Differences in specs of Analog Discovery 2 with and without the BNC Adapater?

[Jeromed]

I know I read somewhere the specs on the scope are different depending on whether you have the BNC adapter or not but I can't find a definitive answer.  Can someone please supply the with and without specs?

And why would the BNC adapter make any difference on the scope specs?  According to the schematic, the only thing different (if you use the DC jumper) is that the + side of probe connections are shorted to signal ground through a 27M Ohm resistor.

[Jeromed]

Ok I found some specs from the Analog Discovery 2 National Instruments page:

Analog Inputs • Two fully differential channels; 14-bit converters; 100 MSPS real-time sample rate • 500uV to 5V/division; 1MΩ, 24pF inputs with 9MHz analog bandwidth (30MHz using BNC Adapter Board)

Arbitrary Waveform Generator • Two channels; 14-bit converters; 100 MSPS real-time sample rate • Single-ended waveforms with offset control and up to ±5 V amplitude • 9MHz analog bandwidth and up to 16k samples/channel (12MHz using BNC Adapter Board)

I noticed that the bandwidth is a LOT less than the sampling rate, perhaps leading the user to think they are getting better information than is really available? (Yes I realize the bandwidth has a lot more to do with the amplitude degradation of the signal as the signal frequency goes up.)

And again I don't understand why the BNC adapter ups the bandwidth as there doesn't seem to be anything special in the BNC circuitry.  Is it the nature of the probes?

All this is making a poor newbie's head swim.

[Jeromed]

Ok, I talked to an EE friend of mine and he explained the difference in bandwidth is NOT because of the BNC adapter but because of the probes you can use with them.  The probes are specifically designed to minimize attenuation (loss of signal) and is one of the reasons the ground (black wire on the probe that should be attached to ground) is so short. And even though the two bnc channels share a common ground, you should always ground each probe individually as failure to do so requires a longer path to ground for the probe that does not have the black alligator clip attached.  That is if you are tempted to use one probe ungrounded because the other probe is grounded, don't do it.