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 amplifier PCB layout

More audio amplifier circuits…



8 Responses to “LM12 150W audio amplifier”

1. robert says:

   September 11, 2009 at 1:25 am

   for project,thanks

   Reply
   • Dave says:

     September 25, 2009 at 1:10 am

     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.

     Reply
     • timo says:

       June 7, 2011 at 9:33 pm

       Hi,
       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.

       Timo

       Reply
2. Alex Dusouza says:

   January 11, 2010 at 9:45 am

   very much interested in the LM12 I,Cs.

   Reply
   • Mario A. Scalia says:

     July 14, 2010 at 7:35 pm

     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 tel.de comercios de bs.as.que lo tengan. desde ya muchas gracias.

     Reply
3. dj sapo says:

   June 19, 2010 at 2:55 pm

   gracias a favoritos….lo armo y comento

   Reply
4. Jonathan says:

   October 2, 2010 at 3:53 am

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

   Reply
5. rohit says:

   January 23, 2012 at 9:54 am

   hi dave,
   do you still have lm12 clk for sale

   Reply