Audio Amplifiers
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Audio Amplifiers

5 Comments

    5 thoughts on “Audio Amplifiers”

    1. Willie Van Zyl says:

      Good evening.

      I recently purchased a kit using 2n3055 on the output, fter assembling everything it look very similar to the autona 125 amplifier. I was wondering if you have a picture of the autona and maybe a circuit diagram. this kit did not come with a circuit diagram only the pcb layout. I am almost certain it is a copy of the autona.

      I found that if you increase the output cap to 4700uF the amp sounds much better and you can easaly drive 4 ohm loads.

      I bought the kit to play with and built into a 10″ cabinet to have some small speakers that i can just pop in the boot. I do have 2 mosfet amps of 1Kw that i use on my 18″ base bins and 15″ tops.

      I would realy appreciate i if you can send me the circuit of the autona.

      kind regards
      willie

      1. admin says:

        Hi Willie

        The Autona modules were very popular in the 70’s and 80’s, ran on an upto 80V DC supply. There was also a 50W version which was similar, only using 2 x 2N3055s. I drew out the schematic years back and will see if I can find it. These modules were great for disco in the good old days 🙂 but really the quality is bad compared to modern units without coupling capacitors. The worst part is the switch-on thump, which I am sure caused more damage to speakers and the 2N3055s than anything else. I always used Toshiba devices, I found them to be more reliable (otherwise RCA). To get rid of switch-on thump use a 5W 100 ohm resistor across relay contacts attached to timer. (in series with load).
        I’ll see if I can get the circuit and attach it to the OPiC Technical Library. Have fun!

        1. Pieter Roux says:

          Know its some time from May till now I Am also looking for autona 125 circuit Dia. any chance please.

    2. conrad says:

      i have a diagram im busy messing around with one now not sure how to set the bias give me your e mail adress and ill mail you a diagram

      1. willie says:

        hi there conrad my e mial is willie.vanzyl@za.sabmiller.com,

        I know how tro set the bias so when you send me a mail i will explain.

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