DSO138, the $23.50, 200 kHz oscilloscope kit - China reviews

This video comments on the building experience, performance and usability of this seemingly great deal. (Spoiler: Don't expect 200 kHz out of it). I do some performance testing on it using arbitrary waveforms and a sine wave up to 110 kHz, revealing some interesting issues.
At its modest price, the DSO138 might appear to be the ultimate in beginner scopes, combining kit building and functionality into a single-allowance price bracket.
Firmware upgrade procedure and review of the 060 firmware here: • DSO138 firmware upgrad...
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[@robiG1991]

firmware version: 113-13801-060 release date: [ 2016.01.05 ] Auto-center trigger level to the middle of signal amplitude when trigger level is focused and OK button is held down for 2 seconds. This is useful for quickly stabilize waveform display. (Thank Gabriel S. for the suggestion!) Auto-center horizontal position when horizontal position is focused and OK button is held down for 2 seconds. (Thank Gabriel S. for the suggestion!) Restore factory default settings when "+" and "-" buttons are held down simultaneously for 2 seconds. Improved frequency measurement by using average voltage level (instead of true 0V level which was used in previous versions) as cycle counting reference. Fixed a bug in trigger level readout error. In previous versions trigger level readout displayed wrong value after VPos alignment was performed.

[@solmillin]

Thanks for your review. Very honest, informative and practical. :)

[@Pamberjack]

You have the accent of a Bond villan, good sir. I like it!

[@1959Berre]

Creepy accent

[@abczyx]

Enjoyed the vid. Props for assembling under the influence. :^) Shame about the weird triggering and range issues, but it's 23.50 USD for fucks sake. I wonder why JYE Tech's logo suddenly appeared on the display at 26:27.

[@richardkell4888]

This is a most useful vid, tks. I like to monitor audio output from my simple homemade radio receivers, a novelty idea but still fascinating to watch.

[@030Joerg]

I built the kit and it works well. Until about 250 kHz can be measured An oscilloscope for little money, wonderful. Greetings from Berlin, Germany Jörg

[@otissumnerbrown]

Thanks! I hope to go though it !

[@moclan582]

Kann man das Set mit einem normalen Lötkolben löten?

[@jlucasound]

I think you did an awesome job!! The intro made my eyes get wider and I went wow! Very unique. At least you weren't REALLY bashing that oscilloscope (I'm still speaking of the intro). The big cap on the circuit board was, well, looked "shocking". Gotta have a little fun with destruction. I am sure they were junk pieces anyway. Great review and I think my DSO138 will work fine for me. I won't use it for anything beyond audio. Thanks man! Love the speech delivery and accent. I can tell you are well educated and know your "stuff".

[@FFcossag]

I'm glad you liked it.

[@qwqehwekrhlfjghdklfj]

@26:00: Your trigger jitter is due to how the digital trigger is generated in hardware. That signal is generated by a PWM output from the microprocessor (signal 'TL_PWM'), which is then passed through a lowpass filter (R16+C9). The output of that circuit is ideally DC, but in fact the PWM frequency carries through. Probe 'TLVL' and you'll see a 50 mVpp, 100 kHz AC waveform riding on the DC output... that's the PWM signal bleeding through R16+C9... increasing R16 and/or C9 will improve performance (to a point). A better solution is to replace R16+C9 with a pi filter.

[@akifrostason2898]

+FFcossag are you supposed to use a DC power supply with the + or the - in the middle? Also. How do you use the test point (TP23) to measure when there is only one single point?

[@lessopinion9707]

+Áki Frostason Most supply's use the center pin as positive, If you have a multi meter check the plug on the scope to see for sure, find a ground on the scope circuit board and test the plug for continuity or ohms reading on the plug contacts.

[@juliannicholls]

I was very impressed with mine. It worked first time, more or less (I had to reflow a couple of pins on the screen connectors). The instructions are very clear and easy to follow. As he says in the video, the switches are a bit cheap, and I had a problem with one initially, but I went round and reflowed several pins and they seem fine now. You need to have some experience soldering before tackling this kit for the following reasons. 1. Only the processor was soldered on in my case, so I had to solder all the other SMD components. IMO this requires solder paste, at least for the opamp. 2. Some of the other components have a very small pitch, e.g. the switches and USB connector. These are probably best soldered with solder paste as well. 3. A couple of the components, e.g. the BNC connector have a high thermal load, making them difficult.

[@danielelise7348]

+FFcossag,cool man,love your channel,keep the vids coming,love the accent too,my girlfriend is Swedish & I'm Australian,so it's nice to hear someone with a similar sounding accent;-)

[@challochjunction2233]

Could you suggest why I might be getting -21V at V- test point when it should be -8V also my test signal is not square on one side.

[@Seegalgalguntijak]

As far as I know, these scopes are based on some Open Hardware platform, so how much of an effort would it be to debug the thing and get it right? Could this still be a scope that you could pick up (in an assembled stage) for something like 50€? Because that's about how much I'd be willing to spend on such a thing (considering how much I'd be using it), but I don't want to do a lot of soldering for assembly, nor would I want something that is completely crappy...

[@FFcossag]

I'd say you're better off just building one yourself. It's extremely easy to solder together, even by kit standards.

[@Seegalgalguntijak]

FFcossag I saw the number of parts and decided that's not for me, LOL. I'd rather have a finished version, especially one that has all the bugs worked out. It doesn't need a front plate though ;)

[@FFcossag]

Seegal Galguntijak You know what they say about quitting without trying, but that's your prerogative. Oh, and if I wasn't clear, the front panel comment was a joke. By frontend, I'm referring to the circuitry that takes the signal from the probe and turns it into something that can be fed into the ADC of the scope.

[@Seegalgalguntijak]

FFcossag Yes, well, I almost never solder something, so I'm not even sure whether I need a scope in the first place. But about the front panel, I was joking there as well (also in my first comment where I mentioned it) - although I interpreted "frontend" even differently, as in "some sort of better graphical user interface" (while it does have a GUI, it's only a very rudimentary one), so thanks for clarifying this - I never knew that this thing you call a frontend was even a thing (or that it's called a frontend), but I can see how that might improve the performance of the device.

[@ChristopherGaul]

Fairly solid review, with one big caveat. Throughout the video the buffer view window slider is set to the wrong position. That's the green bar at the top of the screen. You must set the bar all the way to the right to get the live view. This likely was the cause of the supposed trigger issues as well. With the bar in the centre as shown, you're viewing the capture buffer, not the live data. Oh, and also that unit _may_ have been a counterfeit. Not sure how much that matters, but my genuine model has none of these issues.

[@danielelise7348]

Even after a few drinks,outstanding job mate very neat work & for $23.50,it's kind of hard to complain.What is your first name mate?

[@FFcossag]

+Daniel Malik Thank you, it is indeed hard to complain. My first name is Ludwig, but I never go by it.

[@capoman1]

Very good and detailed review, thank you.

[@cmj20002]

These are very sensitive to voltage on the input. Don't use more than 9 volts to power it. It shows 8-12, but I used 12 volts and the voltage regulator in it burned up. I replaced it and now it works fine again, but 9 volts is max. Most kits come with a plastic case and the scope works ok. Not bad for the money.

[@GnuReligion]

Not sure if it is relevant, but my experience with AMS1117-3.3v regulators, is that they insta-blow at 12V, even with no load.

[@LordPadriac]

Just an FYI most of the issues mentioned in this video have been addressed with firmware updates released since this video was published. I purchased this because I wanted to upgrade several things in my tool kit from hobby to semi-pro as I am now developing guitar pedals. This works beautifully for that. This was an upgrade for me as I had no oscilloscope previously. The pedals I'm working on now need a max of 18v and the audible range for human hearing tops out at 20kHz so this unit is fine. I do intend on upgrading to a full proper scope in a year or so because this will not be able to handle the plate voltages (up to 300v AC or DC)for vacuum tubes I intend on using in alternate pedal versions. It's an awesome little gateway scope. There is an acrylic kit with buttons that stick out of the face and completely enclose and isolate the circuit board available. I'm sure JYE Tech sells it on their site but if you type DSO138 into eBay you'll find it available starting at about $5 US.

[@danijel124]

If this thing would cost 100 dollars everyone would say that its superb :P

[@russho8967]

What FRONT END would you suggest? Can you give us a schematic and "how to" make/use it? Thanks!

[@WarthogARJ]

The Ground to reference to is bottom left: "DGND". It does say in the instructions at Page 2, bottom right.

[@chhupparustom]

Can this be used for displaying audio waveforms?

[@FFcossag]

Yes.

[@chhupparustom]

@@FFcossag Can you provide any guidelines / instructions on its wiring diagram?

[@MegaKencam]

There is an updated firmware available for the DSO138. You should try it and do an update video.

[@FFcossag]

+Kent Campbell Thanks for the tip, I'm going to have to scourge up a serial level converter and give it a go! Cheers.

[@amtpdb1]

Do you have any suggestions on what to change to make it better? There were a couple of suggestions on the manufacturers site in the past. Most hobbies-ts would appreciate things that could be changed by us to the only scope we may have to make it better. Some of us, at the least myself, are just learning and would appreciate any help you can supply to make this scope better for us. Thanks for your video.

[@FFcossag]

The thing this device most desperately needs is a real front-end.

[@Seegalgalguntijak]

You mean like a face plate where the display and the little buttons stick out? ;-)) SCNR...

[@FFcossag]

Seegal Galguntijak Yes, that is definitely what I mean.

[@Elecifun]

Hi there, Using a file or sandpaper to scratch away the zinc on the BNC also USB and switches makes soldering much easier. Took me a while to figure it out ;-)

[@Marcel86_ttv]

This is the genuine way to make one of these 10/10 good sir xD

[@quentinbush]

Being a complete novice I have greatest difficulty reading values of resistors. Sadly the video of your completed board just does show the colour code for the values (to copy) Would you point me in the right direction for say R1, R2 and the stripe colours. Thanks.

[@FFcossag]

I'd say the easiest way to learn is to grab a multimeter and a resistor code table off of Google, and cross-reference what you see on your actual resistors.

[@clauberap1380]

nice video. Do you know if it measures current? Thanks

[@FFcossag]

It does not.

[@MikeSims70]

I got about 20 minutes into this video listening to you repeatedly compare this thing to your far more expensive test equipment, and all I could think of was "Damn ... for less than $25, that is one HELL of kick ass little scope." ... It seems to me that you have reviewed this scope far out of context. There is no way that this scope was ever meant to be compared to equipment that is far more expensive and more completely engineered. No offense chap, but I give this review two thumbs down. Bottom line is that the $23 scope performs as advertised and I feel that what you have shown, proves the scope is worth $23 and then some...

[@FFcossag]

It doesn't perform as advertised, but it is good value for money despite that. I'm pretty sure I concluded that at the end of the video. I think the most important aspect of a review is to point out the odd issues with a product that can only be figured out by buying the product; don't confuse that for a negative stance on the product.

[@MikeSims70]

Personally, I think a review should simply review the product ... and if comparisons are necessary, the product should be compared to same class products. Comparing a $23 scope to equipment that costs 10 times as much or more is hardly a fair and balanced review ... anyone who is in the market for a scope knows damn well that they aren't getting a cadillac for 25 bucks ... just my opinion, however. On a positive note, you certainly are thorough and you leave nothing out. The beginning of the video where you build the scope, then go over every feature was absolutely wonderful since I am considering purchasing one of these ... my needs for a scope are "hobbyist" at best ... once in awhile, I want to see what the signal looks like because I can't always tell if i'm reading an RMS or straight DC ... or like the other day, I removed an adjustable light circuit from a lamp and put it onto a fan, where previously, I had the fan connected to a rather large potentiometer ... with the light dimming circuit, the fan tends to "chatter" at low speeds where it does not chatter when I use only the potentiometer ... it would be nice to see what the power looks like coming off of the dimming circuit as I suspect it does not resemble a smooth sine wave. I think a scope like this would be perfect for a job like that.

[@FFcossag]

***** "the product should be compared to same class products" - I would agree with you if we were talking about competing products. This product, however, is a piece of precision measurement equipment. Its aim is to produce as accurate measurements of quantifiable data as possible. As such, I consider it to be of extraordinary importance to make an effort to see how well it does that - and that requires it to be compared to the most accurate reference possible. The Rigol is not presented as a competitor, it's used to highlight the limits of the cheaper device. As far as your fan goes, the light dimmer circuit is going to produce a "cut off" sine wave. Triac based dimmer circuits work by letting the mains waveform rise to a value set by the adjustment potentiometer, at which point they turn off the triac and return the voltage to 0 until the next mains cycle. So, you end up with a set of little "blips" at the beginning of each cycle, rather than just a small sine wave.

[@snshn3715]

FFcossag. Agree with you here. It is certainly good to know the limitation of this scope from your comparison

[@raf1800]

+FFcoosag I believe this one of most valuable kind of review of the product as soon as this is compared to be useful or not as a cheap measurement tool to have at home for hobby purposes. We even are able to learn a bit on how to evaluate some parameters following your thoughts. Thanks for your review

[@rawux1228]

Well the price range is huge between these two oscilloscopes. Rigol costs like 400$ and dso138 now 15$ so you get what you pay for. I believe its good for its price. Waiting mine to arrive.

[@Inesophet]

cashstrapped me is quite happy with it.

[@otissumnerbrown]

I like the intro!!

[@FFcossag]

You are in a minority.

[@thagrit]

I bought a 25mhz dual channel o scope on eBay for 60 bucks. It was a used unit but way better than that crap.

[@haiaokuwa]

Thanks for this

[@RobertKohut]

Nice. Great for DIY audio amplifier projects....

[@pirateman1966]

Of course this is junk as far as an oscilloscope goes. However, I will buy one. They are now under $20 from AliExpress. I don't need another scope but this thing looks like it is very hacker friendly and I could use it for another project. Thanks for the real nice video explaining the things I wanted to know. BTW, don't let these fools who give ppl thumbs down discourage you. Haters will hate. Nothing you can do about that. I for one, thoroughly enjoyed it.

[@felixcat4346]

I bought one, assembled it and tried to power it up. I used a 9 volt battery it came on for a few minutes then went to the back light screen. Tried using another battery it came on again and I guess when the battery went a bit lower the processor stopped. I tried powering it up with a 10.5 volt computer power supply and no dice. The instructions say it will work with a power supply between something like 6 to 12 volts. So I´m stumped as what´s wrong but it was fun while it lasted.

[@FFcossag]

+Joseph Nicholas It sounds like a power supply issue on the board, perhaps a badly soldered SMD 3.3V regulator. If that's the case, it would probably have died hard when you ran it on 12 V. Thankfully, it's not such a big loss.

[@FFcossag]

***** That's definitely not right - you should probably troubleshoot that, a faulty voltage regulator could end up frying it all if it decides to die the wrong way.

[@felixcat4346]

+FFcossag I found out the problem. I accidentally reversed biased the input diode and it fried the 708 voltage regulator. I finally got a new one today at the local electronics shop for 10 pesos. I now works like it was designed too. I paid about 11 dollars for it from aliexpress during its 11/11 sale last November. It certainly beats using a cro scope I used to own and weights about 30 pounds less. The color display, the hold mode, the single shot mode all seem to make its use much better than the cro.

[@FFcossag]

Joseph Nicholas I'm glad you figured it out - enjoy your little scope.

[@felixcat4346]

Thanks, Your comments helped me find the fault.

[@chopper680]

I miss the old Heathkit Even though they cost a lot, the quality was there

[@101Gabriel_M.]

DAMN... random find on YT... aaaand this video firs 30s... and I love you :"D Subscribe !

[@bennosgarage]

:DDDDDDDDDD thant intro :D i ordered one

[@electronic7979]

Nice

[@Seegalgalguntijak]

The Rigol has the one single problem that it costs over 300€.

[@FFcossag]

To put it this way; I'm happy I didn't learn how to use a scope with a DSO138, because I'd been terribly confused as to how real scopes work.

[@whuzzzup]

If anyone plans to get that thing, make sure you check their website first and get it from a proper seller. There are dozens of counterfeit boards on ebay/ali/whatever. So the real developers don't get any money, and I think they deserve it. The counterfeit sellers are not even cheaper. The original one has a sticker with a serial number and you can ask the developers if it's original.

[@someoneyoudontknow106]

good video but AWFUL intro!

[@HAXAHAX]

someone you don't know I thought this was how to basic for a second

[@NienteNessuno]

How To Basic confirmed

[@Alexelectricalengineering]

Thumbs up :)

[@reatoruv]

I would make this with my frequency meter.

[@WeakPlayerPoker]

I was looking for educational electronics videos, and the first 30 seconds of this made me ruin yet another keyboard. Damn you. I mean, thanks for the laugh.

[@russho8967]

With your background, I think you could replace all the cheap resistors etc. with 1% parts and re-test specs. Also, buy a factory built unit, maybe you made a "little" mistake assembling this? Lastly, try the "firmware update" and retest (with 1% parts). Then, you could possibly offer a solution to us poor folks. Thanks for the video. Maybe a follow up explaining USE would help many people. Your skills at the buttons were not easy to follow. Oh, it there a BETTER 'scope out there in the same price range? I have a need for 8 traces.

[@FFcossag]

You will certainly not get 8 channels for $20. I made another video on the newer firmware, it's linked in the video.

[@1djbecker]

There wouldn't be any advantage in replacing most of the parts with more precise versions. Almost none of them have values that are critical for operation. Perhaps you would want accurate values for the resistors that set the gain in the first and third stage, but they are pretty much good enough. And the gain would be better be calibrated in software, although there is no setting for that. The biggest improvement would come from a quieter, more balanced analog supply for the opamp and a much quieter VDDA analog reference supply for the STM32. The opamp is supplied by a 78L05 and 79L05 pair, which have a mediocre PSRR (power supply ripple rejection) parameter. The STM32 is well know for having power rail noise coupled to the ADC section. One way to compensate is to alternate measuring the internal 1.2V reference, and using that value to correct the external samples. When you need the maximum sample rate, use the second ADC for the compensation. (When you want even faster, run both ADCs on the same input and give up on correcting for noise.)

[@jensvanderploeg7001]

the price i paid was 12.00 dollars

[@vladimir7838]

this is nice if you want to get some practice in soldering

[@imeakdo7]

0:26 waa... whaat??

[@rsattahip]

I considered it a toy for adults.

[@abpccpba]

Introduction shows your mindset not mine BYE.

[@FFcossag]

Enjoy yourself.

[@sofianesellam7395]

would you like to offer it for free ?

[@Kosmonooit]

what's with the accent?

[@FFcossag]

+Kosmonooit There's something with the accent?

[@Kosmonooit]

+FFcossag Can't figure it out, where are you from?

[@FFcossag]

Kosmonooit A non-English speaking country, of course. Finland. I'm glad you didn't just jump on the band wagon and call me British. ;)

[@robh1908]

+Kosmonooit This guy is actually Noah watch?v=Ud4wXa0V7FA

[@FFcossag]

+Rob H Oh jesus. If that's what people hear, I REALLY need to get a better microphone.

[@JamalNetChannel]

Funny intro

[@broderp]

Anyone else wanted to shoot themselves rather than listen to this monotone droning of a review? Just listen to yourself, your comparing it to the Rigol. I'm betting that this isn't targeted at the same audience. I can't imaging someone with the budget and experience having to contemplate which of these to buy. How about a real review and compare it to other kits in the price range?

[@FFcossag]

Among the blind, the one-eyed man reigns king.

[@TheKetsa]

" monotone droning " perfect description !

[@Jimmeh_B]

+FFcossag first time I've come across you on youtube, and last. "What a pretentious tosser you are" I thought to myself when I heard your very "proper" accent, from this answer you've given, turns out I'm right.

[@WarthogARJ]

You said: "Anyone else wanted to shoot themselves rather than listen to this monotone droning of a review?"..... Hmmmmm, so how does it compare to the many videos that you have posted? Hmmm.....I don't think I see any. Be polite or don't post. He's Swedish, his english is very understandable, it's not a "drone.

[@williefleete]

Tips for hobbyists... Get a real scope, even a 20Mhz analogue. These things are shit.

[@0wn4l1fe]

These things work really good for their price. ''Good'' oscilloscopes start at around 400, up to 10.000...

[@cghoselle]

LMAO

[@slawor4]

Just wish feminists had such an LED

[@robprebil]

What a downer! I can barely read the component markings, the instructions paper isn't high quality, it was only wrapped in foam, whaa, whaa, whaaaaaa! OMG - it's a fun $20 oscilloscope! What the hell were you expecting? Why can't you just review it as it really is?

[@FFcossag]

+Rob Prebil Upsides and downsides are upsides and downsides regardless of product price. The DSO138 is great value for money, but that's about it.