Need to buy a digital scope, wary of chinese popular brands - Page 1
Forum section: electronics / testgear

author: BadPenny
author_rank: Contributor
timestamp: August 07, 2018, 09:26:35 am
content: Hi,First post new here, not new completely to electronics in fact in 90’s bought and sold surplus test equipment pre-eBay. I have spent 4 days reading and watching youtube videos on scopes and the video Dave did on the Agilent 64622 scope he used to use interested me to look at it or the HP64645. You might ask is why a 20 year old scope versus a Rigol or Siglent, really its a lack of confidence in chinese QC. I need to buy a $500 scope that works, no b.s. and sending it back to the US for repairs isnt an option. I have confidence in both reliability and accuracy of HP and Tek, and dont need 4 channels.I have lived where there are no local distributors or even anyone I know uses scopes except automotive. We receive cheap really crappy junk unsellable in the USA it seems from China that they dump here in Latin America ( no FTC or consumer protection like the US). I never had the things happen QC wise with Chinese products in the states. Here, completely different. I had an electrolytic capacitor catch on fire inside a DVD player, forks and spoons rust and corrode in few months, LED bulbs 50% failure rate even though UL approved supposedly, etc. I could go on and on, I have a really huge disrespect for this behavior of dumping junk like this here as they take advantage of low income consumers.So I have read all these people buying these $300-400 Chinese scopes and they look pretty decent externally. Inside they look ok too. I dont know how good the shielding is, or heat syncing designs or other trade offs I am making if I go with a new scope versus a old standby brand. I have read various comments good and bad on the Rigol encoder knobs, software issues, etc. not sure if this is all 4 year old software old bugs now fixed or still exists. The iPhones of course are made in China and the QC is amazing.I am retired and planning to do waveform research at my shop on audio signals and circuits, max is human hearing range of 8hz to 20khz. No digital arduino stuff or logic really except 555 timers maybe just all old analog circuits related to guitar pedals and effects. No microwave or RF.I want to do Frequency domain work eventually and the sampling FFT and store waveforms I capture to perhaps design circuits to emulate vacuum tube frequency response, study the VST software tone emulations, Kemper digital unit, Roland COSM effects, Line 6 emulated, etc. I have basic data acquistition experience in Ultrasound back in the 80’s so not starting completely newbie.In the past have used Tek 465, 475, 7000 series mainframes, but they are not an option as they weigh a ton and risk breaking crt’s in transit. I have even used really old reliable tube scopes like the 400 series in the 70’s analog.... but never owned a digital scope or touched any since 1990’s. The companies I worked for were all strictly HP and Tek, no “secondary” brands like Leader, BK, etc brands. So I have put aside the prejudice of Chinese experience with other products to look at the Siglent and Rigol also. Any comments welcomed about your experiences with Chinese 50-100mhz scope models and customer service in the States, I was shocked to see Rigol is in Beaverton where TEK was born. Thanks in advance.

author: tautech
author_rank: Super Contributor
timestamp: August 07, 2018, 09:40:16 am
content: Welcome to the forum.Looking at Siglent USA's 'how to buy' it seems your closest dealer is Mexico.Logicbus SA de CV(33) 3854 5975www.logicbus.com.mxsupport@logicbus.comA good little 2ch DSO is SDS1202X-E, a 200 MHz unit with 1Mpt FFT which for your needs is much better than others in your price bracket.They're a lot scope and once you start diving into datasheets and comparing them all you'll see why.Good luck for your hunt.

author: nctnico
author_rank: Super Contributor
timestamp: August 07, 2018, 10:03:30 am
content: Quote from: BadPenny on August 07, 2018, 09:26:35 amThe only Asian brands I trust are GW Instek (Taiwan) and MicSig (Chinese) because they have stable and mature firmware (unlike their Asian competitors). A Rigol DS1054Z is an exception because Rigol fixed the last bugs in this oscilloscope a couple of months ago (which is several years after the original introduction).A GW Instek GDS1054B may be of interest to you. This has 1MPts FFT and input signal filtering (for example to filter away mains hum) which are very handy for low frequency work.

author: Old Printer
author_rank: Frequent Contributor
timestamp: August 07, 2018, 12:56:08 pm
content: There are at least two audio guys on YouTube that like the Analog Discovery for that. Tomtektest and Elpaso Tube Amps both have several videos on the subject. I have both the AD and the AD2 and really like them.

author: Zucca
author_rank: Unknown
timestamp: August 07, 2018, 01:24:48 pm
content: +1if you want to do only audio, a good cheap ass sound card 24bit 192Kbit/sec with a proper front end can do miracles.If you want morehttps://store.digilentinc.com/analog-discovery-2-100msps-usb-oscilloscope-logic-analyzer-and-variable-power-supply/even morehttps://quantasylum.com/products/qa401-audio-analyzerOnly then buy a scope if you need something more.A good place for bathroom reading:http://www.diyaudio.com/

author: Old Printer
author_rank: Frequent Contributor
timestamp: August 07, 2018, 02:28:12 pm
content: Also Tomtektest worked with an audio analyzer software package that he thought very highly of. It was freely posted on the author's website for a while, then for some reason the author pulled it and went silent. Tom is a very "by the book" guy and stopped openly promoting the software at that point. However once something is posted on the internet it is very hard to make it completely disappear. I had no interest in the software so I never looked for it, but a copy of it might be out there somewhere. I believe Tom still has his videos of it posted.

author: GregDunn
author_rank: Frequent Contributor
timestamp: August 07, 2018, 05:26:30 pm
content: I do audio only, and lived with a Tek 922 for decades. When I finally went digital, the Siglent SDS1000 series seemed the best buy for the money; it's responsive and accurate and (if you care) has an excellent web-based interface to allow remote viewing and control. There's almost nothing in modern digital scopes to go bad; if they run for a few dozen hours they're likely to keep going. Sadly, you're not likely to get a better Tek or Keysight scope unless you spend quite a bit more.

author: BadPenny
author_rank: Contributor
timestamp: August 07, 2018, 05:28:02 pm
content: Thank you all for the audio references, I will go read them now. Come to think about it, I have purchased for resale probably 100+ LCD TFT monitors from Taiwan now 15+ years back. All were great, no defects, no hassles so good point about that.This popularity of the Rigol showing up everywhere in searching it seems was amazing, not sure if a marketing success or just the price. Yet digging deeper it sorta appeared new entry level people were able to afford a brand new digital scope, or unfamilar with scopes as instruments and what they were supposed to do.Years ago I was an Applications Engineer working for a manufacturer of large complex multi tasking systems electro mechanical systems. The software bugs back then by the programmers on old 8086 and 8088 distributed processing for Intel hardware in multibus designs, writing code and compiling and finally loading into eeprom was a huge expense, bad software bankrupted the company. The tools to debug were slow.... fast forward to today and compiling and testing takes much less time a fraction of it. 4 years to fix bugs?, that is bad imo for a pro-sumer sort of product. Were these operational bugs that prevented accurate measurements? Or functional reboots and crashes? How serious were they?Dave did use a Siglent I noticed in his videos for his latest video on the crashing monitor, but the other brands mentioned above I had looked at or not yet seen. The feedback I got from the eBay seller was that I should look at the newer scopes for capturing waveform data. The manufacturing quality and reliability is a real issue, I cant simply send it back easily in UPS ground like when I was in the states.

author: ttelectronic
author_rank: Regular Contributor
timestamp: August 07, 2018, 06:11:01 pm
content: Someone else with more experience can probably help you more. For what I do it works fine for me (Rigol 1054z). If you do go with the Rigol I highly recommend DSRemote/EDFBrowser, it's linux only but a great and extremely useful tool for catching the waveform data from the scope. I run a virtual box with linux to use it.Pretty comprehensive bug list herehttps://www.eevblog.com/forum/testgear/rigol-ds1000z-series-buglist-continued-%28from-fw-00-04-04-03-02%29/

author: nctnico
author_rank: Super Contributor
timestamp: August 07, 2018, 06:12:10 pm
content: Quote from: BadPenny on August 07, 2018, 05:28:02 pmThe problem is that oscilloscope firmware has become a lot more complicated. Software testing is an art and also very time consuming. You really need regression testing along a test plan with fixed release cycles to get it right. The cheaper Chinese brands don't seem to do that at all and use the customers as software testers. It seems a bug which isn't discovered or is affecting only a few customers isn't worth fixing. Kind of a hit & run strategy.Several years ago I bought a higher end Siglent scope for several $k and it turned out to be absolute crap and Siglent didn't want to take it back. After one year I threw it away and bought a different oscilloscope because I needed an oscilloscope which worked right immediately. Siglent expected me to wait forever for them to fix the software which they kind of did nearly 3 years after I bought it. Rigol pulls the same tricks.

author: BadPenny
author_rank: Contributor
timestamp: August 07, 2018, 07:46:17 pm
content: Quote from: nctnico on August 07, 2018, 06:12:10 pmI recall that scenario of “ship it- then as customers complain fix it ad-hoc”, and bugs are prioritized as severity, that really is a hokey way of doing business, especially in today’s world. The US company I worked for in the 80’s did that, we had very complex machines and management were always short term this quarter thinking and financial concerns of operational profit and reporting to bean counters surpassed the need for thorough testing before shipping. I was enlisted and did functional operation testing with no written or organized procedures, just “try and make it crash” mentality. They went out of business eventually.Certainly with asic’s the complexity has increased but I assumed that numerous prepared designs, software libraries and years of past experience, tools, vast resources of free data and information on the net, customer immediate feedback, etc.. they would have QC procedures for these sorts of high volume products and would be better by now 30 years later. Thats disheartening. Mixing analog and digital interface controls and encoders was a problem way back, I thought by now it might be more advanced, reading about the lack of detent controls on one Rigol thread here shocked me, like it was a toy not a test instrument.

author: BadPenny
author_rank: Contributor
timestamp: August 07, 2018, 08:11:43 pm
content: Quote from: Old Printer on August 07, 2018, 12:56:08 pmI am looking at this Analog Discovery device and its impressive. Small, cheap to ship/import, etc. the direct attached breadboard header thing with jumper wires direct is interesting too. But, to display the waveforms I need to use a pc, I wonder if I should jump to Linux now. I reluctantly bought a laptop with Windows 10 in 2017 after years from Dos to old reliable Windows Vista through 2017. I prefer living on the reliable “trailing edge”... lol.The internet direct thing and stupid tie in Microsoft 10 has for constant updates, news, weather and all this crap in interface (I turned updates off in Wndows 10 control panel but my request is evidently ignored) worries me how much of a pain it is to deal with if doing complex work and you walk away for a few minutes and the system reboots under “Microsoft update command”... lol. Skype even shows up unannounced always too, I shut the dumb thing off but it appears to be resident anyway with “updates” constantly. I had a SD card full of data I was transferring damaged by this b.s. of an interrupt and update. I dont trust Windows 10 at all, there must be some secret shut off somewhere. I use mostly Mac devices which are imho better, at least they don’t force updates and require user permission before proceeding. Maybe I should uninstall Windows 10 and put on 7 instead or buy a cheap Linux box. Any suggestions on a simple Linux easy to learn display solution with the waveforms software and Analog Discovery box? I need to read more. Thanks.

author: BadPenny
author_rank: Contributor
timestamp: August 07, 2018, 09:12:51 pm
content: I looked at DIYaudio, good resource I didn’t know about thanks. I saw a post on Virtins software interface and using a M audio Mobile Pre USB interface which I do own already so its an interesting idea of using the sound interface or card to measure. So I suppose I didnt think about the other end of measuring will be using a flat mic input also for this, then output to Audacity also.

author: Wolfgang
author_rank: Super Contributor
timestamp: August 07, 2018, 09:30:33 pm
content: I dont know if I am correct, but the best selling scope of the past few years was the RIGOL DS1052 series.There are a lot of reviews on the net, even some by Dave Jones here on EEVBlog. Its old, but fairly bug freeand dirt cheap.

author: Old Printer
author_rank: Frequent Contributor
timestamp: August 07, 2018, 11:34:49 pm
content: I am still running Windows 7 both at home and at work. It is stable and does what I need. I have been meaning to look into linux on my home pc but have not had the time. A PC and the internet is an important part of my bench, so the Analog Discovery was a good fit and it gave me a lot of tools for learning in one package. Certainly it has it's limits and I will have a dedicated DSO before too long, probably the Siglent SDS1104X-E, but the AD is still a decent logic analyzer so I expect it to be on my bench for a good while.

author: Fsck
author_rank: Super Contributor
timestamp: August 08, 2018, 09:21:33 pm
content: Quote from: Old Printer on August 07, 2018, 11:34:49 pmdon't forget that the AD? (dunno about v1) but the AD2 is 14-bit ADC, so it'll still be a useful data acquisition system compared to an oscilloscope.

author: Old Printer
author_rank: Frequent Contributor
timestamp: August 08, 2018, 11:01:16 pm
content: Quote from: Fsck on August 08, 2018, 09:21:33 pmYes, that is true. Spectrum & Network analyzer and a few other goodies. The AD1 & AD2 are the same 14 bit ADC spec and everything else, but the AD2 has the variable voltage supply, but I have 2 HP 6216A & 1 C PS on my bench and prefer to use those, so I get by fine with the AD1.

author: rstofer
author_rank: Super Contributor
timestamp: August 08, 2018, 11:41:10 pm
content: Quote from: BadPenny on August 07, 2018, 05:28:02 pmThe bugs fixed in the later releases were so far out at the margins that practically nobody ever found them. The use cases were minimal. One of the last bugs to get fixed was a label on the screen 'pluses' instead of 'pulses'. It became a standing joke.It did take 4 years, the scope was released in late 2014 and the bugs were cleaned up by early 2018. Call it 3-1/2 years. Not outstanding but since the bugs were way out at the margins, not too many people were concerned. I certainly wasn't. All I wanted and expected was some squiggly lines that were somehow related to voltage and frequency. I also wanted the decoding of 4 channel SPI. That was my objective and when I bought the scope those features were working.Don't be surprised to find that $17,000 scopes have features that the DS1054Z lacks.Clearly the American and German scopes are better. You should probably head in that direction as you seem worried about the Chinese scopes.

author: BravoV
author_rank: Super Contributor
timestamp: August 09, 2018, 01:21:37 am
content: Wary or worry too much ? Then stop even to consider Chinese brand, your life quality, your sleep, your sanity is worth much more, just buy brand new American or German scope, period.My 2 cents worth.

author: DaJMasta
author_rank: Super Contributor
timestamp: August 09, 2018, 01:34:57 am
content: Or recognize that there are number of Chinese and other brands that sell many times the number of scopes because of their fantastic value by comparison, and very few of them are replacements to the same person.A Rigol, Siglent, etc. would be built down to a price (maybe more than some other brands, but at the lowest price point generally not), but they live up to their specifications, are used by thousands and are extremely well analyzed even just here on the forum, and often offer features and performance that other brands simply can't touch at the same pricepoint.There are definitely firmware and hardware issues that crop up with things... but do you think Keysight or LeCroy don't have the same happening? Definitely not the case, though if you're paying the big premium you may get more responsive tech support.Find a scope that offers you the features and performance you want for a price you can afford, then look for reviews and information from users. That's it. No need to worry about whether X brand churns out shit products or is full of firmware bugs if there are videos of it being used, taken apart, compared to competing products, and tons of information from people who own and use one. It's fair to argue about long term use when looking at stuff built for a shorter life cycle, but if it's almost all solid state... that doesn't come up quite as much. It's also worth saying that even if you get 5-10 years out of a new inexpensive scope, isn't it a pretty tall order to get 5-10 years of use out of a 15 year old used scope from a main brand that goes for the same price? It's going to run into issues too because it's actually 20-25 years old by the time the new one approaches the end of its life. Maybe it's more serviceable, but then the parts may be harder to get, and there are analysis and deep memory related features that are dramatically better in cheap modern scopes than old higher end scopes.It's all a tradeoff... so don't put too much weight on what brand it is and look at performance, features, overall quality of the unit in question, and expected longevity... then see what wins. For plenty of people, that's a lower end Chinese made scope, and that doesn't make their choice wrong.

author: rsjsouza
author_rank: Super Contributor
timestamp: August 09, 2018, 03:01:25 am
content: As others have said, the Rigol DS1054Z has all its bugs settled and it is a very nice oscilloscope for what you need. The Analog Discovery is also well regarded around here, with the benefit of having some very good specs for audio.If, however, you prefer to drive a physical oscilloscope interface and is a bit afraid of jumping to an unknown brand for you, I would also recommend the Keysight DSOX1102G - at 70MHz, 2 channels and with built-in signal generator, it is a good value for your buck.

author: bitseeker
author_rank: Super Contributor
timestamp: August 09, 2018, 03:40:36 am
content: Quote from: BadPenny on August 07, 2018, 09:12:51 pmWelcome to the forum, BadPenny!Since your primary focus is audio and you already have some of the hardware to get started, your main decision point is how much resolution you need for what you want to do in the audio realm. Most oscilloscopes use only 8-bit samples. A few use 10 bits. If that doesn't fit your requirements, then don't think about which oscilloscope to get because that's not the right tool for you.The Analog Discovery (1 or 2) has many tools that can be great for audio. However, note that it uses 14-bit samples. Is that enough for your requirements? If so, then it may be a good option. If your budget allows, you might grab one for supplemental uses if the features are suitable.Otherwise, if you need 16- or 24-bit samples, you're better off sticking with hardware designed for audio.

author: BadPenny
author_rank: Contributor
timestamp: August 09, 2018, 08:55:20 am
content: Quote from: bitseeker on August 09, 2018, 03:40:36 amThanks, I am still absorbing all the data. Looked all day and night several days at various things and at some additional videos and El Paso Tubes found that the AD2 A/C signal (I am looking at small signal guitar mono jack outputs with 8-130k impedance measured with a volt meter) he determined it wasn’t accurate as his HP Audio analyzer and other equipment. But started also looking at the HP 8903b today using the PMillett software. Its going to be a process, the FFT accuracy is important and I almost think I need to have higher res to be able to do what I want, that and I am getting in over my skill level the more I read.I am intrigued at the ability this Kemper unit is able to duplicate tonal qualities in solid state of various popular tube guitar amplifiers, much better technology than anything before it. Amazing, but it costs $2000. Its patented and secret, but from what I can tell watching the thing sweeping and it cycles through the bandwidth at various levels determing amplifier characteristics, of which all are non linear.My initial goal now is a feasibility study. And all I want to do is built a couple of solid state or nutube preamps that emulate specific tonal qualities, ( like AC 30 and Marshall Plexi ) to be able to have low volume warmer tone non dependent on amplifier high volumes. I bought some class D audio amps to drive, but need proper signal conditioning in the front end preamp. The manufacturers like Line 6 and Roland Cosm effects have DSP based products for years, but I have only one pedal that I truly like that is a DI box, but its no good for clean chimey sounds like the AC30 with a treble booster which I used to own. I had to crank to really high gain to get the tone. I have owned numerous modeling amps, none of which I liked and just sold them. Its not like anything I want or need with a bazillion profiles, and want to do it with discrete components without using any signal processing in digital, or if so in some so, sort of lookup table in firmware or ram.Heres a demo of it being used to emulate EVH tone.https://youtu.be/L_XaZqgvr3Uhttps://youtu.be/h0SmSl1aS1w

author: Fungus
author_rank: Super Contributor
timestamp: August 09, 2018, 11:58:00 am
content: Quote from: nctnico on August 07, 2018, 10:03:30 amAlso: If you look for people having hardware failures you won't find many. Those things are solidly built.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: August 09, 2018, 03:27:08 pm
content: With audio you can get a long way with an USB soundcard.Not much reason to hesitate to modify a EUR 20 USB sound card, you can even use an USB isolator if that is beneficial to your goal.Such a card is however never going to show a 100MHz oscillation in your audio circuit.How about buying a 5 to 10 year old Tektronix or Rhode & Schwarts?Those are probably not even halfway the "reliability bathtub" and good for many years of use.No need to worry about dealers or warranty, you probably won't have it

author: Wolfgang
author_rank: Super Contributor
timestamp: August 09, 2018, 04:29:00 pm
content: If you need something that is cheap and just works, choose something old that has stood the test of time. The fancier, the newer, the buggier. Scopes are no exception. Something sold in the millions is probably not too bad.

author: BadPenny
author_rank: Contributor
timestamp: August 10, 2018, 04:47:18 am
content: Well appreciate all the input and ideas. I need to define my requirements deeper than expected and have been looking at all the different options and audio cards, like this company that includes various audio spectral analysis software, their comments about FFT’s were interesting and more thought provoking. Seems as though an Oscilloscope isn’t actually what I need as some of you have pointed out but rather a range of tools like what the Analog Discovery offers.https://www.rme-audio.de/old/english/digicheck/totalyser.htmI have looked at the videos recommended and links to other sites, there is a lot more info and applications data available than I ever expected. In a pro audio forum as well as another review I noticed that the DSP chip sets in one of the modeling units were Analog devices so more info on Analog.com to read. Regarding sample rates, it appears that going with an audio card is better than a oscope, provided it comes with decent drivers or software. I have never used a vector scope as included in the RME Digicheck package, only have seen them in broadcast hardware sales catalogs and not sure about how useful it would be.So, it looks like for now I am going to hold off and research more and not going to rush out to buy an oscilloscope.Couldn’t find a Fluke locally, so my $60. ST 505 chinese multimeter that I just purchased for general use had the back stand tilt bracket simply break off out of the box. Lol. Voltage readings seem ok. The Capacitor measurement seems to operate ok, its not autoranging design but appears to be fairly accurate and stable between selected ranges. The HFE transistor reader does nothing for some reason and I tried several working NPN’s in it, nothing at all just open circuit infinity. I guess that option wasnt really included or the firmware needs an update. Ha. My GF handed me a 1 month old chinese ventilation fan today she bought for $20, she said it didnt work. On closer look, something overheated inside, it seized up and melted. Great, fire hazard. This is too much. Even simple stuff, like we have wooden clothes pins, the 1950’s style purchased at the local Walmart we have here, evidently no incoming QC there either and all have fallen apart after one use, they evidently were designed for single use. Lol.I paid $29 for (3) small 3”x3” printed and drilled kit PCB’s for DIY projects, the package came in today and was a small envelope from somewhere interstate to Miami only $2.50. The shipping, tax, handling, gas surcharge and import sales tax and fees to here from Miami came to an additional $18. Crazy.

author: bitseeker
author_rank: Super Contributor
timestamp: August 10, 2018, 05:01:01 am
content: Quote from: BadPenny on August 10, 2018, 04:47:18 amNo worries. Sounds like you're off to a good start. Better to take the time to get what will fit the bill than have to start over.

author: BadPenny
author_rank: Contributor
timestamp: October 08, 2018, 06:20:34 am
content: Well for the price and seemingly overwhelming popularity- I bought the Rigol 1054z for $349 fulfilled through Amazon by Tequipment/Rigol. I was pleasantly surprised how nice it is, nothing like the other chinese stuff I have purchased locally at all. I had it hand carried to me from someone in the States to avoid shipping costs- which were quoted double the price direct by Tequipment. The soundcard thing would not work for me as I don't have an open IDE Bus like PC in which to play with. Analog discovery I liked and was the same price and I wanted a dedicated device, not having to use a laptop to display. The price/performance and reviews were accurate, and most options are installed (I think) and 50mhz is fine for audio.Funny, first thing I noticed when I plugged it in was how noisy it was. After looking at it abit I got out my mains tester to verify that my guess was correct was 60 hz noise, I discovered the only 110vac outlet I chose to use in the entire house was not grounded... ha.I tried to do some single shot triggered wave forms, but I need to design a simple circuit to have a countdown timer to notify me to trigger (Hit a guitar string) for a one shot, capture the waveform to USB, then reset and repeat this sequence. So I need to look around for something like a 555 timer I guess.I do have a question, I am not sure how to approach this and if I can have a macro on the scope to auto reset the trigger after a certain period of time delay without manually pushing the front panel. Or should I build something to use the external trigger? Any input appreciated. Maybe this should be a question for the beginner thread.I bought Dave's Bryman Multimeter a week ago and it will be hand delivered down here by a friend next week, looking forward to having a decent MM, this other one here is crap.Spent the past month watching ton's of Dave's videos. Really Great stuff- tonight watching him take apart the Yamaha mixing board on #840, and lying down on the entire console knobs like a bed of nails. Wish I would have discovered his channel years back. Bob's your uncle!I need to straighten out my wiring first though.

author: Fungus
author_rank: Super Contributor
timestamp: October 08, 2018, 06:47:42 am
content: Quote from: BadPenny on October 08, 2018, 06:20:34 amnb. The external trigger connector is anoutput.If you want to trigger from an external signal you have to use one of the connectors on the front.