Hi sorry for the maybe infantile kind question
Being in love with lab testing at some point in the future I would like to start my own measurements
At present I have a question
Let's take a signal generator or a scope as examples
The main offer is of digital units
Still on YouTube I see many experts using old analog generators and scopes etc.
My guess is that they are somewhat obsolete ?
If I am right why people are still using them?
My guess however it's been proven wrong at least in one case
A totl Audio Precision analyzer has a analogue sine generator slightly less in THD plus noise than the digital one. It has both options
At present I see two options viable for amateurs
A standalone Signal generator plus USB audio ADC like the e1a ADC or a complete USB audio analyzer like the wonderful qa403
Any advice/suggestion will be very welcome and much appreciated
Thank you very much to All of you
Have a nice day
Gino
Being in love with lab testing at some point in the future I would like to start my own measurements
At present I have a question
Let's take a signal generator or a scope as examples
The main offer is of digital units
Still on YouTube I see many experts using old analog generators and scopes etc.
My guess is that they are somewhat obsolete ?
If I am right why people are still using them?
My guess however it's been proven wrong at least in one case
A totl Audio Precision analyzer has a analogue sine generator slightly less in THD plus noise than the digital one. It has both options
At present I see two options viable for amateurs
A standalone Signal generator plus USB audio ADC like the e1a ADC or a complete USB audio analyzer like the wonderful qa403
Any advice/suggestion will be very welcome and much appreciated
Thank you very much to All of you
Have a nice day
Gino
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Nothing is obsolete as long as it functions correctly. However, one might want a better generator for precision work. Digital ones are truly sinusoidal when compared to the analogue ones that likely use wave-shaping circuits.
However, when it comes to scopes, the quantisation noise of the 8-bit digital ones prohibit precise small signal measurements. But they generally have storage features etc.
Youtube experimenters are not necessarily experts. Digital equipment is often fancy, with keypads, LCD etc. and they make you look rich ...
However, when it comes to scopes, the quantisation noise of the 8-bit digital ones prohibit precise small signal measurements. But they generally have storage features etc.
Youtube experimenters are not necessarily experts. Digital equipment is often fancy, with keypads, LCD etc. and they make you look rich ...
An analog audio oscillator does not use waveshaping.
They use switchable range/frequency.
Only very coarse function generators, often chip based, use wave shaping and are not suited for audio.
As far as old equipment is concerned, it is perfectly useable but if it breaks, hard to repair.
And they are big, heavy and make a lot of (fan) noise.
Agree with @newvirus2008 that 8 bit scopes are limited in resolution and that YouTubers are sometimes great, sometimes have no clue about what they are saying.
Take your chances.
Jan
They use switchable range/frequency.
Only very coarse function generators, often chip based, use wave shaping and are not suited for audio.
As far as old equipment is concerned, it is perfectly useable but if it breaks, hard to repair.
And they are big, heavy and make a lot of (fan) noise.
Agree with @newvirus2008 that 8 bit scopes are limited in resolution and that YouTubers are sometimes great, sometimes have no clue about what they are saying.
Take your chances.
Jan
they are not.
beacuse they still perfectly serve their purpose.
digital measurement equipment has one main advantage: it's cheaper (and offers some other advantages and some disadvantages).
the ideal (digital) measurement instrument for audio is your computer with an audio interface!
It is difficult to read rapidly changing quantities on a digital instrument. And you have to consider the limitation of sampling and bit depth (resolution).
They all have their uses. An adequate digital scope can be had for pretty cheap with features anlog scope could not have. But a working analog scope may be more than good enough for the task. Same for meters. User skill has a lot to do with getting effective use from instruments. I have lots of both types.
And most modern digital units don't require training in lifting heavy loads, nor a shelf two foot deep to place it on...
Hi sorry for the belated reply but i forgot to click on the watch button My mistake
I would like to thank you all for the very kind and valuable advice
if I understand correctly, for a neophyte like me the digital route is better because analogue instruments can be more performing but also decidedly more demanding from different points of view
I am advised to use a sound card as a first step and that is what I will do by trying to analyze a small headphone amp with Arta, who I already know.
I am very curious to see what will come out
Thank you all for your precious and kind support
I would like to thank you all for the very kind and valuable advice
if I understand correctly, for a neophyte like me the digital route is better because analogue instruments can be more performing but also decidedly more demanding from different points of view
I am advised to use a sound card as a first step and that is what I will do by trying to analyze a small headphone amp with Arta, who I already know.
I am very curious to see what will come out
Thank you all for your precious and kind support
Ok i can say that my sound card is not up to the task This is its noise floor with input level at max 😒
it is a Behringer U-Phoria UMC 202HD
very little reason to be euphoric
it is a Behringer U-Phoria UMC 202HD
very little reason to be euphoric
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You did not share enough to understan your measurement. Was the input shorted or open? Also what are you trying to measure? The Eurphoria may not be adequate to measure SOTA harmonic distorion by itself but with a suitable interface it may have neough dynamic range to do what you want. The Cosmos APU and COSMOS Scalar will give the "Euphoria" state of the art measurement capabilities since the "Euphoria" will just be an indicator. Not as simple or easy to use as a QA403 or an APx555 but adequate to the measurement task if distortion is the needed measurement. However a good DVM and simple digital scope would be my first purchases.
I would say that digital devices are good for start up - you go analogue when you actually meet their limits.
And the problem with analogue ones is that they may need service before restored to their initial performance level.
It is not, 202 will give you just results up to 20kHz and that is it. To go beyond you need a better card.
you have some mains signal (50 Hz + harmonics) in there.
make sure you have enough distance from any transformer and PSU circuit and check your ground connections (particularly for ground loops).
also, what is your 0 dB referenced to?
Both are perfectly usable, and I could very well survive using only one of the varieties, but the clever thing to do is to use the best suited type for a given application.
Before my retirement several years ago, I used exclusively digital instruments because of the need to produce massive amounts of data, graphics, Excel files, etc.
In my own lab, I use both types equally: my main scope is a Fluke ana-digi, combining the best of both worlds, I have several multimeters ranging from pure analog (like the gold standard of the sixties, a senior Volt-ohmist VTVM made by RCA) to a pure digital Datron 7 digit dreadnought. I also have the ana-digi version of the multimeters, made by Metrix in the eighties. This one is not a success, unlike the Fluke scope: the analogue display merely serves as a subsidiary display for the digital meter and doesn't bring many advantages.
When you need great absolute accuracy (but does it actually occur in DIY?) digital is more straightforward (extreme accuracy is also possible with analogue, but it requires more intensive work).
For some very specialized measurements, only purely digital or analogue instruments can work, but the analogue niche is shrinking by the day.
For DIY, simply use what is easily available or cheap, and what you are comfortable with. There is no hard rule
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I don't think the approach and question here is the right way of getting proper equipment.
First ask yourself what you want to measure, how often you think you're gonna need that and what resolution/specs are needed for that.
Next ask yourself more practical things, like budget and space on your desk.
Obviously older equipment needs more maintenance, so you need the experience and skills to repair those things as well.
Except for samplerate/bandwith and measuring DC signals, it's pretty hard to beat a very good performing audio interfaces these days. Even in sense of THD+N and SNR.
It's to unfortunate that most of them are limited around 25-40kHz even at the much higher samplerates.
First ask yourself what you want to measure, how often you think you're gonna need that and what resolution/specs are needed for that.
Next ask yourself more practical things, like budget and space on your desk.
Obviously older equipment needs more maintenance, so you need the experience and skills to repair those things as well.
Except for samplerate/bandwith and measuring DC signals, it's pretty hard to beat a very good performing audio interfaces these days. Even in sense of THD+N and SNR.
It's to unfortunate that most of them are limited around 25-40kHz even at the much higher samplerates.
Being in love with lab testing means being in love with automation, if efficiency is an attraction for you. Digital test equipment with computer interfaces lends itself to automated test. Automation requires programming in some environment to control and read data from the instruments.
Automated data collection that comes in a can - like REW - are great for what they do, for what the designer anticipated you'd want to do test wise with an audio soundcard. For what the designer couldnt possibly guess what you want to do for some reason - like, say, plot the 3rd harmonic distortion level against AC line voltage - it's not so easy to ask REW from another routine "give me the data comprising the FFT plot shown on the screen NOW".
I remember thinking in terms of what a running program exposes in terms of data, that I could access from a routine of my own design, either through the same computer or to another computer on the network... I should be able to kick off a frequency sweep through a USB sound card interface connected to the computer out in the garage, from the laptop I'm typing on here in my bed - and see the FR plot of an amp, speaker on screen as the sweep progresses.
As ridiculous as those examples sound, they illustrate that there should be no barrier at all to getting data from a digital instrument, including one comprised of another computer / hardware combo. Which should be easily leveraged to ones advantage doing lab test..
Hi sorry for the belated reply but i had a water leak in my flat
This is how i have connected the sound card ... i guess is called loop ? inputs to outputs directly with unbalanced cable using mono jack to rca adapters
and this is the noise spectrum i get with the switch on Inst and gain to max
if i switch to Line and gain to max
Hi thank you for the very valuable advice I can listen only to max 14k ... for me there is no need to go beyond that at my age