Mini power amp class D

Mini power amp class D (TI TPA3118): a test for guitar amplification

I was curious to try a Class D amplifier chip to fabricate a small but powerfull solid state amplifier for electric guitar. In this video I am using the TPA 3118 from Texas Instrument wich is an amplifier power stage for driving speakers up to 60W with theoretically 100% efficiency. The board is smaller than half of a credit card.

In this video I am using a home made preamplifier which is just a transistor in emisor común configuration. The cabinet has a 10 inch/8 ohm speaker. The power stage is alimented by a laptop power supply 19V/3.42A.

The beginning of the video is the preamp+power amp without any additional effect. At 35s a reverb is added (Strymon Flint). At 1’40 a reverse delay is added (Boss DD7).

The sound is not bad at all, for room playing. There is a hum at low frequencies that on one hand could be due to the absence of metal enclosure, and on the other hand that doesn’t increase with the preamp volume. I have now to test it in a band configuration.