A small amp kit using the TEA2025B chip. Looks pretty much like the design in the datasheet.
The screw terminals wasn't included in the kit but it felt like a good idea adding them. Lesson learned from my CMoy that is basically soldered into its Altoid box never to be moved. Nice with some extra flexibility.
Put together as a small and cheap and battery operable stereo system. I got a pair of Fostex full range speakers to use for this purpose. These are good quality drivers so should be able to keep them if I build better amps in the future.
Total: 12000 JPY (mainly for the speakers)
Worked well. Unless you're throwing a party or is in a big room it's powerful enough with these speakers. Audio quality it seem to sound best at about 1/3 of max volume with a 9V battery. Data below on the TEA2025B chip supports that.
With the screw terminals on the board the final assembly was a breeze.
The 12V wall wart I got didnt work well. I'm not sure about it's specs. I verified it's isolated but might be unregulated and maybe a switcher. Anyway it makes the amp hum. Will try and make some measurements on it later.
Result was a lot better with a single 9V battery.
From data sheet:
The TEA2025B/D is a monolithic integrated circuit intended for use as dual or bridge power audio amplifier portable radio cassette players.
So not exactly a Hi-Fi amp perhaps.
The power output is a function of speaker impedans and input voltage. In 8 ohm 9V give a maximum of 1.4W and 12V give 2.4W.
In 8 ohm the THD (Total Harmonic Distortion) take a big jump above 0.4W in output power.
A stepped stereo attenuator in a separate enclosure. So you don't have to put a high quality volume control pot in every single amplifier build.
Decided I needed a small amplifier on my desk/workbench for listening to music while working, testing DACs and speaker builds. The amplifier chip used is the Tripath TA2024.
The enclosure is a bit on the big side but it's nice not to be cramped and I expect to reuse the enclosure for other modules when this one gets dated.
Here shown with a Airport Express as a source and the stepped attenuator.
For the livingroom. Using two K50 PCB kits.
The amps need a dual power supply (+/- 25V).
2x 60VA 35V center tapped secondary.
IEC connector with switch and fuse holder. Grounded chassi.
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