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Sorry, but don't have a JEDEC or another spec source, care to provide one? Otherwise I'll keep using Wiki and various known manufactures such as On Semi, Vishay, Diodes, and so on.
No, you can't do that, you need to provide links/information/indications of a specific SOURCE, so that people can nod their heads in agreement. Otherwise, things could/would/might get out of hand.
If you want to chuck your own components/stuff, for ANY reason you decide, into the junk pile, that is entirely up to you. But, if you want to create a thread on a public forum, suggesting/hinting that others do the same. You need to justify it, ideally with actual visible/touchable/existing sources of information. Of suitable quality/reliability/trustworthiness.
As far as I understand things. It is entirely normal, for the top three component manufacture's, of a specific component, to have datasheets, which in at least one area of concern, are noticeably better than the worst three component manufacture's, of that component type.
Hypothetical (made up) examples, as I don't want to spend ages checking through datasheets.
The best TTL/CMOS/similar device manufactures, may have a specific parameter, buried deep in the datasheet, which says the worst case leakage current is no more than 0.5 microamps. The cheapest competitors datasheet, may give that parameter, as a looser, 2 microamps. True, that is worse, but in the vast bulk of applications, that will work out just fine. If not (i.e. it does matter), you can either use one of the better parts, in that circuit, or redesign it slightly, to have a lower value pull up resistor or similar.
TL;DR
It is NOT up to US, to provide you with the 'claimed' specification sheet(s), which support your claims. It is up to you. We are perfectly entitled to reject some or all of your sources, such as Wikipedia and other similar, datasheets. As they are NOT part of any official standards, as such. -
Reverse Recovery Time
recovery time yes. capacitance ? no. and before you start saying "they are related" , they are not the same.QuoteWell we've compared apples to apples and according to other 1N4148W specs (Vishay, Diodes, Semtech, MCC, On Semi, and so on) the answer is the Jingdao 1N4148W does not match or even approach the capacitance and reverse recovery (maybe more parameters, but we didn't check) specs!! Exactly why IMO this should not be considered a 1N4148W.
Good. i dug a bit deeper because this intrigues me ( i deal with this kind of crap day in and day out , supply chain , pcb libraries )
So it turns out that the governing standard for letter suffixes is RS-370-B which specifically controls diodes.
The letter structure of a JEDEC number
- 1 digit specifying the number of "useful electrical connections" minus 1. a diode has 2 terminals so it becomes 1 (2-1) . a transistor has 3 terminals so becomes 2.
- the letter N or C. N meaning a registered part , the letter C designating the bare die form. so a 1C4148 would be a unpackaged diode die. stick it in a package and you get a 1N4148....
- two or more digits that are a sequence number in the catalog.
if no other suffixes : this is the "root part" for which only 4 parameters are defined. (already discussed earlier) if a registered jedec package is used this is part of the RDF.
so certain types can have a hard package designator called out. others may skip that.
Suffixes - and / are package / regulation classifications.(see earlier posts.)
Letters:
Letters A to K (except I, that is not allowed because of potential confusion) are revisions of the diode with additional controlled parameters not part of the original RDF (Registered Data Format in JEDEC parlance)
Letter L means leads longer than root package spec
Letter S means leads shorter than root package spec
Letter R means this diode sits reverse in the package. for example a sot23 typically has the cathode at pin 3 , anode at pin 1. the R would reverse the orientation. you will find this more with transistors since it makes single sided layout easier (stereo amplifiers for example: you can mirror layout.)
Letter M meaning microwave diode. they deviate from the above lettering ( this is historical before they started drawing a formal standard , so it gets messy...)
Letter P followed by one or more digits : package variations. Same electrical characteristics just different package. This is also historical. no new parts are allowed with this letter scheme.
the sequence is also specificed : [terminal count][N/C][identifier numbers]<optional variant A..K><optional R reverse ><optional M microwave)
in that order.
so 1N909BRM would be a 1n909 , b variant , Reverse mount , microwave
1N909RBM would be invalid format. (reverse before variant. )
Anything else is not JEDEC but just arbitrary stuff the manufacturers slap on to . so that W means exactly nothing ... where JEDEC is concerned. You'd expect a 1N4148W from abc to be the same as a 1N4148W from xyz , but that is not necessarily the case. And since capacitance is not part of the RDF ...
There are many numbering schemes in circulation that are not JEDEC. everybody seems to slap on whatever and nothing is really controlled.
One clause specifies that JEDEC registered data needs to be marked with an asterisk in the datasheet, and a footnote stating the asterisked parameters are JEDEC registered. I can't find any datasheet where this is marked for the 1n4148w (see the example i gave for the other diode. ). pretty interesting. So all these parts out there are not truly JEDEC 1N4148 . They are close, but no cigar...
JD282 and RS-370-B are the controlling documents. read at your own leisure
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Think we've wasted enough of our and others time and BW on this subject. If you chose to view the 1N4148 as a generic jelly bean diode without much regard to capacitance and reverse recovery parameters, go ahead and do so
I don't see it as time wasted.
I think your capacitance measurements were interesting, and resulting discussion of value. -
Anything else is not JEDEC but just arbitrary stuff the manufacturers slap on to . so that W means exactly nothing ... where JEDEC is concerned. You'd expect a 1N4148W from abc to be the same as a 1N4148W from xyz , but that is not necessarily the case. And since capacitance is not part of the RDF ...
So here's your exact quote from earlier:
The suffix denotes a tightening of an original specification. you can replace a 1N4148 with a 1N4148W , but not the other way around.
So obviously you are completely contradicting yourself here!!!
In one case you state you can replace a 1N4148 with a 1N4148W but not the reverse, then soon after state that the W means nothing, so how can you claim you can replace a 1N41418 with a 1N4148W when as you state the "W" means nothing
This is all we need to know about the value your responses, and what your true knowledge base is!!
Best, -
This is all we need to know about the value your responses, and what your true knowledge base is!!
You're being ridiculous!
You are turning other people/engineers, into simple on/off, black and white 'boxes'. That are either 100% correct/right/accurate all the time, or potentially/fully wrong. People/engineers etc, are NOT as simple as that.
The person who sweeps the floor of someones labs, might say a particular component is WRONG, because it looks a funny colour. They may have absolutely no knowledge of electronics. But that DOESN'T mean that what they say is wrong. Maybe (probably not), that component is WRONG, it could be the case.
Analogy/example, let me poke fun at you:1N41418
You can't even 'spell' 1N4148, so I'm going to ignore all future responses you make. As you can't even get 1N4148 correct!. (Joke, for dramatic effect). -
This thread identifies yet another level of marketing BS.
Most people are aware that 'typical' values in a data sheet rarely are, and only specified limits to performance are meaningful.
What everyone also needs to be aware of is that with Wikipedia or other source which has no contractual traceability the most you can say is that the quoted values are 'typical'.
As you have thoroughly demonstrated there is one manufacturer who slaps a 1N4148 label on a part that does not meet the 'typical' specifications. In this context I am using the OPs statement that most of the specifications on the Wiki are similar. Would the OP be happy if the vender for this part had posted their data sheet on the wiki? An action that anyone can do.
The fundamental message is what free_electron has stated over and over again. Do not count on performance that is not traceable through contractually enforceable documents. Many engineers have learned this lesson the hard way. Most critically when they have implemented some clever design that depends on some components out of specification performance. And then the manufacturer "upgrades" their design, or the original vendor goes out of business, or the original vendor learns of the special value of their part and bins them into another higher priced part number, or some market elephant corners the supply of that version of the part and the alternatives just don't work.
Railing that some vendor didn't follow the herd won't help. They sold their parts, and their market volume is unlikely to be affected by your complaint.
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This is all we need to know about the value your responses, and what your true knowledge base is!!
You're being ridiculous!
You are turning other people/engineers, into simple on/off, black and white 'boxes'. That are either 100% correct/right/accurate all the time, or potentially/fully wrong. People/engineers etc, are NOT as simple as that.
The person who sweeps the floor of someones labs, might say a particular component is WRONG, because it looks a funny colour. They may have absolutely no knowledge of electronics. But that DOESN'T mean that what they say is wrong. Maybe (probably not), that component is WRONG, it could be the case.
Analogy/example, let me poke fun at you:1N41418
You can't even 'spell' 1N4148, so I'm going to ignore all future responses you make. As you can't even get 1N4148 correct!. (Joke, for dramatic effect).
Ridiculous? Don't think so!! Not turning anyone into anything, we'll let them do that by themselves, yourself included
Yes we misspell often, certainly not the first nor the last time. However, we don't spew out a bunch of misinformation as has been shown, and frankly don't have the time nor patience for this kind of BS.
What we got out of this measurement was; not all 1N4148s are equal, and one was way different with measured capacitance 10~14 time greater than the rest, and some SMD 1N4148 have very low capacitance, under 0.7pF, and so on. Thought this might prove useful to some folks, but found a few seem to get really ticked off about this.
Before we started this post we expected a 1N4148 of any flavor to have <4pF capacitance and <4ns reverse recovery based upon many decades of use, despite all the prior discussion and arguing this hasn't changed, as we still consider a 1N4148 to fit within 4pF and 4ns, and frankly that's all that matters here at the Labs!!
BTW keep tabs on our misspelling, I'm sure you'll collect plenty of examples
Best,
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Before we started this post we expected a 1N4148 of any flavor to have <4pF capacitance and <4ns reverse recovery based upon many decades of use, despite all the prior discussion and arguing this hasn't changed, as we still consider a 1N4148 to fit within 4pF and 4ns, and frankly that's all that matters here at the Labs!!
I can appreciate that way of working. You're expecting 1N4148 diodes, to behave with reasonably 'tight' specifications, as mentioned above. Which means that when it is designed into production units. They will behave quickly enough to NOT allow inputs to be potentially (ignore pun) damaged, because the reverse recovery time was too slow, or not allow the full bandwidth capability, again, because of performance/capacitance issues.
So, from that point of view, they are NOT 1N4148 spec devices, and so need to be kept away from 'real' 1N4148's. I.e. put in the junk component pile, or similar.
Others (including me), who say use the manufacture's datahseet, are still right (in some senses). But its characteristics, are more like a 'substitute' slightly/partly equivalent 1N4148 part, rather than a close equivalent one.Ridiculous? Don't think so!! Not turning anyone into anything, we'll let them do that by themselves, yourself included
Yes we misspell often, certainly not the first nor the last time. However, we don't spew out a bunch of misinformation as has been shown, and frankly don't have the time nor patience for this kind of BS.
Well, in that case, let me throw criticism(s) back at you then.
Your measurements, are showing perhaps two datapoints (test diodes), that you tested. But the real issues, if you go into mass production with these devices. Is that, that ONLY represented a particular batch (in all likelihood). The real $64,000,000 question, is how far can the worst possible such diode, be. Which is still able to get through all binning, testing by the manufacturer, followed by any binning/testing at your (production) end.
That is why/where the actual datasheets come into play.
I.e. Although a couple of the test diodes (from a better manufacturer of 1N4148's), may meet your 4pF and 4ns recovery measurements. That doesn't necessarily mean, every single one, supplied for all your production runs, will.
So your tests, are only really part of the solution to keeping your circuit design and products, of reasonable or better quality.
Or to put it into different words. Your measurements, only really gave you some limited typical values, rather than the real/true maximums, that apply to those components. Which could be a lot worse than what you measured, especially across different batches and/or much larger quantities of those diodes.
In some cases, real problems with the components, don't actually show up until significantly higher (or lower) temperatures, are involved. E.g. Leakage currents, can significantly be connected to the junction temperatures.
So your testing was rather limited really.
EDIT: But in all fairness to yourself. I can't really complain. You happened to test a couple of samples, of what were supposed to be 1N4148's (in your perception). On finding out they weren't (so called standard 1N4148's), you decided to report your findings, here in this thread. My criticism is therefore fairly unfair, as a couple of outliers, are enough to spot problems with those diodes. -
So obviously you are completely contradicting yourself here!!!
Letter suffixes in general mean a tightening of the spec. I gave you the list as per RS-370-B. It stops at K for revisions. there are some other letters that have special meaning.QuoteThis is all we need to know about the value your responses, and what your true knowledge base is!!
way to go Mr "wikipedia 1n4148". i'm out.
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So obviously you are completely contradicting yourself here!!!
Letter suffixes in general mean a tightening of the spec. I gave you the list as per RS-370-B. It stops at K for revisions. there are some other letters that have special meaning.QuoteThis is all we need to know about the value your responses, and what your true knowledge base is!!
way to go Mr "wikipedia 1n4148". i'm out.
The OP should of been digesting/listening/reading your nice/sensible/good responses, and sensibly replied to them, himself. Instead he seems to use certain criterion, that puts people on his, 'special' list of people to not pay much attention to.
The OP seems to remind me of engineers, who never, ever make mistakes (I mean that in the sarcastic sense), and anyone who disagrees with them. Even fractionally, gets added to their 'special' list. I suspect the internet, is making it easier for them to do that. I'm not sure they are taking enough account of the fact that basing such choices, on some limited text, that people are making, in posts. Can lead to all sorts of errors of judgement. It is probably a poor quality way of behaving and dealing with fellow people/engineers, as well. But these observations I'm making, could easily be wrong, as the internet/forum medium, hides some of the details, and anyway, who knows what a person is really thinking about. -
You are turning other people/engineers, into simple on/off, black and white 'boxes'. That are either 100% correct/right/accurate all the time, or potentially/fully wrong. People/engineers etc, are NOT as simple as that.
Um?
I am manifestly aware of, and quite fully support the fact that, I am 100% potentially wrong, all of the time. Like, there was any other option? Get real.
But herein lies a microcosm of this thread... there's always going to be those who are wronger than most. Learn to spot them, and ignore them.
Tim -
Um?
I am manifestly aware of, and quite fully support the fact that, I am 100% potentially wrong, all of the time. Like, there was any other option? Get real.
But herein lies a microcosm of this thread... there's always going to be those who are wronger than most. Learn to spot them, and ignore them.
Tim
Reluctantly, I have to admit, you are raising some good point(s), there. But, there are many different types/sorts of engineers (and non-engineers), from educational background, and their ratio of theoretical stuff to practical work. Then age, experience, country and many other factors, can also get thrown into the mix.
But anyway, thanks for the response. I suspect I'm automatically, and subconsciously making similar decisions, to some level/extent. Even if I'm not 100% aware of doing it.
EDIT: Also, to OP. SORRY, if I've caused any offense. When you can't see the person/people involved face to face, it can be all too easy, to offend people. -
@MK14
We did measure a few 1N4148s in different packages (DO-35, SOD123, SOD323), the Jingdao was outliner. All the data sheets we checked show a maximum Tr of 4ns and a maximum C of 4pF, a couple show 2pF, only the Jingdao shows no max C or Tr only a typical C of 5pF and Tr of 8ns. What's interesting about this data sheet is that it shows a graph of C vs V where C is ~10pF at 0.1V, yet states a typical C of 5pF with no reference to bias voltage nor measurement frequency. Please note that almost all sources indicate a max C and Tr, only Jingdao uses typical for both.
gamalot measured an unknown 1N4148WS acquired from Taobao and confirmed a low C of 0.63pF and also a DO-35 1N4148 of less than 1pF also confirming our measurements, see post #19.
We've made mistakes, and will likely do so in the future, but certainly won't try and cover up such and will man-up to the facts!! Most of my later career involved SOTA IC design, a mistake here could easily cost well over $5M, since the mask sets alone cost $5~20M and that was a decade ago, today likely 10X as much. You quickly learn who to trust with critical design tasks, and since many times new folks to the group get "assigned" by management you quickly need to access their individual skill and knowledge level, so a skill learned by necessity!!
Edit: Should mention the good that came out of all this "discussion" was the exceptionally low C of certain 1N4148Ws, I mean a Cj of ~0.66pF @ 0 volt bias
Anyway, no offense taken and none intended
Best, -
almost all sources indicate a max C and Tr, only Jingdao uses typical for both.
Well, during the course of this thread, I did a very quick (online) investigation of that manufacturer, and it seems they are very big, as regards diodes. A huge number of their range (quick look by me), easily perform at very high speed, and with very low (zero volt) capacitances.
So, I'd suspect that there is some reason, why those so called '1N4148W's, have such (relatively) poor specification. (Speculation) It could be they are 'rejects' from other diode lines, or other ways, poorly performing diode dies, became available for their 1N4148W's.
Probably we will never know. Or someone gets overly curious, and investigates the diodes further, in an attempt to identify what they really are.Most of my later career involved SOTA IC design, a mistake here could easily cost well over $5M, since the mask sets alone cost $5~20M and that was a decade ago, today likely 10X as much. You quickly learn who to trust with critical design tasks, and since many times new folks to the group get "assigned" by management you quickly need to access their individual skill and knowledge level, so a skill learned by necessity!!
Thanks, that is a great explanation!
It is a sad reality of life, that some engineers hold great skills, and are really brilliant, in many ways. But, they just have this habit of sometimes being too lazy, and don't bother to check certain things, with the datasheets and/or ask for help when needed (over-confident). Which can lead to overly expensive mistakes. Which can then make them unsuitable for some tasks, such as the $5,000,000+ masks, you mentioned.
Also on reflection. I DON'T feel anything like, as bad about you using Wikipedia, as a reference source, as I originally did. Although there are still some lingering doubts, and there are better, more definitive sources. At least you had a set of sources that the Wikipedia article gave. Which you were able to leaf through and nominally check out.
Sometimes, a Wikipedia article, is the ONLY available source of information. In which case you either use it, or accept not having any information at all, at least for the time being. Some new things in Electronics and Computing, is initially only mentioned in Wikipedia articles, and some (dubious) websites. Until it is officially announced, by the proper/official sources.Edit: Should mention the good that came out of all this "discussion" was the exceptionally low C of certain 1N4148Ws, I mean a Cj of ~0.66pF @ 0 volt bias
That is amazing! Particularly, as it is still a super cheap and available (at least BEFORE the chip shortages), component (1N4148W).
Discussions often create all sorts of new knowledge, and stuff, that was not realized before. -
Well, during the course of this thread, I did a very quick (online) investigation of that manufacturer, and it seems they are very big, as regards diodes. A huge number of their range (quick look by me), easily perform at very high speed, and with very low (zero volt) capacitances.
So, I'd suspect that there is some reason, why those so called '1N4148W's, have such (relatively) poor specification. (Speculation) It could be they are 'rejects' from other diode lines, or other ways, poorly performing diode dies, became available for their 1N4148W's.
Likely some "other" die that was not designed to be a 1N4148 type?QuoteProbably we will never know. Or someone gets overly curious, and investigates the diodes further, in an attempt to identify what they really are.
Maybe noopy can preform his magic de-encapsulating and imagery on the Jingdao and another 1N4148W diode, so can have a look? He's quite good at this, and has mastered the chip imaging skillsQuoteAlso on reflection. I DON'T feel anything like, as bad about you using Wikipedia, as a reference source, as I originally did. Although there are still some lingering doubts, and there are better, more definitive sources. At least you had a set of sources that the Wikipedia article gave. Which you were able to leaf through and nominally check out.
Sometimes, a Wikipedia article, is the ONLY available source of information. In which case you either use it, or accept not having any information at all, at least for the time being. Some new things in Electronics and Computing, is initially only mentioned in Wikipedia articles, and some (dubious) websites. Until it is officially announced, by the proper/official sources.
We know what Wiki is and certainly not a reference to be utilized in an IEEE journal technical paper. We didn't have access to JEDEC, and Wiki did give a nice history from the original TI 1N914-6 way back in 1960, and had references to some manufactures data sheets. So it seemed an acceptable reference in this discussion, not knowing the very mention of Wiki would seem to enrage some folks!!Edit: Should mention the good that came out of all this "discussion" was the exceptionally low C of certain 1N4148Ws, I mean a Cj of ~0.66pF @ 0 volt bias
Agree, that lovely 1N4148W is one low capacitance diode indeed. As mentioned much earlier, wouldn't be surprised to find that some special low-cap diodes are actually 1N4148 die and sold at a premium
That is amazing! Particularly, as it is still a super cheap and available (at least BEFORE the chip shortages), component (1N4148W).
Discussions often create all sorts of new knowledge, and stuff, that was not realized before.
Best, -
Interestingly, there's a MMBT7002 from a handful of small manufacturers, so it seems.
MMBT I don't know the history of, but for sure it's not JEDEC's normal numbering system.
Motorola Miniature Bipolar Transistor - from the people who brought you MPS, MPSA, MJ, MJE and many other famous non-JEDEC parts.
That makes MMBT7002 a real
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Yes, Motorola issued quite a few plastic and SMD packaged versions of chips originally used in TO-92 and metal TO-18, TO-5, etc. packages.
Their data sheets were believable for their production parts.
Years ago (before they were acquired), a field salesperson for International Rectifier cautioned us about "IRFxxx"-numbered parts from other manufacturers, claiming they did not meet the specs in IR datasheets.
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Yes, those old Motorola discrete parts were good, as were the data sheets in the Data Books!! Also the old TI Orange Data Book and the famous National Linear and other Data books were on every engineers desk
Best, -
I certainly was not enraged by the use of Wiki as a source of information. I use it also, and often and believe in the concept sufficiently to donate annually.
But, I remain concerned about belief in Wiki as definitive. Wikipedia both benefits and suffers from its crowd sourced methodology. In the entertainment of "who's who" areas as well as recent history it is dangerous to place any trust in the articles. Technical issues are much more reliable, but still have to be used with a grain of salt. -
Now the dust has settled. In NO WAY, am I trying to disagree, with anything or anyone, which has already been mentioned in this thread. I'm just providing something I just found, while looking for more information, about 1N4148 specifications.
The following video (just for DISCUSSION, I'm in no way saying it is definitive), can't be taken as definitive, by any stretch of the imagination. But it seems to suggest, what I can believe is vaguely close to the reality, and where this thread seems to have headed towards (very approximately). It seems to say that the JEDEC standard, is only defining the naming scheme for the diode, rather than its specifications. It also seems to say there are a minimum set of basic characteristics, for it to be a low cost 1N4148. Such as, no more than 4ns switching speed, at least 150mA current capability, and at least a 100 volts, working voltage capability.
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This thread went surrealistic.
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This thread has made me VERY curious, about the OP's suspect 1N4148W's dies, and where they have come from. So I've been doing some digging. I decided to go through the (problematic 1N4148W's) manufacturer's (Jingdao Microelectronics), diode range. In an attempt to find a suspect, for what the diode die/type, really might be. So, VERY wild speculation on my part. I stopped, as soon as I found a possible candidate, there could be others.
The datasheets reverse recovery time, is quoted as a lot higher (50ns), but that could be because it is measured at different ratings, for the more powerful, at least voltage wise device. The OP's part, doesn't even seem to define the test conditions for its reverse recover time, making it rather difficult, to easily/directly compare these diodes, as regards that part of the specification.
It seems, they sell a '1N4148' like diode, in relatively high voltage terms. Presumably, because of the way the internal structure of the high (relatively) voltage die is. That has caused or is related to the increase in junction capacitance. It is rated for 300(continuous)/350(peak) volts.
The alternative diode I found, has the same package and same junction capacitance, datasheet specification, as the OP original problematic part(s).
Called a BAV3004W, also in a SOD-123 case. I presume (wild guess), it failed the high voltage and/or leakage tests.
Here is the datasheet, of the possible, real die diode:
https://datasheet.lcsc.com/lcsc/2009141737_Shandong-Jingdao-Microelectronics-BAV3004W_C779377.pdf
The possible original part ( https://datasheet.lcsc.com/lcsc/1809291712_Shandong-Jingdao-Microelectronics-1N4148W_C115103.pdf ), at a quick glance, doesn't even seem to define the test characteristics, for the reverse recovery time. -
Curiously, they're not even any good at that one [BAV3004W] either; compare Diodes Inc's version, under 1pF!
FYI, t_rr changes surprisingly little with If, depending more on ratio of forward to turn-off (recovery) current, or ramp rate (dI/dt). So, although you'd prefer recovery tested at level (i.e., 10A for a 10A diode), doing it at e.g. 0.5A, or say 50 ohms in a test jig (for signal diodes), is really not as unrepresentative as you'd think for such a nonlinear device.
Tim -
As an electronic engineer from China, based on my experience, I suggest that when you buy discrete semiconductor devices in LCSC, choose Changjiang Electronics products, they have a longer history and should have more reliable product quality.
https://lcsc.com/product-detail/Switching-Diode_Changjiang-Electronics-Tech-CJ-1N4148W_C2099.html
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As an electronic engineer from China, based on my experience, I suggest that when you buy discrete semiconductor devices in LCSC, choose Changjiang Electronics products, they have a longer history and should have more reliable product quality.
https://lcsc.com/product-detail/Switching-Diode_Changjiang-Electronics-Tech-CJ-1N4148W_C2099.html
Thanks for that recommendation/tip, I'll bear it in mind, in the future.
That is EXACTLY, why I said in an earlier post:If it was a Chinese make. Was it important to check if they were a recommended Chinese make or not ?
Because I had a feeling it has been discussed on here before. You really need to know what you are doing, when buying from Chinese suppliers. Probably more so than western makes. There use to be a guy on here, who seemed to give very good advice about stuff like that, but unfortunately they are not on here any more. (Blue*****, partly hidden, as they want to remain private, now I believe).