3/30/2014

Speaker indicator

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With this indicator you can see how much power an amplifier delivers. The circuit uses a LM 3915, the logarithmic variation of the known LED VU meter IC LM 3914. The circuit is connected directly to the speaker output of the amplifier, and the power state of 0.2 watts to 100 watts. The sensitivity of the circuit can be varied with R1. The basic settings are shown in the table.
 
  • R1 = 10 k (see text)
  • R2 = 10 k
  • R3 = 390 Ω
  • R4 = 2.7 K?
  • C1 = 22 V μF/25
  • LED1-LED10 = LED (color of choice)
  • IC1 = LM 3915

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Microphone amplifier

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The preamplifier amplifies the output signal of a microphone, so that it can be. The further amplified by a power amplifier The circuit provides an output signal line. With two transistors, it is not difficult to build such a circuit. The amplifier produces little noise. In the shown embodiment, the circuit is suitable for microphones 500 and 600 Ω. 200 Ω R1 microphones should be reduces to 220 Ω and C1 should be increased to 4.7 uF. The gain is set by R2. If the average declared value of 22 K? Can be used. The maximum gain is about 200times.
  • R1 = 470 Ω
  • R 2 = 22 K?
  • R3 = 12 K?
  • R4 = 47 k
  • R5 = 820 Ω
  • R6 = 100 Ω
  • R7 = 1 k
  • R8 = 100 k
  • C1, C4 = 2.2 V μF/16
  • C2 = 47 V μF/16
  • C3 = 470 nF
  • T1 = BC 549C
  • T2 = BC 547B

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Microphone Preamplifier

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This is a good pre-amplifier for microphones that can be. Used in, for example, mixing consoles The circuit operates with a dual op-amp type NE 5532. The amplifier must be adjusted. Simply plug the power and control over P1 such that half the supply voltage (6 V) on pin 3 of IC1 state. P2 is then adjusted to the desired volume.
  • R1 = 8,2 kW
  • R2, R4, R5, R6 = 10 kW
  • R3 = 1 k
  • P1 = 4.7 K?
  • P2 = 100 k
  • C1, C2, C4, C6 = 10 uF
  • C3 = 470 nF
  • C5 = 100 nF
  • IC1 NE = 5532

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Phono/line adapter

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In older amps usually have a phono input is available. Today, it is used less and less, and therefore it would be useful if the input can be. Used as line input With this circuit it is. the circuit is actually an attenuator and a filter. The signal is attenuated to the level of a phono-receiving element, and filtered to the RIAA equalization is undone in the amplifier. On 'in' is the line signal, and is connected to the phono input 'from' the amplifier.
  • R1 = 1 M 1%
  • R2 = 82% 1 K?
  • R3 = 1 k 1%
  • C1-C4 = 1 nF 1% Styroflex

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Peak Indicator

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This indicator can be used, or to see if you can get the sound output. Damaged speakers with P1 lets you set the limit at which D1 LED lights. The potentiometer is 100k here, you can experiment. Themselves with other values ​​if you could turn a logical port on the LED or opto coupler would use, you can turn it so that the signal between the preamp and power amp would fall away. Or that the signal to the speakers with the aid of a relay would be turned OFF.

  • R1 = 680 Ω
  • R2 = 1.2 K?
  • P1 = 100 k linearly
  • B1 = 4 x B250C1000 or 1N4003
  • D1 = LED
  • T1 = 2N3904

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Amplifier circuit TDA 1524A

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Description

This amplifier can control the volume, balance and tone controls take over. The circuit operates a specially designed IC, LM 1036. The advantage is that few external components are necessary, and that may be, which are cheaper. Used for controlling monopotmeters speaks scheme for itself. S1 loudness can be adjusted. In the position shown, the loudness. Moreover, the IC TDA 1524A Philips same capabilities.

Circuit Diagram


Part list:

  • R1-R4 = 47 k
  • P1-P4 = 47 k
  • C1 = 47 uF
  • C2, C3 = 470 nF
  • C4, C5, C16 = 10 nF
  • C6, C7 = 10 uF
  • C8, C9 = 390 nF
  • C10-C13 = 220 nF
  • C14, C15 = 4.7 uF
  • IC1 = LM 1036
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VU meter

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This circuit can control analog moving coil meters, for use as a VU meter. The circuit is left connected to the line terminals of the amplifier. VU meter works pretty simple. T1 and T2 increase the signal strength. The signal is then rectified by the two diodes and applied to the meter. The capacitors C3 and C4 ensure that the voltage is slightly flattened and the meter responds less quickly.  After building the circuit, it must be calibrated. For this purpose, the VU meter connected to a tone generator which delivers 0.3V at 1000 Hz. Then P1 is fully open, that is to say that the wiper of P1 is located at the entrance. Then P2 is so cut that regulates the meter full deflection. P1 is then adjusted so that meter reads 0.5 mA (= half the maximum). 
For a stereo VU meter circuit to be built twice.

  • R1 = 1 M
  • R2 = 820 Ω
  • R3 = 2,2 kohm
  • P1, P2 = 100 k
  • C1 = 330 nF
  • C2 = 22 uF
  • C3 = 1 uF
  • C4 = 470 uF
  • T1, T2 = BC 547B
  • M1 = 1 mA meter
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Subwoofer filter LM 741

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Description for Subwoofer filter LM 741:
     If you like I want some more bass in your stereo, you can switch a subwoofer there. This is a speaker that only reflects the bass. Below is a circuit to ensure that the subwoofer gets really only the bass. 
This circuit is used between the signal source (mixer, CD player) and the amplifier. It is an active filter, better than passive filters which are generally mounted behind the amplifier. The circuit is mono because the bass for both channels are equal. The human ear can not yet determine the direction of this bass. 
The first 741 is used as a mixer amplifier. The gain is adjustable with P1. Then, the signal is applied to a second of the order Butterworth-filter. C A(C1 + C2) and C B (C3) can be calculate using the following formulas: where F k , the crossover frequency (the frequency at which filter stops the transmission of sound), pi = 3.1416, R = R3 = R4, F k in Hertz, and C. F. As shown, the filter is now set at 240 Hz. , the supply voltage must be symmetrical, + and - 12-15 V. A suitable diet is the Symmetric mini power supply . If you would like a better sound would have you two 741's replaced by an NE5532. The picture for the layout to be printed at 150DPI (= + / - 33x33mm).
Circuit Diagram:
subwoofer filter lm741 circuit diagram

Part-list:
  • R1, R2 = 47 k
  • R3, R4 = 4.7 K?
  • R5, R6 = 100 Ω
  • P1 = 47 k logarithmically
  • C1-C3 = 100 nF
  • IC1, IC2 = LM 741
Layout and PCB:
Subwoofer filter LM741 layout and pcb

Datasheet for LM741 and NE5532:
LM741 Operational Amplifier - Download
NE5532 Operational Amplifier - Download
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Subwoofer Amplifier 40W

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Description

This amplifier delivers massive power and uses one IC and two power transistors. The circuit consists of an amplifier IC (a TDA 2030A) and a power stage consists of two transistors.  Amplifier can be powered with an asymmetrical supply voltage of 12 to 44 V.

Circuit Diagram:


Subwoofer Amplifier 40W
Subwoofer Amplifier 40W

Part-list:

  • R1-R3, R7 = 100 K?
  • R6 = 8,2 kW
  • R4, R5, R8, R9 = 1.40 Ω 1%
  • R10 = 1 Ω
  • C1 = 470 nF
  • C2 = 10 V μF/63
  • C3 = 4.7 V μF/63
  • C4, C5, C7 = 220 nF
  • C6 = 2200 V μF/50
  • C8 = 1000 V μF/50
  • D1, D2 = 1N4001
  • T1 = BD712 or BD912
  • T2 = BD711 or BD911
  • IC1 = TDA2030A
  • LS = speaker - 4/8 Ω
  • Cooling = Fisher SK08/75
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Ultra-low quiescent current AF power amplifier

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Power Amplifier 300W

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POWER OUTPUT:
  • 200W rms/8 ohm 
  • 310W rms/4 ohm
  • 800W rms/8 ohm (Bridge mode)
FREQUENCE RESPONSE 
  • 20HZ-20KHZ +/-0.5dB 
INPUT SENSITIVITY 
  • 1V for 200W/300W 
HUM AND NOISE
  •  -105dB 
THD 
  • <0.1% 
DAMPING FACTOR
  •  65




Part list:
R1-19= 1Kohm 5WR34-35= 0.1ohm 5WC14-17= 100uF 100V
R2-3= 4.7KohmR36-43= 39ohmC15= 100nF 250V polyester
R4-5= 22ohmR37-42= 5.6Kohm 1WQ1-2-3BC547
R6-14= 10KohmR38-41= 220ohm 5WQ4-5-6= BC557
R7-8= 1KohmR39-40= 0.1ohm 5WQ7-11-12= BD140 or BC640
R9-23*=10K ohmR44-45= 0.1ohm 5WQ8= BC549
R10= 10ohm *see circuit sch.R46= 4.7ohm 2WQ9-10-15= BD139 or BC639
R11-13= 2.2KohmR47= 100ohmQ13-14= MJ15004
R12= 22KohmC1= 2.2uF 25VQ16-17= MJ15003
R15-16= 22ohmC2-6= 330pF ceramicTR1= 2K2 Trimmer
R17-18=  4.7KohmC3-8= 100uF 100VF1-2= 5A Fuse Fast
R20-25= 390ohmC4-9= 100nF 250VD1-3= 5.1V 0.5W Zener
R21= 6.8KohmC5= 100nF 100V polyesterD2= 62V/5W Zener or 47v and 15V in series
R22=  4.7KohmC7= 100uF 25VD4-5= 1N4004
R24-26-33= 220ohmC10= 1.5nF 100V polyesterL1=10 turns diameter 1mm in 15mm diameter tube
R27-32= 100ohm 1WC11-12= 1.5nF 100V polyester
R28,29,30,31= 100ohmC13-16= 100nF 250V polyester*Use R23=6k8 for 4 ohm loudspeakers
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Audio amplifier 16 W

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All resistors are 5 or 10 percent tolerance, 1/4-watt all capacitors are 10 percent tolerance, rated 35 volts or higher this circuit provides 16 watts of amplification. it is built using two LM383 power audio.



U1 U2LM383 8 watt audio amplifier ic
R1, R3220 ohm resistor
R2, R42.2 ohm resistor
R51 megohm resistor
R6100k audio taper potentiometer
C1, C710uf electrolytic capacitor
C2, C5470uf electrolytic capacitor
C3, C4, C60.2uf ceramic capacitor
SPKR14 to 8 ohm speaker (up to 8 inches diameter)
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4 watt audio amplifier circuit

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I have recently included a page about AF amplifers for use with Homebrew rigs. In this I mentioned that I may include a practical one-watt circuit, complete with PCB foil and layout. Here it is, but I have taken the liberty of engineering it to provide 4-watts of AF output and with a frequency response almost suitable for Hi-Fi applications.

The circuit is very simple and incorporates darlington output transistors that will provide more than enough output current than is needed to drive a 3-ohm speaker. The gain may be pre-set for a variety of input levels, making it suitable for amplifying computer and cassette-deck Line-output levels. The input level is also suitable for use with the TDA7000 receiver. All components are easily available and I will shortly be making this project available as a kit. Naturally, the project will be built on a PCB which will also be available separately. Here is the first PCB, assembled and working.

The completed unit is 60mm x 75mm and only 30mm deep. The depth could be reduced to 10mm if the output capacitor is mounted at the speaker and the on-board electrolytics are mounted horisontally. Here are the typical performance figures that may be expected from the finished amplifer using a 3-ohm load with a 13.8-volt supply. I see no reason why the supply voltage cannot be increased a little to obtain more output power:
ParameterMinimumMaximumUnits
Supply voltage815volts
Output power-5.4Watts
I/P for full O/P304000mV (RMS)
Noise O/P no I/P-0.0005Volts RMS
Supply current (no-signal)-50mA
Supply Current (Full O/P)-1.9Amperes
3dB Frequency Response4234000Hertz
6dB Frequency Response2162000Hertz
Distortion at 2-watts-0.01% (Vgain=10)

No heatsinking is required for the output transistors when running at a modest output level with either speech or music. A small heatsink should be fitted to the two TIP41 transistors if running a constant tone level. The heatsink could be bolted directly to the TIP41s without electrical isolation if the heatsinks are not going to touch anything. A heatsink with a 15-square surface area is all that is required. Here is the circuit of the amplifer.


The gain of the amplifer is set by selecting the value of the feedback resistor (Rf) on the PCB. The value of Rf is equal to 4700 / (Vgain -1) where Vgain is the voltage gain required. 4-volts RMS is the full-output level. Here is a guide for selecting the resistor.


ValueVgainTypical use
2K2 3 1300mV RMS - High levels (Small radio speaker)
470R 11 400mV RMS - e.g. computer/tape-deck Line-out
100R 48 80mV RMS - e.g. from TDA7000 RX
33R 143 30mV RMS (e.g. from microphones)


The distortion and noise levels may increase at higher gain levels, but the test board was measured with Vgain = 10 and was driving a 3-ohm car Hi-Fi speaker. With higher-impedance speakers the frequency response will become wider but the output power will reduce a little. There was no trace of instability throughout the AF range and up to 150KHz so I thought it unncecssary to include a Zobel network. Incidentally, four-watts of AF will have the wife banging on the workshop walls, so do not underestimate QRP AF!
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Subwoofer Amplifier

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The fins were added to a simple flat aluminium panel, and are made from 20 x 20 x 3mm aluminium angle. Their purpose is threefold - they improve the performance of the plate as a heatsink (although this is not necessary with the BP4078 PWM amp), they make the panel a lot more rigid, and provide essential protection for the volume control and phase switch. It also looks better IMO - it looks like it means business, rather than looking like one of those wimpy 50W plate amps you see advertised.
Complite, original article sourse and right reserverd here

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Power amplifier 65W with HEXFET

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A medium power amplifier that is characterized by a lot of good sound quality, but simultaneously is very simple in the construction. full article here


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Telephone Headphone Amplifier

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Compact, inexpensive and low component count telecom head- set can be constructed using two readily available transistors and a few other electronic components. This circuit is very useful for hands-free operation of EPABX and pager communication. Since the circuit draws very little current, it is ideal for parallel operation with electronic telephone set. Working of the circuit is simple and straightforward. Resistor R1 and an ordinary neon glow- lamp forms a complete visual ringer circuit. This simple arrangement does not require a DC blocking capacitor because, under idle conditions, the telephone line voltage is insufficient to ionise the neon gas and thus the lamp does not light. Only when the ring signal is being received, it flashes at the ringing rate to indicate an incoming call. The bridge rectifier using diodes D1 through D4 acts as a polarity guard which protects the electronic circuit from any changes in the telephone line polarity. Zener diode D5 at the output of this bridge rectifier is used for additional circuit protection. Section comprising transistor T1, resistors R2, R3 and zener diode D6 forms a constant voltage regulator that provides a low voltage output of about 5 volts. Dial tone and speech signals from exchange are coupled to the receiving sound amplifier stage built around transistors T2 and related parts, i.e. resistors R7, R6 and capacitor C5. Amplified signals from collector of transistor T2 are connected to dynamic receiver RT-200 (used as earpiece) via capacitor C7. A condenser microphone, connected as shown in the circuit, is used as transmitter. Audio signals developed across the microphone are coupled to the base of transistor T1 via capacitor C3. Resistor R4 determines the DC bias required for the microphone. After amplification by transistor T1, the audio signals are coupled to the telephone lines via the diode bridge. The whole circuit can be wired on a very small PCB and housed in a medium size headphone, as shown in the illustration. For better results at low line currents, value of resistor R2 may be reduced after testing

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Loudspeaker as a Microphone

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This circuits allows you to use a cheap loudspeaker as a microphone. Sound waves reaching the speaker cone cause fluctuations in the voice coil. The voice coil moving in the speakers magnetic field will produce a small electrical signal.
The circuit is designed to be used with an operating voltage between 6 and 12 volts dc. The first transistor operates in common base mode. This has the advantage of matching the low input impedance of the speaker to the common base stage, and secondly has a high voltage gain. The second stage is direct coupled and operates in emitter follower. Voltage gain is slightly less than unity, but output impedance is low, and will drive long cables.
Speech quality is not as good compared to an ordinary or ECM microphone, but quite acceptable results can be obtained. Speaker cones with diameters of 1 inch to 3 inches may be used. Speaker impedance may be 4 ohm to 64 ohm. The 8.2 ohm resistor value may be changed to match the actual speakers own impedance.

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Stereo balance tester

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Description

The meter will show volume and tone control balance between left and right stereo amplifiers. For maximum convenience the meter is a zero-center type. Resistors are five percent or better and the diodes a matched pair. Optimum stereo level and phase balance occurs for matched speakers when the meter indicates zero. If the meter indicates either side of zero, the levels are not matched or the wires are incorrectly phased. Check phasing by making certain the meter leads are connected to the amplifier hot terminals and the common leads go to ground.

Circuit Diagram

Stereo balance tester  

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Stereo Circuit Balance Meter

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Description

When L R signals are equal, no output is present from Ul, and pin 6 is at a steady 4.5 V. Unbalanced audio causes the LEDs to vary in brightness,which causes a difference that corresponds to unbalance between channels. 

Circuit Diagram


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Amplifier circuit with Tone Control

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Description

A Motorola TCA5500 or TCA5550 can provide a stereo preamplifier system with tone controls. This circuit provides a gain of about 10X, a 14-dB tone-control range, a 75-dB volume control range, and it can operate from 8 to 18 Vdc. IC2 provides 15 V for ICl, and the input of IC2 can be supplied from the power amplifier`s power supply (+) rail. Dl and R5 should be used if over 30 V input will be used.

Circuit Diagram


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Stereo balance meter 2

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Description

    Outputs from each channel are fed to the two inputs of ICl connected as a differential amplifier. IC2 and 3 are driven by the output of ICl. Output of ICl is connected to the noninverting inputs of IC2 and 3. If the output of ICl approaches the supply rail, the outputs of ICs 2 and 3 will also go high, illuminating LED3. This would happen if the right channel were dominating. If the left channel was dominant, the outputs of ICs 2 and 3 would be low, illuminating LED1. If the two channels are equal in amplitude, the outputs of ICs 2 and 3 would be high and low respectively, lighting up LED2. 

Circuit Diagram

 Stereo balance meter 2


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Stereo balance meter

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Description

Play any stereo disc or tape and then set the amplifier to mono. Adjust left and right channel balance until meter Ml indicates zero; then the left and right output level are identical.

Circuit Diagram


Stereo balance meter

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Guitar treble boost

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Description

Ql is connected as an emitter follower in order to present a high input impedance to the guitar. C2, being a relatively low capacitance, cuts out most of the bass, and C3 with RV1 acts as a simple tone control to cut the treble, and hence the amount of treble boost can be altered.Q2 is a simple preamp to recover signal losses in C2, C3, and RV1.

Circuit Diagram


Guitar treble boost   

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Baxandall Tone-Control Audio Amplifier

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Description

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

Circuit Diagram

Baxandall Tone-Control Audio Amplifier

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Tone control circuit

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Description

A simple single-transistor circuit will give approximately 15 dB boost or cut at 100 Hz and 15 kHz respectively. A low noise audio type transistor is used, and the output can be fed directly into any existing amplifier volume control to which the tone control is to be fitted

Circuit Diagram


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Automatic Level Control Circuit

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Description 

The rectifier input is tied to the input. This makes gain inversely proportional to input level so that a 20-dB drop in input level will produce a 20-dB increase in gain. The output will remain fixed at a constant level. The circuit will maintain an output level of 1 dB for an input range of +14 to -43 dB at 1 kHz.

Circuit Diagram 


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Active crossover circuit with TL074

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An audio source, like a mixer, preamp, EQ, or a recorder, is fed to the input of the Electronic Crossover Circuit. This signal is either AC or coupling, depending on the setting of switch 51, the non-inverting input of buffer amplifier Ul-a, a section of a quad BIFET, low amp TL074 noise made by Texas Instruments op. This stage has a gain of 2, and its output is distributed to both a low pass filter made by R4, R5, C2, C3, and Uld op-amp, and a high-pass filter made by R6, R7, C4, C5, and op amp ULC. These are12 dB / octave Butterworth filters. The response of the Butterworth filter was chosen because it gives the best compromise between the damping and phase.

Active crossover circuit with TL074


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Guitar Effect Circuit

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Description
This is a circuit I have designed for guitar effect builders, I was very unsatisfied with the way everyone was using just a plain old double pole double throw click switch for the bypassing. Most of the time it was very scratchy sounding using that method and I experienced loud pops in my amplifier when switching from straight through to effect. Observing my "Boss" pedals and how they were switched on and off I figured there must be more to it. It took me only about 4 hours to design and test this circuit, It works very well and I'm really satisfied with it so I'll be using it in all the effect pedals I build. It's a very clean bypass both electronically and mechanically.

How it works: the first stage in the schematic is a 4011 nand gate chip set up as a debounced switch to give the logic pulses from the switch to the flip flop. The second stage is the flip flop, this is a 4027 JK flip flop set up in toggle mode, this controls the switching of the 4016 which is an analog switch, this part controls the bypass. That's about all there is to it. The effect which I have used this in so far is a home built "MXR hot tubes distortion" effect. Feel free to put this up on your site and mail it around to friends. The only credit I ask of this is that my name remains on the schematic. Original artile sourse ee.washington.edu

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High Voltage Solid-State Circuits for Tube Guitar Amplifiers

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Circuit Description

The IRF820  MOSFET has a  voltage rating of  500v, it should  work well in  preamp stages of  most tube amps. The 100 ohm  resistor is there  to suppress H.F.  oscillations. If  IRF820 is  physically close  to the 12AX7  plate, you  probably won't  need it. You can see how the MOSFET is equivalent to a triode: Source/Cathode; Gate/Grid; Drain/Plate

You cannot use the MOSFET as a direct replacement for a typical tube gain stage. The MOSFET will not "self bias" like a typical cathode-biased tube stage.The MOSFET is an "enhancement device" while a triode is a "depletion" device. In this circuit, it is not necessary to use a heatsink on the IRF820. You can if you want.

High voltage solid state guitar amplifier

High voltage solid state pream stage guitar amplifier

High voltage solid state reverb driver guitar amplifier

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Guitar Reverb Effect

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Description
The guitar input stage is a class A amplifier with adjustable bias. A 2N3906 PNP tranistor is used for a low noise design on this stage. The output of the preamp stage is sent to three places: the output mixer amp, the reverb driver amp, and the input clipping detector.

The reverb driver amp consists of a phase inverting push-pull circuit made from dual sections of a 5532 high quality audio op-amp. This provides a voltage swing of approximate twice the supply voltage to the reverb impedance matching transformer, allowing higher power transfer. The 100 ohm resistor is critical for insuring a clean drive signal, without it, the op-amps can saturate when driving the transformer, producing unwanted distortion.

The transformer matches the impedance of the driver amplifer to the reverb driver coil and allows a dual phase driving signal to power a reverb coil with one grounded side. The transformer is a standard "70 volt" audio line transformer that is often found on PA systems. One reader reported having good results using a Mouser 42TU013 (1K to 8 ohm) transformer. If you can find a reverb tank with a high impedance driver coil, the transformer may be eliminated, the driver coil will require isolation from ground.

The output of the reverb tank is sent to the reverb recovery amp, it is also a 2N3906 class A low noise stage.

The mixer amplifier is a 2N3904 transistor biased for class A operation. It mixes the dry signal from the input preamplifer with the wet signal from the reverb recovery amp through two 10K resistors. The wet signal level is adjusted by a 10K potentiometer.

The clipping detector stages receive inputs from the guitar preamp and the reverb recovery amp, they act in an identical manner. The 1458 op-amp is wired as a comparator with a threshold that is near the high side of the allowable voltage swing on the associated 2N3906 preamp stage. If the transistor output exceeds this voltage, the 1458 output turns on, causing the 4011 one-shot pulse stretcher circuit to fire. The one-shot circuit activates the LED, and stays on long enough that even minor clipping on the amplifier causes visible blinking.

The power supply filter involves an RC filter between the DC input and the VF1 power bus. VF1 drives the reverb driver, the output amp, and the clipping circuit. VF2 and VF3 are further filtered with their own RC filters, they provide isolated DC for powering the input preamp and reverb recovery amplifier stages.


Guitar Reverb Effect Circuit


Original article sourse solorb.com
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3/21/2014

Subwoofer amplifier TDA7293

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Features

Multipower BCD technology
Very high operating voltage range (±50 V)
DMOS power stage
High output power (100 W into 8 Ω
THD =10%, with VS = ±40 V)
Muting and stand-by functions
No switch on/off noise
Very low distortion
Very low noise
Short-circuit protected (with no input signal applied)
Thermal shutdown
Clip detector
Modularity (several devices can easily be connected in parallel to drive very low impedances)

Description

The TDA7293 is a monolithic integrated circuit in Multiwatt15 package, intended for use as audio class AB amplifier in Hi-Fi field applications, such as home stereo, self powered loudspeakers and Topclass TV. Thanks to the wide voltage range and to the high output current capability it is able to supply the highest power into both 4-Ω and 8-Ω loads. The built-in muting function with turn-on delay  simplifies the remote operation avoiding on-off switching noises. Parallel mode is possible by connecting several  devices and using pin11. High output power can  be delivered to very low impedance loads, so optimizing the thermal dissipation of the system.

Circuit Diagram
Audio amplifier circuit TDA7293
Layout
Layout for audio circuit TDA7293
 PCB
PCB for audio circuit TDA7293

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Amplifier Circuit Diagram Class D

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3/12/2014

200W Power Amplifier

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This 200W power amplifier circuit using IC STK 4050.  STK 4050 is a power amplifier module is very powerful, because the IC is already a module then only needed a little extra components to build a reliable 200W Power Amplifier. Here is a picture series of Power Amplifier ICs 200W use STK 4050 complete with its power supply:

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800W Power Amplifier MOSFET

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Amplifier

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    In this blog we talk about audio amplifiers and I would like to get more detail information about them. An audio power amplifier is an electronic amplifier that amplifies low-power audio signals (signals composed primarily of frequencies between 20 - 20 000 Hz, the human range of hearing) to a level suitable for driving loudspeakers and is the final stage in a typical audio playback chain. 
     If we talk about the history of amplifiers, we can say, the audio amplifier was invented in 1909 by Lee De Forest when he invented the triode vacuum tube. The triode was a three terminal device with a control grid that can modulate the flow of electrons from the filament to the plate. The triode vacuum amplifier was used to make the first AM radio. Early audio power amplifiers were based on vacuum tubes (also known as valves), and some of these achieved notably high quality (e.g., theWilliamson amplifier of 1947-9). Most modern audio amplifiers are based on solid state devices (transistors such as BJTs, FETs andMOSFETs), but there are still some who prefer tube-based amplifiers, and the valve sound. Audio power amplifiers based on transistors became practical with the wide availability of inexpensive transistors in the late 1960s.
    So, an electronic amplifier, or shortened amp is an electronic device that increases the power of a signal. So if you have a sound from a device and want the sound to be amplified, the amplifier is the device that can help you do this. Numerous types of electronic amplifiers are specialized to various applications. An amplifier can refer to anything from an electrical circuit that uses a single active component, to a complete system such as a packaged audio hi-fi amplifier. 
    Amplifier that any device is characterized by different specifications which actually should be taken when it is designed in consideration of them, and here are some highlights:

Noise
andwidth, 
Gain, 
Efficiency, 
Linearity, 
Output dynamic range, 
Rise time, settling time, ringing and over shoot that characterize the step response
Generic Amplifier
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3/09/2014

Analog circuit

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Analog circuit is a electronic systems with a continuously variable signal, in contrast to digital electronics where signals usually take only two different levels. The term "analogue" describes the proportional relationship between a signal and a voltage or current that represents the signal. The word analogue is derived from the Greek word ανάλογος (analogos) meaning "proportional".
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Electronic circuit

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An electronic circuit is composed of individual electronic components, such as resistors, transistors, capacitors, inductors and diodes, connected by conductive wires or traces through which electric current can flow. The combination of components and wires allows various simple and complex operations to be performed: signals can be amplified, computations can be performed, and data can be moved from one place to another. Circuits can be constructed of discrete components connected by individual pieces of wire, but today it is much more common to create interconnections by photolithographic techniques on a laminated substrate (a printed circuit board or PCB) and solder the components to these interconnections to create a finished circuit. In an integrated circuit or IC, the components and interconnections are formed on the same substrate, typically a semiconductor such as silicon or gallium arsenide. Article: ww.wikipedia.org




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3/08/2014

Circuit

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Type of electrical engineering circuit

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3/07/2014

10W Class D power amplifier

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The TDA7480 is a class D audio amplifier assembled in Power DIP (PDIP20) package, specially designed for high efficiency applications, capable of 10W output power at a load of 8w/4w and a total harmonic distorsion of 10%. Requires a split-supply (max. ±20V).

The main selling point of this amplifier is the very low dissipated power compared to normal class AB amplifiers. Only a small "on board" copper area heatsink is required for normal operation. The IC has built-in stand-by and mute feature, overvoltage protection, short circuit protection and thermal overload protection.


The output of the amplifier is a high frequency square wave (~100Khz), rail to rail, with variable duty cycle. To obtain the audio signal, the output must be low pass filtered. The preamplifier provides the voltage gain of the overall amplifier. The second stage is the class D power stage, with a gain 1.5. The class D amplifier stage is done with a multivibrator. With no signal it generates a 50% duty cycle square wave, with signal applied, it changes the duty cycle. The switching frequency is set by the voltage on pin 9.

The most important filter capacitor is C5 between the pins 16 and 17. The value of the parasitic inductance between this capacitance and the IC pins is related to the amplitude of the spikes on the power supply pins at every commutations of the output. For any commutation, there is an abrupt variation of the current in the parasitic inductances in series to the supply. This abrupt variation increases as the output current increases and can be typically of a few amperes on 10ns. With this slew rate of the current, an inductance of a few nH (i.e. the lead inductance of the pin) generates voltage spikes in order of volts. These spikes can cause distortion / offset increase due to the non linear coupling on the internal elementary devices in the signal circuit, overvoltage on the IC, strong noise on the logic signals inside the chip causing incertain logic levels, dangerous for the IC. To avoid these spikes, it is mandatory to put a quality bypass capacitor at a distance lower than 5mm from the pins.

The capacitor C8 on pin 9 must be a low inductance type and should be placed close to the IC. The voltage on this pin sets the switching frequency. The purpose of C8 is to filter the high frequency noise from entering the IC as it could generate distortion/offset.

C4 on pin 8 sets the bandwidth of the class D amplifier. It is important that the reference ground of this capacitor is as near as possible to the IC signal ground.

C3 on pin 11 filters the high frequency noise that can enter in the input and that can cause intermodulation aliasing noise at the output. No signal at frequency greater than half of the switching frequency can enter in the IC without generating aliasing noise.

The electrolitic capacitors must have a good ESR, ESL at switching frequency (around 100Khz) and a sufficient maximum operating voltage.

The low pass filter placed after the switching stage is dimensioned to eliminate the high frequency PWM waves and to feed the audio signal to the loudspeaker. The losses in the filter capacitor C14 due to the ESR will be neglegible if multilayer film capacitors are used.Multilayer Mylar, Polypropilen or Policarbonate film capacitors are recomended, avoid using ceramic capacitors.

The losses in the inductor L1 at low frequencies are mainly due to the coil winding series resistance. At higher frequencies, where the Skin Effect becomes of importance, a multiwire winding could be effective to obtain the maximum in terms of efficiency. However, for most of the applications the use of a single wire winding with adequate cross section is enough. The inductor used for the filter must sustain a DC current greater than the specified current limitation value without saturation and the coil material must show very low hysteresis losses.
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3/06/2014

200W Subwoofer Amplifier Circuit

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Circuit Description

Here is a circuit that uses a mosfet amplifier amplicable for subwoofer as the main booster, or the basis of this boosterAmplifier. Circuit which uses MOSFET Power Amplifier is powered by the output more than 200W Speaker 8 Ohm impedance. We also include a suitable power supply circuit with the use of MOSFETamplifier with 200W of power, not only of his course Schematic diagram for the layout design is also already there.

Amplifier Circuit Diagram

Amplifier Circuit Diagram
200W Mosfet Amplifier LAyout PCB
200W Mosfet Amplifier LAyout PCB

Regulator Circuit Diagram MOSFET AMPLIFIER
Regulator Circuit Diagram MOSFET AMPLIFIER
Regulator PCB MOSFET amplifier
Regulator PCB MOSFET amplifier
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