heat in and out.

If the quiescent current is correct, check the DC offset voltage at the terminals of the speakers. It must be less than + / – 50mV. If all goes well, switch off the device and connect a speaker and an audio signal input.

18Watt amplifier circuit

TDA2003 is a BCL (bridge amplifier is used) and deliver a car to 18W.
TDA-series integrated circuits are well apreciated and used in the amplifier designs and projects. TDA audio amplifier circuits are usually manufactured in Philips and SGS-Thomson.
The most commonly used IC TDA2030 is a small audio amplifier TDA7294 sets and for higher power amplifiers.
In this article we present some representative diagrams of the amplifier circuit TDA: car and home audio amplifier with notes under each diagram.
TDA2003 is a cheap amplifier that is intended to be on a single rail power supply (running unipolar). Provides high output currents (up to 3.5 A), very low harmonic and crossover distortion.

18W Amplifier PCB with TDA2003

The performance is dependent on supply voltage and load resistance. More than 10 watts for 2 ohm speakers with a typical 16V supply, 9V power supply with 8 ohm speakers can be about 1W. Volume potentiometer and coolers provided.

bass booster circuit

Bass Boost is now in good health … If you’re driving, gut-vibrating pulse of disco, or a continuous line of soft rock bottom, hard, or relaxed. One way to get the bass boost its modern without running to buy a piece of expensive capital works is to use a Bass Booster between your guitar, electric organ or what-have-you, and instrument amplifier. A reminder of striped bass from the signal output level of the instrument and amplifies low frequencies, eating everything on earth “to the amplifier sound of the instrument. Of course, over the loudspeaker used with the amplifier, the lower the more powerful: use 15-Inchers Booster with low and you can shake the windows. Bass Booster is battery powered by a standard 9-volt transistor radio. Can be mounted on a small card printed or a VEROBOARD using point wiring point. The call connects between your instrument and amplifier through two standard RCA jacks.

Bass booster implementation

Connect your guitar or other electronic instruments, electronic input connector J1, J2 Connect the output jack for recording your instrument amplifier is commonly used. With the switch S1 off, S2 button when the device is fed directly into the instrument amplifier. P2-cons with a multi-clockwise (off), place switch S1, S2 buttons and P2 lead to the desired level of bass. To reduce back to his natural right Stomp Down to S2 and the key to Bass Booster Out. Do not worry about leaving the switch S1 for a few hours concert. Circuit draws less than 1 mA from the battery so the battery will last for many months.

I see in the data sheets that the OPA541 can deliever 5A continuous and +-40V on the supply side.

subwoofer circuit

The OPA549 can deliever 8A, but can only handle +-30V on the supply side.

Here you can opa541bm, simply use a link from the period after the defeat on each chip back 1 / 8 pins on the opa541bm. Will give you 200 watts at 4 ohms
How do I calculate how many watts to deliever at 2ohm, 4 ohm or 8 ohm? V ^ 2 / R = W, but how can I find out how many volts can deliever. You can not deliever as much as the supply, or am I wrong?
Data opa541 “Voltage Swing = Vs-5, 5 @ IA = 5A”

Power @ 4 / 2 are generally of the P = ((I * root2) ^ 2) * R = R. limited 8/4/2 ..

Ipeak = V / R. Irms = Ipeak * root2. use for people with reduced mobility and Irms Vrms.
The first operational amplifier and was impressed with the results. I, however, that a simple circuit, the amplifier was very good. I do not have a detailed opinion on the quality of sound, as I am not an audiophile. If you are looking for a simple amplifier to the first draft, I suggest a “clone of gain.”

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I decided then to a more powerful amplifier with a copy of the operational amplifier OPA541 High Power’m as free samples. I was impressed with the results of this amplifier as well, using, given the poor quality of components I. An image of this amplifier is below.

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Both power amps have been mentioned by my bench power supply for testing positive with a positive bid for the railroad, providing 0v, and the positive power supply and one for the land, 0V and the second negative power supply rail. That led me to + / – 0-30V supply to an amplifier, easily enough for testing purposes.

I then two 15V 5A gives, and uses as above. I’m still in the construction phase power supply for my past. This is a wide range of + /-40V. This offer will be able to provide me with sufficient power amplifier.

It is in the testing phase, I rail UF 4700, found around these capacitors effect at the time of the construction industry. Shortly after the discovery provides two 15v, I found four capacitors 33,000 UF and now I am with two by rail, amounting to 66,000 UF rail. This amount of capacity, in my opinion are much more serious. This is because it consumes more bass, treble, and large capacitor banks to help the capacitors, the required power.

The project has a normal gain entry to the regular “Fender-like set of” full-range control, treble, bass, midrange and volume.

It is also possible for extra high gain jack, the second phase of the tunnel and its own gain control. This gives you, the predecessor of classical singing boogie Quickly.

New design dual-Stage Master is another control, with 3 watts can a child all the way back and still be able to talk about it! 

3Watt Tube Amp circuit

Electronic components

5W Tube Power Amplifier with EL84

And each of you probably know, I’m not a fan of tubes parallel to all.I would be very interested to know the success of an amplifier EL84 September

I thought everyone should know that I did for the beginning of the plan at first this thread and its good work. Most of all values for ressistors and caps I used are fairly similar, if not the same as what is in the map. Although I used a plug in multiple sets of filterstage before taking the state wave diode rectifier sound. In the first test no sound, so I cliped feedback negative lead goes to ground and it worked and I cliped feedback and lead others there was no difference in sound if c is finished. Its units strong enough and a lot of 12 “speaker very clearly.

Here are the results of the test:

B 1 = 331VDC, 262VDC B = 2, B 3 = 235VDC

EL84 = PIN9 = 261V, 311VDC bias pin7 = = 47th, PIN3 = 6VDC

The amplifier has been from 1954 to 1989, when it came out, except that the operation, the average activity for 15 hours a day. It is not present in damages in excess, in particular the replacement of the tubes, capacitors and resistors, caused by natural wear. The fundamental change came with the replacement of a provision of the tube, to restore diodes. There is only one problem, they try to produce the transformer cost, (it is valid for all pipe manufactured), one of the code is there and it will help. It may cost to replace traditional transformer suitable for EL34. Its products they need (it is the force responsible for all districts), sufficient experience and attention to the high voltage electric shock.

35w tube amplifier

 Electronic Parts

R1=470K 0,5W
R13-21=820K 0.5W
R12-23= 180K 0.5W 
R2-5= 2K2 0.5W
R14-22=5K6  0.5W
R3=150K 0.5W
R15-20= 680K 0.5W
R4= 220K 0.5W
R16-19=100K 0.5W
R6-10= 56K 0.5W
R17-18=3K3 1W
R7=3.9K 0.5W
R24=470R  2W
R8= 220R  0.5W
R9= 1M  0.5W
R11= 39K 1W

C2=220pF 600v
C8-9=0.1uF 630V
C10-14=0.47uF 630V
C4-5=16uF 550V
C11-13=25uF 40V
C1-3-6-7=0.1uf 630V

V1=E80CC 
V2=E80CC 
V3-4=EL34

TR1-2=470R  1W Variable (adj. 270?) Rectifier
tube= Z2C

T1=Audio Transformer for 2x EL34 Push Pull

LM317 Variable Power Supply Regulator

A circuit is timeless. LM317 regulator is a versatile and highly efficient 1.2-37V voltage can provide up to 1.5 Amps. of current with a large heat sink.

audio amplifer 120watt circuit

Here is a simple and easy to build general purpose 120 W. Amplifer with IC number TDA7293 for process sound system.
This amplifer was have the input for a radio, TV, stereo or other line level device.
It also has a phono input for a record player, guitar, microphone or other un-amplified source.
With the addition of a low pass filter at the input, it makes a great amp for a small subwoofer.

Parts

R :  660 Ohm 1/4 W Resistor = 2 pcs.
R : 22K 1/4 W Resistor  = 5 pcs.
R : 10K 1/4 W Resistor = 1 pcs.
R : 30K 1/4 W Resistor = 1 pcs.
C : 2200uF 35V Electrolytic Capacitor = 2 pcs.
C : 0.22uF Capacitor   = 2 pcs.
C : 22uF Capacitor =  4 pcs.
C : 0.45uF Capacitor = 2 pcs.
U1,2 :  TDA7294 100W DMOS AUDIO AMPLIFIER WITH MUTE/ST-BY

T1 :  50V Center Tapped 5 Amp Transformer
S1 : SPST 3 Amp Switch
S2 : DPDT Switch
F1 : 2 Amp Fuse
SPKR1 :  8 Ohm 120W Speaker
MISC : Case, Knobs, Line Cord, Binding Posts Or Phono Plugs (For Input And Output), Heatsinks For Q1 And Q2

100watt Amplifier bipolar circuit

120watt power amplifier circuit

This should be the main power amplifier OCL circuit 120Watt using devices pillar is the integrated circuit
LM12 and diode BY229.
This interesting routes many good bass and treble alive.
convenient to pretend main amplifier. If a friend is the CD therefore has a beautiful
voice and Pre Tone Control is good that some will take something very magical.
 Importantly should choose Power supply source,
which has been fairly high voltage class 38Vdc GND 38V-3A is the current low level.
To decorate the fines resulting from the size finely R4 2 ohm/4W Idle current about 30mA,
or with the whole center just before. Almost forgotten friends should choose the material is good,
good, especially IC LM12 and Transistor everyone.
We are think this project and circuit which friends can play the main power amplifier of this gentleman please.

150W power amplifier circuit

circuit review-diagram B above. It is almost identical, except for connections SIM have been removed and some signs of components have been displaced. 220UF 100nF Although I have shown how C1 3.3UF Electro bipolar, you can use the CAP polyester, if you want. If power will be used for serednochastotnyh or tweeter in the system biamped or triamped, C1 may be reduced by the cost 100nF (-3dB at 72Hz). For general use, you can use a 1uF polyester, giving-3dB frequency of 7.2Hz, but bass extension is better with a higher value, as shown.

New circuit boards can work as Dual Mono Power – PCB track can be divided, and each amplifier is powered by its own proposal. Although IMO not much sense, it also enables the PCB, halved and each half has its own power connector. The output connections can be made for printed circuit pin, or you can use to pay “shovel (AKA speed connection) LUG – Council provides regulations on this subject.

More details can be construction, purchase of PCBs, and all options are described in detail.

As you can see, there are provisions to use TDA7294 well. This circuit is almost identical, but a specification higher. There are links on the board to connect contacts 1 and 5 (it should not be connected to the TDA727). Use TDA7294, fees can run bridged (BTL or bridge tied load) to about 150 W at 8 ohms. I think P87B be used to provide phase signal is necessary for BTL operation. Although it is common to see AMP as a reversal, there is a very low resistance at first, and may lead to unacceptable pressures and possible distortion. P87B be managed separately by each amplifier, and the best way to control the amplifiers.While parallel operation is often recommended, I strongly recommend that you run the amps in parallel. There are very strict requirements for greater tolerance for parallel operation – usually amplifiers must correspond to 0.1% or more for all audio traffic and beyond. A very low output resistance of members, even inconsistencies 100mV (instantly, any voltage and frequency) can cause large amounts of current flowing through the circuits. Although 0.1Ω resistors are usually offered, inconsistencies 100mV voltage (0.15% at the peak voltage 60V) 0.5A cause a circulating current. This leads to overheating and protection of anger involved.

300W Audio Power Amplifier circuit

I will share my experience with the BUZ902DP  with other fans to share my passion for this minimalist perfection.I amplifier for the durable, easy to use, while the high fidelity to the original sound source and advise the partnership, this amplifier with other products of excellent quality.
When I began the design of this amp, my goal was to make a product better suited for the reproduction of complex music and voice. Although I emphasize the high electrical properties, the most important requirement is to create a superior sound, vivid images and superb spatial aural clarity.
Although the average level of listening is usually less than 10 watts, my design concept was to an amplifier with plenty of reserves, but the deviation is for Class A, at the height of the audience of cross-over distortion at a very low level.
There is no place in the pathway, enhances the precision of the tonal characteristics of instruments and voices clearly.
The BUZ902DP is virtually zero phase distortion over the audio range resolution is perfect and completely color the sound.

Amplifier Specification:
Maximum Output: 240 watts rms into 8 Ohms, 380 watts rms into 4 Ohms
Audio Frequency Linearity: 20 Hz – 20 kHz (+0, -0.2 dB)
Closed Loop Gain: 32 dB
Hum and Noise: -90 dB (input short circuit)
Output Offset Voltage: >13 mV (input short circuit)
Phase Linearity: > 13 0 (10 Hz – 20 kHz)
Harmonic Distortion: > 0.007% at rated power
IM Distortion: > .009% at maximum power

400W audio power amplifier circuit

If you like in the sound system or sound this circuit will should like you , This amplifier has two completely separate mono amplifiers with each channel has its own power supply to the order of zero channel crosstalk, a common phenomenon in amplifiers have the same food.

To view the full performance of each supply transformer should be evaluated at 40VAC – 0 – 40VAC at 640VA.

Unlike many models of capacitors is a reservoir to supply the peak currents, I prefer the power transformer in a much faster transient. BUZ902DP Although the specifications are rather modest,

if they can hear you now to experience a large reserve of power available and never any reason to worry that something to do than drive a large number of amplifiers aloud. You do not hear nothing but the truth without distortion at all levels, and I can assure you that this amplifier is required to provide the best features coupled.

200W_MOSFET_Amplifier picture

This project is develop from the MOSFET Power amplifier 100W that posted which it take to use in many activity such as Guitar amp,Mic,or Home theater and you will be to apply it.

As many people prefer because of its robustness MOSFET legendary. Altronics had a MOSFET amplifier with 200W, the product in a 4Ω, and we have decided to take a look at is.

It turns out that on the basis of the Pro One “, as described above, even if this version of Altronics and to the various MOSFETs. He has a rated output of 140W to 200W into 4Ω and 8W. Frequency range of 1 dB 20Hz up to 80kHz (Fig. 1). THD is less than 0.1% at full power (Fig. 2) and signal to noise ratio when compared to 200W is better than -100 dB unweighted.

Power amplifier MOSFET 200W Circuit

Performance of the prototype
Output power (RMS ):… 140W into 8 ohms, 200W into 4 ohms
Frequency Response:. 20Hz – 80kHz-1dB points (see Figure 1)
Input sensitivity: ………… 830mV for 200W into 4 ohms
Distortion: … <0.1% (20 Hz – 20 kHz) (see Fig.2)
Signal-to-Noise Ratio:. > 102dB unweighted, 105dB A-weighted with respect to 200W into 4 ohms
Stability :…………………….. Unconditional

Originally, the “Pro Series One” was developed by Hitachi MOSFET A-3 metal containers. They are no longer available, and their counterparts from plastics are very difficult to obtain. Altronics on this situation and have essentially the same circuits designed for Plastic MOSFET corresponds Exicon by the United Kingdom. This required a re-design of the computer, so that all MOSFET and the pilot for all transistors on a plate are vertically mounted on the radiator.

Besides the use of plastic in the power transistors, which greatly simplifies the assembly of the metal in comparison with A-3 power transistors, have Altronics spring clips in the proximity of the pairs of transistors, so things were still simple. The spring clips, just what the voltage for transistors and there is no harm in a transistor due to struggle more screws.

The heat sink is a black anodized aluminum extrusion with fins on one side. It measures 300 mm long and has a lid that a 80mm fan cooled 24V DC. The fan runs constantly, which means that the radiator is always cool (or at least slightly above the ambient temperature).

Power Amplifier Mosfet 100W Circuit

MOSFET amplifier with MOSFET for your build in electronic hobby.
I would like to show you here a basic MOSFET amplifier or power Amp which Output power is plus/minus 100 Watt/RMS with
8 Ohms or ohter plus/minus 160 Watts /RMS with 4 ohms.
Regarding this circuit simplicity, The distortion is plus/minus 0.1 %.
For band-width -3 db(decibel) is gain for 4 Hz to 96 Khz, it is limited by C1, R1, C2 and R2.
In the two transistors are T1 and T2 makes a first differential stage part, So,current source(I) of +/- one mA is set with resistor R3.

For the upgraded project, The current source(I) is more efficient in stability. Coil P1 allows a fine tuning of direct current voltage at amplifier’s output. Place the Coil P1 with it’s half value for first power up, then turn it slowly for a lowest DC output voltage. Use a first quality compoment.

Electronic Part
C1 = 2,2 µF MKP, MKT 100 V
C2 = 330 pF céramique 50 V
C3 = 100 nF MKP, MKT 100 V
C4 = 100 µF 40 V électro-chimique
C5, C6 = 18 pF céramique 50 V
C7 = 100 nF MKP, MKT 250 V  (C8 = 47 µF 100 V)
R1, R3 = 47 K   (R3 = 330 -> 470 Ohms)
R2 = 2K2
R4, R5 = 3K9
R6 = 1 K
R7 = 27 K
R8, R9, R11 = 100 ohms
R10 = 10 K
R12, R13 = 470 ohms
R14, R15 = 0.33 ohms 5 watts
R16 = 10 ohms 3 watts      (R17 = 1 K    R18, R19 = 10K)
T1, T2, T9,T10 = 2SD756A,2SD716A, BC556B (attention au brochage différent – take care for pin layout)
T7 = IRFP240, 2SK1530, 2SJ162, BUZ900DP, BUZ901DP (attention au brochage different – take care for pin layout : GDS GSD)P1 = 100 ohms  (25 tours – 25 turns)

headphone amplifier circuit

Parts List

R1-4= 1.2Kohm R12= 4.7 ohm C8-10= 470uF 25V
R2-3= 3.9Kohm RV1= 10Kohm  Log. pot. C9-11= 100nF 100V ceramic
R5-10= 10Kohm TR1= 10Kohm Trimmer Q1-3= BC184
R6=100Kohm C1= 4.7uF 63V MKT Q2-4= BC214
R7-9= 2.2Kohm C2-7= 100uF 25V Q5= BD136 or BD538
R8= 150 ohm C3-5= 100nF 100V  MKT Q6= BD135 or BD537
R11-13= 6R8 ohm C4-6= 100uF 16V All resistors is 1/4W 1%

It is a very useful thing , to have a small headphone amplifier , capable of driving a couple of pairs phones. Fortunately, the headphone amp has a much easier job to do, in that neither the output power requirements nor the load characteristics are so severe, since headphones typically have a load, impedance , higher of 50 ohm, (typical 600 ohm), and only require 1-2V RMS. max, for normal output. Since only a low power output is required, a Class A stage, is perfectly feasible. For adequate Class A operation the output transistors Q5-6, should pass say 100mA each. With ?15V supply this would mean 1.5Watts dissipation, so a smallish Heatsink, will be needed for each. With RV1 adjust input audio signal and Tr1 adjust the output DC Offset voltage for 0V (?30mV). For stereo application , you need two unit, of this amp. by L. Hood

-Variable power supplies muti-rate.
-Constant current regulators.
-Battery chargers.

Project Features
-Variable output down to 1.2Vol.
- 3 Amp output current
- Thermal regulation
-Output is short circuit protected
- Amp of Current limit constant with temperature