Scope probes as supplied by Rigol for the low end scopes, a discussion.

[nfmax]

Lightages - I assume you measured the probe capacitance with the probe connected to the scope input. Was it the same input channel? Was the signal from the capacitance meter overloading the input by any chance?

[EEVblog]

For those who really really need to see it 

[leppie]

what if you measure the capacitance of the 2 probes at 1Mhz and 10Mhz ? is there such an option to measure?

if you compensate a probe @ 1kHz, should you compensate for it @ higher frequencies too? or rather, would the compensation be required in a different manner at higher frequencies? so should there be 2 compensation values for 1 lower (below 10khz) and 1 higher (above 1 Mhz)?

Slow probes do not generally have high frequency compensation pots. My TEXAS 250MHz ones has 1 low and 2 high frequency pots.

[Lightages]

First things first: A big  to Dave for doing this video. I certainly believe your results. I guess the differences I see are accounted for by the bandwidth rating differences.

My RP3300 probes do not look like Dave's. Mine have an identical appearance to the RP2200 and have the compensation adjust on the probes and only have the BNC connector at the scope end, no box. I believe Dave's are now called RP3300A and mine are the old version.

nfmax: I measured with the probes connected and disconnected just now and the RP2200 always show a lower capacitance but as we know capacitance can change with frequency.

I also remembered as my head hit the pillow that both probes were connected at the same time for the image I posted so there is no difference in the loading on the signal between the two probes. This means the difference I see on the waveform in that image is solely due to the probes and not a loading issue.

In conclusion the differences I see are real, and due to the bandwidth differences of the probes.

I hope someone feels like doing a bandwidth test of common probes supplied with the lower end scopes. It would be interesting to see the real performance.

P.S. Oh yes, I will continue to use the RP3300 for single and dual channel use for obvious reasons.

[alank2]

My experience is that the RP2200's is that they were not at all in the same league when compared to RP3300/RP1300's.

[DanielS]

My main problem with Rigol's probes right now: I received my scope last week and one of the probe tips came off when I removed the hook attachment for the second or third time.

[wraper]

My RP3300 probes do not look like Dave's. Mine have an identical appearance to the RP2200 and have the compensation adjust on the probes and only have the BNC connector at the scope end, no box. I believe Dave's are now called RP3300A and mine are the old version.

Nope, RP3300A are x10 only and look completely different.

[Lightages]

I wonder if Rigol is rushing out the probes to meet demand and the quality control is lacking for this reason.

So based on the bandwidth calculation Dave showed in the video, the RP2200 probes with the scope give theoretical system bandwidth of 83.2MHz. Yes he corrected his assertion and qualified it, but that is a limit on the bandwidth. The RP3300 probes give a calculated system bandwidth of 96.2MHz. That is much closer the to rated bandwidth of the scope alone.

[ion]

For those who really really need to see it 
EEVblog #707 - Rigol Oscilloscope Probe Performance

I noticed the probe settings on all of the scopes were set to 1X.  Would this have any effect on the results?

[Lightages]

No, the probe setting only changes the indicated values on the screen. It does not affect the acquired signal at all.

[Pjotr]

My main problem with Rigol's probes right now: I received my scope last week and one of the probe tips came off when I removed the hook attachment for the second or third time.

Can second that. The supplied Rigol probes are of mediocre quality mechanically. After half a year of occasionally use, the contact of the gripper to the probe tip of one of my RP3300 probes became loose and horrible unreliable. Rigol must make their money somewhere  But I didn't see the overshoot Lightages showed up in his OP. More the opposite. For comparison the RP33000 compared to a TesTec HF212. Both were connected at the same time to a T-splitter and a 50 ohm feed through terminator. So total source resistance is 25 ohm loaded by 29.5 pF, which gives a LP roll off at 215 MHz. Channel 1 (yellow) = RP3300, Channel 2 (blue) = TesTec HF212. B.t.w. the HF212 has two HF adjusters.

[Lightages]

To be clear, it is not the probe that is ringing or overshooting, it is the actual waveform and the different bandwidths of the different probes show different traces of the same waveform.

[Pjotr]

Ok, then it will be difficult to judge the probes right and adjust them right. What I am missing in this thread: Did you adjust the HF adjustment of the RP3300 as well (the trimmer in the probe itself)?

With a proper square wave I get an almost perfect Gaussian response with a rise time of 3.5 ns on my DS2102 at 100 MHz bandwidth. And with almost no ripples and no overshoot at all.

[Lightages]

Yes, I adjusted the probes correctly on the compensation test point on the scope. The waveform as generated contains the ringing, not the probes. The ringing is the high frequency content I am inspecting and seeing the difference with the different probes.

Coincidentally, 4 new Chinese 300MHz probes arrived today. I will give them a test now.

[Pjotr]

Yes, I adjusted the probes correctly on the compensation test point on the scope.

The RP3300 has 2 adjustment points: One at the BNC connector (LF) and one at the probe tip (HF). The one at the probe tip is hidden and sealed with a small grey rubber plug. That rubber plug is almost invisible and you have to remove it to get to the HF adjustment (at least at the RP3300's I have).

[EEVblog]

The RP3300 has 2 adjustment points: One at the BNC connector (LF) and one at the probe tip (HF). The one at the probe tip is hidden and sealed with a small grey rubber plug. That rubber plug is almost invisible and you have to remove it to get to the HF adjustment (at least at the RP3300's I have).

Wow, you are right. It just looks like part of the case molding on mine, but sure enough, remove it and there is the trimmer.
And sure enough there it is in the manual too 

[Lightages]

I already said, before in this thread, that my RP3300 only have the compensation trimmer on the probe. They are not the ones with the small box at the BNC connector.

I just tested the "P6300" probes I purchased on ebay. They are built OK, but they show almost exactly the same appearance of the waveform as the Rigol RP2200, a little higher peaks on the ringing, but nothing to say they are really better in bandwidth than the RP2200. I paid $15 each for them, and for the price they aren't bad, but certainly not 300MHz by my estimation.

For everyone interested, I consider the question on the probes a closed matter. From the video that Dave did and the differences seen between his probes, what I see seems to match an expectation of a drop from 96.2MHz to 84.2MHz bandwidth, as calculated. It also does answer my question about the probes limiting the bandwidth of the scope. Yes they do theoretically. How much I can only guess by the calculation but it appears somewhat logical from the appearance of the waveforms.

[markce]

Please note that there are RP3300's (grey) and the newer RP3300A's (black). They are different. The non-A's are 16pF and 1/10x and the A's are 13.5pF and 10x only.

[Pjotr]

You're right, looked up the manual: http://www.rigol.com/download/Oversea/DS/User_guide/RP3300A_UserGuide_EN.pdf And those have no HF trimmer 

[Lightages]

Just read some of those replies on Dave's youtube channel for the video.... Everyone thinks I am seeing things, including Dave!

I have concluded that I am actually seeing the difference in the probes. I am not probing incorrectly. I have tried all methods suggested and the results are the same. 

[Bud]

DS2072A says scope input is 16pF. I measured almost 18.5pF @70MHz.

[miguelvp]

My DS2000 came with the newer RP3300A probes with only compensation at the BNC connector and they are 10:1 fixed attenuation, maybe Lightages probes are really the RP3300A.

Here are the specs
Input capacitance 13pF +- 3pF
Bandwidth 300MHz, the non A is 350MHz
No rise time in the spec.

[miguelvp]

DS2072A says scope input is 16pF. I measured almost 18.5pF @70MHz.

16pf +- 5pf
And that is the probe input, don't know about the scope input if it adds more.

Edit: and not a big deal, but I'm not sure why you are rounding up. 18.447pf rounded to one decimal point should be 18.4pf or 18.45pf if using 2 decimal places, yeah picky but we all know how you feel about Rigol

Anyways, well within specs.

[bdivi]

For those who really really need to see it 

Question is about the rise time of the function generator source. If the rise time of the source is limited (which I see in the AWG datasheet as 8ns) then of course the performance of the two probes will be identical - they have 2.3ns and 0.9ns respectively. You have to test them with rise time that is close to the rise time of the scope (which is 3.5ns) in order to see a difference.

The test with 8ns rise time pulse under these conditions is meaningless.?

[markce]

My DS2072A (mid 2014) came with RP3300A's. I measured the input (probe-tip) cap and it is 13.8pF which is nice within 13+/-3pF. The RP3300A's are smaller and only 10x, what I like. They have a nice rubberized feel and a thinner hook. The ground clip is very stiff and the clip-on connection with the probe is exposed. They are also only 300V. Don't expect them to be very durable. I bought one extra quality probe for daily use and keep the RP3300A's for 2nd channel and external trigger.