Electro Schematics

LED Audio Level Meter Circuit

kotagic@gmail.com (ES) — Wed, 25 Apr 2012 19:19:45 PDT

This circuit uses two quad op-amps to form an eight LED audio level meter. The op-amp used in this particular circuit is the LM324. It is a popular IC and should be available from many parts stores.

LED audio level meter schematic

The 1K resistors in the circuit are essential so that the LED's turn on at different audio levels. There is no reason why you can't change these resistors, although anything above 5K may cause some of the LED's to never switch on. This circuit is easily expandable with more op-amps, and is not limited to use with the LM324. Pretty much any op-amp will work as long as you look up the pinouts and make sure everything is properly connected.

The 33K resistor on the schematic is to keep the signal input to the circuit at a low level. It is unlikely you will find a 33K resistor, so the closest you can get should do. The value of this resistor may need to be changed, so it is best you breadboard this circuit before actually constructing it on PCB. The circuit in it's current form will accept line level inputs from sources such as the aux out on a Hi-Fi, all though could be easily modified to accept speaker inputs.

The audio + is connected to the main positive rail, while the audio - is used for signal input. The 50k pot can be used to vary the sensitivity of the circuit.

Circuit Convert Mono to Stereo Audio Signal

kotagic@gmail.com (ES) — Wed, 25 Apr 2012 19:17:01 PDT

This circuit is used to convert a mono audio signal into a stereo signal that can be panned between the left and right channel by a 0-10V control signal, it is intended for analog synthesizer systems.

Circuit Convert Mono to Stereo Audio Signal Schematic

Simple Power Amplifier Circuit

kotagic@gmail.com (ES) — Wed, 25 Apr 2012 19:09:20 PDT

Simple Power Amplifier Circuit Diagram

Transistors:
Tr1 BCY70 (or BC 182L or BC212L or BC214L)
Tr2/3/4 BFY50/51
Tr5 BFX88
Tr6/7 2N3055

Risk of instability if no input connected. When testing, connect R (about 3k3). The Simple Power Amplifier Circuit needs well smoothed power supply of about 20 to 30 volts. Peak power is well over 10 Watts.

100W Power Amplifier Circuit [PCB]

kotagic@gmail.com (ES) — Wed, 25 Apr 2012 19:06:05 PDT

High Power Amplifier

Technical Specifications - Characteristics 100W Power Amplifier :

Output power (f=1 KHz, d=0.5 %): 100 W in 8 ohm

Supply voltage: ................ с 40 V

Quiescent current: ............. 50 mA

Maximum current: ............... 2.6 A

Sensitivity: . 600 mV

Frequency response: ............ 10-35000 Hz (-1 dB)

Distortion HD: ................. 0.01 %

Intermodulation dist.: ......... 0.02 %

Signal/noise: 83 dBConstruction

100W Power Amplifier Circuit Diagram :

L1 : 10 turns with wire 0,5mm turned on a restistor of 1W

If you use a 4Ohm speaker you will place R3,4,17,23 at the board

If you use a 8Ohm speaker you will place D7 D8 and R28.

For R2 and R16 if you don't find a 0,47Ohm place two of 1 Ohm parallel.

R16 must be 0,47Ohm...the 1Ohm must be a typographical error, take care of this, i haven't tested it.

Printed Circuit Board 100W Power Amplifier PCB:

If it does not work :

Check your work for possible dry joints, bridges across adjacent tracks or soldering flux residues that usually cause problems. Check again all the external connections to and from the circuit to see if there is a mistake there.

- See that there are no components missing or inserted in the wrong places.

- Make sure that all the polarised components have been soldered the right way round. - Make sure the supply has the correct voltage and is connected the right way round to your circuit.

- Check your project for faulty or damaged components. If everything checks and your project still fails to work, please contact your retailer and the Smart Kit Service will repair it for you.

source:100W Audio Amplifier

10 W Audio Amplifier Circuit Diagram

kotagic@gmail.com (ES) — Wed, 25 Apr 2012 18:48:08 PDT

This circuit is a general-purpose 10-W audio amplifier for moderate-power PA or modulator use in an AM transmitter. With higher voltages and a change in bias resistors, up to 30 W can be obtained. The Output Stage Amplifier using transistor 2N3055 and MJE2055.

10 W Audio Amplifier Circuit Diagram

3-Way Crossover Speaker Circuit

kotagic@gmail.com (ES) — Wed, 25 Apr 2012 18:42:05 PDT

Design simply what best fit the drivers' capabilities while focusing on keeping the woofer in doing its job handling the bass, the mids handling the full midrange and so on. 500Hz and 4000Hz were chosen as the crossover frequencies. An L-pad circuit I felt was essential in keeping the response of the speaker perfect as possible. I didn't want anything to stick out. A schematic of the Hi-Vi 3 way crossover design is shown below.

3 Way Crossover Speaker Circuit Diagram

Two Colour LED Light Bar Circuit

kotagic@gmail.com (ES) — Tue, 24 Apr 2012 18:51:37 PDT

This circuit is a circuit run on alternating two insignia.It uses the 2-color LED with a built-participating in 3-pin single.This preference look for away the glow of every LED until the base.It turns alternating to one more color.In in the least way to the moon on the moon essential end, afterward the LED end of the first LED.Circuit consists of, nand gate ic.Two 10 Counter circuits IC, and IC JK flip washout.

company of the circuit is not speaking into 3 sets.It is a solid of gesture generators, a set of parade and control.Set the signal generator is IC1a,and IC1b quantity 4011 is a signal generator.The R2, R3, C2 determine the frequency generated.The hint is fed to a set of impressions is the figure 4011 IC2 and IC3.The 10 counter circuits to output to the LED, and Is the same, but the effort should ensue performed individual by the side of region. Therefore, the show from pin 11 of IC 2 and tested pro D2 and D3,To pin 3 of IC4.The integrated circuit IC 4 is a JK flip slump is connected to a T flip flop.The signal input pin 3 and pin 1 is the output hint at.Which sends a signal to the Reset IC either obstruct working.IC4 on the anniversary, it want output the originally moment in time, happening contrast to pin1.IC3 progress to handiwork, IC2 stopped.

IC2 is controlled by signals from pin 1 of IC4, to IC1c.earlier to control IC2.The IC3 is connected to pins 1 through D1 to the control again.

Circuit flashing LED 4017

kotagic@gmail.com (ES) — Tue, 24 Apr 2012 18:41:06 PDT

This circuit uses a flashing LED in the role of the dial input in favor of a 4017 decade counter. mainstream flashing LEDs (eg, DSE cat Z-4044) jiffy on with reference to 2Hz so the outputs Q0-Q9 resolve cycle through on to facilitate rate. For pattern, Q0 will bear on for partly a back up, followed by Q1, then Q2 and that up to Q8 then it will start by the side of Q0 again. Up to nine outputs can survive used. If you would like fewer outputs, link up an earlier output to MR, pin 15. If MR is not used, connect it to 0V.

Uses in support of the circuit include sequencing another strings of Christmas illumination and that. The resistor from CP0 to ground can befall anywhere from almost 330O to about 10kO. drop standards self-control cause the LED to jiffy further brightly if with the aim of is necessary. With a 4.7kO resistor at the same time as given away, the device input CP0 (pin 14) will alternate flanked by about 2V and 7V. To drive heaps of up to 40W on up to 60V, join each one output to the gate of a 2N3055E before equivalent Mosfet (MTP3055E and so on), as publicized in place of Q0.

Rail Detect Voltage - LED Circuit

kotagic@gmail.com (ES) — Tue, 24 Apr 2012 18:22:51 PDT

At this time’s a clean low supply rail detection circuit to outlay peanuts and takes a short time ago 20 minutes before so to make it to. Its power consumption is quite low, so it may perhaps effortlessly be alive built into battery-powered policy. as a replacement for of using an op amp, the circuit is built around three low-cost transistors (Q1-Q3). Diodes D1-D3 form a 1.8V voltage reference (Vref) in favor of the emitter of Q1. If the voltage across the voltage screen formed by R1 and VR1 is fewer than this, Q1 turns on and provisions Q2 with center bias current.

This turns on Q3 into proportion to this bias current which at that time drives LED1. The brightness of the LED gives an indication of the severity of the low voltage condition. The brighter the LED, the minor the supply voltage. Trimpot VR1 is adjusted so with the aim of LED1 emphatically comes on by the side of the desired low-voltage thrust. The current consumption is typically fewer than 2mA as LED1 is sour. as a final point, the help exposed in lieu of RLED is right and proper for 6-12V process. For other voltages, RLED can take place calculated using the formula RLED = (Vcc - 1.8)/0.01 (this equates to a current of approaching 10mA).

CD4017 Digital Dice Circuit

kotagic@gmail.com (ES) — Tue, 24 Apr 2012 18:09:34 PDT

A electronic acquaintances was seeking a star as circuits in vogue your at no cost point in time,a shameful and uncomplicated to made.This dice digital circuit would occur a favorite of all and sundry, by using it to flaunt the records. As you switch to a spin button before it like is tossing a dice. Looks like a random form normally.

A focal point of this circuit,an a secure oscillator 1Khz with IC 555 and RC networks,it resolve be located output to IC2 is Decade counter IC - 4017. After I focus inedible the spin switch, it will be converted to a binary input with a diode matrix D1-D9 (1N4148 before numeral 1N914) and so therefore untouched to a 7 segment put on show with a decoder drive IC refusal. CD4511 (IC3). The brightness of the numeric display, may well occur customized by adjusting the quantity of R3.

LED Circuit with Timer 555

kotagic@gmail.com (ES) — Tue, 24 Apr 2012 17:58:53 PDT

This circuit LED reproduces the first LED sequence at this time used by FISA on behalf of Formula single racing. It may perhaps be alive used with slot car sets (such for example HO shin up AFX/Life Like/Tyco sets) or else means of communication controlled cars. IC1, a 555 timer IC, is used as a watch pulse generator. Its output is fed via NAND gates IC2a and IC2c to IC3, a 4024 binary counter. IC2b inverts the O4 output of 4024 binary counter IC3. originally, IC3 is reset and all its outputs are low, together with O4, which causes IC2b to present-day a rational climax to the pin 8 input of IC2c which after that passes pulses from the 555 timer circuit to the clock input of the 4024. IC3 then begins together with.

Following the count has reached binary 1111, the subsequently pulse sends the O4 output of IC3 high, which disables IC2c and IC3 stops with. The four used outputs of IC3 are connected to a resistor ‘ladder’ which acts to the same degree a clear-cut digital to analog convert-er (DAC). As the count increases so does the voltage produced by the side of the top of the ladder and this is connected to the inverting inputs of four comparators inside IC4 (an LM339) and to IC5, which is a 741 op amp furthermore connected while a comparator.

The categorical inputs of the comparators are connected to the taps of a voltage dividing wall, with the drumming voltages settle on using VR1, a 100kO trimpot. As IC3 counts, the rising stepped voltage from the DAC ladder switches the comparators on clothed in sequence, preliminary with IC4d and working up to IC5. in the same way as both comparator is curved on, its pair off of LEDs is lit; former LEDs 1 & 2, next LEDs 3 & 4 and so on. as soon as all five pairs of LEDs are lit, the then pulse from IC1 moves the binary count of IC3 to 10000, so the DAC voltage drops back to zilch and all LEDs are extinguished. by the same spell, with too stops, for the reason that the area of high pressure on O4 causes IC2c to check extra gate pulses. The circuit in that case remains reserve until the counter is reset by urgent pushbutton switch S1. This allows a recent sequence to initiate.

Mini Roulette Circuit

kotagic@gmail.com (ES) — Tue, 24 Apr 2012 17:49:39 PDT

A mini roulette circuit, whilst the switch S1 the output by pin 1 of the IC1a the voltage is “shrill”,The oscillator circuit output IC2b, IC2c go to work.timer pulse generator fed to IC3, a voltage “high” output to the output pins 3, 11, and pin 12 of the IC3, the LED1-LED10 light trail sequence. Section LED11 extravaganza high - low tip. The output of pin 3, 2, 4, 7, 10, of IC3 represented by high points,Output pins 1, 5, 6, 9, 11 in its place of the IC3 with the low points.The bonanza instead of the LED12.The IC1b, IC2a and IC2d in the role of controls.

Mini Roulette Circuit

Resistor R2 and capacitor C1 determine the era of the output “shrill” output from pin 1 of the IC1a. The capacitor C1 through R2. at what time you press the switch and the voltage dump across C1 pray regularly raise until the most level. It will reset the flip failure IC1a befall the output by pin 1 is “low”. And the oscillator output circuit to break off working, but in attendance are certain LED light are pending, it can exist with the aim of we put a stop to up being the LED. So fix not apprehension, it choice switch a little time.since, particular a instance full stop with the aim of the R2 and C1. The campaign are compulsory to keep a 6-volt power supply. If tainted is 9 volts, have to try in favor of security reasons.

Alarm LED Light Circuit

kotagic@gmail.com (ES) — Tue, 24 Apr 2012 17:41:32 PDT

This circuit yearn for act the performance of the equipment,otherwise Check the fuse here the circuit.The circuit is diminutive and the power supply voltage of all kinds. It demonstrate with LED, 2-color in individual. Which is cathode universal kind,the anode has two separate terminals. If the circuit is functioning well LED, it revealed in wet behind the ears colour.The display is red, as the fuse into the circuit is damaged.The resistor R1 limits the current to gush through the LED is roughly 2 mA.This is an adequate amount to produce the LED light.If it lowers the R1 down, the LED light up.

Alarm LED Light Circuit Diagram

In the conventional setup of the circuit and The fuse is not damaged. The zener diode to prevent the green and red LED illumination up in chorus.Zener diode prevents the LED is simple and red illumination all together.

The piercing efficiency LED, as soon as connected trendy like. The red LED uses high-pressure, so with the intention of single green LED illumination up only. Diodes D3 and D4 wish prevent dodgy instead of the LED. While the semi cycle downbeat voltage of the alternating current voltage.However, if the DC supply voltage.I act not retain to manage diode protection.

A advantage sports car Sound classification is a Requirement not a Luxury

kotagic@gmail.com (ES) — Tue, 24 Apr 2012 17:30:29 PDT

How accomplish you decide which sedan sound system is most excellent on behalf of you? This is a question to facilitate many consumers ask wearing the U. S. every and all sunlight hours. The reality is that just you can decide come again? kind of sound you catch enjoyable and what you are seeking in the sound structure you pray ultimately hold. A good sound system will greatly look up how you feel just about not merely the vehicle you drive but moreover your disposition afterward your on a daily basis exchange. It might seem like such a slight mechanism, the changing of a sound classification, but it does seem to contain such a profound collision on how we start our days. Of classes we all know with the aim of getting your generation sour to a benefit start sets the tone in favor of the whole day and if that day is Monday it sets the tone for not just the generation yet to be but plus the week to happen.

Tune affects almost all aspect of our lives. the majority of us resolve not realize the crash with the intention of melody has on our time-to-day lives and it is quite hard as our humanity seems to remain overflowing with it. It is much easier however, to explain the difference a good sound arrangement makes. It's funny, I discover myself taking part in a hurry through to step unacceptable of supplies so as to take lousy sound systems and speakers that seep out small other than static while I can store pro hours in a stock with the intention of has refined melody singing in the background above a high-quality sound approach. I favor the volume drop and the melody in concert in the background pretty than being the concentrate of my attention.

Generally of us acquire so as to soft song singing at home the background is rather low profile and allows us to become along with our belief and the mission by give while loud tune piercing larger than very old speakers does a lofty deal to disrupt our notions processes which want simply achieve to send off us along to the subsequently chore on our make a list. If you'll notice it seems to facilitate clerks inside the provisions everyplace the loud harmony blares along are often not such as even tempered as individuals in food to recreation song by the side of polite volumes and obtain very well set aside sound systems. I think I would remain ratty too subsequent to listening to melody in a way to music wasn't destined to be heard.

I'm not a harmony snob by in the least revenue; I simply benefit from listening to melody designed for the sake of in point of fact investigation the tune. Loud music is fine every so often but not once I have other things on my mind. I have a preference with the purpose of song keep on featuring in the background as soon as I'm running on the subject of taking worry of errands, even in the car. The token of a good sedan sound logic is to it sounds good even on low volumes. This agency you can have song in the background, hum along, or else simply ignore the song in approve of the clash taking place on the road.

The intention I'm tiresome to produce is to even though you could not realize the influence that a good sports car sound scheme has on harmony right now, you desire undeniably feel the difference it makes above occasion. The better the sound system, the better the sound and harmony is taking into account all, sound.

If you are a devoted lover of melody and squander a celebrated deal of your week otherwise even every certain daylight hours concerning your vehicle, doesn't it make meaning to invest closely in your car sound practice? I know in favor of me with the aim of fussy decision is a nix brainer. I fondness harmony and it is an valuable part of not barely my life but as well the lives of my children. for instance a conclusion we splurge a allotment of clock listening to the data lines arrived our SUV and singing along. Even once we aren't listening to melody, I have listening colloquy broadcasting and the news on NPR. These things are an essential part of my era and I really have all to both and all single adds to my life. since of that, I achieve my investment in a useful sedan sound classification to come to pass a requirement relatively than a luxury.

STK4050V Power Amplifier Modification

kotagic@gmail.com (ES) — Tue, 24 Apr 2012 03:12:49 PDT

The project is based around the hybrid integrated circuit power amplifier with STK4050 manufactured by Sanyo to build a low clatter mono audio amplifier with complete peak quality. Explanation The project has a ceiling output power of 200W while incorporating a volume control. The power supply used participating in the circuit is an on-board type and as of this, barely a hub tapped transformer is considered necessary in place of the powering of the circuit. The sound has a very fine quality and it can stay proven once used in to your place theaters, in computers, and other audio equipments which can as well be used being subwoofer amplifier. On behalf of water down-type audio sets, it can be considered as a compact package.

200W STK4050 Power Amplifier Modification Circuit Diagram

The leg generated arrived thin-type audio sets is being discrete certainly with a good heatsink design. nearby may possibly live reason someplace a shock din may be encountered especially for the period of switch ON and switch inedible. This can be summary by only if a constant current circuit. The design of the circuit can be tailored used for sinking occurrence of thermal shutdown, brief circuit protection for oodles, shock racket muting from exterior power supply. The load resistance be supposed to arrange 8 Ohms profit with 55K Ohms input impedance.

400Watt IRFP448 Power Amplifier

kotagic@gmail.com (ES) — Tue, 24 Apr 2012 02:39:33 PDT

Power amp 400W IRFP448 Circuit

Amplifier circuit these days,We would like to musical you pro the MOSFET 400 watt amplifier is amplifier on my kW shares the same circuit and main PCB design. The barely real difference is the figure of output procedure to the device. We encompass using The IRFP448 design while the MOSFET amplifier 14 O / P procedure. These amplifiers can live used used for almost a few effort with the aim of requires in height performance, low apply din, distortion and brilliant sound quality. Examples would be subwoofer amplifier be supposed to FOH stage Amplifiers, surround a inland waterway a very powerful sound amplifier, et cetera. The 400W MOSFET-amplifier has four tone stages of amplification. We are looking to start several stage appropriate list.

400Watt IRFP448 Power Amplifier Circuit Diagram

The bias and bumper stage

in the role of the entitle suggests All Q ,C and ZD the Bias and buffer phases. Its major goal is to provide a firm MOSFET Gates and offset voltage and the voltage memory amplifier stage of the extraordinary Resource scope. pardon? would engage in devoid of the period response and the effect Slew rate is indeed very bad. The flip part of the coin is not the spare step Introduction of an bonus dominant pole trendy the amplifier opinion disk.

Power amp 400W IRFP448 PCB and the electronic components layout thus as below :

PCB layout design

Component Placement

Nmos Power Amplifier Series

kotagic@gmail.com (ES) — Mon, 23 Apr 2012 09:39:46 PDT

Power Amplifier with quasi complementary model is the final power amplifier with the transistors of the same type (N all) or (P all), not using transistor pairs. Connecting post part 1, in section 2 is still to review mosfet power amplifier. Two output stage configurations capable of delivering up to 350 watts or up to 500 watts into a 4 ohm load.

Nmos Power Amplifier Series

Final Set up And Adjustment
No attempt should be made to set up or test a power amplifier module that is not correctly mounted
on a heatsink. Make sure the main power supply is fused and the work area is clear. First check all
your work and make sure the output devices are insulated from heatsink. The set up is done without
an input or a load connected to the power amplifier.
1. Check the power supply is operating correctly and verify the rail voltages. Switch the power
supply off and check with a multimeter that the rail capacitors have discharged.
2. Correctly connect the ground, positive and negative leads to the power amp module.
3. Remove the PCB fuses and replace with 100 ohm 5 watt resistors. Connect a multimeter
that is set to the 20 volt scale across the positive rail 100 ohm resistor.
4. Check that the power supply connections are correct one last time and switch on. If the
multimeter reading goes off-scale, turn off immediately and find the problem. Check also the
100 ohm 5 watt resistors; they may have gone open cct.
5. If everything seems ok adjust VR2 to set the output stage bias current, by measuring the
voltage across the positive rail resistor. Adjust for a reading of 3 volts per output FET pair. I.e.
For a 6 FET board set for a voltage of 9 volts. This equates to a bias current of 30mA per
FET pair or 90 mA total. For a 10 FET board set for a voltage of 15 volts.
6. If everything seems ok, check the output offset voltage and adjust VR1 to achieve an offset of
less than 10 mV.
7. All being well switch off, back off the bias control trimmer (VR2) and replace the 100 ohm
resistors with 10 ohm 1 watt resistors. Switch on again and re-adjust VR2 to get 0.3 volts per
per FET pair across the positive rail 10 ohm resistor.
8. Switch off, remove the resistors and put the fuses back in. Switch on, re-check the offset
voltage and adjust with VR1 if necessary.
The amp module is ready, connect the input and output and enjoy.

300W Power Amplifier Circuit with 2N773

kotagic@gmail.com (ES) — Mon, 23 Apr 2012 09:32:53 PDT

Power Amplifier 300W with transistor 2N3773

This amplifier was designed to provide a use for the otherwise useless TO3 power transistors that many hobbyists have in their junk pile. With good construction the module is capable of high quality performance and is rated to 300 watts into a 4 ohm load depending on power supply. With the driver and output transistors specified it is limited to DC rails of +/- 70 volts.

Power Amplifier Circuit Diagram

Powerful high quality amplifier

kotagic@gmail.com (ES) — Mon, 23 Apr 2012 09:20:26 PDT

Nmos350 Mk2

This revised version yet to be built improves a few perfomance areas. I considered more complex ideas but this increased the component count and original idea of the amp would have been lost; that is a powerful high quality amplifier that used commonly available and cheap components.

A LED as the voltage reference for the first stage constant current source tracks changes in temperature slightly better that than the old double diode setup.
A cascode second stage makes it faster and more linear.
Better clipping attributes
The fuse has been shifted out of the voltage drive loop between the driver and output stages.

Nmos350 Mk2 Schematic

100 watts Symasym5 Power Amplifier

kotagic@gmail.com (ES) — Mon, 23 Apr 2012 09:17:11 PDT

Symasym5, is a "cute" power amplifier, designed with quality but still low price in mind. This resulted in a ClassAB BJT amplifier, using only TO92 transistors for input and VAS, with a reasonable part count. The topology used is well known and consist of a single diffamp for input, plus a 2nd diffamp with current mirror for VAS. This is followed by normal darlington EF outputstage using modern high beta devices. The circuit uses large amounts of feedback over the whole audioband and an unconventional feedback compensation scheme. Right now symasym is designed to be driven directly from a CD/DVD-player, simply place a 22k poslog stereo pot between player and symasym. (as voltage divider)

Update

The at least change is to reduce C14 from 22pF to 10pF, but i recommend to follow Pavel's advice. I recommend C14 with 10pF also for MJLs, this increases safety margin. Do not forget to read Pavel's Review! A very promising evaluation of the qualities to be expected from symasym. Thanks Pavel ! Another update are the resistors R31/32 to be increased from 22ohm to 47ohm.

Symasym5_3 is an update of v5.2, with an improved board layout concerning power gnd, resulting in lower thd for high frequencies, giving more clarity in sound. The Page for symasym5_2 still exists.

If the gain is too high because symasym is driven from preamp, R30 can be increased from 499ohms to 1k, but in this case R16/19 (22 or 33 ohms, not on schematic, REs to Q1/2) are required to keep feedback at same level and

100 watts Symasym5 Power Amplifier

Some Specs :

THD: ~0.005% (measured) sim'd: 0.002%
Power into 8ohm: 60 watts
Power into 4ohm: 100 watts
Gain: 32dB (~1:40) full output at 0.7v input (0.5v rms)
Feedback: 57dB
GainBandWidth: ~400Mhz
Slewrate: ~20v/us (symetrical)
Supply voltage: +/- 36v
Biasing: 55ma, ~12mv across a single 0.22 ohm
Measurings: RMAA Symasym5 The measuring setup itself is far from perfect, but gives a good idea !
Frequency response: 3.2hz to 145khz (-1db) using 4.7uf input cap
Phaseshift at 10khz: <3°
More will follow !

Schematic

Most Power Supply for Amplifier

kotagic@gmail.com (ES) — Mon, 23 Apr 2012 09:14:00 PDT

Power supply

As with most power amplifiers, the ±60 V power supply need not be regulated. Owing to the relatively high power output, the supply needs a fairly large mains transformer and corresponding smoothing capacitors—see circuit diagram below.

Note that the supply shown is for a mono amplifier; a stereo outfit needs two supplies.

The power supply is straightforward, but can handle a large current. Voltage 'ac'serves as drive for the power-on delay circuit. The transformer is a 625 VA type, and the smoothing capacitors are 10 000 µF, 100 V electrolytic types. The bridge rectifier needs to be mounted on a suitable heat sink or be mounted directly on the bottom cover of the metal enclosure.. The transformer needs two secondary windings, providing 42.5 V each. The prototype used a toroidal transformer with 2x40 V secondaries. The secondary winding of this type of transformer is easily extended: in the prototype 4 turns were added and this gave secondaries of 2x42.5 V.

300W Power Amplifier Elektor

kotagic@gmail.com (ES) — Mon, 23 Apr 2012 09:05:10 PDT

Taken by themselves, the properties of the PA300 amplifier are not revolutionary. But taken in combination, they show something special: a robust 300 watt hi-fi power amplifier that is not too difficult to build. There are several starting points to the design of a power amplifier: pure hi-fi without any compromise; simplicity and reliability; high output power. The design of the present amplifier is a mixture of these. The result is a unit that does not use esoteric components, is not too complex, and is fairly easily reproduced. In fact, it could well be named a 'Hi-fi public address amplifier'.

There will be a few eyebrows raised at the power output of 300 watts (into 4Ohm); it is true, of course, that in the average living room 30–40 W per channel is more than sufficient. However, peaks in the reproduced music may have a power of 10–20 times the average level. This means that some reserve power is desirable. Also, there are loudspeakers around with such a low efficiency that a lot more than 30–40W is needed. And, last but not least, there are many people who want an amplifier for rooms much larger than the average living room, such as an amateur music hall.

the exception of an IC at the input, the circuit of the PA300 amplifier is conventional.

High-End Power Amplifier Circuit

kotagic@gmail.com (ES) — Mon, 23 Apr 2012 08:55:08 PDT

Given is a pretty generic High-End Power Amplifier. Circuit Schematic quite similar to the one that ghosts around the block as "The G0ldm0uth" Amplifier over at DIYA, but with bipolar tripple emitter follower output and not mosfets, output runs at a fair bit of bias current, around 1 Amp in total and uses three complementary pairs of 30MHz (nominal) output transistors.

High-End Power Amplifier Circuit

600 Watt Quasi Amplifier With Mosfet IRFP460

kotagic@gmail.com (ES) — Mon, 23 Apr 2012 08:51:09 PDT

ACTK 400/600 Watt

Two versions of a robust module capable of delivering high powwer for extended periods. The Actrk400 uses 6 n-channel Mosfets in the output stage to deliver around 400 watts into 4 ohms while the Actrk600 uses 12 n-channel Mosfets in the output stage to deliver power in excess of 600 watts into 4 ohms. One constructor has achieved almost 900 watts with the Actrk600 layout using 12 IRFP460 Mosfets.

600 Watt Quasi Amplifier With Mosfet IRFP460

Kit Telephone Amplifier

kotagic@gmail.com (ES) — Mon, 23 Apr 2012 08:42:44 PDT

Not a speakerphone, but a high performance isolated input amplifier that connects directly to a telephone line. Unlike a lot of amplifiers, this one provides both speaker output and line output. Speaker output is perfect for “group listen? applications with standard telephones for group gatherings without the inconvenience and interruption of vox operated speakerphones.

Kit Telephone Amplifier

The K4900 also features line level output designed to be connected to the aux input of any standard audio mixer or amplifier. This makes it perfect for radio stations, home broadcasters, and larger applications that need to connect their phone line into their systems. Features a standard isolation transformer input for zero loading of the phone line. Speaker output is a half watt into 8 ohms. Line output is 0dB (.775Vrms). The circuit runs on 7-10VAC or 9-12VDC at 150mA.