Sunday, November 28, 2010

Jengkol 2n3055-MJE2955 Amplifier 80 Watt

Jengkol 2n3055-MJE2955 Power Amplifier 80 Watt

This amplifier does not claim to be "state of the art", and in fact the base design is now over 20 years old. It is a simple amp to build, uses commonly available parts and is stable and reliable. The design featured is a slight modification of an amp I originally designed many years ago, of which hundreds were built. Most were operated as small PA or instrument amps, but many also found their way into home hi-fi systems. The amp is capable of driving 4 Ohms, but it is starting to push the limits of the transistors, however, even when used at 4 Ohms, very few failures were encountered.

This amplifier circuit no output short circuit protection, so if speaker leads are shorted while the amp is working (with signal), there is a very real risk of the transistors being destroyed. Since this amp was built commercially, the savings were worth the risk - most of these amps were installed in the speaker box, so shorting was not likely (unless the loudspeaker voice coil shorted as happened a few times). Because of the cost of the devices used (minimal), it is a cheap amp to fix even if you do manage to blow it up.

2n3055 Amplifier 80 Watt
Skema Rangkaian 2n3055 Amplifier 80 Watt

If you do not have a dual output bench power supply - Before power is first applied, temporarily install 22 Ohm 5 W wirewound "safety" resistors in place of the fuses. Do not connect the load at this time! When power is applied, check that the DC voltage at the output is less than 1V, and measure each supply rail. They will be different, because of the zener diode feed resistance, but both should be no less than about 20V. If widely different from the above, check all transistors for heating - if any device is hot, turn off the power immediately, then correct the mistake.

Once all appears to be well, connect a speaker load and signal source (still with the safety resistors installed), and check that suitable noises (such as music or tone) issue forth - keep the volume low, or the amp will distort badly with the resistors still there if you try to get too much power out of it.

If the amp has passed these tests, remove the safety resistors and re-install the fuses. Disconnect the speaker load, and turn the amp back on. Verify that the DC voltage at the speaker terminal does not exceed 100mV, and perform another "heat test" on all transistors and resistors. Turn off the power, and re-connect speaker and music source.

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Saturday, November 27, 2010

Audio Amplifier Berbasis Op-Amp

Rangkaian Audio Power Amplifier Berbasis Op-Amp

The amplifier is based on the commonly used class-AB complementary power amplifier with compound pair output transistors. The system uses a TL074 quad opamp to drive the output transistors. As can be seen from figure 1, A2 is used to set the voltage gain of the amplifier. Assuming the voltage gain of a common collector stage to be unity, the overall voltage gain of the amplifier is equal to (R4 / R3) + 1, i.e. the gain of a non-inverting OP-AMP (16 or 24dB, in this case). Since the output transistors are within the feedback loop of A2, A2 also acts to linearise the input characteristic of the complementary pair Q1/Q2 & Q3/Q4. This allows for greater mismatch between the NPN-PNP transistors.

Skema Rangkain Audio Amplifier Berbasis Op-Amp

The biasing to Q1 & Q3 is provided by R6, R7 & diodes D1 & D2. This arrangement biases the transistors just above cut-off and reduces crossover distortion. R6 must be adjusted to the highest value which eliminates crossover distortion. Ideally D1 & D2 should be mounted so they are in contact with the driver transistors - not the main heatsink.

To adjust R6 without an oscilloscope, start with R6 set to maximum, set the volume control R2 to get the minimum audible output with a suitable input source (such as a CD player which gives 0.65Vrms at line out), and listen for any "crackle" in the sound, especially that which seems to be riding on low frequency sounds. If a "crackle" is heard then reduce the value of R6 in very small steps, until the crackle (crossover distortion) becomes inaudible (it can't be eliminated, I feel).

As the output of opamp A2 is being pulled up by the biasing circuit, capacitor C5 must be connected between the output of A2 and ground to prevent the circuit from breaking into oscillations. The value of C5 is not critical, any value between 22nF to 100nF will do. The opamp A1 is a simple buffer which isolates the input circuit from the power stage. C1 & R1 are used to set the lower 3db frequency to around 15Hz, and to obtain an input impedance of about 100K. The upper 3db frequency is determined by R4 & C7, which in this case is approximately 30KHz. The schematic shows only one channel of the stereo amplifier. The amplifier can be used to drive speakers with impedance ranging from 3 Ohms to 8 Ohms, higher impedance speakers could be used but the power output will be substantially less.

The voltage gain of the amplifier can be increased by increasing R4 or decreasing R3, as long as the output swing is kept less than or equal to 3 Volts below the supply rails. This is due to the fact that the maximum output voltage of an opamp is always 2-3 Volts less than the supply rails, before it clips.

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500 Watt Audio Amplifier On-Semi Transistor

500 Watt Audio Amplifier On-Semi Transistor

There are some important updates to this project, as shown below. Recent testing has shown that with the new ON Semi transistors it is possible to obtain a lot more power than previously. The original design was very conservative, and was initially intended to use 2SA1492 and 2SC3856 transistors (rated at 130W) - with 200W (or 230W) devices, some of the original comments and warnings have been amended to suit.

  • This amplifier is not trivial, despite its small size and apparent simplicity. The total DC is over 110V (or as much as 140V DC!), and can kill you.
  • The power dissipated is such that great care is needed with transistor mounting.
  • The single board P68 is capable of full power duty into 4 Ohm loads, but only at the lower supply voltage.
  • For operation at the higher supply voltage, you must use the dual board version.
  • There is NO SHORT CIRCUIT PROTECTION. The amp is designed to be used within a subwoofer or other speaker enclosure, so this has not been included. A short on the output will destroy the amplifier.

500 Watt Audio Amplifier On-Semi TransistorSkema Rangkaian 500 Watt Audio Amplifier On-Semi Transistor

Please note that the specification for this amp has been upgraded, and it is now recommended for continuous high power into 4 Ohms, but You will need to go to extremes with the heatsink (fan cooling is highly recommended). It was originally intended for "light" intermittent duty, suitable for an equalised subwoofer system (for example using the ELF principle - see the Project Page for the info on this circuit). Where continuous high power is required, another 4 output transistors are recommended, wired in the same way as Q9, Q10, Q11 and Q12, and using 0.33 ohm emitter resistors.

Continuous power into 8 ohms is typically over 150W (250W for ±70V supplies), and it can be used without additional transistors at full power into an 8 ohm load all day, every day. The additional transistors are only needed if you want to do the same thing into 4 ohms at maximum supply voltage! Do not even think about using supplies over ±70V, and don't bother asking me if it is ok - it isn.

Thanks to
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56 Watt audio Amplifier IC lm3876 atau 3886

This audio power amplifier project is based almost directly on the "typical application" circuit in the National Semiconductor specification sheet. As it turns out, the typical application circuit is not bad - I would go so far as to say hi-fi in the audiophile sense? Perhaps - with caveats. It has good noise and distortion figures, and is remarkably simple to build if you have the PCB.

Amplifier circuit scheme below shows the original Schematic as shown when this project was originally published. It is almost the same as in the application note, polyester bypass capacitors have been added, and the mute circuit has been disabled

56 Watt audio Amplifier IC lm3876 atau 3886
Skema Rangkaian 56 Watt audio Amplifier IC lm3876 atau 3886

Voltage gain is 27dB as shown, but this can be changed by using a different value resistors for the feedback path (R3, currently 22k, between pins 3 and 9). The inductor consists of 10 turns of 0.4mm enamelled copper wire, wound around the body of the 10 Ohm resistor. The insulation must be scraped off each end and the wire is soldered to the ends of the resistor.

The 10 Ohm and 2.7 Ohm resistors must be 1 Watt types, and all others should be 1% metal film. All electrolytic capacitors should be rated at 50V if at all possible, and the 100nF (0.1uF) caps for the supplies should be as close as possible to the IC to prevent oscillation.

The supply voltage should be about + / - 35 Volts at full load, which will let this little guy provide a maximum of 56 Watts (rated minimum output at 25 degrees C). To enable maximum power, it is important to get the lowest possible case to heatsink thermal resistance. This will be Achieved by mounting with no insulating mica washer, but be warned that the heatsink will be at the-ve supply voltage and will have to be insulated from the chassis.

Layout IC lm3876/lm3886Layout IC lm3876/lm3886
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Friday, November 26, 2010


This VU (volume-unit) meter is capable of monitoring anddisplaying power levels present at the speaker terminals ofan stereo audio power amplifier.
The levels are displayed in ten discrete steps. This meter is not designed to give an
accurate display of the power levels.It is designed to give an approximate visual indication of the audio power output of each channel. For many situations - disco, parties - this is all which is required: the flashing LED's add atmosphere to the situation.
LM3915. This is a monolithic Dot/Bar Display Driver IC made by National Semiconductor. It takes an analog voltage input on pin 5 then drives 10 LED's providing a logarithmic 3dB/step analog display. When measuring power, a 3dB increase means that the power input has doubled. As the power doubles, an additional LED will be lit until the maximum is reached. The display can be bar or moving dot depending on the connection of pin 9 to the positive supply. The LED drive current is regulated which eliminates the need for current limiting resistors.

The supply voltage can be between 3V to 25V. You can download the data sheet from the National Semiconductor website at:
The IC is suited to signals with a wide dynamic range such as audio, power, light intensity. In many applications a bargraph meter is faster, more rugged and has higher visibility than an analog (moving coil) or LCD meter.
P1-----100K TRIMMER POT.
C1-----10mf 25v
D1..D10---LED red
I.C. ----LM3915

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Wednesday, November 17, 2010

Driver + Amplifier Sub Woofer

This Driver + Amplifier Sub Woofer circuit can be connected to an existing car stereo amplifier, adding the often required extra "punch" to the music by driving a subwoofer. As low frequencies are omnidirectional, a single amplifier is necessary to drive this dedicated loudspeaker.

Skema Rangkain Driver + Amplifier Sub Woofer

List Componet

P1_____________10K Log Potentiometer
P2_____________22K Dual gang Linear Potentiometer

R1,R4___________1K 1/4W Resistors
R2,R3,R5,R6____10K 1/4W Resistors
R7,R8_________100K 1/4W Resistors
R9,R10,R13_____47K 1/4W Resistors
R11,R12________15K 1/4W Resistors
R14,R15,R17____47K 1/4W Resistors
R16_____________6K8 1/4W Resistor
R18_____________1K5 1/4W Resistor

C1,C2,C3,C6_____4µ7 25V Electrolytic Capacitors
C4,C5__________68nF 63V Polyester Capacitors
C7_____________33nF 63V Polyester Capacitor
C8,C9_________220µF 25V Electrolytic Capacitors
C10___________470nF 63V Polyester Capacitor
C11___________100nF 63V Polyester Capacitor
C12__________2200µF 25V Electrolytic Capacitor

D1______________LED any color and type

Q1,Q2_________BC547 45V 100mA NPN Transistors

IC1___________TL072 Dual BIFET Op-Amp
IC2_________TDA1516BQ 24W BTL Car Radio Power Amplifier IC
SW1____________DPDT toggle or slide Switch
SW2____________SPST toggle or slide Switch capable of withstanding a current of at least 3A

The power amplifier used is a good and cheap BTL (Bridge Tied Load) 13 in IC made by Philips (now NXP Semiconductors) requiring a very low
parts count and capable of delivering about 22W into a 4 Ohm load at the standard car battery voltage of 14.4V.


  • IC2 must be mounted on a suitable finned heatsink
  • Due to the long time constant set by R17 and C9 in the dc voltage stabilizer, the whole amplifier will become fully operative about 15 - 30 sec. after switch-on.
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6 Volt Headphone Amplifier

Some lovers of High Fidelity headphone listening prefer the use of battery powered headphone amplifiers, not only for portable units but also for home "table" applications. This design is intended to fulfil their needs and its topology is derived from the Portable Headphone Amplifier featuring an NPN/PNP compound pair emitter follower output stage. An improved output driving capability is gained by making this a push-pull Class-B arrangement. Output power can reach 100mW RMS into a 16 Ohm load at 6V supply with low standing and mean current consumption, allowing long battery duration.

The single voltage gain stage allows the easy implementation of a shunt-feedback circuitry giving excellent frequency stability.

Rangkaian 6 Volt  Headphone AmplifierSkema Rangkaian 6 Volt Headphone Amplifier

List Component of Headphone Amplifier:
P1_____________22K  Dual gang Log Potentiometer (ready for Stereo)

R1_____________15K 1/4W Resistor
R2____________100K 1/4W Resistor
R3____________100K 1/2W Trimmer Cermet
R4_____________47K 1/4W Resistor
R5____________470R 1/4W Resistor
R6____________500R 1/2W Trimmer Cermet
R7______________1K 1/4W Resistor
R8,R9__________18K 1/4W Resistors
R10,R11_________2R2 1/4W Resistors
R12____________33R 1/4W Resistor
R13_____________4K7 1/4W Resistor

C1,C2__________10µF 25V Electrolytic Capacitors
C3,C5_________100nF 63V Polyester Capacitors
C4,C6_________220µF 25V Electrolytic Capacitors

Q1,Q2,Q5______BC560C 45V 100mA Low noise High gain PNP Transistors
Q3,Q4_________BC550C 45V 100mA Low noise High gain NPN Transistor
Q6____________BC327 45V 800mA PNP Transistor
Q7____________BC337 45V 800mA NPN Transistor

J1_____________RCA audio input socket
J2_____________6mm. or 3mm. Stereo Jack socket
B1_____________6V Battery

  • Before setting quiescent current rotate the volume control P1 to the minimum, Trimmer R6 to maximum resistance and Trimmer R3 to about the middle of its travel.
  • Connect a suitable headphone set or, better, a 33 Ohm 1/2W resistor to the amplifier output.
  • Switch on the supply and measure the battery voltage with a Multimeter set to about 10Vdc fsd.
  • Connect the Multimeter across the positive end of C4 and the negative ground.
  • Rotate R3 in order to read on the Multimeter display exactly half of the battery voltage previously measured.
  • Switch off the supply, disconnect the Multimeter and reconnect it, set to measure about 10mA fsd, in series to the positive supply of the amplifier.
  • Switch on the supply and rotate R6 slowly until a reading of about 3mA is displayed.
  • Check again the voltage at the positive end of C4 and readjust R3 if necessary.
  • Wait about 15 minutes, watch if the current is varying and readjust if necessary.
  • Those lucky enough to reach an oscilloscope and a 1KHz sine wave generator, can drive the amplifier to the maximum output power and adjust R3 in order to obtain a symmetrical clipping of the sine wave displayed.
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Phono Amplifier

In recent years, following CD's introduction, vinyl recordings are almost disappeared. Nevertheless, a phono preamplifier is still useful for listening old vinyl discs from a well preserved collection. This simple but efficient circuit devised for cheap moving-magnet cartridges, can be used in connection with the audio power amplifiers shown in these webpages, featuring low noise, good RIAA frequency response curve, low distortion and good high frequency transients behavior due to passive equalization in the 1 to 20KHz range. Transistors and associated components provide ±18V supply to the op-amp, improving headroom and maximum output voltage.

Rangkain Phono Amplifier
Skema Rangkain Phono Amplifier

Component List Of Phono Amplifier
R1_________47K   1/4W Resistor
R2________100R 1/4W Resistor
R3__________6K8 1/4W Resistor
R4_________68K 1/4W Resistor
R5,R6_______2K7 1/4W Resistor
R7__________2K2 1/4W Resistor
R8_________39K 1/4W Resistor
C1-C3_____100µF 25V Electrolytic Capacitors
C4,C5______47nF 63V Polyester Capacitors 5% tolerance
D1,D2__BZX79C18 18V 500mW Zener Diodes
IC1_______LM833 Low noise Dual Op-amp
Q1________BC337 45V 800mA NPN Transistor
Q2________BC327 45V 800mA PNP Transistor


  • R2, R3, R4, R7, R8, C4 & C5 should be low tolerance types.
  • Schematic shows left channel and power supply.
  • For stereo operation R1, R2, R3, R4, R7, R8; J1; C1, C4 & C5 must be doubled.
  • Numbers in parentheses show IC1 right channel pin connections.

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6.9 Watt Audio Amplifier Kelas A

This circuit of audio amplifier push-pull single-ended Class A is capable of providing a sound comparable to those valve amplifiers, delivering more output power (6.9W measured across a 8 Ohm loudspeaker cabinet load), less THD, higher input sensitivity and better linearity.

Voltage and current required for this circuit are 24V and 700mA respectively. The only penalty for the transistor operated circuit is the necessity of using a rather large heatsink for Q2 and Q3. In any case, the amount of heat generated by this circuit can be comparable to that of a one-valve amplifier. An optional bass-boost facility can be added, by means of R5 and C5.

Rangkaian Audio Amplifier Kelass ASkema Rangkaian Audio Amplifier Kelas A

Component list of audio amplifier kelas A
P1_____________47K  Log. Potentiometer (Dual-gang for stereo)

R1____________100K 1/4W Resistor
R2_____________12K 1/4W Resistor (See Notes)
R3_____________47K 1/4W Resistor
R4______________8K2 1/4W Resistor
R5______________1K5 1/4W Resistor (Optional, see Notes)
R6______________2K7 1/4W Resistor
R7,R9_________100R 1/4W Resistors
R8____________560R 1/2W Resistor (See Notes)
R10_____________1R 1/2W Resistor

C1,C2__________10µF 63V Electrolytic Capacitors
C3_____________47µF 25V Electrolytic Capacitor
C4____________100µF 35V Electrolytic Capacitor
C5____________150nF 63V Polyester Capacitor (Optional, see Notes)
C6,C7_________220µF 25V Electrolytic Capacitors
C8___________1000µF 25V Electrolytic Capacitor

Q1___________BC560C 45V 100mA Low noise High gain PNP Transistor
Q2,Q3________BD439 60V 4A NPN Transistors

  • If necessary, R2 can be adjusted to obtain 13V across C8 positive lead and negative ground.
  • Total current drawing of the circuit, best measured by inserting the probes of an Avo-meter across the positive output of the power supply and the positive rail input of the amplifier, must be 700mA. Adjust R8 to obtain this value if necessary.
  • Q2 and Q3 must be mounted on a finned heatsink of 120x50x25mm. minimum dimensions.
  • Add R5 and C5 if the bass-boost facility is required.
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Tuesday, November 16, 2010

Mosfet Audio Amplifier 60watt - 90watt

This circuit was designed to produce high quality and powerful audio power amplifier that would provide 60W-90W power output.

Skema Rangkaian Mosfet Audio Amplifier
Skema Rangkaian Mosfet Audio Amplifier

Daftar Component Audio Amplifier Mosfet

The transistors Q6 & Q7 should be fitted on a small and U-shaped heatsink while a larger heatsink is used to mount the transistors Q8 & Q9. For the regulation of voltage, the trimmer R10 is set to its minimum resistance which is made possible when powering ON the amplifier and then adjusting R10 until the drawing of the current reaches about 120 mA to 130 mA. If necessary, the current will need to be readjusted when after 15minutes, the current keeps on varying.

The circuit power supplay suggested value for capacitors C1 & C2 should be at the required minimum for a mono amplifier. The capacitance values may be increased up to 10000 uF when used in stereo configurations to achieved optimum performance. To eliminate ground loops and hums, an appropriate grounding is very essential. This will be done by connecting R1, R3, C2, C3, & C4 to the same point of the ground sides and the ground input wire while in the output ground, C7-C11 & R7 will be connected. Finally, the input and output grounds will be connected separately to the power supply ground.
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Monday, November 15, 2010

Audio Ampifier Khusus Untuk Gitar

This is a circuit of an audio amplifier for the guitar. This circuit can reproduce a Combo amplifier of the type very common in the 'Sixties and the' Seventies of the past century. It is well suited as a guitar amplifier but it will do a good job with any kind of electronic musical instrument or microphone.
5W power output was a common feature of these widespread devices due to the general adoption of a class A single-tube output stage (see the Vox AC-4 model). Furthermore, nowadays we can do without the old-fashioned streetcars VIB-feature frequently included in those designs.

Rangkaian Ampifier GitarSkema Rangkaian Audio Ampifier Khusus Untuk Gitar

List Component Of Gitar Ampifier

P1______________4K7 Linear Potentiometer
P2_____________10K Log. Potentiometer

R1,R2__________68K 1/4W Resistors
R3____________220K 1/4W Resistor
R4,R6,R11_______4K7 1/4W Resistors
R5_____________27K 1/4W Resistor
R7______________1K 1/4W Resistor
R8______________3K3 1/2W Resistor
R9______________2K 1/2W Trimmer Cermet
R10___________470R 1/4W Resistor
R12_____________1K5 1/4W Resistor
R13___________470K 1/4W Resistor
R14____________33K 1/4W Resistor

C1____________100pF 63V Ceramic Capacitor
C2____________100nF 63V Polyester Capacitor
C3____________470µF 35V Electrolytic Capacitor
C4____________220nF 63V Polyester Capacitor (Optional, see Notes)
C5_____________47µF 25V Electrolytic Capacitor (Optional, see Notes)
C6______________1µF 63V Polyester Capacitor
C7,C8,C9,C10___47µF 25V Electrolytic Capacitors
C11____________47pF 63V Ceramic Capacitor
C12__________1000µF 35V Electrolytic Capacitor
C13__________2200µF 35V Electrolytic Capacitor

D1_____________5mm. Red LED
D2,D3________1N4004 400V 1A Diodes

Q1,Q2________2N3819 General-purpose N-Channel FETs
Q3____________BC182 50V 200mA NPN Transistor
Q4____________BD135 45V 1.5A NPN Transistor (See Notes)
Q5____________BDX53A 60V 8A NPN Darlington Transistor
Q6____________BDX54A 60V 8A PNP Darlington Transistor

J1,J2________6.3mm. Mono Jack sockets

SW1____________1 pole 3 ways rotary switch (Optional, see Notes)
SW2____________SPST Mains switch

F1_____________1.6A Fuse with socket

T1_____________220V Primary, 48V Center-tapped Secondary
20 to 30VA Mains transformer

PL1____________Male Mains plug

SPKR___________One or more speakers wired in series or in parallel
Total resulting impedance: 8 or 4 Ohm
Minimum power handling: 20W

The present circuit can deliver 10W of output power when driving an 8 Ohm load, or about 18W @ 4 Ohm.It also features a two-FET Preamplifier, two inputs with different sensitivity, a treble-cut control and an optional switch allowing powerful overdrive or treble-enhancement.
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4.5Volt Transistor Audio Amplifier

This is a 4-transistor amplifier suitable for a variety of projects including receivers, intercoms, microphones, telephone pick-up coils, and general audio monitoring. The amplifier has a power isolation circuit and bandwidth limiting to reduce oscillations and "motorboating". The values are not particularly critical and modest deviations from the indicated values will not significantly degrade the performance.

4.5Volt Transistor Amplifier

Skema Rangkaian 4.5Volt Transistor Amplifier

Three cell battery packs giving about 4.5 volts are recommended for most transformerless audio amplifiers driving small 8 ohm speakers. The battery life will be considerably longer than a 9 volt rectangular battery and the cell resistance will remain lower over the life of the battery resulting in less distortion and stability problems.

The amplifier may be modified to work with a 9 volt battery if desired by moving the output transistors' bias point. Lowering the 33k resistor connected from the second transistor's base to ground to about 10k will move the voltage on the output electrolytic capacitor to about 1/2 the supply voltage. This bias change gives more signal swing before clipping occurs and this change is not necessary if the volume is adequate.

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30Watt Amplifier stereo with STK465

This 30Watt Amplifier stereo has two channels of amplifier in a nutshell. It is a formal designing that develops positively all the particularities completing. Concretely, we observe that the not inverting entry completed (pins 2 and 15, for each channel), is supplied from divider of tendency, which ensures tendency from the tendency of expense completing. At the same time with the entry in each channel, exists a capacitor 470rF, which achieves the unharnessing, in that it concerns the AC components of high frequency, while en line a capacitor 1mF allows in the amplifier to be supplied from desirable flourish acoustic frequencies, fence simultaneous the continuous component.

Bronchi unharnessing it is realised with the help of networking of two resistances 33KW and 330W and a capacitor 100mF, which finally ensures factor of aid equal with 100. Finally, at the same time with the exit exists networking RC (0,1mF - 4,7 Ohm) that it attends to the minimisation of phenomenon crossover. The amplifier can be supplied from a line of double polarity. Still it can function under a wide region of tendencies (±10V as ±28V). The requirements of current depend from the force of expense and it can they begin from 120mA up to 1A. It is very important the catering to be sufficiently unharnessing, so that is avoided imports of annoying noises.

Rangakaian Amplifier stereo  STK465Skema Rangakaian Amplifier stereo STK465

For the realisation of manufacture you are consulted the forms 2 and 3 that portray the PCB and placement of materials in this. Does not exist a dangerous element in the manufacture that it should him you are careful particularly, so much at the soldering, what at the use. Be careful the electrolytic capacitors, the placement cooler completed and naturally the polarity of lines of catering. One still directive in what it concerns the catering: good it is it is used power supply with big capacitors standardisation or still better stabilised.

PCB Amplifier stereo STK465Gambar PCB Amplifier stereo STK465
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Friday, November 12, 2010

Build a Tube Preamp for guitar with tone control

I decided recently to build a tube preamp for my home studio. Please note, however, that this is not a circuit for the novice electronics builder. The circuit itself is simple, but unlike most semiconductor projects, this one uses voltages near 300V. The danger of electrocution is present and neither the author can assume responsibility for protecting you.
If you are not familiar with good construction and safety practices for high – voltage electronics, do not attempt to build this circuit.

So how does it sound?

This preamp won’t make the sound of an overdriven Marshall stack, nor is it a heavy metal distortion unit, but it does produce tonal colors ranging from a slight “warming” to soft distortion. Turning down the drive control produces a somewhat brighter sound with no distortion? Turning the drive all the way up produces distortion that really bites on the bass strings and softens out on the higher notes. Driving the unit hard also produces a bit of a compression effect. With my two – finger power chord playing style, I find the overall effect quite pleasing.

Circuit description

The preamp circuit, based on a design in the 1975 RCA Receiving Tube Manual, uses a 12AX7 tube as a two stage, voltage gain amplifier.
This “generic” circuit is similar to what you will find in most guitar amp rpeamps.
The 12AX7 (6N2P and ECC83 are equivalent tubes) is probably the most common tube used in the music business. Almost all current tube effects use this tube, as do most vintage tube amps.
The 12AX7 was designed for use in audio applications requiring exceptionally low hum and noise levels. It is a high gain, twin triode device, having tow identical sections sharing a common heater filament.
The guitar or other input feeds J1 and goes to the grid of the first tube stage, which produces a voltage gain of about 30.
This boosts the guitar’s 40 mV (nominal) input up to about up to about 1.2V.
Coupling capacitor C2 picks off the amplified signal while blocking the high voltage plate supply. The signal then goes through the tone control circuit (R5-R9 and C3-C6) before feeding the second stage’s input. Potentiometer R10 is a voltage divider that sets the drive.
The second tube stage provides a gain of ten. The output signal couples through blocking capacitor C8 to the load resistance (R13 and R14). Control R14 varies the output signal level at J2, up to a maximum of about 1.5V. this should feed a relatively high impedance stage; 600ohm mixer inputs are not recommended. Resistors R4 and R12 are bias resistors that allow the tube cathodes to develop a positive potential with respect to ground. Capacitors C1 and C7 filter any ripple appearing across these resistors.


Transformer is a dual secondary type rated at 250VAC center-tapped for the tube’s plate supply and 6.3VAC for the tube filament.
The output from a full-wave rectifier is 0.7 times the input AC voltage, so about 185V appears across C10 and under load, about 140V appears across.
Any transformer that produces 150 to 275VAC should work fine.
You can also use a transformer with a 12VAC filament winding by grounding ground pin 9 of the 12AX7 and running the 12VAC into pins 4 and 5.


R1, R5, R13------------47K 1/2W
R2----------------------1M 1/2W
R3, R8----------------100K 1/2W
R4---------------------2.2K 1/2W
R6, R9, R10-------------1M potentiometer
R7---------------------10K 1/2W
R11--------------------68K 1/2W
R12--------------------15K 1/2W
R14--------------------50K potentiometer
R15--------------------47K 1W
R16------------------220K 1/2W

C1, C7------------------25mf 62V
C2, C8-----------------220nf 400V ceramic disk
C3----------------------20nf 400V ceramic disk
C4, C6------------------1.2nf 400V ceramic disk
C5---------------------220pf 400V ceramic disk
C9, C10-------------33-47mf 400V electrolytic

D1 – D4------------------1N4004
F1-----------------------0.1A fuse
J1, J2--------------------phone jack
T------------------------2x250V 50ma + 6V 1 A transformer

V1-----------------------12AX7 or ECC83, 6N2P
S1---------------------- -switch
Misc---------------------9-pin tube socket

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Sunday, November 7, 2010

600 WATT HI-FI Power Amplifiers PA600

Attached is the schematic of a PA or subwoofer power amplifier capable of delivering about 650W RMS into 4­ loads. The original design was called ’PA 600’ and was first published in the German magazine ’Elrad’ in 1990.
Towards the end of 1995, a scaled-down version of this circuit appeared in ’Elektor’ as ’PA 300’.
It is virtually the same circuit except for a less powerful output stage (now two complementary
pairs instead of five with additional driver stage) and minor changes in component selection and values. However, as ’Elektor’ is much more popular, many people built a ’PA 300’ without knowing it was scaled down from a bigger amplifier.
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Saturday, November 6, 2010

6 watt Stereo Amplifier IC LA4440

There is a 6 watt Stereo Amplifier based IC LA4440. This circuit very simple because uses very less components other than the IC LA4440.

rangkaian stereo amplifier IC LA4440
Skema rangkaian stereo amplifier IC LA4440

Features IC4440:

Built-in 2 channels (dual) enabling use in stereo and bridge amplifier applications.
Dual : 6Watt *2 (typ.)Bridge : 19Watt (typ.)
Minimun number of external parts required.
Small pop noise at the time of power supply ON/OFF and good starting balance.
Good ripple rejection : 46dB (typ.)
Good channel separation.
Small residual noise (Rg=0).
Low distortion over a wide range from low frequencies to high frequencies.
Easy to design radiator fin.
Built-in audio muting function.
Built-in protectors.
a. Thermal protector
b. Overvoltage, surge voltage protector
c. Pin-to-pin short protector

IC LA4440

Layout IC LA4440

1 NF1
2 IN 1
3 Preamp. GND
4 Audio Muting
5 DC
6 IN2
7 NF2
8 Power AMP GND2
9 B.S2
10 OUT2
11 Vcc
12 OUT1
13 B.S1
14 Power AMP GND1
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Thursday, November 4, 2010


The KA22429 is a monolithic integrated circuit designed for Portable FM radio.
It is consistng of RF input stage, Mixer, IF, Mute control and Loop (earphone drive) AMP.
It is suitable a pocket - size radio.


  • Minimum number of external parts required
  • It is able to a single trimmer tuning
  • No FM det coil
  • It is FLL detect system (76KHz)
  • Operating voltage: Vcc= 1.8V~6.0V
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