Author Topic: How do I know when to buy an oscilloscope?  (Read 12844 times)

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Offline nctnico

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Re: How do I know when to buy an oscilloscope?
« Reply #25 on: March 07, 2015, 10:15:03 pm »
So an affordable  hobbyist range DSO is a better tool than an analog scope for designing / troubleshooting audio amps?
That is just audiophoolery talking. When I got my first (analog) scope the first thing that annoyed me was that looking at signals below 10Hz was extremely annoying. How the hell do you want to work on audio if you can't see signals below 10Hz??  :palm:

Besides that an oscilloscope isn't a very good tool to judge the quality and determine signal levels with absolute accuracy in general. For that you'll need a distortion/spectrum analyser and an AC voltmeter. Luckily most modern DSOs have some spectrum analysis (FFT) features.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline markce

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Re: How do I know when to buy an oscilloscope?
« Reply #26 on: March 07, 2015, 10:21:41 pm »
You do not need an oscilloscope. Would be handy is not enough.
Buy a specific one if you're really convinced you need one, and have minimum requirements.
For now, just as an experiment, buy an analog scope cheap second hand.
 

Offline Wmacky

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Re: How do I know when to buy an oscilloscope?
« Reply #27 on: March 07, 2015, 10:29:08 pm »
So an affordable  hobbyist range DSO is a better tool than an analog scope for designing / troubleshooting audio amps?
That is just audiophoolery talking. When I got my first (analog) scope the first thing that annoyed me was that looking at signals below 10Hz was extremely annoying. How the hell do you want to work on audio if you can't see signals below 10Hz??  :palm:

Besides that an oscilloscope isn't a very good tool to judge the quality and determine signal levels with absolute accuracy in general. For that you'll need a distortion/spectrum analyser and an AC voltmeter. Luckily most modern DSOs have some spectrum analysis (FFT) features.

Interesting. I do know that a SA would be very useful for audio, but was told the FFT function on my Rigol 1102 was useless for audio due to bit depth I believe? It was said that even a cheap Ebay audio card SA would be a better SA. Has this changed with the current generation? Say a 2072A, or even  a 1054Z?   That alone would push me to upgrade.
« Last Edit: March 07, 2015, 10:32:12 pm by Wmacky »
 

Offline miguelvp

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Re: How do I know when to buy an oscilloscope?
« Reply #28 on: March 07, 2015, 10:32:38 pm »
He already has a function generator, the scope will help you make better use of it. Also buying a cheap used analog scope can be more costly, at the price of the DS1054z I wouldn't gamble on an old scope.
 

Offline Neganur

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Re: How do I know when to buy an oscilloscope?
« Reply #29 on: March 07, 2015, 10:46:55 pm »
So an affordable  hobbyist range DSO is a better tool than an analog scope for designing / troubleshooting audio amps?  This is very contrary to what I have read, unless things of changed in the last 5 years?  If you talking about very expensive DSO's that would be irrelevant for me as some of us are just hobbyist and don't work in a lab at JPL.
You're not arguing for anything, you're just protesting (what exactly were the reasons stated in your source ?).
Bring an example why it is worse or better in your opinion for the task you mentioned :)

And since you're saying 'affordable' maybe mention an actual price range too because, as others noted, audio bandwidth does not require an X00 MHz BW analogue scope either.
 

Offline Neganur

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Re: How do I know when to buy an oscilloscope?
« Reply #30 on: March 07, 2015, 10:57:28 pm »
Interesting. I do know that a SA would be very useful for audio, but was told the FFT function on my Rigol 1102 was useless for audio due to bit depth I believe? It was said that even a cheap Ebay audio card SA would be a better SA. Has this changed with the current generation? Say a 2072A, or even  a 1054Z?   That alone would push me to upgrade.

You can't compare a 24-bit audio card with maybe 192 kHz sampling (you said cheap  ebay) with an 8-bit oscilloscope and then say that the FFT resolution sucks on the scope.

You probably also would use an FFT analyser (dynamic signal analyser). But I ponder the need for such a device for troubleshooting. Characterising the performance yeah, but to find a faulty cap or bias point you're better off with a voltmeter.
 

Offline nctnico

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Re: How do I know when to buy an oscilloscope?
« Reply #31 on: March 07, 2015, 11:28:16 pm »
FFT helps to check the bandwidth of a circuit or get a feeling about the distortion of an amplifier.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline atferrari

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Re: How do I know when to buy an oscilloscope?
« Reply #32 on: March 08, 2015, 12:53:55 am »
Hey, the time is now!

 Buy and move on. Experience that you could collect with it is the most important.
Agustín Tomás
In theory, there is no difference between theory and practice. In practice, however, there is.
 

Offline Wmacky

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Re: How do I know when to buy an oscilloscope?
« Reply #33 on: March 08, 2015, 01:07:17 am »
So an affordable  hobbyist range DSO is a better tool than an analog scope for designing / troubleshooting audio amps?  This is very contrary to what I have read, unless things of changed in the last 5 years?  If you talking about very expensive DSO's that would be irrelevant for me as some of us are just hobbyist and don't work in a lab at JPL.
You're not arguing for anything, you're just protesting (what exactly were the reasons stated in your source ?).
Bring an example why it is worse or better in your opinion for the task you mentioned :)

And since you're saying 'affordable' maybe mention an actual price range too because, as others noted, audio bandwidth does not require an X00 MHz BW analogue scope either.

?
Perhaps it's a language barrier issue, but I don't fully understand your post. Protesting? What am I'm protesting? I had asked a question with no protest? As I stated, this advice was read, so I wouldn't have any personal examples. As to a price range, see my follow up post regarding models.
 

Offline siggi

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Re: How do I know when to buy an oscilloscope?
« Reply #34 on: March 08, 2015, 01:08:07 am »
Buy an oscilloscope as soon as you can. Buy the cheapest, meanest oscilloscope you can find that works. It's the difference between seeing or not - everything else is gravy :).
Upgrade when you need to, and when you know more....


Sent from my iPad using Tapatalk
 

Offline atferrari

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Re: How do I know when to buy an oscilloscope?
« Reply #35 on: March 08, 2015, 01:26:10 am »
Many people out there believes 192k can grant them privilege to hear ultrasonic.
Oh, can't they?  :-[  :D  :-DD
Agustín Tomás
In theory, there is no difference between theory and practice. In practice, however, there is.
 

Offline Neganur

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Re: How do I know when to buy an oscilloscope?
« Reply #36 on: March 08, 2015, 01:55:29 am »
?
Perhaps it's a language barrier issue, but I don't fully understand your post. Protesting? What am I'm protesting? I had asked a question with no protest? As I stated, this advice was read, so I wouldn't have any personal examples. As to a price range, see my follow up post regarding models.

Yes, it's most likely language - I meant 'contradiction'* as in 'absence of agreement', 'disputing a fact', you were only opposing your own statement "DSO is a better tool for audio" without providing facts to back up the claim. I was hoping you could quote the source with its actual reasoning. Else there is no way to confirm the claim.

*: perhaps this . The man wants to argue but his dialogue partner only changes the polarity of the sentences and hence, does not argue. You were protesting against your own statement about the DSO as tool for audio.

But I guess you really meant to ask "are DSOs really better at this?", since as you say you have no personal examples.

Yeah I think that a DSO has the edge there, the analogue ones can't do FFT at all (if we're talking the  Rigol 2000 or 1000 series price range), both may have 500 uV/div etc.
And even for those, the ebay example you mentioned (the board I linked was just the first that came up, there are even Creative labs cards for that price) will outperform the scopes due to the dynamic range of its ADC.
« Last Edit: March 08, 2015, 01:58:14 am by Neganur »
 

Offline nctnico

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Re: How do I know when to buy an oscilloscope?
« Reply #37 on: March 08, 2015, 02:17:03 am »
IMHO the digilent Analog Discovery (www.digilentinc.com/Products/Detail.cfm?NavPath=2,842,1018&Prod=ANALOG-DISCOVERY ) could be an interesting tool for audio and LF use. It uses a resolution of 14bit for signal acquisition and generation. You can even use it as a vector network analyser to create a amplitude and phase response (of an audio circuit). I would trust it more than a cheap sound card.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline EEVblog

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Re: How do I know when to buy an oscilloscope?
« Reply #38 on: March 08, 2015, 03:37:33 am »
I'm a 17 year old Mexican student and electronics hobbyist, and I'm convinced that I will be an electronics engineer.

You've just answered your own question!
It's right at this exact point you need to buy an oscilloscope.
 

Offline dany-boy

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Re: How do I know when to buy an oscilloscope?
« Reply #39 on: March 10, 2015, 02:11:25 am »
Wow! I never though such a simple question would get so much attention and spark such an interesting discussion between DSO’s and CRO’s. Even Dave has replied to my question  :scared:! Thank you very much for all of your advice and I’ll soon buy a Rigol DS1045Z as per all the positive reviews.
Again, thank you very much to all of you for your amazing advice  :-+
Sincerely Daniel
 


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