Amplifier AK-699D

AK-699D low cost mini-ampifier

Encouraged by the reviews of the Lepai amplifier I found a similar one called the AK-699D. A review of the amplifier is found here on You Tube, curiously in Russian. https://www.youtube.com/watch?v=zWqwxKHe3kM

The front panel of the unit

Internals - Main chip with the heat sink

Top view of the system

Testing with speaker drivers

Tested the unit out with a 6" woofer driver I purchased in the 1990s from Radio Shack a 'Realistic' - 6 inch, 20-50W maximum, 8 ohms impedance speaker. The sound coming out of the 6 inch sounded somewhat distorted. The left and right speakers sounded different, pointing to speaker damage.

Next was a 4 inch Pioneer 8 Ohm unit rated at a maximum of 20 Watts. This one sounded much cleaner, so I knew that it was the former woofer that was the problem. These speakers were used in a mini-bookshelf systemt that outperformed computer speakers, but these were hastily built, and had to be dismantled eventually.

Sound

How is the sound of the AK-699D? I would describe it as clean, wide open, and a little antiseptic. Bass is not its strong point. but this could be due to the limited testing environment.

Further Testing

Testing for about an hour with full volumes and full bass for a short time resulted in very hot amplifier case as well as speaker coil. Unit was quickly switched off for cooling. Later testing at lower volumes showed no heating effects. Sound was notes as clear, but once again lacking in bass. In any case the drivers were mounted on an open baffle which would normally reduce bass response. However testing with smaller 2 watt PC speaker and portabel stereos hooked up to the speaker cables resulted in much fuller sound with more bass. The smaller amps would display distortion at high volumes.

The amplifier has since been given away as I was never satisfied with the sound it produced.