Keysight DSOX3014T vs DSOX1204G - is it really worth 3.5 times the money? Vote! - Page 1
Forum section: electronics / testgear

author: Bussmann
author_rank: Newbie
timestamp: August 07, 2019, 07:09:16 pm
content: Hi,A noob here. Thinking of getting a new scope for mostly audio use. No need for decoding capabilities. Still use a Tek 2247A that is great for waveform display but not accurate in measurements with anything lower than 100mV.For the new scope, I will need 4 channels, responsive UI, accurate measurements and a robust build to last a few years. Tried the Rigol, Siglent and even R&S RTB but did not like them: the Rigol layout was busy and distracting, the Siglent encoders were mushy and overshoots most of the time, and the RTB had a strange noise floor. Tried the PC-based stuff too and did not like them not having dials.So, for a purchase that will need to endure the next 10-20 years, is the 3014T worth the extra money when the 1204G provides most of what it can do for less than 1/3 of the money? Does "you get what you pay for" apply here?Thanks.

author: tautech
author_rank: Super Contributor
timestamp: August 07, 2019, 08:33:09 pm
content: Quote from: Bussmann on August 07, 2019, 07:09:16 pmWelcome to the forum.Yes, first time use of a DSO after only using CRO's can be a bit awkward as the controls take no effort to rotate.What model Siglent did you trial ?

author: Mr. Scram
author_rank: Super Contributor
timestamp: August 07, 2019, 08:42:03 pm
content: Quote from: Bussmann on August 07, 2019, 07:09:16 pmThe 3014T seems to mostly make sense for higher bandwidths and MSO functionality. The 1000X series does offer ridiculous value for money and seems to be really pushing the boundaries of a high end experience at budget segment prices.

author: thm_w
author_rank: Super Contributor
timestamp: August 07, 2019, 09:08:34 pm
content: R&S RTB or Siglent (you didn't specify which model) are going to be the best bet for audio measurements.If you let some small UI difference or "strange noise floor" (which is what, high RMS noise? was it outside of the spec?) distract you, then you are selling yourself short.Rigol MSO5000 is a great choice for digital, so would not fit your use case.Spending a ton of money up front and expecting a scope to last 10-20 years is also misguided IMO. Get the 1204G if it fits your unique requirements, then in 5-10 years a replacement will be released and you can upgrade to that with the money saved.

author: Bussmann
author_rank: Newbie
timestamp: August 07, 2019, 09:19:34 pm
content: Hi tautech,Thanks for the welcome. I actually splurged and got the rebatched 1104 version for double the money hoping to get local support. Attached is a picture of the pubs that came with the T3D version. The scope looked identical except for the badge on the bezel and there is no Siglent logo on the screen. There was no logo period.Hi Mr. Scram,I asked the question as I suspect you are right. If you have a 1000X on hand, can you comment on the feel of the knobs - detent or no detent, feel like 3000T or feel cheap? It was a major reason I did not keep the Siglent.Hi thm_wRTB2004 and T3DSO1104, the re-badged version of the SDS1104X-E.The "strange noise floor" is one that varied by nearly 70µV over the course of 2 hours during use, but there was no published noise specs for the RTB so it cannot be considered "out of spec". It varied between 30µV and 100µV RMS AC1M no BWL.Ergonomics is a big deal to me so imprecise encoders and sloppy switches do not pass the test.Thanks to everyone for your comments.

author: Mr. Scram
author_rank: Super Contributor
timestamp: August 07, 2019, 09:43:22 pm
content: Dave comments on the knobs and indents being the same as on the 2000X and 3000X series around the 1:40 mark.https://youtu.be/9KcOQsVxtoU

author: Bussmann
author_rank: Newbie
timestamp: August 07, 2019, 09:46:18 pm
content: Thank you Mr. Scram! Nice.Quote from: Mr. Scram on August 07, 2019, 09:43:22 pm

author: tautech
author_rank: Super Contributor
timestamp: August 07, 2019, 09:55:21 pm
content: Quote from: Bussmann on August 07, 2019, 09:19:34 pmYou already have great support in Ohio:https://www.siglentamerica.com/It's unknown how up to date LeCroy are with SDS1*04X-E firmware as there's been several versions that have addressed self cal accuracies and added lots of additional functionality since the X-E's were released.On the encoders, I've just reached across to my pre-release beta unit and I notice they are no different to any I do pre-despatch checks on......detents are quite well enough defined however use style does have an affect on 'felt' feedback. The modern compact DSO can be best used for some operations with three fingers atop of the unit with thumb and forefinger rotating the controls and that better hand support promotes more precise adjustments where the larger and heavier scopes often don't require this operation style.Encoder knob size can have a bearing on this too but all in all it's related to previous CRO use where knobs take some effort to rotate which is not the case for DSO's.EEVblog (Dave) has done several videos on 'noise on DSO's' and a couple more recent ones on this baseline noise 'real' measurement thank you might want to watch:

author: Mr. Scram
author_rank: Super Contributor
timestamp: August 07, 2019, 09:59:57 pm
content: In case it had gone unnoticed I'll quote Dave.Quote from: EEVblog on August 07, 2019, 09:10:21 am

author: Bussmann
author_rank: Newbie
timestamp: August 07, 2019, 10:01:36 pm
content: HI tautech,Thank you so much for the pointers!The touch thing is kinda personal and I know what works for me may not be good for anyone else. Perhaps the most important to me to know that an 1/2/5 adjustment means 3 clicks that i can feel without looking at the scope. I was not able to feel this on the T3/Siglent. I could on the RTB, and of course, on the Tek, you know you clicked it.There are now a few videos to watch so thank you. I am glad I signed up here!Hi Mr. Scram,I am a noob so I just soak it up. I thank everyone for helping!!Quote from: tautech on August 07, 2019, 09:55:21 pm

author: Helix70
author_rank: Unknown
timestamp: August 07, 2019, 10:53:28 pm
content: Hi,I use the MSOX3014T on a daily basis. We also have a 1000x series. To answer the title of the thread, Yes. It is really worth it - *If you use it*.The bandwidth is largely irrelevant. I only have, and need, 100Mhz for my use. But 1M waveforms per second means it has the horsepower to process all the waveforms, so you don't miss the trigger. There are many videos that give more details of the features.The touch screen is very useful and intuitive, is was more probe options, can be updated more if thats your thing, does far better with decoding serial, much better UI in general.Basically, the way i feel about my MSO3014T is you would need to pry it from my cold dead hands. But it isn't for the shelf. It wants and needs to be used to be justified.

author: Bussmann
author_rank: Newbie
timestamp: August 07, 2019, 11:05:43 pm
content: Hi there,Thank you for your feedback. This is what I wanted to know. I also read the manual of the 1000X in the meantime, and found that the built-in measurements is a subset of the others. Make sense for a bargain but I'd better to sure before I leap and get something short of a dollar!Thanks again.Quote from: Helix70 on August 07, 2019, 10:53:28 pm

author: nctnico
author_rank: Super Contributor
timestamp: August 08, 2019, 12:55:36 pm
content: Make sure to try the R&S RTM3000 series as well. IMHO the 10 bit ADCs do offer an advantage over 8 bit for analog signals especially when you want to zoom in on details.

author: Bussmann
author_rank: Newbie
timestamp: August 08, 2019, 02:02:18 pm
content: Will do. Thanks for the suggestion.Quote from: nctnico on August 08, 2019, 12:55:36 pm

author: nez
author_rank: Regular Contributor
timestamp: August 09, 2019, 11:54:37 pm
content: Hi! My own noob questions out of curiosity:)It seem's that 10 bit resolution would be quite useful as nctnico mentioned.But how about waveforms per second? If one is working in the audio frequency range (we'll say only audio, for sake of discussion), what's the approximate ceiling on useful waveforms/sec, and what would be overkill?My other question is on averaging to clear the noise. Is the audio-centric workflow straightforward to the point where you'd want to use averaging to handle noise (i.e. the signal shape you analyze is repeated with no cycle-to-cycle variation)? Or, is it actually more complex than that, and averaging would not really be used?

author: Bussmann
author_rank: Newbie
timestamp: August 10, 2019, 02:23:54 am
content: Well, the math would say 10-bit ADCs should have an advantage, but practically for audio, even 10-bit is not ideal for frequency domain. I have a 24 192 sound card for that.And I think you nailed in on the head: what analog scopes take for granted easily showing XY waveforms most DSO simply struggle at. Only DSOs with very fast waveform update rate like Keysights can do it easily. Hence the original question - is 1204G fast enough to do a good XY or is the 1,000,000 rate on the DSOX3014T really necessary? No answer yet so far.Averaging is the other thing because noise at low frequencies are particularly challenging - both for display and triggering. So far, not sure there is a way out of spending the big bucks for the T.Quote from: nez on August 09, 2019, 11:54:37 pm

author: nctnico
author_rank: Super Contributor
timestamp: August 10, 2019, 07:21:56 am
content: Quote from: nez on August 09, 2019, 11:54:37 pmWaveforms/s is a way overhyped number for marketing purposes. Remember that a waveform needs to be captured first before display so it is a function of samplerate versus time/div; therefore the highest waveforms/s are achieved at a very specific time/div setting. Anything over 1000 waveforms/s is basically overkill. Now some people will say that with low waveforms/s you won't catch glitches but if you are hunting for glitches a much better way is to use mask testing, longer memory (show many cycles) or a trigger. That way you don't need to stare at the screen without blinking.Back to audio use: you can use averaging but then the signal needs to be repetitive indeed. A more useful mode is high-res which is even better when starting from 10 bits instead of 8.

author: Mr. Scram
author_rank: Super Contributor
timestamp: August 10, 2019, 02:42:40 pm
content: Some critics have argued the waveform update rate isn't a relevant metric, but the numerous manufacturers emphasizing the improved waveform update rates of their new product ranges suggest the market may feel differently. That being said it does appear a high waveform update rate is useful for a specific subset of problems and I'm not sure audio related work is part of that subset. Are incidental glitches a problem in the audio world, other than in digital buses? Don't expect the XY mode of any DSO to be as good as those on CROs, Keysight or any other brand. DSOs outperform CROs in pretty much every metric but XY mode appears to be an exception.

author: Someone
author_rank: Super Contributor
timestamp: August 11, 2019, 01:32:32 am
content: Quote from: Mr. Scram on August 10, 2019, 02:42:40 pmIts a little more nuanced than just banner specifications and biggest number is always best. Its important to take in all the characteristics of the scope, for example the waveform rate of a Tek DPO4000:The solid line for each memory depth is where the full memory fits on the screen and there is no aliasing. Dotted lines off to the right the visible window is a short segment of the set memory depth, while off to the left is where aliasing occurs. Most audio work would be down around the 1E-2 to 1E-4 seconds per division region where the update rate is dominated by the acquisition and not the blind/turnaround time... except the longer memory depths which are required to avoid aliasing on that scope.

author: EEVblog
author_rank: Unknown
timestamp: August 11, 2019, 01:45:32 am
content: Quote from: Bussmann on August 07, 2019, 07:09:16 pmFor your needs the 1204G is plenty, but it's not the best for low level signals. A scope with a true 500uV range might be what you are after for audio work.It uses the exact same Megazoom IV ASIC and the 3000 and 4000 series does, so apart from the front end bandwith the hardware is essentially the same (minus touch screen).What they do is limit in software the memory and features available in that ASIC.All the manufacturers limit products like this, it's about market segmentation.

author: EEVblog
author_rank: Unknown
timestamp: August 11, 2019, 01:49:36 am
content: Quote from: tautech on August 07, 2019, 09:55:21 pm

author: Bussmann
author_rank: Newbie
timestamp: August 11, 2019, 03:14:46 am
content: Everyone has valid points and this noob is no closer to a decision. So I am asking for votes to see if the numbers tell a clear picture.Quote from: EEVblog on August 11, 2019, 01:45:32 am

author: Mr. Scram
author_rank: Super Contributor
timestamp: August 11, 2019, 03:48:37 am
content: How do you intend to use the XY mode?

author: EEVblog
author_rank: Unknown
timestamp: August 11, 2019, 04:08:16 am
content: Quote from: Bussmann on August 11, 2019, 03:14:46 amUnfortunately the numbers won't tell you. Small details matter, a lot.Your need for an X-Y mode is fairly unique. For that why not stick with an analog scope?I would focus on the low noise audio requirement first, for which the Keysight isn't well suited due to it's software magnified front end.But it's just one of many (often conflicting) requirements.For starters, what is your budget? and if you are considering the 3000T it's obviously rather high.When you have a large budget then other things come into play, like maybe more than one scope for different requirements.e.g. a general cheap-ish 4CH scope for general daily use + a specialised scope for analog audio performance (could even be a high resolution USB scope) might be a better solution and than s single expensive scope that doesn't do all that you want.

author: Bussmann
author_rank: Newbie
timestamp: August 11, 2019, 04:47:11 am
content: @Mr. Scram - XY for channel separation waveform display@DaveHere are observations of various scope behavior before I posted my questions:1. I played with a friend's 14-bit National Instrument PXI-5122 scope and it was dreadfully slow, even though it was supposed to be sampling at 100MS/s.2. While we know 8-bit and even 10bit scope noise floor is likely inadequate for audio, even the NI 14-bit scope's noise floor was no better than 105dBV. And that's not anywhere near any 24 192 soundcard at -140 to -150dBV.3. I already have a 24 192 soundcard running ARTA and it worked pretty well for frequency domain work but for time domain, its <400kS/s sampling means very jagged waveforms on DSO, especially when zoomed in a bit.4. I also already have a Tek 2247a analog scope - it's a hybrid scope - ADCs for measurements and readouts, analog tube for waveform display, but it has no storage, and when zoomed in to see rise time on higher frequencies, the waveform is barely visible.The quest to find a scope that can do near-analog waveform displays, give better than 0.5% accuracy measurements (the Tek 2247A is like 15% to my eyes) and can zoom in - live or history mode - to see and measure without squinting. The 24 192 soundcard can do all the frequency domain stuff like FFTs, THD and sweeps but they cannot do good waveforms. Therefore my preference is really to see a waveform better than to measure it better.Budget is under $5k - the DSOX3014T would be a real stretch as it's a lot more than the DSOX3014A and 3.5x that of the DSOX1204G. The RTB seems to give up responsiveness when it's taxed.Quote from: EEVblog on August 11, 2019, 04:08:16 am

author: EEVblog
author_rank: Unknown
timestamp: August 11, 2019, 04:54:39 am
content: BussmannCan you please explain the forum user account ci11

author: tautech
author_rank: Super Contributor
timestamp: August 11, 2019, 09:06:57 am
content: Quote from: Bussmann on August 11, 2019, 03:14:46 amLet's add further to the confusion.Threads like your's come come along from time to time and there's a wealth of info here tucked away in forum archives.Here's a reasonably recent one comparing the entry level Keysight to other entry level DSO's which in itself is a little unfair to put a 2GSa/s DSO against 1GSa/s DSO's and as you might imagine when getting up in frequency the 2GSa/s DSO's have some advantage.When we dropped a 2GSa/s $600 2ch Siglent into the mix it allowed for a fairer apple vs apples comparison:https://www.eevblog.com/forum/testgear/dso-bandwidth-test-sds1104x-e-dsox1102g-to1104-gds1054b/QuoteProviding the channel frequency disparity is not too great DSO's can do well enough here.Tell us what you need exactly and I'm sure there's enough of us here with 2ch AWG's that can do a videos for a fair comparison.

author: 2N3055
author_rank: Super Contributor
timestamp: August 11, 2019, 10:24:24 am
content: To OP.Sorry for this, I mean no disrespect, but I'm going to be blunt..Tautech is right.. This is getting nowhere. I will try to summarize what others and myself think..You seem to have very strong opinions about things based on little knowledge, and some misconception.1. USB scopes are plenty fast, it's just they have no buttons. Picoscope 3000D can get up to 100000 WFM's per second. It is more scope than most of people need, with some very advanced features. But some people need (want?) physical scope (with buttons and no PC).2. You say you want tools to work on audio. Good. So you need a scope that doesn't have much bandwidth, and has low noise and high sensitivity, so you can see signals from microphones and MC pickups and such...3. I'm still confused about need for X-Y display (apart from oscilloscope art). Do you use it as an audio vectorscope? Could you please explain it a bit more, I would like to know more about it.- Rigol DS2102A (2GSa/sec, 100MHZ 2ch, 500uV/div)- Siglent SDS1104X-E (1GSa/sec, 100MHZ 4ch, 500uV/div)- Siglent SDS2202X-E (2GSa/sec, 200MHZ 2ch, 500uV/div)- Micsig TO1074 Plus (1GSa/sec, 70MHZ 4ch, 500uV/div)All of these are up to some 600 USD. If you really need 4ch, then I would chose Siglent SDS1104X-E (1GSa/sec, 100MHZ 4ch, 500uV/div) for audio equipment.It is waay more capable instrument than DSOX1204G despite not being fancy name.It is more scope than you need for what you described.And you get all the digital decodes and very long memory that will be useful at frequencies you're looking at.. And it is fast and OK to use.DSOX3014T is not a good scope for audio. It is meant for other uses...For the rest of the money up to DSOX3014T, keep the analog scope you have for X-Y (i agree with Dave), and find a good used Audio Precision audio analyser. Or buy QuantAsylum QA401 Audio Analyzer... Or keep your ARTA setup, it is probably more than enough.You seem to have decided to treat yourself with "premium product", you know you don't need it, and now you want us to persuade you it's worth it.In your case it's not.Nicer knobs, nice logo on the front and actually worse specs for your use case are not worth the money.Just buy Siglent SDS1104X-E and be amazed how good it is compared to what you had before.And if you have leftover money buy other specialized audio equipment, because if you want audio measurements, there is no scope in the world that comes even close to even the cheapest audio analysers. You don't like the knobs? You'll get used to it after a week.. EVERY new piece of equipment feels weird to me when I first start using it. MSOX3104T felt weird too at first, and I had to remember where the options are (there is ton of them), had to remember it has touch screen etc etc... After a week or two, it became normal.This is what I would do in your position. And it seems all the responders mostly. You don't need a poll. People already voted.If you want to buy "premium" product for the purpose that it will make you feel better that you have treated yourself to something nice, then by all means do it, it's your money.Hope you don't take this the wrong way.Best regards,

author: Fungus
author_rank: Super Contributor
timestamp: August 11, 2019, 10:51:40 am
content: Quote from: 2N3055 on August 11, 2019, 10:24:24 amSeems that way.Quote from: 2N3055 on August 11, 2019, 10:24:24 amThis guy is a salesman's dream. If he wants clicky knobs, he wants clicky knobs. Let him buy the more expensive device. Specs aren't good enough? Move up the model range to something that is...

author: Performa01
author_rank: Super Contributor
timestamp: August 11, 2019, 01:19:52 pm
content: Quote from: EEVblog on August 11, 2019, 04:54:39 amThat rings a bell - I already asked myself where from I got that déjà vu...A request from member ci11 was the whole reason why I've added a couple of posts to my review thread, starting at reply #136:https://www.eevblog.com/forum/testgear/siglent-sds1104x-e-in-depth-review/msg2021602/#msg2021602The final challenge was to display a low frequency 150µV signal (reply #138), which of course doesn't yield pretty results even with a 500µV/div frontend. At 10Hz the 1/f noise is substantial on any modern scope with split path input buffers (and no, it'snotthe CMOS technology but the circuit architecture!) and then there are only some 18 counts (~ 4 bits) resolution left for signals that low. Amazing enough what just 16 times averaging still can squeeze out of this.The same posting also shows a true 16 bit DSO in comparison, which does a very decent job, even though the highest sensitivity is only 2mV/div.With regard to X-Y, it's certainly not the lack of speed that makes modern DSOs inferior to an analog scope, but the lack of resolution. With only 8 bits, you get 256 signal levels at best, which means you have 2 vertical pixels per LSB on the screen in Y-t mode. This is not a real problem, because in Y-t mode we still have full resolution on the X-axis.In X-Y mode, we have the limited resolution on both axes, so each measurement point is a 2x2 pixel square. That doesn't look very pretty. A good intensity graded display can mask this, but the trace gets rather thick and the lack of detail is still there. 10 bits would certainly help with this.Even better if you have 16 bits like with the PicoScope 4262, see attached video (just rename it to .mp4).This certainly outperforms analog scopes, if only because we can have the result at full resolution on a full HD screen.

author: 2N3055
author_rank: Super Contributor
timestamp: August 11, 2019, 01:29:53 pm
content: Also there was the question about low amplitude signals and solid triggering....My contribution from Picoscope 4262.No filtering, 16bit.With filtering and resolution enhancement is much cleaner...Tool for the job.P.S. @Performa01, it's your fault that I had to get 4262.... At least that's what I said to SWIMBO

author: Performa01
author_rank: Super Contributor
timestamp: August 11, 2019, 01:50:23 pm
content: Quote from: 2N3055 on August 11, 2019, 01:29:53 pmI don't mind to be the fall guy - as long as that purchase made you happy!I only hope your SWIMBO isn't cross with me now!

author: 2N3055
author_rank: Super Contributor
timestamp: August 11, 2019, 02:06:41 pm
content: Quote from: Performa01 on August 11, 2019, 01:50:23 pmJust joking...4262 is nothing short of amazing. With it's 8-9uV noise floor, I can measure power supply noise directly, audio stuff, etc. I use it a lot actually. It was a good purchase, really, thank you for drawing my attention to it...Best regards,

author: egonotto
author_rank: Super Contributor
timestamp: August 11, 2019, 03:17:59 pm
content: Hello,for that I have a 4262 are the posts of Performa01 not whole unimportant.As I don't know was SWIMBO means I search.Now I know it is "Oberste Heeresleitung" (topmost army command)@2N3055: you wrote "because if you want audio measurements, there is no scope in the world that comes even close to even the cheapest audio analysers".I think the 4262 comes very close. So a Picoscope 4262 and a Siglent SDS1104X-E can be a good solution for TOBest regardsegonotto

author: Mr. Scram
author_rank: Super Contributor
timestamp: August 11, 2019, 03:36:37 pm
content: Quote from: 2N3055 on August 11, 2019, 02:06:41 pmCan't you do power supply noise measurements on the DSOX3014T? I thought it was part of the power analysis suite. Looks like Keysight calls it output analysis.https://literature.cdn.keysight.com/litweb/pdf/5990-8869EN.pdf?id=2096805

author: 2N3055
author_rank: Super Contributor
timestamp: August 11, 2019, 03:47:19 pm
content: Quote from: egonotto on August 11, 2019, 03:17:59 pmIt also means Minister of Finance too...You are right, I use it for audio, for what I do. Nevertheless, audio analysers stil another level better. But for what I do (and hear) Pico does all I need. But I don't do advanced stuff.I agree, that is a good pairing. And still much cheaper than DSOX3014T, combined.Regards,

author: 2N3055
author_rank: Super Contributor
timestamp: August 11, 2019, 03:57:19 pm
content: Quote from: Mr. Scram on August 11, 2019, 03:36:37 pmYes, you are correct, that is a part of PWR option. But it is suitable only for ripple on switching power supplies. Lowest real V/div range is 4 mv/div, lower than that is software zoom.Pico 4262 has noise floor of 8-9uV. With it, you can measure low noise linear supplies, directly, without preamplifier. And to measure noise on LTZ1000, you would need only 100X magnification.

author: Mr. Scram
author_rank: Super Contributor
timestamp: August 11, 2019, 05:26:51 pm
content: Quote from: 2N3055 on August 11, 2019, 03:57:19 pmThanks for clarifying, that makes sense. What kind of preamplifier would you use for these kinds of measurements? I've no idea what kind of bandwidth and gain would be suitable.

author: 2N3055
author_rank: Super Contributor
timestamp: August 11, 2019, 08:24:30 pm
content: Quote from: Mr. Scram on August 11, 2019, 05:26:51 pmIt all depends what are you measuring. Is source low or high impedance? Are you interested in 1/f noise, 0.1 Hz to 10 Hz bandwidth is interesting. On general purpose PSUs industry standards are 10 Hz-100 kHz and 100 Hz-100 kHz... So you need front end that should be correct for your source impedance, and you can filter by using analog filters, or you can capture and filter in software, providing you don't have large contributions from out of band that would compromise your dynamic range, in which case you would need analog filtering anyways, or combination of both. I'm looking at making LT1037 based first stage to experiment a bit.. I don't have preamp at the moment. That is why I said 4262 is great because you can direct sample all "normal" PSU in bandwidth from DC to 5MHz.

author: Performa01
author_rank: Super Contributor
timestamp: August 11, 2019, 09:30:51 pm
content: Ideally, the preamp would exceed the bandwidth of the DSO, i.e. >5MHz, but that's a tough requirement for low noise / high gain. I think we never need high impedance for these kind of very low noise measurements, hence bipolar audio amplifiers can be used. An input impedance of 100k should still be possible, but DC input coupling would be difficult because of the high input bias current. AC coupling on the other hand has the disadvantage that the source impeance is increased at low frequencies, hence also the noise. A 10µF PP capacitor at the input would result in about 1dB drop at 1Hz, which might be an acceptable compromise, but it is physically big and expensive.I would recommend the LM4562NA dual op amp (or the very similar LME49720). Cascading the two amplifiers with a gain of 20dB each results in a total gain of 40dB that is flat up to at least 1MHz (-6dB bandwidth ~5MHz in theory). Input noise density would be 2.7nV/sqrt(Hz) typical.For significantly more money, the OPA2211(A)I provides an input noise density of typical 1.1nV/sqrt(Hz) and similar performance otherwise.If high input impedance and/or DC coupling is a must, then the AD8676A with typical 2.8nV/sqrt(Hz) can be considered - but the bandwidth is significantly (about 5-6 times) lower.

author: EEVblog
author_rank: Unknown
timestamp: August 13, 2019, 10:13:39 am
content: Quote from: Mr. Scram on August 11, 2019, 05:26:51 pmIndustry standard PSU noise bandwidth is 20MHz. It's one of the reasons why 20MHz is the standard BW limits on all modern digital scopes.

author: 2N3055
author_rank: Super Contributor
timestamp: August 13, 2019, 11:42:26 am
content: Quote from: EEVblog on August 13, 2019, 10:13:39 amThat is correct as per standard measurement protocol for switching PSU-s for desktop computer, monitor, printer, notebook computer, fax machine, photocopy machine and etc. For linear supplies for audio preamp you might measure to 100kHz or for some fast switcher for super fast FPGA you might go up to 500MHz if that is what is of interest to you.