Virtins unknown USB DSO's vs. other bench 100Mhz 1GSa/s DSO's? - Page 1
Forum section: electronics / testgear

author: KNA
author_rank: Newbie
timestamp: August 10, 2014, 06:54:02 am
content: Hey there,I'm looking for my first 100MHz oscilloscope around ~AU$400 for my EE studies and I'm drowning in information that all leads back to this forum. However, I stumbled acrossVirtins range of USB oscilloscopes. I cannot find any reviews on the net, apart from the feedback left on theireBay store, so I'm hoping someone here has some experience with them.Virtins USB oscilloscopes use theirMulti-Instrument softwarewhich has a free 21 day trial everyone can try and overall I have nothing else to compare it too but I like it. There are quite a few reviews favorable on the software itself. Plus their DSO's have a arbitrary signal generator in them, with some maxing out at ± 2 V 10-bit 200MSPS 60MHz, which is nice, two birds, one stone.Only thing I'm not sure about is that Virtins best oscilloscope VT DSO-2820E is 8~16Bit 200MSPS 80MHz, I suppose limited by USB2 speeds, where the standard comparable Rigol DS1052E/DS1102E, Siglent SDS1102CML, Owon SDS7102EV, Hantek DSO5102B, are all 8bit 100Mhz 1GSa/s 1M+ memory, i.e. much better sample rate and bandwidth, but the Virtins have memory limited only by your computer.Plus the only DSO oscilloscope I've used is the Tektronix TDS220 (which I don't mind) where with a USB scope there are no physical knobs and buttons but I'm not to fussed. However you're using a clear massive PC screen.Then if I go for a bench DSO, I'm uncertain what to get in the 100Mhz 1GSa/s range, hard to compare them with their different ages:Rigol DS1052E/DS1102E: Well regarded, lots of support here, hackable to 100MHz, 1Mpts, fairly old now, I saw someone has interfaced with it using python which is coolSiglent SDS1102CML: I don't actually remember why I liked this over the rigol, larger screen maybe, 2Mpts, but same specs as the rigolOwon SDS7102EV: 10Mpts, LAN!, VGA, largest high res screen, also saw python interfacing in this forum, I've seen marmad 3yo review, Dave didn't particularly like it (or maybe another Owon) from memory, have they fixed the firmware?Hantek DSO5102B: Linux based so hackable to 200Mhz, 1MptsSo I guess the question boils down to:Has anyone used a Virtins oscilloscope, what are your impressions?Should I go with a USB scope? I know the general consensus is that people don't particularly like them.What others have I missed in the ~AU$400 price range?At the moment I'm still very undecided but narrowed it down to the most bang for buck, which in my mind are the Rigol DS1052E/DS1102E, Owon SDS7102EV or Virtins VT DSO-2820E.

author: Creep
author_rank: Regular Contributor
timestamp: August 10, 2014, 07:10:38 am
content: After using a Hantek USB scope for a while I can tell you this: using it is not much of a joy. Right now you say your okay without physical buttons and knobs but after getting to use it for a bit you will start craving for them. On the 100$ range the usb dso might but okay because of the really harsh budget, but even then only if you can't get your hands on an analog scope.I would suggest you going for one of the real desktop DSOs. If you can piece together a bit more cash, the Rigol DS1074Z (after having a quick look on ebay you can get it for 640 AU $ in australia, probably can find it cheaper as well, not too sure about prices in AU) would be leaps and bounds ahead of the scopes you mentioned. If however 400 AU$ is your final budget, the choise is not going to be as simple, though most people will probably suggest you to stick with the Rigol DS1052E.

author: KNA
author_rank: Newbie
timestamp: August 10, 2014, 08:44:40 am
content: Quote from: Creep on August 10, 2014, 07:10:38 amI've seen some Hantek usb scopes on youtube an they look fairly poor, plus they are 20Mhz, which is lower than what I'm after. Then again, after playing around with the Virtins scopes Multi instruments program with my sound card, it has a nice interface and you get to use a massive computer screen. However, it is truly satisfying and convenient using physical buttons and knobs of a bench scope.QuoteI have checked out the Rigol DS1074Z and 2074A(?) and thanks for looking but they are the next step up in budget as a student. Maybe someday I'll upgrade to one but at the moment the Rigol DS1052E does seem a solid choice. I keep thinking though that the DS1052E is from 2008, surely there must be something better in that price range, and perhaps it's the Owon SDS7102EV, on paper, with the massive memory, screen, connectivity options (LAN interface)? I still have to further research again what issues it has. I guess however this is the industrial equipment market, they settle on good designs for years/decades and therefore the DS1052E isn't relatively that old.

author: tautech
author_rank: Super Contributor
timestamp: August 10, 2014, 08:57:43 am
content: You wouldn't be disappointed with a Siglent SDS1102CML.The model is proven and firmware mature.When I started with DSO's they were all 5" screen models in your price range.The change to 7" IMO was a great advance, menus could be up on screen and you still had a 5" screen(10 div Horizontal).If price if of real concern, you could get a CNL and add the extra memory or 1072CML/CNL that share the same HW as 100 MHz modelsI have a good number of CNL's sold with zero problems to date.

author: IanB
author_rank: Super Contributor
timestamp: August 10, 2014, 09:01:23 am
content: Quote from: KNA on August 10, 2014, 08:44:40 amThe 1052E is basic, but it is reliable and functional. These days I think the 1102E is only $50 more. I have found my 1102E to do just what it is supposed to do, exactly according to the manual, and I have not come across any firmware bugs or annoyances.Some of the other brands in the same price bracket may offer more features, but they may also have more quirks.

author: artag
author_rank: Super Contributor
timestamp: August 10, 2014, 02:02:37 pm
content: The software on a USB scope is absolutely critical to whether it's a good buy.I used to always prefer 'hard' instruments - not messing around moving windows on a laptop but with proper knobs to twiddle. Then I used Saleae's LA software and although I still like a physical interface I'm prepared to believe that it can be done right. The key is to think of it as a PC application aimed at being usable and making the best of the environment, not putting up a picture of an oscilloscope and using the GUI to tweak imitation knobs. That gives you the worst of both worlds, with only a slight familiarity advantage to compensate.

author: nctnico
author_rank: Super Contributor
timestamp: August 10, 2014, 02:37:22 pm
content: IMHO a logic analyser is much better to use with a PC software interface. Most modern higher end logic analysers are just that: a PC with acquisition hardware. Actually the logic analyser mainframes you can buy from Tektronix today are nothing more than a power supply and a network interface to the acquisition modules. You can choose to use your own PC or buy one pre-installed from Tektronix.That being typed: an oscilloscope is easier to use with real buttons or a good touch screen interface. Having to click or slide through all kinds of settings is a nuisance. Some people actually build USB keyboard emulators to have real controls for the USB oscilloscope.

author: Mark_O
author_rank: Frequent Contributor
timestamp: August 11, 2014, 09:06:59 am
content: Quote from: KNA on August 10, 2014, 06:54:02 amNo, that is incorrect. The limitations there are all internal. USB2 limitations don't come into the picture until you switch to streaming mode.QuoteCorrect. And much better than 40k samples (20k/channel in 2-channel mode).QuoteYes, as long as one-channel at 10 MSa/s, or 2-channels at half that, are adequate for your needs. Those are the Virtins USB2 streaming constraints. All USB2 streaming scopes have similar limitations, though most are typically about twice that fast.

author: leafi
author_rank: Regular Contributor
timestamp: November 15, 2015, 07:24:55 am
content: I know this post is very old but I thought that me responding to it may help others who may be considering getting one of these. I actually purchased a VT DSO this week. I purchased the highest end model VT DSO-2A20E. It is advertised as a 80MHz 10-16 bit oscilloscope with 200Msps and a 60Mhz AWG. The ADC inside is a 10 bit Analog devices part and I believe it is being overclocked as I think the part is a -105 which should be 105Msps. I will check the part number when I get back to work.The board design did not have any apparent rework or bogged parts on it however it is obvious that they do not clean the boards as there is a ton of (what I hope is no clean) flux and some solder balls around. The model I purchased has an Altera Cyclone 3 and USB 2 HS.What I really needed was a small portable scope which can be battery powered such as attached to a laptop which this will do. I also wanted one I could stream to the PC hard drive although it is maxed out at 10Msps which sucks but that is USB2 HS for you. I was looking to get a pico scope 3000 series as it is USB3 however it appears their streaming is also that slow. Saelig has the 3503D I believe for around 500 bucks. If Pico can up the streaming capture on it to something close to what Saleae logic pro 16 can do Ill probably just get one. (unless Saleae can get their analog BW up). The 5MHz really hurt me on a project.If anyone actually cares to know more about this family of scopes let me know.

author: Mark_O
author_rank: Frequent Contributor
timestamp: November 15, 2015, 04:12:29 pm
content: Quote from: leafi on November 15, 2015, 07:24:55 amJust curious how much that "quality" cost you? Because it sounds pretty shoddy to me.QuoteNo, that is not USB2 for you. As I mentioned a year ago, other USB2 DSOs can easily manage twice that rate. Some can even approach 30M, assuming we're talking about 8-bit sampling. Of course, at 10-bits, that will burn 2-bytes per sample, cutting your speed in half. And that's the price you pay. In the case of the Virtins though, I'm not confident that what you're getting is really 10-bits, so you may not be seeing as much benefit for that price as you're anticipating.QuoteI assume you're referring to the ps3000D series, which has USB3. And while I agree that it doesappearto be that slow, their Specs are woefully inadequate. And that is for two reasons. 1) they're often far out of date, and reflect capabilities from years past, or even previous models. And 2) they strive to be very conservative, and post worst-case numbers. While that may have some merit, when the numbers are so pessimistic that it would be difficult to find a situation where things got that bad, it is counterproductive for both parties. Even their USB2 models can manage twice the rate they spec in streaming to their software, but it is highly dependent on the PC you're using. So they're reluctant to go out on a limb.QuoteI'm guessing you're referring to the ps3203d, which is priced at $525 there. That's for the 2-channel, analog-only model. No MSO. I'm not familiar with any 3503d model ever being in their lineup. And the USB3 Pico mayalreadybe able to stream just as fast as the LP16... but it won't give you 12-bit sampling, at any speed.QuoteDon't hold your breath on that. You haven't made it clear what your actual needs are, but if you don't need the logic channels, any Saleae is probably not going to be your best choice. That's kind of their strong point, with the analog on the side as a bonus feature.

author: leafi
author_rank: Regular Contributor
timestamp: November 16, 2015, 02:48:48 am
content: Hey MarkI got the scope from Amazon for 420. Honestly it sounded pretty shoddy to me too but it was between this or the Pico scope 3203D (not the 3503d) and I thought it would be better to have the ability to do higher resolution. (I can sort of hear the Indiana Jones Movie in my head telling me I have chosen poorly lol) But if the thing totally sucks I can always do a tear down of it and let others know but it can fill a role for a portable scope I can bring to customers sites for debugging.From what I have seen on the Pico forums they were saying Picos were limited to 10Msps in their SW (it used to be 1Msps but it got increased) but could go higher if use the SDK to make your own capture program. What other ones would you recommend which have higher streaming capture sample rates?Currently I do not need digital however I needed the ability to capture long data streams which would have been far outside of the capture depth of my current equipment. DS2072 unlocked or a DS1074ZS unlocked.The bare minimum I guess was an 8bit scope to stream to the PC. I would prefer USB3 with a fast sample rate and high BW but I don't really have a spec I need to hit. Having an AWG included would also be nice as means I wouldn't have to drag a bench oscilloscope and a bench AWG out of the lab and over to my desk to debug. Having digital would also be nice so you can correlate the digital and analog in time but it is not a total necessity especially on a budget. I would love to hear your suggestions / recommendations. I'm not sure if the price tags will be above the pain threshold for test equipment though.Also I almost forgot. I also needed the ability to do a basic scalar network analyzer for low frequency filters. The SW had the ability to peak detect on the spectrum analyzer and the signal generator could sweep in log. This is not absolutely necessary but it is something I needed for my current project which caused me to look for this. (besides the frustration of trying to make room at my desk for the DS2072 and the DG4062. It just takes up a good deal of space that I did not have.) I looked for USB as the project I have currently is very sensitive to ground loop noise so I can run the oscilloscope and sig gen from a battery powered laptop and there will not be a ground connection.

author: Mark_O
author_rank: Frequent Contributor
timestamp: November 16, 2015, 07:20:12 pm
content: Quote from: leafi on November 16, 2015, 02:48:48 amJust because I am skeptical that it will meet it's performance claims, does not mean it will not. You'd have to try it to see.QuoteIt's a good point that the limits imposed by the PS6 application are completely artificial (both in speed and capacity), and could be set by PicoTech to anything they wanted. I've been trying to convince them for about a year now that there are PC's that have more than a couple hundred MB of RAM.And thus their 100MSa limit is unreasonably low. I've downloaded their software, and was playing with it in Demo mode, which leaves a number of questions unanswered.QuoteYes, their USB3 scopes can easily handle streams at ~150 MB/s, and use all the memory you've got. But while they do include both sample code, and an API document, that doesn't mean that everyone has a programming background, and is comfortable taking advantage of those capabilities.QuoteHow long is "long", and how fast do you need? That has a huge impact on what will and won't be viable for your tasks. High end on one or the other isn't very difficult. High end on BOTH at the same time may be difficult, expensive, or even impossible. In those cases, segmented acquisition may be a solution, if what you need to see is "bursty".QuoteThat's another nice feature of the Pico's, as well as the Virtins. I also agree (while many won't) that having a compact acquisition pod near a laptop PC (within USB cable distance) is often a very good working solution. For some, the convenience of an integrated display and control knobs outweighs every other consideration.QuoteThe Virtins may actually turn out to be a good match for your specific requirements (e.g. log-sweeps), even if it's not the best general-purpose tool out there. It may wind up being the most cost-effective combination instrument.

author: Mark_O
author_rank: Frequent Contributor
timestamp: November 16, 2015, 08:37:14 pm
content: Quote from: leafi on November 15, 2015, 07:24:55 amOnce you get beyond it's max streaming speed (which limits BW pretty dramatically), it's small 40KB internal capacity (10KSa/chan in 10-bit mode, or 100us bursts), seemed rather confining as well.But I will still be interested to hear what your findings are, when you get around to working with this unit.