So this being the first amplifier I’ve designed and built, there are a few tools I’m going to need.
Firstly, a decent quality voltmeter – better than the cheapie I’m currently using, and most importantly something rated to handle the voltages I’ll be measuring – up to 500V DC and 400V AC.
Secondly – a signal generator. Very necessary for putting test signals into the amp to determine if it’s doing what it should. Normally these things can cost tens to several hundred dollars, depending on how full-featured and robustly built you want them. In my case since I am only interested in audio frequencies, an app on the Android tablet will serve the purpose
Keuwlsoft Function Generator – Free and without advertising.
Next: An oscilloscope. After looking at the options available I’ve decided on a dual-channel “soft” oscilloscope – one that uses a laptop for the control and display.
Instrustar Oscilloscope hardware – the rest of it’s in software.
Finally, I’ve also got a power transformer on the way. After evaluating all of the commercial off-the-shelf products and becoming increasingly dismayed by the cost, I decided to see if a local manufacturer could make me one based on my spec.
Luckily they could, and for about half the price of buying one from an overseas manufacturer. The power transformer is the single largest and heaviest item in the whole project, I expect it to weigh in at around 10-12 kg.
This was the spec I passed to the manufacturer:
Handily drawn on my Surface Pro. I love that computer!
Luckily this was enough of a spec for them and the transformer will be wound and sent to me, expected arrival 2 to 3 weeks.
Next steps: Finish designing the preamp stage. I’ve decided on the topology and just need to draw up the circuit, which involves cursing at the rather primitive diagramming software. I’ll post that up next.