Please recommend a scope (or other device) purely for audio testing.

[uktony]

Thanks for all the replies and just to add a few points:

• I already have a 30MHz Owon 'scope
• I also have a Velleman PCSU200 'scope + waveform generator

(lousy software)

• I am building preamps *not* power amps
• I have a FocusRite Scarlett 2i2 (V2) USB interface (192kHz)

I realise that the Tsunami device has it's limitations, however as a basic measuring tool I reckon it'll suit my purpose in this instance.

I was looking for further insight into my measurements, as I've been finding that some of my designs show a rising response just at the top end of my sound card measurement ability ~85kHz which I though was odd (it's not the sound card or the measuring software).

Finally - my Owon 'scope has an FFT function which isn't bad, however apart from basic screen grabs, accessing the data from a PC results in a .bin file which only the Owon software can read.

[tggzzz]

@tggzzz: great, now tell him how to read data from an analog scope into a computer! 

You appear to have missed the word "preliminary". That may, or may not, be sufficient for his purposes.

Personally I would think that if he is interested in audio signals, then looking at MHz signals is only beneficial as a sanity check to verify there's nothing stupid happening. An analogue scope might be sufficient for that.

If not, then the Digilent Analog Discovery is probably a reasonable choice, but that is 10* more expensive and the OP has limited finances. I have no idea whether the AD would be sufficient for audiophile level testing.

[Fungus]

Personally I would think that if he is interested in audio signals, then looking at MHz signals is only beneficial as a sanity check to verify there's nothing stupid happening. An analogue scope might be sufficient for that.

If you live in a place where they're easy to find for $25.

If not, then the Digilent Analog Discovery is probably a reasonable choice, but that is 10* more expensive and the OP has limited finances. I have no idea whether the AD would be sufficient for audiophile level testing.

Will your analog 'scope do frequency sweeps and bode plots? That's what audio work needs and the AD will do that nicely (much better than any 8-bit DSO).

[uktony]

This is a screenshot of a 5Hz to 1MHz on my Owon 'scope.

I enabled persistence to get a solid image.

Unfortunately there's no logarithmic option that I can find.

This sweep was generated by an AD9850 DDS generator that I control with an Arduino. I wrote a Windows program in vb.net to control it.

[tggzzz]

Personally I would think that if he is interested in audio signals, then looking at MHz signals is only beneficial as a sanity check to verify there's nothing stupid happening. An analogue scope might be sufficient for that.

If you live in a place where they're easy to find for $25.

I know West Yorkshire is "oop t'north", but it isn't that remote There are several available on gumtree and fleabay!

If not, then the Digilent Analog Discovery is probably a reasonable choice, but that is 10* more expensive and the OP has limited finances. I have no idea whether the AD would be sufficient for audiophile level testing.

Will your analog 'scope do frequency sweeps and bode plots? That's what audio work needs and the AD will do that nicely (much better than any 8-bit DSO).

While desirable, they might not be necessary. Given the OP can sweep a AD9850, he could generate a log frequency plot. Log amplitude would require a log amplifier.

Is 14-bit sufficient for the OP's puposes? Audiophiles might think not.

It is up to the OP to determine what else he could do with any money saved (oops: not spent).

[Fungus]

Is 14-bit sufficient for the OP's puposes? Audiophiles might think not.

The number of bits just sets the noise floor.

The noise floor demanded by audiophiles isn't the same as the noise floor needed for a piece of test gear.

[tggzzz]

Is 14-bit sufficient for the OP's puposes? Audiophiles might think not.

The number of bits just sets the noise floor.

Plus, implicitly/indirectly, some other performance points, e.g. intermodulation and SFDR. Noise floor isn't the only parameter; see my .sig.

The noise floor demanded by audiophiles isn't the same as the noise floor needed for a piece of test gear.

Which has the more stringent requirement depends on the tests being done and, in the case of audiophiles, the person

[Fungus]

The noise floor demanded by audiophiles isn't the same as the noise floor needed for a piece of test gear.

Which has the more stringent requirement depends on the tests being done and, in the case of audiophiles, the person

That's why I used 'demanded' and 'needed'. 

[Loboscope]

As everybody knows, audiophiles/audiophools are not interested in measurements and they will not make measurements. Because they have their "Golden Ears", and they are convinced, that these "Golden Ears" will even outperform the most recent Audio Precision gear so that ap will get jealous. Why bother about cost-intensive collected data of audio-gear when you have these "Golden Ears" and you will hear immediately the difference? 

Back to topic:
As I wrote before in other posts I always recommend the software "hpw-works" [http://www.hpw-works.com/] for measuring audio-gear. Together with a good/professional interface/sound-card you will be able to determine any relevant technical data of your audio-gear, reliable and with high precision - of course within the frequency-limits of your interface.

[Gary.M]

As everybody knows, audiophiles/audiophools are not interested in measurements and they will not make measurements. Because they have their "Golden Ears", and they are convinced, that these "Golden Ears" will even outperform the most recent Audio Precision gear so that ap will get jealous. Why bother about cost-intensive collected data of audio-gear when you have these "Golden Ears" and you will hear immediately the difference? 

Back to topic:
As I wrote before in other posts I always recommend the software "hpw-works" [http://www.hpw-works.com/] for measuring audio-gear. Together with a good/professional interface/sound-card you will be able to determine any relevant technical data of your audio-gear, reliable and with high precision - of course within the frequency-limits of your interface.

Stupid comments Lobo(Tomy)scope.

The op needs an Analogue Discovery as others have said. Look for one on ebay. You can use the network Analyzer to do what you want. Open loop bode plots?

Sent from my x600 using Tapatalk

[Gary.M]

The op needs an Analogue Discovery as others have said. Look for one on ebay. You can use the network Analyzer to do what you want. Open loop bode plots?

From HpW website:

...
Various signal analysis are performed like RMS, DR, THD, THD-N and more.
...

Also, RMAA is another great software for such purpose.

Soundcard based software won't do what the op said he wanted to do.

Sent from my x600 using Tapatalk

[uktony]

The op needs an Analogue Discovery as others have said. Look for one on ebay. You can use the network Analyzer to do what you want. Open loop bode plots?

From HpW website:

...
Various signal analysis are performed like RMS, DR, THD, THD-N and more.
...

Also, RMAA is another great software for such purpose.

Soundcard based software won't do what the op said he wanted to do.

Sent from my x600 using Tapatalk

Indeed - I already ahve RMAA PRO and Audiotester. I also use Realtime Analyzer from here -> http://www.ymec.com/products/app/ra2.htm

All of the above are good software, but are still limited by sound card bandwidth of course.

HpW (very, very quirky and difficult to navigate) was evaluated, however that too would still be constrained by the limits of the sound card bandwidth.

Finding a used Analogue Discovery has proven to be difficult, as I guess people don't part with them in a hurry (even the first version).

The QA401 from QuantAsylum was also looked at, but again it's way over my budget.

I started this thread with the idea that someone might suggest something I've never heard of, or perhaps even a method / device I had not even considered.

But evidently I think I had considered all options!