150W OCL STEREO AMPLIFIER
Of course this paper is not based on scientific research, but only my personal view because I often find this amplifier schematics and kits in electronics stores in Indonesia not only in Jakarta.
This is not a sophisticated amplifier, but a simple amplifier with a pretty good performance. This amplifier has been there long before I knew about electronics. You can find this kit in all corners of Indonesia with many version. It is well known as the simple amplifier kit that many people have build it in Indonesia. Many amateur and professional builders who are very good at making these amplifiers. They modify it to get big power and hold amplifiers are used for many hours. Even myself have several times made this amplifier for many purposes and request from friends.
Amplifier is used for amateur and professional music concerts. Dangdut concert held in the usual entertainment events and weddings mostly use this DIY amplifier. The art show and shadow puppets also use this amplifier.
Base on this 75W power amplifier circuit we can make a big power amplifiers. Generally, the output power amplifier raised by increasing the number of final transistors in parallel or bridge configuration. Originally the amp using a pair of 2N3055 and MJ2955 transistor at final stage. Now alot of builder using SANKEN 2SC2922 and 2SA1216 for final stage.
This is link of blogger who also write about this amp.
http://solfegio.indonesianforum.net/t3477-modif-pa-ocl-150w >> Indonesia’s DIY audio forum
And This is my version of OCL Amplifier 150W (75+75). It’s a stereo amplifier using general component with original value, Except for final stage I use Sanken 2SC2922 and 2SA1216 . All parts to build this amp is easy to get. It cost around USD 12 for the amplifier kit and USD 30 for the power supply.
Since the amp doesn’t have any protection so I use a speaker protector kit to protect my speaker. If there some fault or bad final transistor this OCL amplifier could burn your speaker without mercy because the DC current is flow directly to your speaker. This protector kit protect from DC current if there any fault at the amp circuit. It’s cost only USD 2, so it does not mean hundreds of dollars compared to the speakers.