Video Review & Teardown of the Analog Arts SL987 USB Combo Instrument - Page 1
Forum section: electronics / testgear

author: Hugoneus
author_rank: Frequent Contributor
timestamp: February 09, 2015, 02:54:40 pm
content: In this episode Shahriar takes a close look at the Analog Arts USB based mixed-domain instrument. The SL987 offers an oscilloscope, arbitrary waveform generator, FFT-based spectrum analyzer, pattern generator and logic analyzer in a compact form factor.The teardown of the unit is presented along with the datasheet of every major component on the PCB. Some design limitations and concerns are presented along with basic performance verifications.Watch the video here: [46 Minutes]http://youtu.be/F-1uA4Iwce8More videos at The Signal Path:http://www.TheSignalPath.com

author: photon
author_rank: Frequent Contributor
timestamp: February 09, 2015, 08:34:30 pm
content: Thanks for the post and teardown. The USB connector with host ports on each end is not possilble, AFAIK. I wonder what happened there? It could be that their circuit board had mistakenly put a host port connector instead of a device port connector. If someone thinks they can use such a connector with 2 host ports to connect 2 PC's via USB, then this would not work.

author: Monkeh
author_rank: Super Contributor
timestamp: February 09, 2015, 08:37:22 pm
content: That.. is pretty horrific.

author: photon
author_rank: Frequent Contributor
timestamp: February 09, 2015, 09:44:57 pm
content: I think it interesting that USB has spec'd a new connector, call TYPE-C, that will be universal, in the sense that there will be a single connector for both host and device. Also, it will have no up or down polarity in the plug, will support all versions of USB plus allow support for other bus protocols. It will negotiate all these issues, plus who is supplying power and how much, at plug-in time. The spec allows up to 100 watts of power!

author: electr_peter
author_rank: Unknown
timestamp: February 09, 2015, 10:13:17 pm
content: Claimed "1GHz BW", wobbly BNC jacks, cross-talk all over the place, massive undersampling for BW, inadequate shielding, mysterious DC offsets, digital or analog modes only, ...At least SW side is working without hiccups.This device is well suited for lower (say 10-40 MHz) freq probing/logic probing/signal gen, but at this price point market is dense. Maybe manufacturer tried to amplify best possible scenario for specs to stand out. I think that built-in signal gen + scope is very useful for frequency response testing.Comparison with bench scopes would be not be reasonable, because of different amount of processing/memory on main board. As mentioned in the video, DS1000Z series are hard to compete with.As for USB connector, I think it is very reasonable choice. It is easy to connect, holds contacts well and gets good support from PCB. USB B is similar or a bit worse in some aspects, micro/mini are too weak in comparison. The only disadvantage - cable is harder to source.

author: Hugoneus
author_rank: Frequent Contributor
timestamp: February 09, 2015, 10:20:52 pm
content: Unfortunately as you can imagine the company is not very happy with my review. As I mentioned I gave it the benefit of the doubt with regards to the board (assuming that it was a prototype). And I mentioned that for lower frequency inputs its performance is reasonable.However, I would have betrayed my commitment to science and engineering if I didn't speak about its problems.

author: Monkeh
author_rank: Super Contributor
timestamp: February 09, 2015, 10:23:52 pm
content: Quote from: electr_peter on February 09, 2015, 10:13:17 pmIt's a stupid choice, it's non-compliant and the cables are, as a result, not standard.Quote from: Hugoneus on February 09, 2015, 10:20:52 pmYou were very kind to it. Much kinder than it deserved. They should have known better than to send something like that to someone who actually knows what they're talking about.

author: AF6LJ
author_rank: Unknown
timestamp: February 09, 2015, 10:35:07 pm
content: Very Scary.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: February 09, 2015, 10:36:16 pm
content: Quote from: Hugoneus on February 09, 2015, 10:20:52 pmWell if they shipped you what looks like little more than a prototype what did they expect...?I have seen USB A's abused like this on a couple of occasions, and USB A-A cables are fairly available, but it's an unnecessary annoyance.

author: electr_peter
author_rank: Unknown
timestamp: February 09, 2015, 10:48:52 pm
content: Quote from: Monkeh on February 09, 2015, 10:23:52 pmIt is non-compliant (what will happen when two hosts are connected with such cable?) and it should be marked with bright colors to inform general public about it. However, it is not that bad if only connector is concerned - one can do much worse. It is better than some non-standard connector for USB port or something crazy like plug/plug (male to male) IEC mains connector...Thanks to Shahriar for such complete review of device as it is. Detailed explanations of schematics, comments on parts spec, fault finding, real performance testing and comparison to specsThis is real journalism of technical topics.

author: c4757p
author_rank: Super Contributor
timestamp: February 09, 2015, 11:45:30 pm
content: Damnyou're a nice dude. This thing's a total heap of garbage, they're so lucky they got the kind review you gave it.It needs to be reviewed with a hammer.

author: EEVblog
author_rank: Unknown
timestamp: February 09, 2015, 11:47:21 pm
content: There isn't much Art inside that! Yuck!

author: Hugoneus
author_rank: Frequent Contributor
timestamp: February 09, 2015, 11:48:31 pm
content: Quote from: EEVblog on February 09, 2015, 11:47:21 pmIt would have been interesting to hear what you thought about it. As I said, I feel bad about the review and I have given them a chance to address the issues and get back to me.

author: EEVblog
author_rank: Unknown
timestamp: February 09, 2015, 11:50:05 pm
content: Quote from: c4757p on February 09, 2015, 11:45:30 pmA Widlerizer hammer!

author: c4757p
author_rank: Super Contributor
timestamp: February 09, 2015, 11:52:46 pm
content: Quote from: Hugoneus on February 09, 2015, 10:20:52 pmI understand why it might disappoint you that they're Unimpressed, but dude, you scored a big one for integrity. You were honest about this thing, fair and balanced in every way - you gave it a chance when it deserved one, told the truth when the truth needed to be told, and as much as possible let the viewer reach his own decision. If they think the problem is your review and not their product, they have a serious disconnect with reality.There's a reason your equipment reviews are my favorite of all of them. Analog Arts might not be happy, but I definitely thank you.

author: Hugoneus
author_rank: Frequent Contributor
timestamp: February 09, 2015, 11:55:34 pm
content: Quote from: c4757p on February 09, 2015, 11:52:46 pmI appreciate that.

author: EEVblog
author_rank: Unknown
timestamp: February 09, 2015, 11:55:46 pm
content: Quote from: Hugoneus on February 09, 2015, 11:48:31 pmI only briefly watch the inside teardown bit, but that was enough. Seeing that I doubt I would have even bothered continuing with any review.For a company that claims:QuoteYou have to wonder how they could be this incompetent?$1260 and the best and most expensive product in their range? Yikes.

author: EEVblog
author_rank: Unknown
timestamp: February 10, 2015, 12:00:02 am
content: Quote from: c4757p on February 09, 2015, 11:52:46 pmThe funny thing is I've been criticised for doing thatI've found that people want a strong opinion one way or the other, Yay or Nay.If I did anything less than toss it across the room, I'd get hate mail and accused of having sold out

author: c4757p
author_rank: Super Contributor
timestamp: February 10, 2015, 12:02:53 am
content: Quote from: EEVblog on February 10, 2015, 12:00:02 amPeople expect you to be mean.

author: EEVblog
author_rank: Unknown
timestamp: February 10, 2015, 12:05:40 am
content: Quote from: c4757p on February 10, 2015, 12:02:53 amI suspect they confuse meanness with brutal untactful honestyOk, I'm mean

author: Lukas
author_rank: Frequent Contributor
timestamp: February 10, 2015, 12:26:58 am
content: 1GHz with a 100MSa/s ADC is not completely impossible. You may use a comparator and a TDC to determine the exact triggering instant and then accumulate over multiple acquisitions. HP did that in the 54600 series and manged to get >100MHz bandwidth out of a 20MSa/s ADC.

author: Hugoneus
author_rank: Frequent Contributor
timestamp: February 10, 2015, 12:39:41 am
content: Quote from: Lukas on February 10, 2015, 12:26:58 amAs I mentioned in the video, such a system requires either a coherent precision time-base signal or an entirely different architecture. The problem arises from the fact that the instrument makes mistakes on computing the actual frequency of the signal being applied once it is above Nyquist. And it can only do this on periodic signals (and if the period fits within the captured memory). It is essentially trying to reconstruct the aliased signal from multiple periods.

author: photon
author_rank: Frequent Contributor
timestamp: February 10, 2015, 02:37:20 am
content: Quote from: electr_peter on February 09, 2015, 10:48:52 pmYes, it is indeed broke. Since a USB hosts supplies power on VBUS, having 2 hosts connected together, type-A to type-A, will short their supplies and can cause damage. On the other hand, I agree that if one of the 2 ports is a device, then this problem does not occur since a device does not supply power but rather consumes it. The only type-A to type-A connector that I would trust would be one where the cable contains a small circuit board that bridges the two ports. Such cables exist and are handy to network 2 PC's using USB, but they require a special driver and are more expensive.

author: Lukas
author_rank: Frequent Contributor
timestamp: February 10, 2015, 07:17:30 am
content: Quote from: Hugoneus on February 10, 2015, 12:39:41 amI guess you're thinking of sampling oscilloscopes like the DCA from Keysight? Random sampling oscilloscopes like the 54600 don't require a coherent clock/trigger, since they determine the clock-to-trigger relationship on each trigger event using a TDC.

author: nfmax
author_rank: Super Contributor
timestamp: February 10, 2015, 11:00:17 am
content: The Intronix LogicPort USB logic analyser also uses a type A connector, and they supply a typeA/typeA cable with it. I've never seen this done elsewhere before.

author: nctnico
author_rank: Super Contributor
timestamp: February 10, 2015, 01:51:32 pm
content: Quote from: Hugoneus on February 10, 2015, 12:39:41 amIMHO the oscilloscope bit isn't much and the claim of 1GHz is way overstated. Without 50 Ohm inputs that is impossible to achieve. BTW: about a decade ago I've made something very similar (see my avatar picture) with up to 1Gpts per channel and 10 bit resolution. I cancelled that project due to Rigol introducing cheap oscilloscopes.It's a pity the reviewer didn't go deeper into the logic analyser and more importantly the pattern generator. If I look at the prices the logic analyser and pattern generator capabilities are interesting. I'm still looking for a good digital pattern generator solution which can generate UART, SPI, I2C, etc patterns from a simply GUI.edit: typo

author: nctnico
author_rank: Super Contributor
timestamp: February 11, 2015, 01:36:04 am
content: I downloaded & installed the software to have a look at the pattern generator part. It is pretty basic. It allows to generate sine and triangle waveforms and set/clear signals to 0 and 1. However the way signal generation is implemented is rather clumsy. You have to select a function and then click which bit of that function is to be put on a certain signal. Also no way to set the output level which made me loose interest in this device.

author: zapta
author_rank: Super Contributor
timestamp: February 11, 2015, 01:38:18 am
content: Quote from: Hugoneus on February 09, 2015, 02:54:40 pmExcellent review. I liked the depth and the style. Thanks for doing it.

author: JasperNL
author_rank: Contributor
timestamp: February 11, 2015, 12:20:37 pm
content: QuoteDon't feel bad about it. I like the way you reviewed this piece of junk. First the block diagram with the theory of operation. Then you compare the used components with the claimed specs. At his moment you discovered some major problems with the system architecture. Finally you take some actual measurements to confirm the problems. Thats just perfect. You discovered the problems before you turned it onYou point out the problems, gave the benefit of the doubt and the chance to solve the problems. Analog Arts should be lucky with your gentle review!

author: Hugoneus
author_rank: Frequent Contributor
timestamp: February 11, 2015, 04:52:51 pm
content: I have to say, this review has caused a lot of headache! The YouTube comments areI added my observations to the comment section too. A $1260 dollar product should be a serious product in my opinion.A kind EEVBlog member has pointed that people who are questioning my review have had their account created on the day (or the next day) the review was released.How disappointing...

author: MadTux
author_rank: Frequent Contributor
timestamp: February 11, 2015, 06:30:59 pm
content: WTF, 1260$ for a 50MHz Scope and a AWG with broken offset and a 15MHz square wave that looks like a sine wave?!! LOL. 150-250$ would be more appropriate. Any old HP 16500 will beat that thing for a fraction the price.Maybe someone should create a list of equipment you wouldn't want to buy (D-105 reference, that thing, HP instruments with German HP ASICs inside, HP 8116A, 8112A etc. ....)

author: macgyver0815
author_rank: Contributor
timestamp: February 14, 2015, 12:58:21 pm
content: That review made my day - thank you ShahriarPlease don't feel bad about the reaction of that company (and their troll postings on youtube) - it was an honest review and in my opinion you were VERY polite and they should be thankful for that.What reaction did they expect from an expert that can even track down issues in $50k microwave equipment?I guess they haven't watched your other videos before sending you the unit for test

author: JoeN
author_rank: Frequent Contributor
timestamp: February 28, 2015, 08:59:02 pm
content: I finally just got to this review. I just stopped 8 minutes in to see if anyone here had commented on it so far because I thought there might be a comment or two. I'm not sure I can even continue. I have never been a fan of "cringe-comedy" - it's hugely unpleasant for me to see Jack get embarrassed by his own self for the 100th time (Jack Tipper, not Jack Bauer). I'm getting the same feeling now watching this video and it makes it hard. How the heck did they manage to melt a relay?

author: amyk
author_rank: Super Contributor
timestamp: February 28, 2015, 09:25:57 pm
content: Quote from: EEVblog on February 09, 2015, 11:55:46 pmI agree, this seems more like what some random Chinese company would do...