Little Gem Amplifier

Instructables, with yet another DIYproject, have built an inexpensive amplifier, which is based on the 1/2W Little Gem amp from RunOffGrove. The specialty of this device lies in its size, where this extraordinary sounding small amp has separate volume and gain controls and is literally easy to build.

The materials required for this project are enclosure, speaker, speaker grill, LM386N amplifier chip, LED, 9 volt battery or power supply, 25 Ω 25W potentiometer, 5K Ω 25W audio taper potentiometer, 0.047 µF and 0.01 µF capacitor, 220 µF and 100 µF electrolytic capacitor, 10 Ω resistor, SPST switch, 1/4″ mono phono jack, 8 pin DIP IC socket, PC board and some wires and Knobs.

The tutorial starts with the building of the enclosure. Instead of a cardboard amplifier that cannot last for more than a year, you can opt for something stable like a wooden index card box. Here, in this project, the later material is used ad refurnished with Dremel circle cutter to cut out the speaker opening along with the hinge and clasp.

To Wire the Circuit, few changes were made in the schematics. The battery was swapped for a 12v wall wart and also a power switch and led power indicator was added to the amp. The LM386 power amplifier chip was fixed in an IC socket to easily swap it out during construction.

Finally, a speaker grille was constructed by cutting a hole in a piece of 1/8″ MDF and then layering it with the reclaimed grill cloth.

After, the speaker was screwed using some screw cups for the finished look, the transformer was housed inside the amp for easier portability. For finishing, a piece of scrap aluminum sheet was bolted inside the box under the oval cutout to mount the controls along with a reclaimed handle that was fastened to the top. The originality of wood was retained by avoiding sanding or finishing on the outside of the box.

The overall price of the device was limited to $15, if you are able to find the speaker for free. The resulted amp will create a nice mellow sound, loud enough for a room. Now, just plug in your favorite guitar and enjoy. For more details, visit the following link – :