Test set-up - Part 1

I'd like an amplifier test set-up that is a bit more comprehensive than a calibrated MM. Crazy, I know.

For a hobbyist, it looks like there are two general areas of investigation, each requiring a specific type of set-up, though there might be some overlap. As a first priority, I'd like to be able to verify decent, safe functioning and perform troubleshooting if needed. In some distant utopia, the ability to measure distortion and the like would be great.

But for now, I'd like to stick to verifying basic functioning and troubleshooting. This seems to be the domain of an oscilloscope and waveform generator - Im I close or no cigar? Read on if I'm close, otherwise please point me in the right direction (or tell me I'm a danger to myself and others - put the soldering iron down!).

Pre-loved analogue scopes are a popular recommendation, though they are not readily available here in Australia - we pull stuff out of the ground; we don't make or repair stuff. With my ineptitude in mind, maybe a modern, easy-to-use, low maintenance digital scope might be better - something that when I'm getting weird results, I'm confident it is either user error or amp under test... and not the scope. The cheaper Rigol scopes are frequently recommended for beginners and hobbyists - anyone have an opinion on these for audio work? Other suggestions? I suspect I might need to use this thing to measure power supplies - so, a 10x probe is essential?

What about waveform generators? What waves (and noise?) are essential versus nice-to-have? GWInstek do some audio waveform generators: these produce sine and square waves at audio frequencies; could these be a simple and adequate place to start? Rigol have some 14 and 16 bit waveform generators that have more features, but I don't know what value there might be in those.... the 2 Channel 14 bit jobbies included in the scope, which does make them attactive but may just add complexity I don't need.

I've only started to look into this (obviously) and would really appreciate some advice and direction...

Cheers.
 

paulbottlehead

Active Member
Yes, but a cheap DSO. Owon, Rigol, etc. are all fine for the job. Old analog scopes were a good option when a new scope was $1000, but now they are $250, so not so much of a good deal. The 10x probe should come with just about any new scope you get. They do come in handy.

For a generator, what you need is substantially less than what the least expensive generators will provide. A 5mHz or 10mHz AWG will be about as basic as you can get, and it's still overkill.

For distortion measurements, you just need a solid USB sound card, the DSO scope that you're planning to buy, and some resistors.
 
Thanks Paul. Seems like I'm on the right track. Using these tools is a different matter: more learning ahead... one test at a time.

This audio function generator seems rather basic having a low distortion square and sine from 10Hz to 1MHz: GAG-810. Enough?
 
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