DIY Amplifier from danish magazine for ZX Spectrum re-created in KiCad as close as possible to original design. This constructions was published in Ny Elektronik issue 3 in 1984.
This is the constructions as published in the magazine in 1984.
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| Schema | PCB | Components layout |
The main goal was to get the schema redrawn in KiCad and a first try at a PCB, in order to build a version to check if everything works.
| Schema | KiCad | PCB |
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First version of PBC was done by manually layout of tracks, according to the original component layouts from the magazine
As the first version worked perfektly, the main goal was to add relevant plugs for EAR and DC power and resize the board to fit in a suitable enclosure. I even had to create a new footprint for the DC plug, but than again - great learning. Also a small trimmer-pot has been added, in order to be able to recude the noise that is generated in general - it can be skipped and replaced with a small wire, if you wish.
| KiCad | PCB |
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For the track layout, I decided to go with the autoroute plugin - as it makes a nice layout and makes a double sidded print as well.
The new PCB is adjusted to fit in a box of size 84mm X 56mm X 20mm. For example this enclosure box from Hammond
And this is how the final product turned out, fitting nicely in a standard enclosure.
| Enclosure | Assembled | In use |
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You will need the following componets:
- R1 - 10 Ohm 1/4W
- P1 - 4,7 kOhm Potentiometer, logarithmic mono
- C1 - 4,7 nF - ceramic
- C2 - 22 uF/16V - electrolytic
- C3 - 22 uF/16V - electrolytic
- C4 100 uF/16V - electrolytic
- C5 0,1 uF/35V tantalum
- IC1 - LM386N
- Trimmer Top Adjust P5/10 50K (Optional)
- Speaker 8 Ohm, pin headers, DC and Minijack plugs