VOLTCRAFT DOV series

[Martin72]

I had my suspicions, and the fact that the UI looks different wouldn't have been an issue.
The pictures of the inside, however, certainly were—thanks for pointing that out... 

[egonotto]

Hello,

I'm interested in the noise at 20 MHz on the Voltcraft, especially at 1 mV/div but also at 1 V/div. Ideally, with a short circuit at the input or a 50-ohm terminator.

In addition to RMS, the peak-to-peak voltage would also be of interest.

Best regards,
egonotto

[Martin72]

I'm going to run through my usual test routine...
I want to find out if the Voltcraft/Owon is at least on par with the Rigol DHO800 series.

[Aldo22]

According to the tracking information, my Voltcraft Scope is supposed to arrive as early as next Monday.

So?
First impressions?
If it's not total junk, I might order one myself, too.

[Smepic]

First, check if they ship the oscilloscope to your country.

I tried to buy it, but it seems that both Voelkner and Conrad.de only ship to Germany.

[Martin72]

So?
First impressions?
If it's not total junk, I might order one myself, too.

Hold on, hold on—I had to work first, so I picked it up on my way back...
But now I have it here.
Packaged very spartanly—you could say very eco-friendly—the probe heads were in the box without a bag, the probe accessories were in a paper bag, and the scope didn’t have a separate bag either.
First impression: the build quality feels solid.
Almost all the knobs lack a click when turning, which feels a bit odd.
I turned it on briefly and played around with it a bit; the fan is, of course, pretty loud and a bit “wobbly,” but the boot time is OK.
I'll run more tests over the next few days, a little bit each night after work.

Here are a few photos; due to the image limit, they've been split into two posts.

[Martin72]

Rest of the pics..

[Aldo22]

Thanks for the pictures!

I have a strange question.
There's a trigger output on the back, right?
What does the signal look like there when it triggers (SyncOutput)?
+3.3V?

Thanks!

[Martin72]

Hi,
Yes, that's a 3.3V level at the trigger output.

[KungFuJosh]

Guessing by the resolution, I'd say that was captured on the SDS3000X HD.

[Martin72]

The candidate has 100 points.

Speaking of screenshots—after I had to search for it (there’s no dedicated button/direct access for it)—here’s a screenshot of the Voltcraft, showing the calibration signal for the probes.
There seems to be a glitch “up there,” but I'll double-check it tomorrow with a different scope.

[tautech]

Guessing by the resolution, I'd say that was captured on the SDS3000X HD.

Back a few posts I see a SDS5108X HD on Martins bench......there's a couple clues to which model it is. 

[Martin72]

I had rolled a die beforehand to decide which scope to use.

[KungFuJosh]

Guessing by the resolution, I'd say that was captured on the SDS3000X HD.

Back a few posts I see a SDS5108X HD on Martins bench......there's a couple clues to which model it is. 

Sure, but without going into details about our friend's "humble" TE inventory, we know that whatever Siglent scopes he may or may not have do not share screen resolutions.

[Rising Edge]

In the German user manual, beginning from page 19, they show an Android Desktop within the scope and fairly regular Apps. They also listed the Android system in the specs.

[2N3055]

Guessing by the resolution, I'd say that was captured on the SDS3000X HD.

Back a few posts I see a SDS5108X HD on Martins bench......there's a couple clues to which model it is. 

Sure, but without going into details about our friend's "humble" TE inventory, we know that whatever Siglent scopes he may or may not have do not share screen resolutions.

We may, or may not, confirm or deny facts or lack thereof.....
 

[Aldo22]

In the German user manual, beginning from page 19, they show an Android Desktop within the scope and fairly regular Apps. They also listed the Android system in the specs.

Yes, there's also a Firefox browser you can use to read EEVblog whenever you have a moment. 
You can also print directly via network etc.

The oscilloscope is just another "app".

[Aldo22]

There seems to be a glitch “up there,” but I'll double-check it tomorrow with a different scope.

Quite “busy” settings for the 1 kHz test signal (200μs/div).
1.25 GSa/s - 10 M - No bandwidth limit

[Martin72]

This has little to do with the settings.
I connected the Siglent to the calibration output of the DOV704 and observed the same behavior.
The signal is somewhat noisy; see the two images.

[Aldo22]

The signal is somewhat noisy; see the two images.

OK, but I'm not particularly interested in the calibration signal.
It think it is sufficient for its intended purpose.

Can you show the noise floor at 1 mV/div?
Or a square wave at 10, 20, and 50 MHz?

How do memory depth, sampling rate, number of channels, and 12-bit mode depend on each other?

Thanks!

[Martin72]

OK, but I'm not particularly interested in the calibration signal.

But I'm interested in that.

I took some noise measurements today.


Self-noise Test/Rise Time/Web Server

I performed the tests at 1 ms/div and the maximum sampling rate.
The inputs were shielded using BNC caps.
CH1, the test channel, was optionally terminated with a 50-ohm resistor.
After powering on, the channel has an offset that drifts during operation until it “settles” and remains stable.
When cold, it’s up to 2.2 mV; you can literally watch the drift decrease as the fan kicks in (the fan is temperature-controlled—a nice little feature).
Then the offset drops into negative territory and stays there.
An auto-calibration (the fastest I’ve ever experienced) hardly changed anything.
But that’s not important for noise measurement; here, thankfully, the “Stdev” measurement parameter is selected.

Interesting:
At 2 mV/division or lower, the channel is automatically limited to 20 MHz; this cannot be disabled.
Only at 5 mV/division or higher do you have the option to choose between 20 MHz and full bandwidth.

Also interesting:
The values for 50-ohm and 1-Mohm termination are almost identical.

Less impressive:
The “Hi-Res” mode is effectively useless.
It has no effect on the measurements, and I ultimately confirmed this with the Bodnar pulser.
The rise time remains the same regardless of whether the mode is set to normal or Hi-Res.
Especially since there are no additional settings available in the menu for Hi-Res.
It brings back memories of the old Rigol MSO 5000 days...
Rise time:
This, in turn, is very good; a Bodnar pulse with a 50-ohm terminator results in a rise time of just over 2 ns, which means the bandwidth is significantly higher than the model predicts.
FFT:
I gave it a quick test run because I had the 10 MHz square wave from the Bodnar connected to it.
Phew... Anything less than that would be nothing at all.
No axis labels—that's really bad.
But I'll get back to the FFT and the menus and their features later, because, as I said, I'm just running through my standard test program.
Oh, and I also had the web server running briefly.
Nothing interesting, except—another negative point—I can’t find an update function for the Scope in the web server either.
And that’s something it really needs, without wanting to get too far ahead of myself.
I’ll be testing and showing a few more things, but the general direction of my opinion is already pretty clear.
The Scope is worth its price.
Namely, the current price of €180–200.
It’s no Rigol DHO800 killer.

[Martin72]

How do memory depth, sampling rate, number of channels, and 12-bit mode depend on each other?

I’ll show you that in the next few days, too.
I don’t get home until the evening and only have an hour or so to myself, so the individual tests will take a few more days.
Here are two more pictures of the web server.
The Scope also has Wi-Fi built in, so I’ll try that out when I get the chance.

[Aldo22]

Thanks for the review!

FFT:

No axis labels—that's really bad.

What does the label switch do (common, custom)?

[Martin72]

Hmmmm....That would actually be a possibility—good point.

[egonotto]

Hello,

thanks. It seems there’s a 7.5 kHz interference on Channel 1 in addition to the noise. Is it just as bad on the other channels?
But for the price, it’s still a nice device.

Best regards,
egonotto