+ Post New Thread
Page 1 of 2 1 2 LastLast
Results 1 to 20 of 35
  1. #1
    Advanced Member level 3
    Points: 4,258, Level: 15
    rajaram04's Avatar
    Join Date
    Jun 2012
    Location
    earth
    Posts
    856
    Helped
    6 / 6
    Points
    4,258
    Level
    15

    4558 ic circuit diagram for simple audio amplifier

    Hello sir

    For ic 4558 i am not getting any audio amplifier circuit diagram here or anywhere though i need a very simple one , please help . .thanks

  2. #2
    Advanced Member level 5
    Points: 11,015, Level: 25

    Join Date
    Apr 2012
    Posts
    1,981
    Helped
    637 / 637
    Points
    11,015
    Level
    25

    Re: 4558 ic circuit diagram for simple audio amplifier

    The RC4558 is a dual opamp. The datasheet says each half is electrically similar to a uA741. So you can use it in any 741 circuit.
    Last edited by godfreyl; 15th December 2013 at 07:59.



  3. #3
    Advanced Member level 3
    Points: 4,258, Level: 15
    rajaram04's Avatar
    Join Date
    Jun 2012
    Location
    earth
    Posts
    856
    Helped
    6 / 6
    Points
    4,258
    Level
    15

    Re: 4558 ic circuit diagram for simple audio amplifier

    Quote Originally Posted by godfreyl View Post
    The RC4558 is a dual opamp. The datasheet says ieach half is electrically similar to a uA741. So you can use it in any 741 circuit.
    okk ! well is it a good one as an audio amp ? or suitable for short term applications like head phone amp.etc ?????



    •   Alt14th December 2013, 23:35

      advertising

        
       

  4. #4
    Advanced Member level 5
    Points: 48,446, Level: 53
    Achievements:
    7 years registered
    Audioguru's Avatar
    Join Date
    Jan 2008
    Location
    Toronto area of Canada
    Posts
    8,423
    Helped
    1966 / 1966
    Points
    48,446
    Level
    53

    Re: 4558 ic circuit diagram for simple audio amplifier

    The datasheet for the 4558 shows that each of its opamps can drive a 10k load very well and drive a 2k ohms load not good but not too badly.
    It is not a stereo power amplifier. Instead it was designed to be the preamp in a record player or tape player that drives the inputs of a power amplifier.

    What is the impedance of your headphones? 2k ohms or more? I doubt it because most headphones today are 32 ohms.



  5. #5
    Advanced Member level 3
    Points: 4,258, Level: 15
    rajaram04's Avatar
    Join Date
    Jun 2012
    Location
    earth
    Posts
    856
    Helped
    6 / 6
    Points
    4,258
    Level
    15

    Re: 4558 ic circuit diagram for simple audio amplifier

    Quote Originally Posted by Audioguru View Post
    The datasheet for the 4558 shows that each of its opamps can drive a 10k load very well and drive a 2k ohms load not good but not too badly.
    It is not a stereo power amplifier. Instead it was designed to be the preamp in a record player or tape player that drives the inputs of a power amplifier.

    What is the impedance of your headphones? 2k ohms or more? I doubt it because most headphones today are 32 ohms.



    and how to measure the impedance of head phone ? its an earplug actually by nokia



  6. #6
    Advanced Member level 5
    Points: 48,446, Level: 53
    Achievements:
    7 years registered
    Audioguru's Avatar
    Join Date
    Jan 2008
    Location
    Toronto area of Canada
    Posts
    8,423
    Helped
    1966 / 1966
    Points
    48,446
    Level
    53

    Re: 4558 ic circuit diagram for simple audio amplifier

    Quote Originally Posted by rajaram04 View Post
    and how to measure the impedance of head phone ? its an earplug actually by nokia
    Impedance is resistance to an AC signal. Measure its resistance with a multimeter. Its resistance will be a little less than its impedance.
    The resistance of the headphones (earplug kind) for an iphone is 33.4 ohms for each ear and it needs a little power amplifier to drive it.



  7. #7
    Advanced Member level 3
    Points: 4,258, Level: 15
    rajaram04's Avatar
    Join Date
    Jun 2012
    Location
    earth
    Posts
    856
    Helped
    6 / 6
    Points
    4,258
    Level
    15

    Re: 4558 ic circuit diagram for simple audio amplifier

    Quote Originally Posted by Audioguru View Post
    Impedance is resistance to an AC signal. Measure its resistance with a multimeter. Its resistance will be a little less than its impedance.
    The resistance of the headphones (earplug kind) for an iphone is 33.4 ohms for each ear and it needs a little power amplifier to drive it.


    hmm i tested but maximum range of 2000k on a multimeter i got no reading . .



    •   Alt18th December 2013, 06:59

      advertising

        
       

  8. #8
    Advanced Member level 5
    Points: 48,446, Level: 53
    Achievements:
    7 years registered
    Audioguru's Avatar
    Join Date
    Jan 2008
    Location
    Toronto area of Canada
    Posts
    8,423
    Helped
    1966 / 1966
    Points
    48,446
    Level
    53

    Re: 4558 ic circuit diagram for simple audio amplifier

    Quote Originally Posted by rajaram04 View Post
    hmm i tested but maximum range of 2000k on a multimeter i got no reading . .
    Then your earphones must be the 60 years old "crystal" (piezo) kind. In the WEST, headphones are the modern "dynamic" (coil and magnet) kind.

    Here is a list of earphone types: http://en.wikipedia.org/wiki/Headphones



  9. #9
    Super Moderator
    Points: 239,566, Level: 100
    Awards:
    1st Helpful Member

    Join Date
    Jan 2008
    Location
    Bochum, Germany
    Posts
    41,505
    Helped
    12663 / 12663
    Points
    239,566
    Level
    100

    Re: 4558 ic circuit diagram for simple audio amplifier

    Then your earphones must be the 60 years old "crystal" (piezo) kind
    At those days, Nokia has been making rubber boots as far as I know. There must be a different explanation, e.g. incorrrect measurment.



  10. #10
    Advanced Member level 5
    Points: 11,015, Level: 25

    Join Date
    Apr 2012
    Posts
    1,981
    Helped
    637 / 637
    Points
    11,015
    Level
    25

    Re: 4558 ic circuit diagram for simple audio amplifier

    Quote Originally Posted by rajaram04 View Post
    hmm i tested but maximum range of 2000k on a multimeter i got no reading . .
    Now try a more sensible range like 200 or 2K.



    •   Alt18th December 2013, 17:37

      advertising

        
       

  11. #11
    Advanced Member level 5
    Points: 48,446, Level: 53
    Achievements:
    7 years registered
    Audioguru's Avatar
    Join Date
    Jan 2008
    Location
    Toronto area of Canada
    Posts
    8,423
    Helped
    1966 / 1966
    Points
    48,446
    Level
    53

    Re: 4558 ic circuit diagram for simple audio amplifier

    Quote Originally Posted by rajaram04 View Post
    hmm i tested but maximum range of 2000k on a multimeter i got no reading . .
    Because the reading is very low? That is normal on such a high range.

    2000k is 2 million ohms. A 32 ohm earphone would measure almost zero.
    But on a range of 200 ohms maximum then the 32 ohm earphone would measure about 30.



  12. #12
    Advanced Member level 3
    Points: 4,258, Level: 15
    rajaram04's Avatar
    Join Date
    Jun 2012
    Location
    earth
    Posts
    856
    Helped
    6 / 6
    Points
    4,258
    Level
    15

    Re: 4558 ic circuit diagram for simple audio amplifier

    ohh haha lots of amazing discussions & explanations , well i got that in range of 200 ohms but i everytime i connect the meter & getting diffrent results like sometimes 15 ohms sometime 28 ohms sometime 32 ohms then 40 ohms n so on . . dont know why , but maximum time i got 24 & 28E



  13. #13
    Advanced Member level 5
    Points: 48,446, Level: 53
    Achievements:
    7 years registered
    Audioguru's Avatar
    Join Date
    Jan 2008
    Location
    Toronto area of Canada
    Posts
    8,423
    Helped
    1966 / 1966
    Points
    48,446
    Level
    53

    Re: 4558 ic circuit diagram for simple audio amplifier

    Finger prints on the meter probes and earphone plug cause the very low resistance to change. Your earphone are probably 16 ohms for each ear so you need a little stereo power amplifier to drive them.

    I looked in Google Images for Earphones Amplifier Circuit With Opamp and found hundreds of circuits.



  14. #14
    Advanced Member level 3
    Points: 4,258, Level: 15
    rajaram04's Avatar
    Join Date
    Jun 2012
    Location
    earth
    Posts
    856
    Helped
    6 / 6
    Points
    4,258
    Level
    15

    Re: 4558 ic circuit diagram for simple audio amplifier

    Quote Originally Posted by Audioguru View Post
    Finger prints on the meter probes and earphone plug cause the very low resistance to change. Your earphone are probably 16 ohms for each ear so you need a little stereo power amplifier to drive them.

    I looked in Google Images for Earphones Amplifier Circuit With Opamp and found hundreds of circuits.



    hmm ya i too got many & randomly selected here as a compact one but transistor is the issue in following diagram

    Click image for larger version. 

Name:	hifi-headphone-amplifier.gif 
Views:	23 
Size:	86.5 KB 
ID:	100085

    please help me in implanting an equivalent for those two

    rest of the component is with me . . .thanks



  15. #15
    Super Moderator
    Points: 239,566, Level: 100
    Awards:
    1st Helpful Member

    Join Date
    Jan 2008
    Location
    Bochum, Germany
    Posts
    41,505
    Helped
    12663 / 12663
    Points
    239,566
    Level
    100

    Re: 4558 ic circuit diagram for simple audio amplifier

    The circuit will work with any pair of medium power NPN/PNP transistors, let's say > 1 W.



  16. #16
    Advanced Member level 3
    Points: 4,258, Level: 15
    rajaram04's Avatar
    Join Date
    Jun 2012
    Location
    earth
    Posts
    856
    Helped
    6 / 6
    Points
    4,258
    Level
    15

    Re: 4558 ic circuit diagram for simple audio amplifier

    Quote Originally Posted by FvM View Post
    The circuit will work with any pair of medium power NPN/PNP transistors, let's say > 1 W.
    any example for commonly available ??????

    i am choosing bc547 & bc557 for now . . please help



    •   Alt21st December 2013, 00:36

      advertising

        
       

  17. #17
    Advanced Member level 5
    Points: 48,446, Level: 53
    Achievements:
    7 years registered
    Audioguru's Avatar
    Join Date
    Jan 2008
    Location
    Toronto area of Canada
    Posts
    8,423
    Helped
    1966 / 1966
    Points
    48,446
    Level
    53

    Re: 4558 ic circuit diagram for simple audio amplifier

    The low current BC547 and BC557 transistors will blow up if the output of the amplifier is shorted when it is playing loudly.
    I would use TIP31 and TIP32 medium power transistors that will survive.
    This amplifier might produce enough loudness in earphones to deafen you so maybe you will need an attenuator resistor in series with each earphone.



  18. #18
    Advanced Member level 3
    Points: 4,258, Level: 15
    rajaram04's Avatar
    Join Date
    Jun 2012
    Location
    earth
    Posts
    856
    Helped
    6 / 6
    Points
    4,258
    Level
    15

    Re: 4558 ic circuit diagram for simple audio amplifier

    Quote Originally Posted by Audioguru View Post
    The low current BC547 and BC557 transistors will blow up if the output of the amplifier is shorted when it is playing loudly.
    I would use TIP31 and TIP32 medium power transistors that will survive.
    This amplifier might produce enough loudness in earphones to deafen you so maybe you will need an attenuator resistor in series with each earphone.


    hm i see . . ya kk got it . . so what about substitute or say equivalent for TIP31 etc ?



  19. #19
    Advanced Member level 5
    Points: 48,446, Level: 53
    Achievements:
    7 years registered
    Audioguru's Avatar
    Join Date
    Jan 2008
    Location
    Toronto area of Canada
    Posts
    8,423
    Helped
    1966 / 1966
    Points
    48,446
    Level
    53

    Re: 4558 ic circuit diagram for simple audio amplifier

    I am not in your country so I do not know what is available there. I can buy ANYTHING here.



  20. #20
    Advanced Member level 5
    Points: 11,015, Level: 25

    Join Date
    Apr 2012
    Posts
    1,981
    Helped
    637 / 637
    Points
    11,015
    Level
    25

    Re: 4558 ic circuit diagram for simple audio amplifier

    Any of these transistor pairs should be good:

    NPN / PNP
    mje340 / mje350
    bd139 / bd140
    2sc4793 / 2sa1837
    2sc3421 / 2sa1358



--[[ ]]--