UNI-T UT-P06 300Mhz passive Probes. Are they any good? - Page 1
Forum section: electronics / testgear

author: battlecoder
author_rank: Regular Contributor
timestamp: October 04, 2023, 10:56:12 pm
content: I recently bought a second hand Agilent/Keysight scope, software-upgraded to 200Mhz bandwidth by the owner, and it came with 150Mhz Keysight probes. Now, a rise-time test seems to indicate that the probes are capable of slightly above 150Mhz bandwidth, but don't really do 200Mhz (kudos to Keysight for having probes that actually match their specs with room to spare).I have ONE 350Mhz probe from another scope (Rigol) that helped me verify that the instrument does indeed have >200Mhz bandwidth, so I think it would be a crime to not have a set of probes that take advantage of the full scope bandwidth.New original Keysight probes are rather expensive, so I was looking at alternatives (for example old Agilent N2863A or N2863B probes, which I'm considering an option).In the process, however, I stumbled upon the Uni-T UT-P06 probes, and there's not really a lot of reviews of them. Even on this forum I was able to find just a couple of mentions of them (but with some typos, like UT-06) and no indication of whether they are good or bad probes. These probes seem to have a compensation range well within the scope's input capacitance so they should work. They are also like $35 a piece, so I'm expecting them to be better than the extremely cheap generic ones from AliExpress, but probably not as good as the original Keysight/Agilent ones.Unlike the Keysight probes the Uni-T ones are x1/x10 switchable, which makes them more flexible but probably also not the best?I would be extremely interested in any performance measurement, review or general opinion from people who have them, or have used them in the past.

author: battlecoder
author_rank: Regular Contributor
timestamp: October 05, 2023, 03:37:50 pm
content: A bit of an update: I'm also considering the Texas 250 probes, and the P2200, which despite being 200Mhz are reported to work well up to 400-ish Mhz.I don't like that they are *all* switchable probes, but as long as they meet their specified bandwidth with an acceptably flat response I should be fine.However, if anyone here has a better recommendation for reasonable-quality probes for a 200Mhz scope, that don't cost an eye and a half, please let me know.If I don't get any specific recommendation I guess I'll use my gut (and wallet) to make the decision, and will report back to either warn people or recommend what I got. That way I can make this post useful to others, at the very least.

author: KungFuJosh
author_rank: Super Contributor
timestamp: October 05, 2023, 05:48:03 pm
content: Take a look at probemaster.com instead. Their probes are fantastic, and significantly better than anything UniT has ever conceived (better prices too).

author: battlecoder
author_rank: Regular Contributor
timestamp: October 05, 2023, 07:13:27 pm
content: Quote from: KungFuJosh on October 05, 2023, 05:48:03 pmThanks for the recommendation! I've heard of probemaster before and it's always been with extremely positive comments. While they might be better than the probes I was looking at, I don't think it's fair to say they have better prices. According to their webpage, the basic fixed 10x, 3.5 feet, 250Mhz probe is already ~$60, while Uni-T's, 300Mhz model is ~$35. A set of 4 probes plus shipping is going to cost me as much as ordering a kit of old stock Agilent probes from eBay (although I would rather have a kit of new quality probes, than old, used probes).Now, $60 for a probe wouldn't be too wild if I only needed one. But I want to (ideally) buy probes for the 4 channels, and at that point this becomes a slightly harder problem.Maybe I should just get likeonehigh quality, high bandwidth probe for one channel of the scope, and use the 150Mhz probes I already have for the 3 remaining channels. Being fully honest the chances of me requiring high-bandwidth measurements for all 4 channels simultaneously are near zero.

author: KungFuJosh
author_rank: Super Contributor
timestamp: October 05, 2023, 07:48:51 pm
content: Quote from: battlecoder on October 05, 2023, 07:13:27 pmOh, I only did a quick search, and the prices were crazy for the UniT (like $135 for 1 probe).Anyway, get a probemaster master kit (you can get them including 3 or 4 probes). They're worth every penny, and include a little discount. I have a few different kits for my scope, and more kits for my DMMs...it's a bit silly, but they're great. The attachment accessories are awesome.Your scope maxes at 200MHz. Mine maxes at 500MHz, and I still only use 250MHz probes. Active probes are supposed to be much better than passive probes for higher frequencies, so I wouldn't waste money on passives over 250MHz. Most of my probes are the 4905-1RA, but I also have different models for other uses too like the 4902-1RA. I don't have a fixed 1x probe from them yet, so I will probably get the 4903-1 that can do up to 38MHz, which is pretty awesome for a 1x probe.

author: mwb1100
author_rank: Frequent Contributor
timestamp: October 05, 2023, 07:53:25 pm
content: Rigol's 350MHz PVP2350 probes run a bit less than $50, so about halfway between the Uni-T UT-P06 and the Probemaster 250MHz probes.Since you already have one (I assume the probe you mentioned was a PVP2350) you're in a good position to determine if the $10-$15 premium over the Uni-T's is worth avoiding whatever risk you might perceive with the Uni-T probes.

author: battlecoder
author_rank: Regular Contributor
timestamp: October 05, 2023, 09:23:46 pm
content: Quote from: mwb1100 on October 05, 2023, 07:53:25 pmWell I feel stupid now. I didn't think of checking the price for Rigol probes. Since I already have one (that I got in a bit of a lucky accident) I could just complete the set of 4.The one I have, however, is the RP3300A, which is apparently obsolete now :/ TEquipment lists the RP3300A as discontinued and "replaced by PVP2350", so if I want them to be all the same model, to ensure same performance across all channels, I would still need to get 4 (so much for saving money I guess. They are still cheaper than the probe masters, though). Interestingly enough, the RP3300A is fixed 10x while the PVP2350 is 1x/10x switchable. I wonder why they went that wayQuote from: KungFuJosh on October 05, 2023, 07:48:51 pmI didn't look into the Master kits! They are extremely tempting. Not sure if I need them with readout though, as absolutely none of my oscilloscopes even support that (The 150Mhz Keysight probes I have come with the readout pin, BUT the oscilloscope itself doesn't have the detection ring so they just look cool I guess) So a kit of 4905-1 could be an option.

author: KungFuJosh
author_rank: Super Contributor
timestamp: October 06, 2023, 12:59:55 am
content: Quote from: battlecoder on October 05, 2023, 09:23:46 pmIf cost is your only concern, then sure, skip the readout and save the money. However, you may get a scope in the future with readout, and won't need to buy more probes if you want to use that feature. Then again, if you save your defaults as 10x and only use 10x probes, readout isn't that exciting.The little accessories that come with the master kits are awesome. I wound up buying a lot of extras too. I use the pico grabbers all the time with my scope and DMMs to grab onto tiny stuff, including SMT chips. The wires that attach to the pico grabbers can also directly connect to standard 1mm pins (though sometimes I stretch them out, which is why I have 3 sets of them for my DMMs 😉)If you build the master kit then it's $206 for a master kit with four of the 4905-1 probes:https://probemaster.com/design-your-own-4900-series-master-probe-kit/It's about $35 more if you want the RA versions for all 4 probes.

author: battlecoder
author_rank: Regular Contributor
timestamp: October 06, 2023, 03:36:36 am
content: Quote from: KungFuJosh on October 06, 2023, 12:59:55 amI've been looking at their page the entire day. I wasn't that interested in the deluxe accessories until I noticed the probe-to-bnc adapter which is a must to me, but this is already getting wildly out of my budget. Shipping to my country isn't particularly cheap, even if I pick "Fedex Economy" (the cheapest option).My budget was roughly $150~$200-ish was already stretching it (but still worth it considering the extremely positive reviews), but even that "basic" kit (no readout pin and no accessories) goes into ~$250 with shipping. Adding readout probes and accessories and it goes straight into $300 land.My last experience with Fedex was also awful. I bought a set of Agilent Logic analyzer probes and accessories from ebay (for the very same scope. Its previous owner sold me the unit with basically only the things that came with it in the box, and none of the hardware upgrades they bought except for the VGA/LAN output that maybe he didn't even notice was still plugged in), and that time I ended up paying a rather hefty amount in "FedEx handling and import fees" that added up to almost $200, more than doubling the price of the LA probe set, so I'm also not looking forward to using their service again.The other international shipping option offered by Probemaster is UPS, which is twice as expensive as Fedex (but maybe I won't get royally effed with made-up fees on arrival, like with Fedex). But I'm not sure if that's a gamble I'm willing to take, and it also takes the probes even further out of budget anyway.The probemaster kit looks incredible, but considering that there's no way I'm making them fit into my budget (unless I teleport to their store and back home), I think I'll leave them for a future in which I can afford to spend $300 in probes again.EDIT: Just to further show how ridiculous the shipping costs get to my country: I tried checking on Tequipment how much would it cost me to get the Rigol probes, and the shipping alone, estimated by their page, is $241.33so I'm trying to get a quote from a local distributor. Maybe the Rigol probes are the best I can do without selling my organs, provided that I can get them locally.

author: KungFuJosh
author_rank: Super Contributor
timestamp: October 06, 2023, 04:04:45 am
content: There are other dealers that sell probemaster probes. welectron.com is one. There might be others.Personally, I would wait until I could afford the better option. The master kit is also available with only 3 probes if you need to cut the cost.

author: battlecoder
author_rank: Regular Contributor
timestamp: October 06, 2023, 06:42:20 pm
content: Quote from: KungFuJosh on October 06, 2023, 04:04:45 amI mean...maybe? I don't want to use bad probes with the most decent scope I've gotten for my lab, so maybe saving for really good ones makes sense.In the meantime I got a quote from a local distributor. The Rigol probes would cost approximately $50 each, and if I get the exact model that I already have (of which they have stock, despite the probe being discontinued) I would only need 3, and the whole operation would fit neatly in my $150 budget.Now, I also need a couple of cheap ~200Mhz probes for a FNIRSI portable scope that came with extremely garbage probes, so I'll probably get a couple of P2200 for it.For what is worth, I found this other post in the forum:https://www.eevblog.com/forum/reviews/cheap-china-p6xxx-probes-good-bad/msg490775/#msg490775. User "calin" apparently got the UNI-T P06 probes (Reply #12) which I opened this post for, and their review (#21) is that they "work a treat". I mean, I wish there were some numbers in that review, but at least they seem to have a positive experience with them.

author: battlecoder
author_rank: Regular Contributor
timestamp: October 07, 2023, 12:50:50 am
content: Btw, I tried to perform a more reasonable test of the Rigol RP3300A probe to determine whether biting the bullet and upgrading from the stock 150Mhz Keysight probes to a set of Rigol probes was worth it (which is so far the best plan that fits my budget).Surprisingly, the Keysight probes (N2862B) despite being only rated for 150Mhz gave me a virtually identical risetime to the one I got using the RP3300A (350Mhz) probe (it was almost a matter of which one flickered more between 1.6 and 1.7ns). Performing a -3dB test also gave me very similar results (~230Mhz bandwidth) with both probes, so, measurement-wise I don't think I would be getting a lot from the upgrade.Now, I'm surprised that the Keysight probes measured similarly to a higher bandwidth probe. I had previously estimated that they were limiting my bandwidth to approximately 175Mhz, but admittedly it could have been just shoddy probing in my previous attempt.Of course the 350Mhz probe should be able to get a bit more of the higher >200Mhz frequency content without as much attenuation as the 150Mhz probe gets, and as such gives a slightly better square wave, but I'm not sure if it's enough to justify upgrading.Here's a comparison of a 20Mhz square wave that should have a risetime of < 1nS (I only know it's < 1nS. I don't have a scope with that kind of bandwidth).The yellow trace (CH1) is the Keysight N2862B 150Mhz probe.The orange trace (REF) is the Rigol RP3300A 350Mhz probe.I used averaging to rule out any noise or ripple from the generator itself.The trace with the Rigol probe is slightly flatter, but that's basically it. Unless I'm missing something here (I'm not an expert, so if there's anything else interesting going on here please let me know).

author: Performa01
author_rank: Super Contributor
timestamp: October 07, 2023, 12:20:55 pm
content: Quote from: battlecoder on October 07, 2023, 12:50:50 amNow you have finally got a vague idea about one simple fact that so many people tenaciously ignore: Any properly designed x10 probe will peform up to several 100 MHz in the industry standard test setup with 25 ohms source impedance, no matter what the specifications say. In practical use though, they all will only perform well at higher frequencies if connected to insensitive low impedance nodes. Furthermore, other than the LF compensation, there's also the HF compensation, which is user adjustable (only) on some more expensive probes.Most probes are not user adjustable for the HF matching. They are matched to the scopes where they belong to. Consequently, it doesn't sound like a good plan to e.g. use a Rigol probe (without HF adjustment) on a Keysight oscilloscope. It might work okay, but it could also fail miserably. I have once tested a bunch of different probes on a 300 MHz Siglent scope. With the original (300 MHz) probes it reached a bandwidth of 450 MHz (yes, probes can expand the total system bandwidth beyond the bandwidth of the scope alone), but a humble 100 MHz Tektronix probe also came close to 400 MHz AFAIR. By contrast, a fancy 500 MHz Keysight probe performed less favourably, particularly was it worse than the 100 MHz Tektronix one.The popular rise time test can be misleading. Firstly we cannot really calculate the scope bandwidth from the risetime as long as we don't know the exact frequency response (lowpass characteristic) of the frontend. Secondly risetime measurements can be flawed for many reasons, e.g. on scopes that do not measure the whole record but decimated data, like the Keysight Megazoom scopes do or also if the pulse form is not perfect but has a lot of overshoot - maybe due to improper HF matching of the probe...Finally, probes in conjunction with the rather complex input network of a DSO do not usually have a clean lowpass characteristics. Somewhere in this forum I have demonstrated the frequency response of a cheap Siglent PP510 probe up to 1 GHz - and it showed a positive amplitude error at very high frequencies (>900 MHz). In conjunction with fast pulses (e.g. leo Bodnar) This can lead to false good looking rise time measurements, even though the probe isn't actually very useful because of the high ripple in the frequency response. Even just 1 dB amplitude error at certain frequencies will cause visible pulse distortions on the screen.So wile pulse measurements are nice as an additional piece of information, probe performance can only be accurately measured with a levelled signal generator or AWG. Only if such a measurement with trustworthy equipment confirms that the existing probes are inadequate, I would ever start thinking about alternatives. The only really interesting specification is the tip capacitance. If you can find a probe that has significantly lower capacitance and is still perorming equally well in the industry standard bandwidth test, then it's worth buying. But I doubt that you will easily find one that meets these requirements.Here's some food for thought (reply #56):https://www.eevblog.com/forum/testgear/siglent-sds1104x-e-in-depth-review/msg1434665/#msg1434665also here (reply #191):https://www.eevblog.com/forum/testgear/siglent-sds1104x-e-in-depth-review/msg3290546/#msg3290546

author: KungFuJosh
author_rank: Super Contributor
timestamp: October 07, 2023, 03:15:09 pm
content: Quote from: Performa01 on October 07, 2023, 12:20:55 pmThanks for sharing those links, I was too lazy to search for them. 😉A couple other things worth pointing out with those Rigol probes are:- Only rated to 300V in 10x mode (150V in 1x)- Looks like they're larger and stiffer than better probes that use silicone like the probemaster probes (which are rated for 600V).That's why I say don't upgrade unless it's actually an upgrade, and wait until you can afford to.

author: battlecoder
author_rank: Regular Contributor
timestamp: October 07, 2023, 04:33:08 pm
content: Quote from: Performa01 on October 07, 2023, 12:20:55 pmThanks for the detailed response. This is my first dive into the depths of probe performance, so all of the information you've shared and detailed comparisons are extremely useful to me.I think the Texas 250 Mhz probes have two adjustable capacitors, so I assume they are for LF and HF adjustment. Would that be a better option if I were to pick a set of probes that can eventually work with other scopes?Quote from: KungFuJosh on October 07, 2023, 03:15:09 pmYou have absolutely no idea how tempted I am by the probemaster kit, so waiting is definitely one of the top options right now (especially after discovering that the included Keysight probes are performing a lot better than I expected).

author: KungFuJosh
author_rank: Super Contributor
timestamp: October 07, 2023, 05:02:07 pm
content: Quote from: battlecoder on October 07, 2023, 04:33:08 pmlol, of course I know! I don't get anything out of telling you about the probemaster stuff...but I've ordered a lot of stuff from them because they're awesome. They're worth the wait. And BTW- I also totally understand your situation where I'm guessing you probably don't actually need any more probes immediately, but you want to be prepared for when you think you will need them... I have a lot of nice probes, but rarely use more than 1 or 2. 😉

author: battlecoder
author_rank: Regular Contributor
timestamp: October 07, 2023, 06:14:30 pm
content: Quote from: KungFuJosh on October 07, 2023, 05:02:07 pmThat's basically it. I don'tneedto squeeze the full bandwidth out of the scope right now. The things I normally do don't require a lot of high speed. I used a 50Mhz scope for the longest time. Later upgraded to 100Mhz and I was happy with that for several years. Now I got a 200Mhz scope and I'm beyond ecstatic. I want to get the most out of the scope, and I was under the impression that I wasn't, due to the probes.I've learned a lot during this entire thread, both due to user suggestions and insights, like yours and Performa01's, and my own tests (That I started doing "properly" just recently), so thank you both.I will not buy any fancy or expensive probe just yet, but since I still need a cheap-ish pair for a FNIRSI scope I will probably buy a pair of the Uni-T or the P2200 probes that I can easily get from AliExpress at a reasonable price.

author: KungFuJosh
author_rank: Super Contributor
timestamp: October 07, 2023, 07:14:25 pm
content: Quote from: battlecoder on October 07, 2023, 06:14:30 pmOkay. One question though: How many probes do you own right now? How many do you use at one time, even if using 2 scopes?You will likely eventually buy those nice probemaster probes, and then you'll have a few extra "cheaper" probes magically available. 😉

author: battlecoder
author_rank: Regular Contributor
timestamp: October 07, 2023, 08:17:53 pm
content: Quote from: KungFuJosh on October 07, 2023, 07:14:25 pmI have exactly enough probes for every oscilloscope I own. No "spares" per se.A lot of the probes don't see a lot of use, though. Partly because I have several scopes that I don't use often, but also because I normally don't do more than 1 or 2 channel measurements, even on the 4-channel scopes I own.Now, all the probes I have on the low-end and portable devices are generic, unbranded cheap probes that either came with them, or I bought separately, and only one pair of them has a performance so bad that I will probably be replacing them soon. I wouldn't use them on my main scopes.My "main" scopes, however, is where I want the "quality" probes; A Rigol DS1054Z (4 channels, 100Mhz) and my newly acquired Keysight DSO2000X 200Mhz scope.The Keysight, despite having been upgraded to 200Mhz, came with the 150 Mhz stock probes (because the seller sold me the unit "as it came in the box").The Rigol has "mostly" the stock probes too, but they are already good enough for the unit (150Mhz probes on a 100Mhz scope).Why "Mostly" on the Rigol? Well, that's where the RP3300A 350Mhz probe comes from. I wasunluckyenough to get a defective probe with my Rigol DS1054Z. The probe was working fine in 1x, but it was dodgy af and barely working on 10x (bad switch contact). When I approached my local distributor with the issue they told me they didn't have stock of the original probes and offered me the RP3300A instead, so technically my DS1054Z has only 3 perfectly working "stock" probes, one probe that is "1x only" (which I probably should've thrown away), and the RP3300A which is a bit too much for the scope so I normally don't use it unless I truly need 4 channels on that one scope.If any of those probes were to fail, I would be left with not enough probes for all my scopes (although assuming some level of compatibility between them I could "borrow" a probe from another scope and use it. It's *not* like I needallmy scopes, withallof their channels, simultaneously ).So;TLDR? I have barely enough probes for my scopes. One of them is an oddball that is not "factory supplied" but became my higher performance probe. How many do I regularly use? like 2 or 3

author: KungFuJosh
author_rank: Super Contributor
timestamp: October 07, 2023, 10:24:17 pm
content: Like I said, you're not lacking probes. 😉

author: battlecoder
author_rank: Regular Contributor
timestamp: October 08, 2023, 02:27:06 am
content: Quote from: KungFuJosh on October 07, 2023, 10:24:17 pmI mean... I also like to keep them compensated (and color coded) to the channels of the scope I use them with. I don't normally switch probes around even on the same device. The only probe that was not strictly associated to a scope/channel was the 350 Mhz probe.But yes, true, It's not like I would struggle to find a probe (or an oscilloscope) here.

author: Performa01
author_rank: Super Contributor
timestamp: October 08, 2023, 09:24:55 am
content: Quote from: battlecoder on October 07, 2023, 04:33:08 pmYes. Like I said, matching a random probe with a random scope is sort of a gamble. Having a user adjustable HF compensation helps a lot in this regard, but still cannot guarantee perfectly flawless performance, as my test with the TesTec TT-MF312 has demonstrated.Furthermore I wanted to remind you on another problem - it's not the probe, but theprobing. For all my tests, I have used a probe-coax adapter, connected to a 25 ohms source, which does not even remotely resemble the normal use case. In practice you might have higher impedance nodes and you use the supplied ground leads. This way you cannot get any meaningful results at high frequencies anyway, see reply #62 here:https://www.eevblog.com/forum/testgear/siglent-sds1104x-e-in-depth-review/msg1435196/#msg1435196Look at the awful pulse responses - any pulse measurements the scope might have will be meaningless with heavily distorted signals like this.To cut a long story short, as long as you are not measuring low impedance nodes and stick to short ground springs instead of the crocodile clips, probe quality doesn't matter and resuls above some 30 MHz will be just visual indicators, but not measurements. And do not forget, this is valid for sine waves only. Even a 1 MHz square wave with short rise time will be distorted, because its harmonics might extend up to several hundred MHz.

author: battlecoder
author_rank: Regular Contributor
timestamp: October 08, 2023, 10:02:57 pm
content: Quote from: Performa01 on October 08, 2023, 09:24:55 amThanks again for the incredibly insightful response. I've been made extremely aware of how probing at "high" frequencies is problematic during the last several days, due to this very same thread. In fact, I don't quite remember how I originally measured that the probes were limiting my bandwidth (the reason I started looking for >250Mhz probes), but I'm 99% sure it was due to badprobing, as I later did a proper bandwidth test with a probe-bnc adapter and a 25 ohms source that confirmed that the probes were pretty OK up to the whole oscilloscope bandwidth.As you say, "proper" bandwidth checks are done in conditions that are far from normal circuit probing, though, so that's also something to keep in mind.