Dec 22, 2011

Make a High Power 250 Watt MosFet Amplifier DJ Circuit

The powerful DJ 250 watt mosfet amplifier circuit design provided in this article is reasonably easy to build and will produce thumping music into the connected loudspeaker. Use of HEXFETs at the output ensures monstrous current and voltage amplification.

The involvement of MOSFETs or rather HEXFETs at the output stage of this 250 watt mosfet amplifier circuit promises high and efficient amplification of both voltage and current. The circuit particularly exhibits impressing features like low distortion and external offset voltage and quiescent current adjustments.


Input Stage







Output Stage




Circuit Description

This outstanding 250 watt mosfet amplifier circuit can be used as a DJ amplifier in concerts, parties, open grounds etc. The design being symmetrical produces negligible distortions. Let’s try to analyze the circuit details:
Referring to the circuit diagram, we see that the input stages primarily consists of two differential amplifiers. The blocks T1 and T2 are actually matched paired dual transistors in one package, but you may go for discrete transistors, just make sure their hFes are properly matched. Use a couple of BC 547 and BC 557 for the NPN and the PNP types respectively.
A differential configuration is probably the perfect way of integrating two signals, for example here the input and the feedback signals are mixed so efficiently.
Typically the ratio of the collector/emitter resistances of T1 determines the amplification of this stage.
The DC operating reference for T1 and T2 is received from a couple of transistors T3 and T4 along with the associated LEDs.
The above LED/ Transistor network also helps to provide a constant current source to the input stage as it virtually remains unaffected to ambient temperature variations, but preferably the LED/ transistor pair should be attached together by gluing them together or at least soldered very close to each other over the PCB.
Immediately after the coupling capacitor C1, the network comprising of R2, R3 and C2 forms an effective low pass filter and helps maintaining a bandwidth to a level suitable for the amplifier.
Another small network at the input, involving a 1M preset and a couple of 2M2 resistors helps adjusting the off-set voltage so that the DC component at the output of the amplifier stays at zero potential.
After the differential stage an intermediate driver stage is introduced comprising T5 and T7. The configuration consisting of T6, R9 and R17 forms a kind of variable voltage regulator, which is used to set the quiescent current consumption of the circuit.
The boosted signal from the above stage goes to the driver stage consisting of T8 and T9 which are effectively used to drive the output power stage involving the HEXFETs T10 and T11 where the signals ultimately undergoes a massive current and voltage amplification.
From the diagram it is clearly identifiable that T10 is a p-channel and T11 is an n-channel FET. This configuration allows efficient amplification of both current and voltage at this stage. The overall amplification is though limited to 3 due to the feedback wiring of R22/R23 and also with R8/C2. The limitation ensures low distortion at the output.
Unlike bipolar transistors, here the outputs stage incorporating HEXFETs have a distinct advantage over its age old counter part. HEXFETs being positive temperature coefficient devices are equipped with the inherent property of limiting their drain source as the case temperature tend to get too hot, safeguarding the device from thermal runaway situations and getting burnt off.
Resistor R26 and the series capacitor compensate the rising impedance of the loudspeaker at higher frequencies. Inductor L1 is placed to safeguard the loudspeaker from instantaneous rising peak signals.

Parts List

R1 = 100K
R2 = 100K
R3 = 2K
R4,5,6,7 = 33 E
R8 = 3K3,
R9 = 1K PRESET,
R10,11,12,13 = 1K2,
R14,15 = 470E,
R16 = 3K3,
R17 = 470E,
R18,19,21,24 = 12E,
R22 = 220, 5 WATT
R20,25 = 220E,
R23 = 56E, 5 WATTS
R26 = 5E6, ½ WATT
C1 = 2.2uF, PPC,
C2 = 1n,
C3 = 330pF,
C6 = 0.1uF, mkt,
T3 = BC557B,
T4 = BC547B,
T7,9 = TIP32,
T5,6,8 = TIP31,
T10 = IRF9540,
T11 = IRF540,




81 comments:

  1. i will make it shortly .pls help me in making PCB . pls show the sony mega bass ckt diagram can i get genuine sony spare parts ?

    ReplyDelete
    Replies
    1. Procure a 10 by 10 inches copper clad first, then I'll tell you how to make a PCB

      Delete
    2. already have copper clad and all the PCB making equipments and procedure problem is with design software which will be easier to me i don't know pls suggest . why sony music is too much clear than others ? i want the mega bass ckt diagram .

      Delete
    3. I don't use a software, I do it on corelDraw....I will try to find a mega bass circuit, if I find one, I'll surely inform you.

      Delete
    4. its too difficult, please please please make the PCB diagram for me please ..
      can you please design a 3D surround sound ckt for this amplifier .

      Delete
    5. OK first try the following circuit:

      http://www.free-circuit.com/2011/07/18/300-watt-mosfet-real-hi-fi-power-amplifier/

      Delete
  2. Hi swagatam,
    Thanks for your wonderful work here. It is not easy to update and maintain such a blog and i must commend you. I have a request for a 1,500watt amplifier. Please try to get me a working circuit diagram and detailed explanation for this. I will sincerely appreciate and reward you the little way i can.
    Regards.

    ReplyDelete
    Replies
    1. Hi Masterfiles, Please check out the following link, the design looks very promising and would possibly satisfy your needs:

      http://www.tasel.net/1500-watt-power-amplifier/1500w-power-amplifier-circuit-diagram/

      Delete
    2. Thanks for the link sir.
      Could you please explain the circuit diagram? Also i doubt if i can find suitable transformer for the power supply section in my country. I have been searching with no result yet. can you suggest the way out?
      Thanks

      Delete
    3. It's a standard design having a differential stage, followed by a driver stage and finally a power output stage.

      The transformer will need to be made-to-order, the high voltage is necessary for implementing the extreme high wattage output from the circuit, and for keeping the wires and the transformer dimensions smaller.

      Delete
  3. Hi Swagatam,
    The coil just before the speaker has no value, what are your suggestions?

    Cheers

    ReplyDelete
    Replies
    1. it's 20 turns of 22swg enameled copper wire over a 1 ohm 5 watt resistor connected parallel to it.

      Delete
  4. pls give a circuit for 5.2/7.2 surround system.

    ReplyDelete
  5. what about the current & voltage & ohm's rate of this amp (what is the cost of IRF9540,IRF540

    ReplyDelete
  6. if i will add 2 pair of more output mosfet then how much watt i will get

    ReplyDelete
    Replies
    1. You can do it, the power would increase substantially, just make sure to add a 0.22 ohm 1 watt resistors in series with the source of each mosfet, and also use separate gate resistors for each mosfets.

      Delete
  7. plz sir, can u tell me the price of the two mosfet IRF9540,IRF540

    ReplyDelete
  8. sir can u please tell me the cost of IRF9540,IRF540

    ReplyDelete
    Replies
    1. in my area(erode,tamilnadu,india) the IRF540 is 40/- rupees and IRF9540 is 50/- rupees only.

      Delete
  9. I have two 6 ohm speakers and want to build a speaker system with very good quality right from scratch( from 3.5 mm jack). Got any circuit for that?

    ReplyDelete
    Replies
    1. you can try this one:

      http://homemadecircuitsandschematics.blogspot.in/2012/04/how-to-make-simplest-100-watt-mosfet.html

      Delete
  10. I have 4 ohm super speakers.. will you help to make a amplifier at home for suitable for this 4 ohm speakers with simple way to understand circuits and gave a proper list to used equipments in this............... please help me...

    ReplyDelete
    Replies
    1. You can try the following circuit, this is much easier, but you will need a PCB for this:

      http://homemadecircuitsandschematics.blogspot.in/2012/04/how-to-make-simplest-100-watt-mosfet.html

      Delete
  11. I really appreciate this circuits and others too. But I am sorry to say that it's of no use until you provide complete information like PCB design and complete parts list. Most of the projects I have seen here are just having few images, only few have parts list.

    ReplyDelete
  12. Dear sir ,
    How to make offset zero. Wat is the supply voltage...
    Thanks n regards

    ReplyDelete
    Replies
    1. Dear style, you can do it by adjusting R9, supply is 30-0-30V DC 5 amps

      Delete
  13. Dear Sir,
    the voltage and amps required for this ckt?
    Regards

    ReplyDelete
  14. Hi Sir, what happens to power sharing & output in an amplifier using transistors A1943 & C5200 because each is 100W power dissipation(power calculations of the output stage)?
    And what most contributes to how powerful an amplifier can be in TRANSISTOR AMPLIFIERS?

    ReplyDelete
    Replies
    1. Hi kakooza, the transistor number is not important, it's the specifications that matter, if the specs match then the transistor will work as efficiently as expected from them.

      the output devices primarily decide the power level of the amplifier, but only if the power supply is optimally rated, lower supply specs will result in poor output quality and distortions.

      Delete
  15. Thanks so much for the detailed explanation. But one thing I would like to know before building it; have you or anyone else actually built the circuit using the given values?

    ReplyDelete
    Replies
    1. It has been tested by the "elektor electronics" engineers

      Delete
  16. In this ckt which type of diode is used and value mention diode d1 and d2 as given in ckt?
    And which type of inductance and value?
    Where i connect audio in hub or audio in socket?

    ReplyDelete
    Replies
    1. D1, D2 are LEDs.

      wind 20 turns of any thin magnet wire over R26.

      connect music input across R1

      Delete
  17. Sir, there are showing two images of circuit.
    tell me how can i connect both are.

    ReplyDelete
    Replies
    1. Vivek, connect the matching dotted lines of the two images with other, for example the (+) will go to the (+) line, (-) to the negative and so on

      Delete
  18. sir in need a circuit for 3phase induction motor protection which can automatically switched off the motor when it is over heated or one phase is off or phase is reversed or ov and uv protection

    ReplyDelete
    Replies
    1. Sanket,
      for heat protection you could try the first concept from this article

      http://www.homemade-circuits.com/2016/08/incubator-temperature-controller.html

      for single phase preventor, the following design could be employed

      http://2.bp.blogspot.com/-XzawKd-l-0U/Uh9Vk0K4s3I/AAAAAAAAALg/IszErlsABRw/w1200-h630-p-nu/single+phase+preventor+circuit.jpg

      Delete
  19. sir what is the name of T1 & T2 transistor,

    ReplyDelete
  20. all parts are ready to built, but little confustion what is T1 & T2 (any other alternate transistor if not aveailabe pair transistor)

    ReplyDelete
    Replies
    1. those are "matched transistor pairs", please google "100mA NPN matched transistor pair" and "100mA PNP matched transistor pair".....you will be able to find the values.

      Delete
    2. or alternatively you can simply use two BC547 and two BC557 for the NPN and PNP pairs respectively by matching their hFe values as close as possible.

      Delete
  21. Sir, what about delay circuit? give/guide me in details

    ReplyDelete
    Replies
    1. Vijay, you can try the following circuit

      http://www.homemade-circuits.com/2013/02/make-this-simple-delay-on-circuit.html

      Delete
    2. thx sir, 330PF, 22nF capacitor not available, any alternative?

      Delete
    3. half ckt builted on bread-board, waiting for alternative capacitor value from u sir!!

      Delete
  22. sir, i am right speaker one end is connected to ground through delay circuit!

    ReplyDelete
  23. what is value of capacitor c4,c5 and capacitor series with R26

    ReplyDelete
  24. Sir In this circuit,mentioned name are double, that is R5 & C2. Value are same?

    ReplyDelete
    Replies
    1. No it could be a mistake, the values are not same I don't remember now, I'll have to check it in my old books, it may take little time may be two days

      Delete
  25. Tell the values as soon as possible sir,I will Wait.

    ReplyDelete
    Replies
    1. A updated a similar diagram at the bottom, you can make it accordingly...

      R5 = 22K
      C2 = 330pF

      Delete
  26. sir, already i brought parts as per old circuit(total=800 Rs), so lets continue.which is that first R5 & C2 or after that? and (small doubt it will work)

    ReplyDelete
    Replies
    1. Vijay, it is the right side R5, and C2...yes it will work

      Delete
  27. Which is more output sound. 250w dj amplifiers or ic 4440 amplifier

    ReplyDelete
    Replies
    1. you can yourself compare by checking their datasheets

      Delete
  28. Sir I made PCB and all parts placed but no sound only humming sound in speaker,
    I connected multimeter plus to output and mins to GND, range 20v DC for feedback reading its getting 15v and no
    Variable even I adjusting R9 i.e 1k port

    ReplyDelete
    Replies
    1. Vijay, how did you adjust the 1K preset??

      It's for setting up the quiescent current.

      please read the following article to learn how to adjust the preset for setting up the correct quiescent current.

      quiescent current means current which the amplifier will consume without any music, or in the idle state.

      http://www.homemade-circuits.com/2012/01/how-to-make-hi-fi-100-watt-amplifier.html

      Delete
  29. Sir, R23 get heating solved by attending loose connection,but now R16 getting heated and no audio output

    ReplyDelete
    Replies
    1. Vijay, that means you might have other faults also, or a transistors may be faulty or wrongly connected....I cannot troubleshoot your circuit without seeing it.

      Delete
  30. Sir I connected ammeter in series with positive by shorting output to ground,but in multimeter no reading only zero

    ReplyDelete
    Replies
    1. If the ammeter is showing nothing then how come R16 is getting hot?

      check quiescent current by shorting the input terminals, and by removing the speaker....don't short the output.

      Delete
  31. Please, help me sir I spend more time in this ckt but no success

    ReplyDelete
    Replies
    1. build a new circuit and this time build the lat circuit from this article

      http://www.homemade-circuits.com/2012/01/how-to-make-hi-fi-100-watt-amplifier.html

      this circuit was tested by me personally.

      i too had problems at first, and i was very new to electronics at that but i could troubleshoot it myself and make it work perfectly.

      make sure your parts are of good quality.

      Delete
  32. Sir, any one done/tested this ckt and got success

    ReplyDelete
    Replies
    1. All these circuits are taken from elektor electronics magazine, and these have been tested by the elektor electronics engineers.

      Delete
  33. Sir,I want post PCB image, Wts is email

    ReplyDelete
    Replies
    1. Vijay, sending PCB image will not help, you will have to troubleshoot it yourself, or build it again from the scratch, it's not so difficult.....keep trying you will succeed.

      Delete
  34. Sir, Send easy method, testing the transistor and MOSFETs

    ReplyDelete
    Replies
    1. Vijay, there's only a standard method to test BJT and mosfets....BJTs are easy to test but mosfets are not....you can refer to youtube and search this, you will be able to find some video tutorials....

      but you will have to remove the transistors from the PCB before checking them.

      Delete

Swagatam Majumdar
Swagatam MajumdarHi Friends, Welcome to my site, a place where you will discover a massive collection of electronic circuit ideas, mostly requested by the dedicated readers and exclusively designed by me for their customized application needs. I have posted more than 1100 circuit designs in this site, if you have a personalized circuit requirement you may feel free to request it through the comment box, if it seems feasible to me then surely you may find it published here with your credentials attached in the post, thanks and please keep reading



 
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