496
Item nr.
Digital novelty amplifier.
| Production | The Netherlands, 2019.
Price was 2.60 €. |
|---|---|
| Semi- conductors | PAM8403 Amplifier IC. |
| Cabinet | Toy truck (length 19cm). Size 19x4.5x3cm. Weight 112gr. |
| Power | DC 3-6V. |
Like the Simson, it is based on a small module containg the PAM8403 class D amplifier IC, which can deliver about 2x3W when supplied from 5 to 6V. Toppoint is a company where you can order various small goods, imprinted with your company logo, to give out as presents to relations. Their mini truck is normally €2.69, but then comes without a built-in amplifier. I got the truck in a thrift shop for 1 euro. Building this amplifier cost me about €2.60. The truck was 1 euro and the PAM board was 61cts. Two 3.5mm jacks are 30ct, 2 LS connectors are 42ct, 4 M3 bolts with nut around 10ct, the knob 8ct, and the DC connector was 9 cts (all ordered from AliExpress).
What is this hum suppression circuit? Static hum, picked up by unshielded cables from electric field, is quite high impedance. The input impedance of this amplifier is 50kiloOhm, while I drive it from a laptop or MP3 player with 32 Ohms (or even less) output. The "special" circuitry is nothing more than a resistor (150 to 1000 Ohms) over the amplifier input. This hardly affects the normal signals, but virtually shortcuts any hum. In the inside of the Simson, you can see the resistors soldered to the input jack. The truck amp has the hum suppressor resistors (820 Ohms) on the amplifier board behind the volume pot (not visible on the inside picture below).
| Obtained | 8/2019 from Home built. |
|---|---|
| Condition | 9; there is some discoloring of the truck, unfortunately. |
| Value (est.) | 3,3€. |
Building the amplifier starts with a small toy I got from the local trash store. 
As you can see, the amplifier board fits in quite well, but still it is a tough job to get all the stuff inside and place the wiring! On the top edge you'll see the headphone jack and the small amplifier board. The bottom edge (backside of the truck actually) has, from left to right, the AUX input, DC jack, left speaker, and right speaker.
