Best hack upgrade oscilloscope for $1-2k ? - Page 1
Forum section: electronics / testgear

author: covert
author_rank: Newbie
timestamp: May 17, 2021, 08:04:53 am
content: Hard to keep track with all the hacks but what is the best scope with hack upgrade for around $1-$2 k ? Pre tax time spend up.. Just looking for something to grow into. Will be replacing my Siglent SDS1062CM.

author: tautech
author_rank: Super Contributor
timestamp: May 17, 2021, 08:55:32 am
content: Welcome to the forum.Have a hard look at SDS2104X Plus.https://www.eevblog.com/forum/testgear/siglent-sds2000x-plus-coming/

author: normi
author_rank: Regular Contributor
timestamp: May 17, 2021, 04:35:20 pm
content: That's highly subjective, you need to be clear on what features you need and which are more important than others. A $3000 scope may not have some of the features or specs of a $1000 scope. Life would be much easier if as scope prices increased they added more to what cheaper scopes had, so you would only needed to pay more to get more. Manufactures focus on particular features some more than others.

author: Fungus
author_rank: Super Contributor
timestamp: May 17, 2021, 08:31:28 pm
content: There's no way to answer that without knowing what it's going to be used for.(...unless you're a Siglent distributor, in which case the answer isalwaysobvious)

author: Trader
author_rank: Frequent Contributor
timestamp: May 17, 2021, 09:17:06 pm
content: Siglent SDS2104X Plus 100MHz, but you can hack it to "SDS2354X Plus" 500MHz, AWG 50MHzRigol MSO5072* or MSO5074 70MHz, but you can hack it to "MSO5354" 350MHz, AWG 25MHz* I read that the MSO5072 comes with 4 channels, the 2 disabled channels can be enabled by hacking it.Keysight DSOX1204G 70MHz (hack it to maybe 200MHz)Tektronics TBS2074B 70MHz (if hackable, maybe up to 200MHz)

author: nctnico
author_rank: Super Contributor
timestamp: May 17, 2021, 09:29:12 pm
content: Quote from: normi on May 17, 2021, 04:35:20 pmAgreed. What good does a whole bunch of 'free' features do you if the one you actually need isn't among them?

author: Fungus
author_rank: Super Contributor
timestamp: May 18, 2021, 04:52:48 am
content: Quote from: Trader on May 17, 2021, 09:17:06 pmPretty much this.I'm not sure if the Tek is hackable though.Quote from: Trader on May 17, 2021, 09:17:06 pmThey can be enabled but there's only $100 difference and you'll have to buy two more probes, so...

author: covert
author_rank: Newbie
timestamp: May 18, 2021, 11:07:16 pm
content: Thanks for the replies everyone. I'll have a good look over the list and tell you where I end up going.

author: Trader
author_rank: Frequent Contributor
timestamp: May 19, 2021, 08:04:20 pm
content: Quote from: covert on May 18, 2021, 11:07:16 pmA piece of extra and useful information, the Rigol MSO5074 (70MHz) already comes with 4 probes of 350MHz, the others, you need to buy new probes, and high-speed probes are expensive.Let us know what did you decide.

author: bdunham7
author_rank: Super Contributor
timestamp: May 19, 2021, 08:41:03 pm
content: Has anyone tested the Rigol PVP2350? A 1X/10X switchable 350MHz probe seems a bit sketchy. Other 350MHz probes, including the Siglent SP2035, are 10X only and cost a lot more.

author: Fungus
author_rank: Super Contributor
timestamp: May 19, 2021, 10:36:23 pm
content: Quote from: covert on May 18, 2021, 11:07:16 pmIf you're prepared to spend about $1.5k then the Rigol is probably off the list for being right at the bottom of the price range. It's between the Keysight and the Siglent.The keysight is super fast at everything and has a real analog feel to it due to all the sample memory being inside the ASIC. The downside to that is that it doens't have a lot of it - ASIC space is limited.If you're heavily into digital stuff then that's not good and you should probably get the Siglent. If you're more of an analog guy then it's not much of a problem and the analog feel and responsiveness of the keysight can't be beat.

author: kcbrown
author_rank: Frequent Contributor
timestamp: May 20, 2021, 02:49:38 am
content: Within the range of $1k to $2k, why isn't the Instek MSO 4 channel series in the running? It has a very responsive UI if my GDS-1054B is any indication, and it should be hackable, no?Is the sample rate for it (1GS/s) too low for it to be a reasonable candidate? Admittedly, if it were me, I'd go for the SDS2000X+ over the Instek, even with the Instek's superior UI responsiveness, but if you're more into the analog side of the equation then the Instek's spectrum app, which Ithinkcan be had via hackery, may be hard to beat.

author: nctnico
author_rank: Super Contributor
timestamp: May 20, 2021, 08:11:27 am
content: Quote from: kcbrown on May 20, 2021, 02:49:38 amYes, that is a good option as well and it has some neat features the others don't have (like digital signal filtering).

author: bdunham7
author_rank: Super Contributor
timestamp: May 20, 2021, 03:39:52 pm
content: https://www.tequipment.net/Instek/MSO-2204EA/Mixed-Signal-Oscilloscopes-(MSO)/#descriptionIt looks like it includes everything including the logic probe kit, arb-gen, 200MHz and all the software options for under $1500. No hacking, no extras.

author: Fungus
author_rank: Super Contributor
timestamp: May 20, 2021, 04:58:12 pm
content: Quote from: bdunham7 on May 20, 2021, 03:39:52 pmLooks like a bargain to me.

author: normi
author_rank: Regular Contributor
timestamp: May 21, 2021, 04:44:04 pm
content: The Video from Howard Long "Comparing the Rigol MSO5000 vs Siglent SDS2000X Plus" is dated, some of the issues are corrected by firmware and a lot of it is his own personal peeves which in most cases are not really valid in a comparison.Example.1. Siglent does not have ability to search decoded data, Rigol can but only on the 4 analog channel. He focuses on the fact that it does not do it on the digital channels. Siglent can't do it so that is the major point.2. Rigol has HDMI out Siglent no form of vidoe output, he focuses on the black border around the video, which most televisions will resize to fill screen and even without doing this the screen is fairly large so the border is not a bother.3. I don't have issues with the probes switching between 10x and 1x, I don't like that the switch is the same colour as the rest of the probe. This is all personal and would not apply to everyone.4. The buttons don't line up, Rigol has buttons allowing you 2 options to control scope Siglent doesn't that should be the major point. The buttons do line up, there is a constant theme across the scope with a 45 degree slant on edges, the buttons all line up with the slant. Style over substance.5. The XY mode issue was corrected in a firmware, and I don't see any 1ns delay in LA display, possible may have been corrected in firmware.6. Other things are not peculiar to the scope as they exist in a number of other brands, so may be there by design.7. The major difference between the scopes are that the Rigol has a higher noise floor, and the Siglents sample rate can not effectively support its bandwidth unless you only use 2 channels, and even some experts say that it still does not meet the requirement with only 2 channels on. It basically is a 250Mhz scope with 3 or more channels turned on.

author: Fungus
author_rank: Super Contributor
timestamp: May 21, 2021, 07:43:02 pm
content: Quote from: normi on May 21, 2021, 04:44:04 pmYep, that's why the Siglent Fanboys keep reposting it endlessly.The price difference between Rigol/Siglent is also something that they never mention - the Siglent is significantly more expensive (50%-ish)

author: tautech
author_rank: Super Contributor
timestamp: May 21, 2021, 08:36:50 pm
content: Quote from: normi on May 21, 2021, 04:44:04 pmCorrect. 2 firmwares have been released since Howard did his video.QuoteWhere do you come to this conclusion when the SDS2000X Plus range uses two 2 GSa/a ADC's* where a 350 MHz rating on 4 active channels doesnotbreak Nyquist.It does break Nyquist when the 500 MHz option is installed so SDS2504X Plus is rated as a 2ch 500 MHz DSO and when channel use is not properly assigned the channel tab notifies the operator that the BW is 350 MHz or Full.* Each with 200 Mpts memory support.

author: nctnico
author_rank: Super Contributor
timestamp: May 21, 2021, 09:31:20 pm
content: Quote from: normi on May 21, 2021, 04:44:04 pmThe thing with reviews is that you have to extract the pieces of information which are important to you. In the end a reviewer always has a different point of view compared to your own.

author: Fungus
author_rank: Super Contributor
timestamp: May 22, 2021, 08:07:02 am
content: But still, the stated budget is from $1k to $2k so I assumed the Rigol was off the list for being right at the bottom. The Instek/Keysight/Siglent are closer to the middle of that range anddooffer more.At the end of the day though, a forum can only provide a shortlist. Personal needs/tastes are a factor and only OP can make the final decision.

author: normi
author_rank: Regular Contributor
timestamp: May 22, 2021, 04:12:21 pm
content: Quote from: tautech on May 21, 2021, 08:36:50 pmIf we are talking about pure and clean sine waves then Nyquist applies and a little over 2 x sample rate works, but in the real world we have to compensate for the possibility of other frequencies being present in the signal. Most scopes are the Gaussian type which decline in amplitude as frequency increases to the 3db point, at which we rate the bandwidth. They don't block frequencies like a wall at that point, they still pick up frequencies above. If the scope does not have the sample rate to cover those frequencies above then aliasing occurs and what is displayed on the scope is incorrect. When you do a 500Mhz measurement at 1Ghz sample rate it is easily seen as the wave is heavily distorted but if you did a 350Mhz measurement and there is some 500mhz noise leaking into the signal your scope will display a distorted signal which would look totally different than what it should look like with the noise added to it. You may not be able to tell with any confidence if aliasing is taking place, you could do a bandwidth filter if scope has that available, but you would lose seeing the effect of the noise.The recommended sample rate should be 4-5 times the maximum frequency in the signal, I have heard Dave saying it, Tektronix and Keysight have papers which say it, so don't take my word for it.I was first looking at the SDS2104X Plus, but my requirement was for a 350Mhz, 2 G/s four channel scope, and based on this I realized it did not meet the specification. I actually learnt about the MSO5000 in a Siglent thread.

author: bdunham7
author_rank: Super Contributor
timestamp: May 22, 2021, 04:51:08 pm
content: Quote from: normi on May 22, 2021, 04:12:21 pmThere are some issues with your analysis that would be better examined by using real-world tests rather than theorizing. I don't have an MSO5074 or an SDS2104X+ to hack and compare (if anyone wants to send me them, PM me for my address), but these issues have been explored on plenty of other units.First, if you examine a signal with a scope and that signal has significant energy at frequencies above the bandwidth of the scope, the result will be distorted regardless of Nyquist issues--this happens even on analog scopes. The rated bandwidth of a scope means just that, not the maximum periodic frequency of a signal that it can faithfully reproduce without distortion. The most obvious example is square waves, but the same principle applies to any waveform. The actual manifestation of the distortion is complex and varies for each particular situation.Second, if you are referring to strong over-bandwidth signals to be displayed, aliased or not, this is nothing new or unusual. The Rigol 1054Z (hacked) will display 300MHz + signals fairly cleanly, just attenuated. If you go over Nyquist, the signal gets reflected down, but in order to be fooled by having an over-Nyquist signal reflected down to 350MHz on the SDS2000X+ with all 4 channels active, you would need a strong 650MHz signal. That's just not very likely in real-world scope use. Now if you see a 450MHz signal, you have to wonder whether it is 450 or 550, but again, a bit of real-world experimentation will show you that this is not the first thing one ought to worry about.Third, you say you wanted a "4-channel 350MHz" scope. Frankly I have to wonder why. I really would struggle to think of a reason to use all 4 channels at once at that bandwidth, and those that I might dream up would really need some careful setup and deskewing to work. But, even allowing for the possibility that you might have such a need, I would expect anyone comparing the two scopes to notice and point out that that the Rigol lacks 50 ohm inputs. Between that and the switchable 1X/10X probes, I think you will have far more problems getting undistorted readings on the Rigol at 350MHz regardless of the sample rate being double.

author: nctnico
author_rank: Super Contributor
timestamp: May 22, 2021, 04:54:49 pm
content: Quote from: normi on May 22, 2021, 04:12:21 pmNo. Many DSOs have much steeper filters nowadays. Oscilloscopes with a Gaussian roll-off are the thing of the past. In turn this means that you can get more bandwidth for your samplerate at the cost of impulse response. Oscilloscope designers aren't stupid so they will make the anti-aliasing filters in a way so excessive aliasing is prevented.

author: Fungus
author_rank: Super Contributor
timestamp: May 22, 2021, 07:34:46 pm
content: Quote from: bdunham7 on May 22, 2021, 04:51:08 pmA simple trick is to turn off other channels to increase the sample rate on the channel that's in doubt.If the display changes drastically then you know you weren't seeing the true signal before because of undersampling.

author: normi
author_rank: Regular Contributor
timestamp: May 22, 2021, 11:55:20 pm
content: Quote from: bdunham7 on May 22, 2021, 04:51:08 pmI intentionally used 350Mhz and 500Mhz because we all agree that the scope goes into serious aliasing if more than 2 channels are on and a 500Mhz signal is measured by any channel. So in my example the 500MHz is not outside of the bandwidth of the scope. Therefore your point would not be applicable here as the signal is not outside the bandwidth. If we are talking about other scopes which have high energy frequencies past their bandwidth then a number of things may come into play.1. Attenuation at the frequencies above -3db tend to attenuate much faster than before the -3db thus reducing the effect.2. They could maintain sample rates much higher than Nyquist criteria to cover this.3. They don't follow gaussian type.The increase sample rate is not to cover all frequencies above bandwidth only those within a range that is not attenuated enough. All frequencies above the bandwidth will have an impact on measured signal regardless of sample rate, and we both agree on that, however the signal displayed on the scope that is under-sampled will be different than what is on the scope with proper sampling. Both will not display the correct waveform because the higher frequency will be far more attenuated, but if this higher frequency is not noise but a component of the wave then the scope showing the alias will be so off that you would have no clue as to what's happening.Your point about the 650Mhz is similar to an experience I recently had, this is real world not theory. I was testing a RF amplifier and had a low strength 10MHZ signal feeding the amplifier, I was using my older 100Mhz scope and sine wave looked fairly normal. I switched over to the MSO5000 and noticed a totally distorted wave, I was confused and turned off the AWG and a clean 420MHz wave appeared on the display, I had seen the frequency before and immediately realized that this was coming from circuit board nearby that had been left powered on. The cable connected to the amplifier input ran close to it and amplified the signal strong enough to cause interference. My experience disproves the unlikelihood of high strength higher frequency entering your measurement, in my case the higher frequency was 42 times the signal of interest, not less than 2 times in your example. If that 420MHZ was aliased because of low sample rate then I would be searching all over to find where it was coming from because the frequency would be incorrect. Both scopes in question would not have issues with the 420Mhz but over 500MHZ the Siglent would be aliased and the Rigol would not.I use higher frequencies to view square waves, 3 most cases. 50 ohm termination is for connection to other 50ohm devices, if I do video I would need 75 ohm. On the rare occasions I use a 50ohm termination pass through and it works fine, but a lot of circuits are not 50 ohms and a low impedance sometimes load circuit. The advantage of using the external termination is that I don't have to worry about burning out the oscilloscope's internal components since 50 ohm port is limited to 5Vrms, I can easily buy another external terminator. But again I don't need it as I don't do much RF stuff and the few are at low IF frequencies.In summary the example I gave still stands, more than 2 channels enabled on the Siglent will be aliased by any component above 500Mhz since these are still within its -3db point and not significantly attenuated. You could if possible put in bandwidth limit filters to removed signals above 500Mhz. As it relates to the general argument about the Nyquist and frequencies outside of bandwidth which is not the case in this situation, I would have to side with the experts who recommend the sample rate to be up to 5 times the bandwidth.

author: e0ne199
author_rank: Regular Contributor
timestamp: May 23, 2021, 12:12:41 am
content: anyone here can tell me which A-brand oscilloscope can be hacked to 500MHz?

author: bdunham7
author_rank: Super Contributor
timestamp: May 23, 2021, 05:05:34 am
content: Quote from: normi on May 22, 2021, 11:55:20 pmBut it is outside the rated bandwidth, which is 350MHz when both channels in a pair are on. I don't know if Siglent actually reduces the bandwidth in some manner in this instance--I would hope that they would. And if I'm not mistaken, there is an additional 200MHz bandwidth limiter on the higher frequency models. I would probably engage that any time I was using more than 2 channels.QuoteThe first part is exactly correct. I'm not sure what you mean by displaying the correct waveform or being so far off that you have no clue. Oscilloscopes rarely display anything worth looking at in an 'exactly correct' way. In any case, unless your sample rate is 2X the highest frequency component present, you'll have issues of some sort or another.QuoteHere I think you've misunderstood--I didn't say you wouldn't have higher frequencies than you expect. Your stray signal was 42X the 'test signal but was still within Nyquist of the Rigol and just barely out of the rated bandwidth and apparently quite strong relative to the desired signal. There's no expectation that it would be suppressed nor would it be reflected down by either scope in question. B/T/W, your 100MHz scope handled it just fine, right? What was its sampling rate? If it were 250MSa/S, would you have seen aliasing? Let's say your signal was 520MHz and you were running the Siglent in 4-channel mode. Whatever part of it was not attenuated would fold back to 480MHz, which would be 'wrong'. The only question would be how well the scope attenuates this over-bandwidth signal and I don't have one to test. My experience with other Siglent and Rigol models suggest that they don't handle approaches to the Nyquist limit very nicely at all. I've mentioned this before and user rfloop pointed out, among other things, that this was a necessary consequence of maintaining a good step response and that it wouldn't be an issue in most real use cases. Yes, as I have myself demonstrated, strong over-bandwidth signals wreak some havoc on these scopes and it is best to stay as far away from Nyquist as possible. I've referred to my SDS1(2)04X-E as an excellent two-channel scope because at 1GSa/S it handles over-bandwidth signals reasonably well but at 500MSa/S, it looks terrible. It hasn't shown up in a real-world example for me yet and for your example, while I guess it is 'real world', it's not something I'd worry about too much as I don't expect a scope to solve every problem. Besides, what would happen if that signal was 1.1GHz? More samples are great--with this I agree--but there's always some weird thing that can happen.QuoteOn my Tektronix scopes that have 50R inputs, if you overload them they switch back to 1M. You can always just use the 1M setting with a 50R (or other) external terminator, but the step response won't be as good, or at least it certainly isn't on my 2465B. If your square waves look good enough with an external terminator, then you probably don't need 350MHz bandwidth... I would hope that Siglent also disconnects the internal 50R termination in case of overload, since they have to have the relay for it anyway. If they don't do this then they should.QuoteMore samples is better, no doubt. They also can make up for shortcomings elsewhere in the design. If Siglent had 2GSa/S for each channel, they might arguably have a better product--but then it would cost more as those ADCs aren't cheap. Rigol has gone their own way with their custom chipset that has a very high sampling rate at a lower cost, but with some real compromises. It would be interesting to see a head-to-head comparison of their actual analog display performance.

author: normi
author_rank: Regular Contributor
timestamp: May 23, 2021, 01:50:11 pm
content: If you have need for a 50 ohm terminated scope then one should get it, the possibility of burning it out should not stop you. Just be aware of the possibility and take precautions, if the scope is for use by multiple individuals like in an school lab then the risk is exponentially more. I was just pointing out one advantage to using external terminator.For reviews of scope we need to come up with a list of tests conducted under the same conditions that can compare all scopes, so buyers can have confidence that reviews are comparing apples to apples and are free from bias and subjectivity. There are a number of sites which do this for consumer electronics and it makes it easy for a consumer to disregard manufacture hype and see whether stated specification is real. If a television advertised as having a viewing angle 30 degrees then we should be able to test that with measuring devices following a fixed procedure. If not then some reviewers will say it is 30 degrees others 40, and guess what; they are both correct. What I consider good at 30 degrees may be bad with your eyes, my room may be darker than yours, with standards we can be confident that results are measurable against each other.Possible all the oscilloscope aficionados can start a thread on standard testing procedures for scopes, there are existing procedures but all procedures are not the same and therefore not a standard, and may be not worth comparing.

author: bdunham7
author_rank: Super Contributor
timestamp: May 23, 2021, 04:40:36 pm
content: Quote from: nctnico on May 22, 2021, 04:54:49 pmActually Siglent (and perhaps LeCroy) appears not to have taken that approach, at least in the models I've seen. They've optimized step response and maxed out the bandwidth for their sample rate, so you can demonstrate aliasing quite readily. I don't think they are 'stupid' for doing so, its a design choice. I do wish they would add a second bandwidth limiter, appropriate for a particular scope, that would minimize aliasing at the expense of the step response. This can actually be done in software to a certain extent, so it shouldn't be an expense issue. The 200MHz BW limit on the SDS2000X+ series seems a reasonable choice.Here's an SDS1204X-E, 200MHz @ 1GSa/S with a fast edge 10MHz square wave input. You can see that the spectrum response closely matches theory out to 300MHz or so and then rolls off, but is not totally suppressed even at 500MHz. Step response is everything you could ask of a 200MHz scope.

author: nctnico
author_rank: Super Contributor
timestamp: May 23, 2021, 06:28:54 pm
content: Quote from: bdunham7 on May 23, 2021, 04:40:36 pmIf you look at what the bandwith limit actually does you'll see it is 1) done in the analog domain in the pre-amplifier stage and 2) give the oscilloscope a Gaussian roll-off at the expense of bandwidth. With a brick-wall (ish) anti-aliasing filter a DSO can cater to both needs: have maximum bandwidth given the samplerate or have a Gaussian roll-off at the expense of bandwidth.

author: covert
author_rank: Newbie
timestamp: May 26, 2021, 05:22:29 am
content: Thanks everyone. I'm a proud owner of a MSO5074. Came with some of the features enabled in the free bundle deal but thanks to user "db6178" is was a easy quick patch to all the features.