Siglent SDS2000X Plus

[2N3055]

To measure distortion, you can use a notch filter to "cut" the first harmonic.

For distortion measurements, I use a Picotech 4262 DSO, as this provides 96 dB dynamic range already without any tricks.

This scope is confused by a bandwidth of only 5 MHz.
A 5000 series picoscope with switchable vertical resolution ADC is not suitable for this purpose?

It has bandwidth of 5MHz, more than enough for audio, vibration measurements etc..
It also has a noise floor of 8 uV rms... !!!
SFDR: 96 dB typical @ 10 kHz, –1 dBfs input. Around 0,002% distortion.
It also includes low distortion DC to 20 kHz AWG. (102 dB typical @ 10 kHz, -1 dBfs output).

It is actually pretty unique instrument..

5000 Series is excellent general purpose scope that has better resolution than even average 12 bit scope. But higher resolutions come at cost:
16 bit mode comes with lower sample rate of 62.5 MS/s and on single channel only.  So in 16 bit you have 30MHz single channel scope.
SFDR in14 to 16-bit modes: 70 dB at 100 kHz full scale input. (around 0,03% distortion)
That one too is pretty unique instrument, that can serve as general purpose scope and have higher resolution when needed with some compromises.

5000 is good enough to service and check on audio equipment for musicians (PA, instrument amplifiers). You just cannot measure very low distortion. Probably good enough for normal musical equipment. It is just that 4262 is order of magnitude better.

[2N3055]

Should be more than enough when measuring distortions in music-range up to 20khz.

It turns out that one device is needed to measure distortion, and to see, for example, the self-excitation of an electronic circuit at tens of megahertz, another device is needed ...

Distortion of what?
If you're working in radio frequencies, than RF equipment is what you need. I would say a good spectrum analyser would be an instrument for that task.

[Garga]

Hi Performa01!
Thanks a lot for the help, I look into the Picotech 4262. 
Regards Garga

[blurpy]

For measuring distortion on audio devices, a QuantAsylum QA401/QA402 is what I use. It's cheaper than a picoscope, but only does audio measurement. That means you need a scope for other types of measurements though.

[Martin72]

Next month, I will have a neutrik a1 for this...

[Bad_Driver]

I got for the audio stuff after long search an old Terratec  DMX6 Fire USB, 192 kHz, 24 bit audio interface.
Works well with Win10, low noise and useable up to 90 kHz, there is enough Audio software out in the web that get the job done.

[Garga]

Hi blurpy!

I've looked at the QuantAsylum QA401 before, but other forums have had problems with software compatibility (Windows). Meanwhile, the Q401 has been discontinued and replaced with the Q402 as a new product, but production is stalling. I am looking for a reliable solution at an affordable price.
What is your experience with the Q402?

Regards Garga

[Calvin]

Hi,

for audio applications the QuantAsylum or a good soundcard with (free) Software like HolmImpulse etc. will go a long way ... all featuring 24Bit ADCs and DACs.
Analyzers like the Quant typically have the edge regarding the analog frontend (relay switched attenuators, balanced inputs, etc.), which also allows for easier handling and settings.
Beyond ~100kHz up to ~10MHz the Digilent´s 14Bit AnalogDiscovery2 might just be the device of choice ... especially as it can be configured as scope, Audio Analyzer, VNA, SA, AWG, etc.
I have both, the Quant and the Digilent and use the Quant reguarly ... and never had issues regarding Windows with any of both.

regards
Calvin

[blurpy]

Hi blurpy!

I've looked at the QuantAsylum QA401 before, but other forums have had problems with software compatibility (Windows). Meanwhile, the Q401 has been discontinued and replaced with the Q402 as a new product, but production is stalling. I am looking for a reliable solution at an affordable price.
What is your experience with the Q402?

Regards Garga

Maybe you are thinking of QA400? They used some parts in that one that modern Windows does not have drivers for. This is as far as I know not an issue with QA401 or QA402. I don't have any experience with Windows myself and use both of them from Linux only.

The QA401 didn't have a user interface for Linux so I made a web interface for it: https://github.com/blurpy/qa401w
And the software for QA402 has official Linux support with a UI, but since it's very new it crashes a lot, so I maintain a web interface for that as well: https://github.com/blurpy/qa40xw

I've done a comparison of how they perform, which you can see here: https://forum.quantasylum.com/t/effect-of-attenuation-level-on-results/494/12

Having spent a lot of time with these devices, I think they are really nice for the price, and I use them a lot. The QA402 needs refinement in the software, but that looks to be improving. The plug and play part is what I like the most, as I've messed around with sound card measurements before and it's a lot of hassle dealing with attenuation and keeping the signal from being messed up by the OS or other software.

You are right that QuantAsylum is struggling with parts delivery, like many others.
Maybe send them a message and ask about it?

[Garga]

Thank you all very much for your help!

I'll check the manufacturer's website for information.

Regards Garga

[2N3055]

Hi blurpy!

I've looked at the QuantAsylum QA401 before, but other forums have had problems with software compatibility (Windows). Meanwhile, the Q401 has been discontinued and replaced with the Q402 as a new product, but production is stalling. I am looking for a reliable solution at an affordable price.
What is your experience with the Q402?

Regards Garga

Maybe you are thinking of QA400? They used some parts in that one that modern Windows does not have drivers for. This is as far as I know not an issue with QA401 or QA402. I don't have any experience with Windows myself and use both of them from Linux only.

The QA401 didn't have a user interface for Linux so I made a web interface for it: https://github.com/blurpy/qa401w
And the software for QA402 has official Linux support with a UI, but since it's very new it crashes a lot, so I maintain a web interface for that as well: https://github.com/blurpy/qa40xw

I've done a comparison of how they perform, which you can see here: https://forum.quantasylum.com/t/effect-of-attenuation-level-on-results/494/12

Having spent a lot of time with these devices, I think they are really nice for the price, and I use them a lot. The QA402 needs refinement in the software, but that looks to be improving. The plug and play part is what I like the most, as I've messed around with sound card measurements before and it's a lot of hassle dealing with attenuation and keeping the signal from being messed up by the OS or other software.

You are right that QuantAsylum is struggling with parts delivery, like many others.
Maybe send them a message and ask about it?

I think Q402 is excellent device. I was thinking of maybe buying one but they do have problems now.
From the site:

"Update 17-Aug-2021: The QA402 is on backorder. Given the scarce part availability, we don't yet know when it will be back in stock. As soon as we do, we'll start taking orders again."
That is last update.

That basically made me stop and think. Not only I cannot order one now, but also that is brand new device that also needed software rewrite. So software now is not nowhere near something "full production". And than all this problems with parts, I'm franky going to wait and see if they are still here in 6 months and if the development went on. Otherwise there is risk to get stuck with nice piece of hardware that has half done software and vendor went bust...

[oz2cpu]

well lets say the audio equipment is really bad ?
the SDS2000 in 10 bit mode, could tell THD down to 0.1% actually,
it could still be cool with a THD calculation live on the scope, specially when you play with DIY audio.
it must be possible to do this in software ?

[piramida]

5000 is good enough to service and check on audio equipment for musicians (PA, instrument amplifiers). You just cannot measure very low distortion. Probably good enough for normal musical equipment. It is just that 4262 is order of magnitude better.

The Pico 4262 seems to be a really unique device ... I'll have to take a closer look ...

But it is not clear why 16bit and 30 MHz for Pico5000 is worse than 16bit and 5MHz for Pico4262?

Pico4262: SFDR 96 dB typical @ 10 kHz, –1 dBfs input
Pico5000: SFDR 14 to 16-bit modes: 70 dB at 100 kHz full scale input.

Maybe the question is in bandwidth and for the same bandwidth, will the SFDR data be the same too?
Maybe these are some wrong bits for the Pico5000?
P.S. Sorry for the offtopic.

[Bad_Driver]

Last OT post regarding LF scopes. Yes the pico 4262 looks nice but the price is ….mmh…. impressive. And for audio it is OTT.

As oz2cpu wrote the SDS is useable for regular audio stuff in HiFi range. And to be realistic, my last hearing test
proves that my upper limits are around 12 kHz.  But you can not have this discussion with an „Audiophile“.

As mentioned I use the SDS as well but FFT in the LF range is slow and not convenient. But with a good sound interface
and a software as AudioTester you get everything you want.

[Peter_O]

With my master of physics I'd say: You are right. I'm an old guy and I will most probably miss sinus frequencies above 10kHz.
I use 5way-Speakers with super tweeters above 9.2kHz. When I feed these super tweeters only , I do hear only some low level sizzling scratchy noise. Easy to decide that this does not contribute anything worth reproducing.

But on the other hand: Coming from 5-way reproduction, switching off the super tweeters does destroy the music completely. Anybody will hear that and nobody would accept to listen without the super tweeters.

Seems that music perception is more complex than the added abilities to recognize certain sinus frequencies with conscious hearing.

To get back on topic:
I really like modern DSOs like the 2k+ to have fourier capabilities sufficient for audio stuff, whatever rabbit hole audiophiles are running down.  :-)

[Bad_Driver]

With my Ph.D. in engineering I agree. You can not hear it, but you recognize the missing of something.
Unfortunately it becomes worser with my hearing. First time I was full aware of this was during listening
of „Shine on you crazy diamond“ Part 1 and I could only hardly hear the soft clinking in the beginning 

[Peter_O]

Next "Hifi" we buy might be some kind of those little ones you plug into the ears.   

[Martin72]

Guys, please...stop it.

[Bad_Driver]

Guys, please...stop it.

Sorry for the dertour 

[Frex]

Hello,

I own the SDS2104X-Plus and it's a very good peace of gear, very good value for money.
Anyway, for THD measurements of audio stuff it's definitively the wrong choice.
Even you internal PC audio soudcard will do much better.
The 8 bits resolution of the scope  is the main limiting factor.

To check  have made a measurement of a 10kHz high purity sine wave
(THD <-130dBc) with 1Vrms amplitude (0dBV).
You can show the FFT result below.
I made the test at 1kHz too with similar results.
Noise floor level is very good (high res 10 bits mode + FFT average 2MPTS),
but harmonics level are very high.
So If you want to use it for such purpose, you cant be very  demanding 


Frex

[maxspb69]

Having made a logic probe for the SDS2000 (Big thanks to oz2cpu), I was surprised to not find such an important item  as setting the trigger hysteresis in the digital channels menu. Without the possibility of triggering hysteresis, the edges of the pulses have random jitter and phantom spurs even at low frequency signals. As a result, time measurements become meaningless when using a logic analyzer. And how did the Siglent's engineers  miss such an important point?

[tautech]

Having made a logic probe for the SDS2000 (Big thanks to oz2cpu), I was surprised to not find such an important item  as setting the trigger hysteresis in the digital channels menu. Without the possibility of triggering hysteresis, the edges of the pulses have random jitter and phantom spurs even at low frequency signals. As a result, time measurements become meaningless when using a logic analyzer. And how did the Siglent's engineers  miss such an important point?

Your answer is on this page. Study all later posts carefully:
https://www.eevblog.com/forum/testgear/diy-logic-analyzer-probe-and-pods-for-siglent-scopes/msg3509216/#msg3509216

[maxspb69]

Thanks tautech, I didn't even know about this topic!

[bson]

Seems that music perception is more complex than the added abilities to recognize certain sinus frequencies with conscious hearing.

Here's an experiment.  If you have a function gen, connect a set of headphones to it.  Set the output to a low voltage, like 0.1V rms and 1kHz.  Turn up the amplitude until you reach normal listening volume.  Then turn up the frequency to where you can't hear it anymore, for me that's 12-13kHz depending on ear.  Then turn it up a little further, another 2kHz.  Finally turn up the amplitude; at some point while you can't hear the tone you can feel it.  Like you feel its presence, or a pressure on your head/ears.  Don't go further to avoid hearing damage.

I'm pretty sure the same thing happens with music as well - a subtle element of this feeling of presence, modulated to the music, makes it more realistic.

[thinkfat]

I'm sure your brain will be happy to fill in the tones that it knows to usually go with that particular sensation, even if the ears have grown numb to them.