LM12 150W Audio Amplifier

LM12 operational amplifier can output currents up to 10A. The LM12 in encapsulated in TO-3 with 4 pins, can support up to 800W and has enough internal protections to prevent slacks from over-currents or over-heating.

You can use LM12CL with 30 V maximum voltage or LM12C with 40V maximum.
The L1 coil has 40 turns 1mm copper, coiled over R4. If you use LM12CL it is recomended to have toroidal transformer 2 x 22V. The output must be between 7 and 12A. Filtering capacitors must have at least 20.000 uF.
LM12 must be mounted with screws on a big heatsink (=< 1.50 C/W) and electric isolated form the heatsink

LM12 amplifier circuit diagram

lm12 150w audio amplifier circuit diagram

LM12 amplifier PCB layout

lm12 150w pcb layout


Join the conversation!

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  • Peter Jordi

    I would like to buy 3 pieces
    LM12 from you for 25CAD each.
    You doing that over Ebay?
    Kind regards Peter

  • rohit

    hi dave,
    do you still have lm12 clk for sale

  • Jonathan

    donde concha se consigue ese lm 12 XD vivo en colombia y no e podido encontrar ese integrado

  • dj sapo

    gracias a favoritos….lo armo y comento

  • Alex Dusouza

    very much interested in the LM12 I,Cs.

    • Mario A. Scalia

      Hola como estan.Vivo en gral.Roca Rio Negro Argentina estoy muy interesado en armar el amplificador de audio con el LM 12.Me encuentro con la dificultad de conseguir el mismo y sobre todo por el elevado precio que tiene en esta zona.Por favor necesitaria si me pueden dar direcciones o comercios de lo tengan. desde ya muchas gracias.

  • robert

    for project,thanks

    • naseem hussain


      I have LM12CLK in my stock , if you still need these , let me know your target price.

      thanks Naseem Hussain

    • kenact

      I realize this post is several years old, but do you still have any LM12CLKs?

    • Dave

      I’ve got about 60 Genuine National Semiconductor LM12CLK’s that were used in a high end subwoofer amp back in the 90’s
      We changed the design and a bunch of these IC’s ended up in my garage. I totlaay forgot about them for about ten years.

      They are selling for around $35.00 each on ebay now and I was planning on listing mine. If you are interrested you can have as many as you want for $20.00 each

      I’ve also got some Motorola MJ11013 and MJ11014 Complimentary Darlington Transitors that were used as a final output stage to boost the power. I think the amp was rated at around 250watts. Sorry no schematic of the old amp.

    • timo

      do you still have the LM12s available? I just blew a pair of thesed from my audio amp and would need replacements. Please let me know if they are still for sale.