Micsig dp10007 or dp750-100 differential probe - Page 1
Forum section: electronics / testgear

author: pbs74
author_rank: Contributor
timestamp: August 21, 2022, 09:38:32 pm
content: Hi,I would like to buy a differential probe to make probing with my grounded scope a bit safer.I have no prior experience with differential probes, and will probing audio equipment and amplifiers (so faily low voltage) as well as SMPS (higher voltage).I had my mind set for DP10007, but DP750-100 is now out, and seems to have superceeded DP10007 on the Chinese Micsig homepage.The new DP750-100 has 750V peak (vs 700), and according to specs a better CMRR of 80dB to 100KHz, and 60dB to 1MHz (vs 80dB at 50Hz, 60 dB at 20KHz, and 50dB at 1MHz).On the other hand, the DP750-100 is worse than DP10007 wrt output voltage of max 1.4V (vs 7V) and ±2% gain accuracy (vs 1%)Do anyone have experience with the new DP750-100 yet or opinions about whether to favor (claimed) CMRR over max out voltage and gain, when used with fairly high sensitive Siglent SDS1104X-E oscilloscope?Thanks

author: alm
author_rank: Super Contributor
timestamp: August 21, 2022, 10:02:39 pm
content: I don't have experience with either probe, but for my use differential probes with a lower attenuation factor are more useful: the DHP10007 is 10x/100x, while the DP750-100 is 50x/500x. That's because I'm not using them on particular high voltages. I'm more often running into the noise floor of measuring low level signals than the high voltage limit. I would imagine the same is true if you use them on amplifiers.

author: H.O
author_rank: Frequent Contributor
timestamp: August 22, 2022, 05:33:30 am
content: I have a DP750-100. I had my mind set on the DP10007 due to its 10/100 attenuation but got the the DP750-100 instead. For measuring differential bus signals (RS485 etc) it works perfectly fine, seethis postfor example. I can't comment on CMMR and I have only used for a couple of hours total so take this for what it is.I like the form factor of it, a whole lot less bulky than your normal HV diff probe. Build quality is overall very nice, it looks and feels like a high end device but if I wiggle the BNC connector/electronic housing around, as you do when pressing the button on it, the trace will move around on me. I'm not sure if the issue is with the actual BNC or with the pogo-pin connection between the probe and powersupply adapter or something else. Obviously this effect is less visible when measuring 400V compared to me measuring 3.3V. For mytypicalusecase the bulky multimeter brobes with its detachable tips aren't ideal but I don't mind them for probing the DC bus of a VFD so it is what it is.I wouldn't mind a second one, they're not that expensive so if I get one I'd probably cut the probes off and attach something more suitable for low(ish) voltage measuring on digital bus signals etc.

author: LaurentR
author_rank: Frequent Contributor
timestamp: August 23, 2022, 06:25:19 am
content: Quote from: alm on August 21, 2022, 10:02:39 pmWas looking at exactly that since I have various HV probes I use for lower voltages (incl the 10007).If you believe the datasheets, despite the 50x attenuation vs 10x, the 750-100 has lower input-referred noise than the 10007... (12 mVrms vs 15 mVrms), and has better CMRR, which makes it quite an interesting choice.

author: alm
author_rank: Super Contributor
timestamp: August 23, 2022, 08:30:12 am
content: In theory that makes 120 mV noise relative to the input signal for the 10007 at 10x and 750 mV noise for the 750-100 at 50x.Since there's people with both probes here, maybe you could come up with a comparison, like measuring a 1Vpp 1kHz square wave with both probes single-ended? So one input to the signal, and the other input to ground.

author: LaurentR
author_rank: Frequent Contributor
timestamp: August 23, 2022, 03:30:07 pm
content: Quote from: alm on August 23, 2022, 08:30:12 amInput-referred noise, so already multiplied.

author: pbs74
author_rank: Contributor
timestamp: August 23, 2022, 08:06:21 pm
content: Quote from: LaurentR on August 23, 2022, 06:25:19 amYes, noise is slightly better in 50x, but twice as high for 500x compared to DP10007.Micsig homepage (https://www.micsig.com/Differential%20Probe01/) even lists input-referred noise at 3mVpp (i.e., 1mVrms), but I expect that to be wrong given datasheet download on same page has the 12mVrms/120mVrms.Quote from: H.O on August 22, 2022, 05:33:30 amWhat is your impression of the noise, have you tried measuring the same (safe) signal with and without the differential probe?Quote from: H.O on August 22, 2022, 05:33:30 amDoes this also happen when probing/moving the cables around, or only when pressing the buttons on the bnc housing?Quote from: H.O on August 22, 2022, 05:33:30 amThe DP10007 seems to have normal 4mm banana ends, allowing using various multimeter probes. Does the DP750 have 4mm banana at the probe ends, allowing connecting to extension cords (with lower CMRR)?

author: ojete
author_rank: Contributor
timestamp: August 24, 2022, 10:11:35 am
content: Be careful if you cut the connectors of the DP750 because it uses a coaxial cable unlike the DP10007 and most differential probes.

author: H.O
author_rank: Frequent Contributor
timestamp: August 24, 2022, 06:48:00 pm
content: If I move the the probe so that the cable moves the the BNC connector housing then trace moves around. This is very vissble on 1V/div and below, not so much on 5V/div and above (probe set to x50). It's most sensitive in the up/down direction which is why I think it might be the pogo pins. It doesn't bother me that much but still doesn't feel quite right, perhaps I should the Micsig and or the distributor about it.Here's a screenshot of a 100kHz 250mV peak-to-peak square wave being measured. DP750-100 on Ch1, set to x50 and a Rigol RP3500 x10 probe on Ch 3. Both channels have 20M BW-limit turned on.And here it is a 1V peak-to-peak.I don't have a DP10007 to compare with but I'm not too concerned with this as I don't see me using it for anything below 1V.The business end of the probes are basically 4mm shrouded banana plugs and should fit into any 4mm banana shrouded socket.As for the brobe cables being coaxial, yes I've read that in the datasheet but the shield can't really be connected up in the probe itself so if I were to do some sort of PCB based probe head I could either just isolate the shield(s) or perhaps tie them to a ground plane on the probe head PCB.

author: H.O
author_rank: Frequent Contributor
timestamp: August 27, 2022, 09:57:23 am
content: I just found that the probes on the DP750-100 can be disassembled, possibly opening up for custom probe adapters. I have no idea what type of connector it is though. Contrary to my inital thought it looks like the shielding extends all the way down to the finger guard of the probe itself.

author: Micsig_support
author_rank: Regular Contributor
timestamp: August 30, 2022, 10:40:52 am
content: Quote from: H.O on August 27, 2022, 09:57:23 am'this is not the connector. not for any probe adapters.

author: H.O
author_rank: Frequent Contributor
timestamp: August 30, 2022, 05:40:37 pm
content: Thanks for the input. OK, then what is it? :-)Obviously I wasn't talking about any of the included accessories (the crockodile clips, probe tips and/or the grabbers).What I was talking about was making a custom probe assembly completely replacing the bulky multimeter probes with something more useful for low(ish) voltage probing on PCBs (a CAN bus for example).Do you have any input on the issue with the probe offset jumping all over the place when touching/moving the BNC connector housing connected to the scope? Is this normal? I've tried on two scopes and it does the same thing. I can send a video if you want.

author: pbs74
author_rank: Contributor
timestamp: October 13, 2022, 10:13:37 am
content: I have not had a chance to proceed with a purchase yet (still in favor of new DP750 though), but just saw this recent Youtube review of it (including measuring against DP10013) and wanted to share/attach to this thread in case of value for others

author: pbs74
author_rank: Contributor
timestamp: October 13, 2022, 10:21:15 am
content: Quote from: Micsig_support on August 30, 2022, 10:40:52 amHi Micsig_support, I see a number of different specs on the DP750-100 CMRR - on Micsigs own website, datasheet and product page have different specs, and I also see different specs quoted across resellers.Can you please confirm the correct CMRR numbers?Thanks, Peter

author: pbs74
author_rank: Contributor
timestamp: March 31, 2023, 10:48:52 am
content: Quote from: H.O on August 22, 2022, 05:33:30 amHi H.O.,I put my hobby a bit on hold, but looking to purchase diff probe now. How have your experience with the DP750 been the last half year, still satisfied and would recommend it?

author: H.O
author_rank: Frequent Contributor
timestamp: March 31, 2023, 03:05:21 pm
content: This is not something that gets used very often here. When I have used it it's been on RS485 and CAN bus stuff so <10V and the issue with the trace offset moving around when you touch/move the connector bothers me ever so slightly, it does subtract from the otherwise very nice look and feel of the probe. Remember that when it comes to differential high(ish) voltage probes this one is cheap.I have not done any sort of CCMR tests or anything.

author: Randy222
author_rank: Frequent Contributor
timestamp: December 15, 2023, 06:29:44 pm
content: Is the 75-100 good enough to do FFT analysis on US mains power (120-230vac rms 60Hz)? Or would it itself introduce too much noise?