This is my 1st amplifier project, a PAM8403D.
The chip was 99p, the speakers £2.46 (3W rated), the transformer (2A rated) about £2.98, the USB module 99p and the relay £1.98 because it didn't come from China 😛
I tried it with an RCA socket that I had lying around and a 700ma Blackberry transformer and it distorted over 50% volume from the PC, with a 2A module it runs to OK to 100%. There is some hum & noise with no audio playing, but not excessive (IME).
The USB module is used to get audio from the PC and take 5v to activate the mains relay.
A PC IEC mains cable is chopped in half & joined using chocolate block, so that it is basically 1 power cable to the PC & the speakers. The power cable stays plugged into the mains but the transformer isn't powered until the PC comes on & gives 5v to the relay. There is a separate 3A fuse between the chocolate block and the transformer.
The case is just made of off-cuts from laying a new kitchen floor & a piece of baton. I've got a sample of speaker cloth (99p) & am making covers for the speakers.
It's a held together with Gorilla Glue with a couple of blobs of hot glue for cable routing.
The chip was 99p, the speakers £2.46 (3W rated), the transformer (2A rated) about £2.98, the USB module 99p and the relay £1.98 because it didn't come from China 😛
I tried it with an RCA socket that I had lying around and a 700ma Blackberry transformer and it distorted over 50% volume from the PC, with a 2A module it runs to OK to 100%. There is some hum & noise with no audio playing, but not excessive (IME).
The USB module is used to get audio from the PC and take 5v to activate the mains relay.
A PC IEC mains cable is chopped in half & joined using chocolate block, so that it is basically 1 power cable to the PC & the speakers. The power cable stays plugged into the mains but the transformer isn't powered until the PC comes on & gives 5v to the relay. There is a separate 3A fuse between the chocolate block and the transformer.
The case is just made of off-cuts from laying a new kitchen floor & a piece of baton. I've got a sample of speaker cloth (99p) & am making covers for the speakers.
It's a held together with Gorilla Glue with a couple of blobs of hot glue for cable routing.
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Yes, it's a bit unpolished. The box is a specific shape to fit above a touch-screen PC in the kitchen.
Any tips welcome!
I'm waiting for some matrix stripboard from China, although the PAM chips I have seem to have funny spacing, needs more investigation.
Also on order is an XS3868 bluetooth module and some more 3W speakers. And there is a Raspberry Pi Zero on the shelf that could do with some amplification.
Any tips welcome!
I'm waiting for some matrix stripboard from China, although the PAM chips I have seem to have funny spacing, needs more investigation.
Also on order is an XS3868 bluetooth module and some more 3W speakers. And there is a Raspberry Pi Zero on the shelf that could do with some amplification.
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