DSO Recomendation

[Fungus]

BTW note that the jitter spec on the Picoscope 5000 series is severely inadequate for the high resolutions/samplerate they specify. See www.linear.com/docs/25374

I wonder if Wolfie's read that. 

[Fungus]

Given that, why is the Picoscope better?

Because that particular model costs $2000.

(ie. they can spend a lot more on the amplifiers, etc., than a $400 Rigol which also has to include a screen, ethernet, USB and control knobs in the $400 price)

[MrW0lf]

Why aren't other 8 bit scopes able to achieve the same thing?

Wild guess - since it is 16bit scope in some modes, they have put much higher effort into overall system design compared to regular 8bit scope, making 8bit mode operating at about theoretical max. There are some FFTs tests done that show that overall implementation quality is rather good:
https://www.eevblog.com/forum/testgear/fft-spectrum-analysis-reviewed/

Some random outtake from here:
https://www.eevblog.com/forum/testgear/fft-spectrum-analysis-reviewed/msg921288/#msg921288

"I just did some captures with a couple of PicoScopes and also a LeCroy WaveAce 102 in all cases the input was a 1.8V pk-pk 20kHz low distortion sine wave.  SFDR figures:

LeCroy WaveAce 102    50dB (approx)
PicoScope 5244B          68dB (8 bit mode)
PicoScope 5244B          78dB (16 bit mode)
PicoScope 4262            93dB (16 bit)"

BTW note that the jitter spec on the Picoscope 5000 series is severely inadequate for the high resolutions/samplerate they specify. See www.linear.com/docs/25374

Just to be clear - what exact specs you are talking about? After little homework found these:

AD2: no spec
Tek TBS2000: Time base accuracy ±25 ppm over any ?1 ms interval; Sample jitter: no spec
DS1000Z: Timebase Accuracy: <=±25 ppm (typical); Clock Drift <=±5 ppm/year; Sample jitter: no spec
Pico 5443A:  Initial timebase accuracy: ±2 ppm; Timebase drift: ±1 ppm/year; Sample jitter: 3 ps RMS, typical

Are we on the same page with numbers?

Also, 1% accuracy talk was about DC accuracy, what it has to do with timebase accuracy at all? 

From FFT tests its evident that 5000 is not strictly optimized 16bit scope indeed, but on the other hand it's excellent 8bit scope. Probably 12bit mode lands squarely in the middle. If sole purpose is ultra accurate, low frequency 16bit work, there are specialized scopes for that.

So overall dunno if there is really anything to whine about. In my practice they usually work better than spec. So expecting delivery of 2408B to finally work on some projects, not debugging measurement hardware all the time

[Fungus]

Why aren't other 8 bit scopes able to achieve the same thing?

Wild guess - since it is 16bit scope in some modes, they have put much higher effort into overall system design compared to regular 8bit scope

Having a $2000 budget probably helped, too.

[MrW0lf]

Having a $2000 budget probably helped, too.

Well quality costs. Comparably it's not more expensive than AD2 chosen by OP. Cannot imagine what Tek would charge for such scopes if they sell some silly probe adapters for $400 per pc

[rstofer]

Awesome feedback guys, thanks!

I am decided on the AD2. Just waiting for next paycheck in 2 weeks
Quick last question about it: what is the difference between "WaveForms" and "WaveForms 2015"?

Spend the time to review the specs for input voltages, power supply capability, etc.  Direct input is limited to +- 25V - clearly enough for a lot of electronics projects but probably not enough for some circuits.

You can use x10 scope probes and probably should.  You would need the BNC adapter board.  I don't use mine unless I am getting out of the realm of low frequency and low voltages (I tend to work at 5V or less).

Read the note in section 2 here:
https://reference.digilentinc.com/reference/instrumentation/analog-discovery-2/reference-manual?redirect=1

It takes a bit of reading to digest what it says.  Read is several times! Basically, the AD is grounded through the USB connection unless a USB isolator is used.  There needs to be a common ground between the circuit under test and the AD.  So, when I use a separate wall wart for a supply, it better be floating because I am going to create a ground at the project (usually on the - side of the wall wart) and connect one of the AD black ground wires to that point.  It isn't enough to just probe the circuit with the two scope leads (differential input like orange and orange/white or blue and blue/white), you need to get a black wire in there somewhere.

The easy way to think about this is that the blue/white or orange/white scope input wires should be connected to the circuit ground as should one of the adjacent black wires.  Look at the BNC adapter schematic to figure out how Digilent handles SGND - pins 25, 28 and 30.

https://reference.digilentinc.com/_media/analog_discovery_bnc_adapter_board:discoverybnc_sch.pdf

It isn't nearly as big a bother as the note implies and it is made a whole lot easier if you are using the AD power supplies but I have to believe that the BNC adapter is the right way to use the thing as a scope.  Then you can use conventional scope probes and all the SGND stuff is taken care of.

If you really need differential inputs, no problem.  Just make sure that the black wire connects to circuit ground.

After a few moments of thought, this all becomes much ado about nothing.  But there are circuits where the voltages are out of range or the circuit ground can't be connected to earth ground.  These circuits need a lot more thought.

This stuff all applies to regular scopes as well.  Dave has made a video describing how to avoid blowing up a scope.  It all has to do with the ground connection!  That thing can be a real issue.

[bsas]

Spend the time to review the specs for input voltages, power supply capability, etc.  Direct input is limited to +- 25V - clearly enough for a lot of electronics projects but probably not enough for some circuits.

You can use x10 scope probes and probably should.  You would need the BNC adapter board.  I don't use mine unless I am getting out of the realm of low frequency and low voltages (I tend to work at 5V or less).

(...)  Look at the BNC adapter schematic to figure out how Digilent handles SGND - pins 25, 28 and 30.

Thanks for the advise! My goal is to work on guitar pedals, so, basically 9V DC low current (less then 100mA) circuits. So, the limit looks more then enough for me.
Even so, I will buy the "PRO" bundle that comes with the 1x and the 10x probes, and the BNC adapter. I was planning that anyway.
Also, I will buy the 9V breadboard USB adapter from Digilent (PowerBRICKS). The benefit is that it is more then enough power for my circuits (9V 130mA if I am not wrong) and they will share common ground since both the power supply and the AD will be connected to my computer USB bus.

[rstofer]

Spend the time to review the specs for input voltages, power supply capability, etc.  Direct input is limited to +- 25V - clearly enough for a lot of electronics projects but probably not enough for some circuits.

You can use x10 scope probes and probably should.  You would need the BNC adapter board.  I don't use mine unless I am getting out of the realm of low frequency and low voltages (I tend to work at 5V or less).

(...)  Look at the BNC adapter schematic to figure out how Digilent handles SGND - pins 25, 28 and 30.

Thanks for the advise! My goal is to work on guitar pedals, so, basically 9V DC low current (less then 100mA) circuits. So, the limit looks more then enough for me.
Even so, I will buy the "PRO" bundle that comes with the 1x and the 10x probes, and the BNC adapter. I was planning that anyway.
Also, I will buy the 9V breadboard USB adapter from Digilent (PowerBRICKS). The benefit is that it is more then enough power for my circuits (9V 130mA if I am not wrong) and they will share common ground since both the power supply and the AD will be connected to my computer USB bus.

Outstanding approach!  I haven't tried the PowerBRICKS but I plan to order a set in the near future.  They seem to be quite handy for breadboarding.

BTW, I don't connect much of anything directly to my Surface Book.  I have a powered USB hub with 7 USB ports and 3 charging ports.  Like this:
https://www.amazon.com/gp/product/B00VDVCQ84/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

I should probably add a USB Isolator between the Book and the Hub but they get very pricey when considering USB 2.0.  USB 1.1 would be very slow in comparison.