RM99 Car AMP

Originally I had decided that 2 6.5″ mid range in the front was enough for my car’s sound system. But then when I was installing the head unit, I found out that the previous owner had left all the wirings for an amp in the car, including high-quality audio cables and thick power cables. And rewiring the whole thing would be a big mess so I decided to get an amp to make things easier. And this amp costs RM99 only, considering what it has in store for us inside.


Don’t believe what is written on it. 900W will blow any speaker into pieces.

Normally I won’t recommend anyone to go Brothers to buy stuff because many of their products are very low standard. But this amp is a bit different. It’s cheap but it contains something that most cheap amps don’t have.


A toroidal transformer! (the green donut thing with wires wound over it)

A little about why amps are more powerful with a toroidal transformer. Take your headunit for example. It doesn’t have a toroidal transformer. That means it only has 12 volts to work with. Most likely it will produce an output of +- 6v. But with a toroidal transformer, the voltage can be stepped up. Now the amp has maybe 24 volts to work with. So it will probably produce an output of +-12v. Using ohm’s law, current is proportional with voltage if the resistance is kept constant. The speakers windings resistance is constant. So with higher voltage, it gets higher current and thus higher output power. This is just a very rough view of how an amp works. For more info, do a google search ;)

We did an experiment by connecting a 12v car bulb to the amp’s output. The video here will justify the output power (around 75W RMS as estimated by Tan)


Soon I will get it installed properly in the car and to drive my 2 Blaupunkt speakers. Continue reading