Choosing a PSU, what should I look for - Page 1
Forum section: electronics / beginners

author: Moriambar
author_rank: Unknown
timestamp: February 19, 2019, 07:37:19 pm
content: Hey there.I am in need of a PSU. The old unit that was gifted me (it has at least 30 years) is not enough anymore.I usually do not do much power-stuff, and also am kinda on a budget (I can spend up to around 400€ if the benefits are so huge to justify that, but perhaps I do not need expensive things).I basically need:at least two outputsat least two of the outputs should be able to go to ~20/30V2A are enough, although I know that 3A is usually quite standard. I normally do not need more than 1Ashort circuit protection is ESSENTIAL since otherwise I would blow up everything after the first 10 minutesperhaps, as a beginner, there's something else I need that I do not knowbest if seller is europe-basedAfter gathering all these requirements, I found (on a seller website) the following products. I actually do not know how to choose because basically I cannot justify the price difference in any way. Also, albeit on a budget, I do not want to buy absolute crap. So here we areNumber one is a KORAD KD3305D (never heard of KORAD before)https://www.welectron.com/Korad-KD3305D-Labornetzteil_1Datasheet. It's really cheap, and it seems to have everything I need, although I do not know whether it is ok/reliable.Next is another KORAD, KA3305Phttps://www.welectron.com/Korad-KA3305P-Benchtop-Power-SupplyDatasheet. It costs a little more. No clue what the difference is, apart from having a single knob instead of one knob per channel…Now I've got a SIGLENT, SPD3303Chttps://www.welectron.com/Siglent-SPD3303C-Benchtop-Power-Supply. It costs almost 100€ more than the first Korad. Apart from the siglent brand, I do not know why since it delivers less power than the korad at a lower resolution too.Finally, the monster, which is basically kinda an overbudget thing (but if it's remarkably better than the others I'm willing to make), the Siglent SPD3303X-E, which costs 2.5 times the first korad;https://www.welectron.com/Siglent-SPD3303X-E-Benchtop-Power-Supplydatasheet. It seems that the price is justified by a nicer interface and a better connectivity which I do not care about, but perhaps there's more to it I'm missing.So after all of this I actually do not know. Is there anything better out there for my purpose, that I simply ignored just going to one seller? Which one do you think is best for my needs?Thanks to anyone who will help me choose and understand better. Cheers

author: KL27x
author_rank: Super Contributor
timestamp: February 19, 2019, 09:19:04 pm
content: The Korad "P" is programmable.I use a Korad PSU. There's some overshoot when you first turn it on. That's a complaint that is common. Also, you can't instantly switch between two different voltage settings without cutting power. The relay turns off, and you have to turn it back on.I broke my Korad, because the stupid encoder stopped working. I took it apart and put a drop of mineral oil in the encoder. But I decided to test it before putting it back together and shorted something on the front panel. (There are like 4 different PCB all screwed and plugged together, and when out of the housing hindsight shows there is one point that can short when the pcb's flop around in the headers).After replacing the obviously burned out shift register, i find the encoder works perfectly, again. All the display and controls works, but something else broke and there's no output. I bought another... mostly because it proved good enough for me and I don't feel like re-learning how to use a new bench PSU. But my needs are very modest and this is the fanciest PSU I have ever used, so compared to the two other POS i have purchased that burned THEMSELVES up, I'm easy to please.

author: sambonator
author_rank: Regular Contributor
timestamp: February 20, 2019, 12:03:37 am
content: Some of the latest reviews on Amazon are negative.https://www.amazon.com/KORAD-KA3305P-Programmable-Precision-Adjustable/dp/B012LMOI84I opted to get a used GW Instek GPD-3303S instead.

author: Mr. Scram
author_rank: Super Contributor
timestamp: February 20, 2019, 12:26:13 am
content: Quote from: sambonator on February 20, 2019, 12:03:37 amThat GW-Instek is pretty sweet, but it's also in a different class and price bracket.

author: MarkF
author_rank: Super Contributor
timestamp: February 20, 2019, 01:03:43 am
content: Here is a quick look at the GwInstek GPE-3323 and a short comparison to the Siglent SPD-3303X-En at the end.

author: Wolfgang
author_rank: Super Contributor
timestamp: February 20, 2019, 01:21:31 am
content: Quote from: Moriambar on February 19, 2019, 07:37:19 pmWhy no RIGOL DP832 on your list ? Does more than you asked for, fully programmable, long enough on the market for the bugs to be gone. I like it !

author: sambonator
author_rank: Regular Contributor
timestamp: February 20, 2019, 01:46:59 am
content: Quote from: Mr. Scram on February 20, 2019, 12:26:13 amYes... so I qualified it with the word "used".

author: Calvin
author_rank: Regular Contributor
timestamp: February 20, 2019, 02:34:59 am
content: Hi,I recently bought me the Siglent SPD3303C and I'm very happy with it.It,s accurate, stable and well behaved.So far I haven't seen any overshoot or glitches that may be a danger to the load.Output voltages remain comfortably stable under load (for a non remote sense supply) and noise is low.It certainly is short circuit proof .... the manual asks You to short the supply rails when testing OCP function.It's easy and intuitive to handle ... the front face layout is arranged logically.I prefer to have a knob to easily and quickly change values instead of keypads .I also prefer good old 7-segment displays ... possibly in different colors for voltage and current .... easy to read at a short glance ... keep it clean and simple ... You want information, not a light show.The afore mentioned Rigol for me is a prime example of how not to design the UI of a 'tool'.The cooling fan of the Siglent remains quite low in volume until You draw considerable power.It offers some basic programming capability through a couple of front face buttons and a bit more refined ones via the web control.The Siglent does cost more than the Korad, but I've the feeling, that below it's budget Youre taking the risc of buying too expensive .... i.e chances are growing You buy an accident-to-happen instead of a decent device ... quality comes at a price.regardsCalvin

author: Moriambar
author_rank: Unknown
timestamp: February 20, 2019, 07:12:00 am
content: Quote from: sambonator on February 20, 2019, 12:03:37 amWow that costs 3x the base Korad and 2x the Siglent... at least in Europe I only found that at farnell for 500€ (excl VAT). That's way out of budgetAs per the "used" bit: I don't know: I kinda need it quick and do not have the time to wait for an used offer (and also pray that it works!)Thanks anyway

author: Moriambar
author_rank: Unknown
timestamp: February 20, 2019, 07:13:27 am
content: Quote from: Wolfgang on February 20, 2019, 01:21:31 amMore than 100€ out of budget, that's why. It costs around 500 + VAT

author: Wolfgang
author_rank: Super Contributor
timestamp: February 20, 2019, 11:00:27 am
content: OK, thats the list price. With 20% off, you would be in target, almost.

author: Moriambar
author_rank: Unknown
timestamp: February 20, 2019, 12:11:36 pm
content: Quote from: Wolfgang on February 20, 2019, 11:00:27 am500+VAT in italy is 610€ (albeit on ebay I find it for over 600€); so it would be 488 with 20% off (if one can find that: do you have any hints on where to look for it?). It's still over my budget by almost 100€.It could be nice, I trust you, but it's simply too expensive unfortunately. I could do with about 40% off!Thanks for the idea. But let me renew the question: do you know where to find PSUs with 20% off?Cheers

author: Wolfgang
author_rank: Super Contributor
timestamp: February 20, 2019, 01:07:41 pm
content: ... one of the good occasions is the Ham Radio Fair in Friedrichshafen. RIGOL has a big stand there ...And they gave 20% off to all purchases done there. I bought quite some stuff from them, and I am satisfied with most of their equipment.

author: Moriambar
author_rank: Unknown
timestamp: February 20, 2019, 01:11:32 pm
content: Quote from: Wolfgang on February 20, 2019, 01:07:41 pmWell, I'm not exactly near it (around 600Km trip) but still it would cost too much for me, as I pointed out before. That's unfortunate, I know, but I'm poorI'm open for donations though

author: Wolfgang
author_rank: Super Contributor
timestamp: February 20, 2019, 01:21:20 pm
content: another try would be Batronix. Full price is about 500€, but you could ask for an offer. And shipping in Europe is free.

author: Moriambar
author_rank: Unknown
timestamp: February 20, 2019, 03:04:14 pm
content: Quote from: Wolfgang on February 20, 2019, 01:21:20 pmWell, perhaps I will, but I doubt they will say "look: an unknown Italian customer wants a single unit! Let's give this to him with a 25% discount!"But one can never know

author: Calvin
author_rank: Regular Contributor
timestamp: February 21, 2019, 06:17:33 am
content: Hi,The Rigol simply doesn´t look like a decent tool, but rather like "Transformers-meet-Hello-Kitty".If I were CEO and had two little Kids, a girl and a boy and asked them to design a power supply front face .... I think something looking like the Rigol could emerge.Hey Rigol ... keep it clean and simple ... we need tools not toys!jauuCalvin

author: Wolfgang
author_rank: Super Contributor
timestamp: February 21, 2019, 11:21:11 am
content: ... I would rather not buy electronic equipment based on aesthetics. For the purists there is a monochrome version (DP832 without A).

author: rstofer
author_rank: Super Contributor
timestamp: February 21, 2019, 07:57:59 pm
content: Quote from: Wolfgang on February 21, 2019, 11:21:11 amAnd also without the extra digit of resolution.I think the 832 can be unlocked to get that extra digit of resolution but I don't know if that allows for the color display. Probably not.I simply don't care enough about the extra digit to unlock mine nor do I care enough to pay more than twice as much.

author: rstofer
author_rank: Super Contributor
timestamp: February 21, 2019, 08:29:03 pm
content: Quote from: Calvin on February 21, 2019, 06:17:33 amEver used one for any length of time?I can enter voltage and current values with the keypad in terms of mV, V, mA, A depending on a button push. I can tweak these values with the rotary encoder.I can select which of the 3 channels gets adjusted and I can set voltage, overvoltage limit, constant current and overcurrent shutdown values. There is a difference between constant current setting and overcurrent shutdown. If the DUT hits the overcurrent or overvoltage limit, all channels shut down immediately. And I can see all 12 of these settings at all times. Further, I don't have to short the output to make the current settings with some kind of potentiometer, all values are set digitally. 12 settings...I also get a larger display of output voltage, current and watts. For all 3 channels simultaneously.So, we have 21 different values constantly displayed, try that with 7 segment displays.The only thing I find objectionable is the fact that I have to confirm with a second button press that I want to turn on all 3 channels simultaneously. Not a big deal but, gee, I just pushed the All on/off button, let's get it done already! I understand why it is done so I will get over it.In any event, the DP832 is probably out of the price range so it really doesn't matter.

author: Moriambar
author_rank: Unknown
timestamp: February 21, 2019, 08:35:31 pm
content: Quote from: rstofer on February 21, 2019, 08:29:03 pmExactly.Albeit it's interesting to see other units (and get envious for not being able to afford them), really there's no way for me to get that psu, so for this topic is immaterial how good it is.Anyway, in a couple of days I'll decide, but I probably will choose the SPD3303C, because it seems the best I can afford apparently (and especially among the ones I suggested), unless something else pops up.Cheers

author: rstofer
author_rank: Super Contributor
timestamp: February 22, 2019, 01:22:57 am
content: It should be fine!

author: james_s
author_rank: Super Contributor
timestamp: February 22, 2019, 04:47:12 am
content: If I were going to spend that much, I'd be looking at a nice used HP/Agilent, Tektronix, etc rather than low end Chinese brands.

author: Moriambar
author_rank: Unknown
timestamp: February 22, 2019, 07:20:51 am
content: Quote from: james_s on February 22, 2019, 04:47:12 amWell, apart from finding the used ones (much easier in the us than in europe), one never knows how good the conditions of used stuff is.I am surely not capable of a repair, and I think that buying a used unit for 300€ and then find out that is broken is basically throwing away the money (and I cannot afford it).Also I wouldn't be able to choose the specs.BUT.If you want and can help me regarding used stuff I can think about it, although I feel it risky since it's basically all the money I got.The baseline is: I need an at least dual channel psu. I cannot afford more than 300-400€ max all included.Cheers

author: rstofer
author_rank: Super Contributor
timestamp: February 22, 2019, 08:20:18 am
content: At some point, choosing equipment by consensus is a waste of time. Everybody likes what they have, they dislike what they just got rid of (with reason) and it all breaks down with no definitive answers. There is always something just a little better for a little more money. And buying used is truly a risk. Sometimes it works out, sometimes not so much. Sellers almost never pay return shipping so you are out money even if you can send it back.Drive a stake in the ground, buy something and don't look back. Years from now, if you need something else, sell what you have and buy it. In the meantime you will have gotten years of usage and gained a real awareness of what you like or dislike in some type of equipment.

author: Moriambar
author_rank: Unknown
timestamp: February 22, 2019, 08:22:18 am
content: Quote from: rstofer on February 22, 2019, 08:20:18 amthanks.Yes I think that I achieved what I aimed for with this topic: get guidance among the items I already pre-selected. I'll buy asap.Cheers

author: Calvin
author_rank: Regular Contributor
timestamp: February 22, 2019, 09:49:00 am
content: Hi,@ #17QuoteMe neither. And the reply was not about aesthetics of a device but useability.When the layout design is such that You loose on easy and intuitive handling, if You have to look twice what is what and where, then the layout simply sucks.regardsCalvin

author: Wolfgang
author_rank: Super Contributor
timestamp: February 22, 2019, 10:48:19 am
content: ... well, even easiness and usability are personal judgements. Me personally never had to think what the buttons on my 832 could mean.Being one of the worlds best selling PSUs handling problems dont see to be very common.

author: forrestc
author_rank: Unknown
timestamp: February 22, 2019, 10:51:44 am
content: Quote from: Moriambar on February 20, 2019, 12:11:36 pmBatronix currently has the DP832 for $498.61 inclusive of VAT w/free shipping. I have a DP832A on my bench and am perfectly happy with it, and would wholeheartedly recommend it. If something happened where I had to start my bench over, this would be on my short list of things to buy. If it was a hobbiest bench, I'd probably skip the 'A' and just buy the DP832. I also can't think of many reasons why one would want to spend more than this on a supply. I could use a bit higher voltage and current on occasion for my applications (which is why I have a Sorensen LHP-60-18 sitting under the DP832A). Sometimes people need certain other specs.However, I truly understand the budget thing. Here's the deal: If I was budget constrained I'd go a completely different path. For most purposes, the quality of a power supply isn't all that important as long as it provides enough power, is fairly well regulated, and doesn't fail regularly or in a way that destroys the item attached to it. Most electronics is ok within 10% of the stated voltage (i.e. a 5V rail can be from 4.5 to 5.5V). Most supplies are also pretty good at staying where you set them, even if the display isn't all that accurate. So, I wouldn't bother spending hardly any money at all.I'd probably start by buying one of the modules Dave talks about on EEVblog 1030:Taking this, I'd go find an appropriate power supply at the top end of the range for the supply module. It wouldn't be surprising to be able to pick up a surplus power supply from a laptop at a thrift store (appx 20V), and then use one of these to get a 0-18V supply for a grand total of under 30EUR.When I'm doing hobbiest type electronics here, I often don't bother with the variable power supply and just use a wall transformer or a USB power supply. So for the second supply, I might just forego the variable supply and collect a set of wall adapters of interest. You'll probably want ones in the 5V, 9V and 12V range. Be aware that some of the older ones aren't regulated so for example 9V supply would put out much higher voltage until it is placed under load. Any newer switching ones (the small light ones) will put out pretty close to the exact voltage. They'll also be short circuit protected at some multiple of the rated voltage. I have several 5V USB adapters that are from reputable sources that I use quite often, and then a couple 9V and 12V ones for things which need higher voltage.One reason that I end up not using a variable power supply is that I ended up buying some small power supplies which plug directly into the power bus of a breadboard and take either a 5V usb in or a 9V wall transformer (depending on the model - I have two), and then spits out either 3.3V or 5V on the rail depending on the setting of a couple of switches/jumpers. With this, most protyping projects I do I don't need anything other than the wall transformer.Now, I know you wanted something quick and that you know works, so this may not be appealing to you. In this case, don't overlook some of the lower cost single-output devices - like the KORAD KD3005D on the same site you linked to earlier. For a hobbiest this is just fine, and the advantage of a single output device when you're talking a cheap supply is that if/when it dies, you still have a working power supply. Versus a dual one you may or may not have one channel working. Added bonus if you buy two separate types/brands since what kills one is less likely to kill them both.

author: tautech
author_rank: Super Contributor
timestamp: February 23, 2019, 02:38:58 am
content: Quote from: Moriambar on February 21, 2019, 08:35:31 pmDon't, get the SPD3303X-E instead and unlock it to an X model and get the 1mV/mA resolution.The Siglent .ads thread has the unlock info, it's very simple.The display is much nicer and more informative than the older C models.The Hamburg and USA Siglent websites haven't been updated to show the newer GUI that was implemented in firmware after the X/X-E were released.The Shenzhen website shows how they look now:http://www.siglent.com/ENs/pdxx.aspx?id=1132&T=2&tid=17

author: Moriambar
author_rank: Unknown
timestamp: February 23, 2019, 08:40:53 am
content: Quote from: tautech on February 23, 2019, 02:38:58 amWell, I actually do not see the added value for 1.5x the price (I mean, I will have to save some extra money to get the x-e since it's out of budget practically). I mean: do I really need the 1mV/1mA? I cannot see how. Apart from the GUI revamp (nice but not worth 150€), I actually do not see what else this unit gives that I can use:Power consumption (I don't actually care about it)Save/recall function (I actually do not have the need for it, it's nice but comes at a price)Timing info and pc interaction I really really do not care aboutPerhaps there's something else I don't know about and I'm missing it. Please point that out if it is so. As it stands I think that paying a lot more money to have functionalities that really don't fit with my usage it's a waste of money.As rstofer said:Quote from: rstofer on February 22, 2019, 08:20:18 amI think there's no extra value in the x/xe model for me, but as a beginner I might be wrong!

author: Calvin
author_rank: Regular Contributor
timestamp: February 23, 2019, 02:13:18 pm
content: Hi,"well, even easiness and usability are personal judgements."Well, Yes and NoOf course does personal judgement play an important role, but there are certain common design rules that lead to an easy and intuitive layout.Examples:Rigol DP832A:- distance between the connectors is all the same and quite close --> arrange + and - connectors as (channel)groups for easy identification- Channel On/Off switches left-to-right arrangement (1-2-3) differs from that of the Display (1-3-2) --> no words, just- Channel On/Off switches situated just on the opposite rim of the casing far off of the associated connectors --> simply- "All" channel button appears logically as part of the encoder/Keypad block -->- radially segmented display with almost an overkill of information and hence mostly very small Fonts --> arrange either horizontaly or vertically, reduce the number count of infos and allow for large easy to read Fonts for the most important infos.- arrangement of infos differ between channels. For ch 1 and 2 it´s vertical, for ch3 its mixed hor/vert -->- redundant infos on a anyhow crowded display. The center circle repeats the set value of the highlighted channel --> why??- 36 buttons, 1 knob, 1 switch -->- 11 (!!! if I counted correctly) different button shapes -->- and finally -and just for optics- the mains power switchOf course it is not easy to layout the front for intuitive easy handling when you have to cope with so much functionality.Still Rigol could have done a much much better job here ... and on almost all of their new devices.They employ hundreds of engineers in their R&D department .... but why not a single competent industrial designer?You expected a same layout within the family? Well, not with Rigol darling!Rigol DP831A- channel arrangement in the display is 2-1-3 -->- channel connectors layout is not highvoltage/highvoltage/lowvoltage (DP832A) but just the opposite LV/HV/HVSiglent SPD3303X- connectors are arranged in groups -->- On/Off buttons in proximity to the connectors -->- channel arrangement in display coincides with connector layout -->- no display for third channel -->- Fonts for ´secondary´ infos very small -->- 15 buttons in only 3 shapes and arranged logically in groups -->- noy keypad for quick and easy programming -->- CC/CV LEDS situated right above the channel´s connectors -->Siglent SPD3303C- connectors are arranged in groups -->- On/Off buttons in proximity to the connectors -->- channel arrangement in display coincides with connector layout -->- no display for third channel -->- only most important infos shown -->- large easy to read and color-coded Fonts -->- 15 buttons in only 3 shapes and arranged logically in groups -->- CC/CV LEDS situated right above the channel´s connectors -->The Siglent layouts are not perfect either, but they certainly did a much better job than Rigol.Display infos are easier to recognize and to read, with the 3303C beeing the easiest (admittedly no big deal to get that title with the least of infos on display).Buttons, knobs and connectors are clearly arranged in amore logical way and are more intuitive to handle.If it were for same specs and functionality I´d rather choose the device with the clearly better layouted front and UI.regardsCalvin

author: Mr. Scram
author_rank: Super Contributor
timestamp: February 23, 2019, 06:28:16 pm
content: Honestly, I'd just go with the ubiquitous Korad 3005D-2S. It's relatively cheap, it does what you want and it's fairly convenient to use. If you can afford it you could consider a computer controllable power supply or one with a graphing screen, which are definitely nice-to-haves, but not as vital as a power supply you can beat on.

author: Moriambar
author_rank: Unknown
timestamp: February 23, 2019, 07:59:19 pm
content: Quote from: Mr. Scram on February 23, 2019, 06:28:16 pmThank you. I want my computer as far as possible from my bench so I don't know about the computer controllable one. Also I just need a PSU, I wouldn't know how to use the graphing or anything.Cheers

author: Mr. Scram
author_rank: Super Contributor
timestamp: February 23, 2019, 08:39:39 pm
content: Quote from: Moriambar on February 23, 2019, 07:59:19 pmThat Korad is a nicely positioned between the sketchy cheap units and the quite expensive fancy ones. It's not perfect, but it's safe and stable. It's more than good enough to use as a daily driver. The UI isn't terrible either, although some people have more problems with it than I have.

author: james_s
author_rank: Super Contributor
timestamp: February 23, 2019, 10:32:22 pm
content: I've used fancy programmable power supplies before and found most of them to be lacking in one way or another. I also have no need for computer control, given a choice I'll take old fashioned analog knobs and meters any day.

author: rdl
author_rank: Super Contributor
timestamp: February 23, 2019, 10:54:41 pm
content: In my mind both Siglent and Rigol have too many drawbacks to work around. I could never have anything from Siglent on my bench knowing it was probably rusting away on the inside. And Rigol with their toy-like, cluttered up front panels just look stupid. I'll stick with my used HP, Agilent, and Tektronix stuff. If I lived in Europe I'd probably be looking for a used TTi or R&S power supply.

author: Mr. Scram
author_rank: Super Contributor
timestamp: February 24, 2019, 03:45:32 am
content: Quote from: rdl on February 23, 2019, 10:54:41 pmPeople who buy Siglent or Rigol typically do so because buying HP, Agilent or Tektronix isn't viable. Buying old kit could be doable, but that has its own drawbacks.

author: james_s
author_rank: Super Contributor
timestamp: February 24, 2019, 05:00:30 am
content: I've almost exclusively bought used gear and it has worked out very well. The one time I remember I did buy a new Chinese bench DMM I pretty quickly found I hated it, sold it after a few months and bought a used Fluke 45.

author: tautech
author_rank: Super Contributor
timestamp: February 24, 2019, 05:16:34 am
content: Quote from: rdl on February 23, 2019, 10:54:41 pmThat statement implies you're not well read or well educated.1. Any Siglent panel rust issues have been addressed some years ago and better zinc plated panel steel sourced.2. Galvanized steel:If the zinc coating is scratched or otherwise locally damaged and steel is exposed, the surrounding areas of zinc coating form a galvanic cell with the exposed steel and protect it from corrosion. This is a form of localized cathodic protection - the zinc acts as a sacrificial anode.https://en.wikipedia.org/wiki/Cathodic_protection3. If you think Siglent are the only instruments you will find rust in, think again as you're in some dream world.4. I have a Tek TDS2012B with rusty chassis work but only on the cut edges, this is entirely normal.5. The galv sheet that forms an instrument chassis is guillotined and punched, these processes shear the zinc plating and expose the parent steel which then starts to rust to a point where a process called Cathodic protection takes over and gives protection of the parent steel.To prove this process works for the non-believer, grind the zinc from a portion of galv steel and leave it in the weather....in will not rust unduly !Todays educational lesson over.

author: Mr. Scram
author_rank: Super Contributor
timestamp: February 24, 2019, 05:21:18 am
content: Quote from: james_s on February 24, 2019, 05:00:30 amYMMV. One isn't exactly a large sample group.

author: Mr. Scram
author_rank: Super Contributor
timestamp: February 24, 2019, 05:24:47 am
content: Quote from: tautech on February 24, 2019, 05:16:34 amThe lesson is that you're trying to peddle your kit.Siglent had rust issues other manufacturers don't have, but recent units seem better. It's probably an example of budget conscious manufacturers learning where to cut corners and where not to do so.

author: tautech
author_rank: Super Contributor
timestamp: February 24, 2019, 05:33:10 am
content: Quote from: Mr. Scram on February 24, 2019, 05:24:47 amYou too are not well read.The original problem arose from a faulty batch of panel steel supplied to the company that made chassis for Siglent.This has been discussed at length on at least a couple of occasions here over the years.It is NOT as terminal for an instrument as crook PSU's or FRAM issues that some manufacturers have.

author: Mr. Scram
author_rank: Super Contributor
timestamp: February 24, 2019, 06:13:21 am
content: Quote from: tautech on February 24, 2019, 05:33:10 amBelittling people who don't buy into the excuses isn't the smartest of moves. Even if there was "a faulty batch" Siglent is solely responsible for the quality of the products it puts out. That's what internal quality control is for. Besides, the problems seem a bit too widespread for it to be a single batch.Admitting a mistake and showing improvements have been made is fine. Blaming others and downplaying the issue is exactly what people expect from chancy Chinese manufacturers and exactly what they don't need if they want to move up in the world. Own your mistakes and people will respect you for it, like the manufacturer with FRAM issues is doing.

author: Calvin
author_rank: Regular Contributor
timestamp: February 24, 2019, 07:32:45 am
content: Hi,as you said ... no manufacturer is perfect.You can find countless threads and vids about bugs, dodgyness, plain failure, ill design and construction of devices.And You can tag any name plate on those threads, not just chinese.Also there is no doubt that modern devices are way not manufactured as solid as old ones.I assume nobody expects actual Tektronix/KS/Fluke/R&S/etc. devices to last 40years+ ... especially not their´budget lines´Siglent has certainly done a great job with their X-series devices ... very capable devices, of course built to a price ad yes with some bugs at the beginning .... but then, why buy a A-Brand device with an hefty premium if its not proportionally better, or longer living, less buggy, or gives more reliable measurements?As several threads hint Siglent seems ´listening´ to what users critizise about and the bugfix and improvement update rate is above average.I regard this as confidence generating behaviour .... they care about their products.regardsCalvinps. to not give food to the impression of A-Brand bashing, here´s a 3-channel power supply where I find the layout of the front face simply excellent.With 33 buttons 2 knobs, a power button and similar face area it almost equals the Rigol DP832A .... but whoaaah what a difference!!btw. Welectron offers those ´on sale´ at the time for ~10% less.

author: tautech
author_rank: Super Contributor
timestamp: February 24, 2019, 08:03:10 am
content: Quote from: Mr. Scram on February 24, 2019, 06:13:21 amI'll stick firmly to what I have posted and still call you unread.....or just too damn lazy to hunt out the appropriate threads, quotes and posts.Catch up time, the most recent of this below is 3+ years old.Start here:Quote from: EEVblog on March 25, 2014, 09:35:36 amAnd:Quote from: Siglent on April 09, 2015, 10:16:08 amAnd:Quote from: EEVblog on April 09, 2015, 05:26:18 amAnd:https://www.eevblog.com/forum/testgear/siglent-they-filed-a-_wrongful-trademark-claim_/msg785401/#msg785401(thread locked)Post by EEVblog:QuoteYes, they changed their process and fixed it.They were very poor at communicating this though.

author: forrestc
author_rank: Unknown
timestamp: February 24, 2019, 09:03:30 am
content: Quote from: Calvin on February 23, 2019, 02:13:18 pmThe above have largely been fixed a couple/few years back:Seehttp://www.mjlorton.com/forum/index.php?topic=652.0As far as the intuitive button placements - i.e. near the channels, etc, once you switch to the new "classic" display style things feel more intuitive. Yes, there are some odd placements, but I will say that it didn't take me long to just commit to muscle memory where they are.I will say that for me entering the actual voltage is a big plus, and it's pretty intuitive - push the channel button if necessary to select your channel (or note your channel is selected in the display), then start pushing numbers and decimal point. Then push V, mV, mA or A as relevant.

author: Moriambar
author_rank: Unknown
timestamp: February 24, 2019, 09:12:51 am
content: Quote from: rdl on February 23, 2019, 10:54:41 pmThe fact is that new = warranty (at least 2 years). Old = no guarantee. Also old = has already lasted for a number of years so its lifespan is (theoretically) shorter.I actually have no real clue how to repair any of these if they fail me and that would translate in money loss. This not taking into account the fact that used stuff is usually (albeit not always) sold by normal people and not trusted sellers.That's why I would never spend on used stuff: the risk of wasting money is too damn high and I do not have the luxury of wasting any money.

author: james_s
author_rank: Super Contributor
timestamp: February 24, 2019, 06:44:35 pm
content: Quote from: Mr. Scram on February 24, 2019, 05:21:18 amDo I really have to point out that I'm not the only one here who has used gear? Thousands of people buy used gear and for most it works out just fine. Older higher end equipment tends to be very well made.

author: Moriambar
author_rank: Unknown
timestamp: February 24, 2019, 06:47:24 pm
content: Quote from: james_s on February 24, 2019, 06:44:35 pmOf course you're right. Everyone buys at their own risk. I simply cannot afford the risk.

author: Mr. Scram
author_rank: Super Contributor
timestamp: February 24, 2019, 07:45:10 pm
content: Quote from: james_s on February 24, 2019, 06:44:35 pmI was talking about your experience with a Chinese unit, not even taking things like confirmation bias into account.

author: rstofer
author_rank: Super Contributor
timestamp: February 24, 2019, 08:00:59 pm
content: Quote from: Moriambar on February 23, 2019, 07:59:19 pmBut... A lot of hobby level electronics revolves around Arduinos and other microcontrollers. Personally, I like to play with FPGAs. More important is the Digilent Analog Discovery 2 - you should really check it out. You get a lot of test equipment in a pocket sized box but, yes, it needs a computer. It's a terrific tool!I can't imagine not having a computer along side my work area (I'm deliberately not calling it a bench). I have a table top fully around 3 sides of a bedroom/hobby room. In the center of the U is where I play with electronics. The rest of the tabletop is relegated to computers, printers and assorted networking stuff. Lots of computers...I guess if I were doing audio I might not need a computer unless I wanted to measure THD with the Analog Discovery. Or maybe if I was interested in the phase response and gain (versus frequency, of course) of some amp but I don't do audio...Every development board I buy has a USB programming port. If it didn't, I wouldn't buy it!

author: Moriambar
author_rank: Unknown
timestamp: February 24, 2019, 08:12:29 pm
content: Quote from: rstofer on February 24, 2019, 08:00:59 pmWhen I use micros I program them far from the "bench". My old computer got stolen from me and had to buy a new one this year and I'm too scared of that blowing up to keeping it near. So it's "no way José". That's also why I invested in the SDS1104x-e oscilloscope: its logic decoding is fantastic. I really love dedicated instrumentation such as scopes and such and I really hate pc-based stuff such as logic analyzers. Granted: they're needed sometimes, but the 10$ cheap chinese one I have is already overkill for me. And when I have to use it boy am I scared to bring my precious laptop nearby hahah.To summarize: computer-> as far from the bench as possible. Both because I'm not confident enough and because I do hate pc-driven instrumentation. Perhaps one day I'll buy a cheap ass computer and put it on the bench and if it blows up who cares. But not now!EDIT: please do mind that mine are a beginner needs, and that I practically do not know how to use a bjt (since I use mosfets as switches and never needed a transistor for anything else!)

author: rdl
author_rank: Super Contributor
timestamp: February 24, 2019, 09:09:41 pm
content: I was only pointing out the worst issue (to me) of the two power supplies. Maybe Siglent did fix the rust problem. The EEVblog 828 teardown of the SPD3303X does show the problem still in December of 2015, but maybe that was old stock. At least the Siglent power supply does look much better than the Rigol, though I'm not too fond of the colors.

author: Mr. Scram
author_rank: Super Contributor
timestamp: February 24, 2019, 09:31:08 pm
content: Quote from: tautech on February 24, 2019, 08:03:10 amYou don't seem to understand how harmful your behaviour is for the image of the brand. If you want to look like a chancy Chinese outfit, shooting and insulting the messengers, downplaying the issue and saying it's not the fault of the brand is the way to do it. Flat out denial and unpleasantness aren't going to win you customers. Proper brands own up to their mistakes and don't attempt to insult anyone who mentions them. Daniel Bogdanoff won't be seen doing whatever it is you're doing on here.I did read up on the issue and found Dave was offered a second review unit, but he wasn't interested in that since he just caught Siglent employees making sock puppet accounts on here. The only large outfit to ever be caught at that point and as far as I'm aware it still is.Quote from: EEVblog on April 09, 2015, 05:26:18 am

author: rstofer
author_rank: Super Contributor
timestamp: February 24, 2019, 09:39:39 pm
content: Quote from: Moriambar on February 24, 2019, 08:12:29 pmI worry about it too! I primarily use a high end model of the Surface Book. I forget what it cost but it was a bunch! A replacement at Best Buy today is $2900 plus tax so about $3200 out the door (plus the extended warranty for another $279 give or take). So, I have a powered USB hub for driving my projects. On the way by, I get 3 charging ports...https://www.amazon.com/gp/product/B00VDVCQ84You can also buy USB isolators and I have a couple but haven't played with them. One problem with the whole electronics thing versus PCs is the fact that we use external supplies. We have a source of power that didn't start with the USB port. Most of my projects do, in fact, use the power from the USB port. In a lot of ways, this is safer than combining USB and wall wart power on the same board. Those boards that have this feature vary widely in how they protect the USB port.Here is one way to power a breadboard from USB and keep everything on the same power source, Power Bricks:https://store.digilentinc.com/powerbricks-breadboardable-dual-output-usb-power-supplies/As with anything, there are limitations. I have a complete set but I haven't been doing any breadboarding. I'll see how it turns out...I wish they made a +-15V brick for op amp projects! 12V might be enough with modern op amps but not with the older models and a +-10V signal swing.I don't know of any good way to get a decent Bode' Plot from anything less than a full blown network analyzer without using something like the Analog Discovery 2. I really want a log scale for frequency and I really want the Y axis scaled in dB and degrees and while there are some dubious workarounds on a scope, they aren't Bode' Plots when they're done.When you want to discuss impedance with your grandson, it's nice to be able to show the Bode' Plot and discuss the break points and roll-off rates with diagrams that are properly scaled and annotated. Even an ME student is going to have to take a course in Circuits. Yes, I'm an evangelist for the AD2.

author: Moriambar
author_rank: Unknown
timestamp: February 24, 2019, 09:51:29 pm
content: Quote from: rstofer on February 24, 2019, 09:39:39 pmThanks for the info, the power bricks surely look rather interesting. I will look to the rest too.QuoteNever had the need of a bode plot actually. I only did a bit around 20 years ago or so in one uni lab, but never again. I repeat: I do basically only digital stuff. Program the arduino and then remove the pc and power it from the psu or something like that (I never use usb + anything else: it's either all via usb or all via psu). Couple of ICs and a couple of mosfets. I never needed an op-amp or a bjt either, true story!I appreciate your passion about the AD2; I'm sure it's a wonderful product. But for my current needs is basically useless, throwing away 260+$ (plus shipping and tax). Perhaps in the future I will be able to appreciate its power and versatility and buy one of its descendants!Right now it falls in the "I kinda know what it does, I actually do not know how can people find it useful" category, right with the arb-generators.

author: james_s
author_rank: Super Contributor
timestamp: February 25, 2019, 07:03:51 am
content: Quote from: Mr. Scram on February 24, 2019, 07:45:10 pmWill anybody say with a straight face that low end gear like Rigol, Siglent, etc are anywhere close to the quality of slightly older HP/Agilent/Tektronix gear that probably cost 10x as much when new?How many cheap Chinese power supplies has Dave shown in his videos that were crap? Some are decent, but I'll take a used HP *any* day over a new hobbyist brand at the same price.

author: Mr. Scram
author_rank: Super Contributor
timestamp: February 26, 2019, 08:52:10 pm
content: Quote from: james_s on February 25, 2019, 07:03:51 amTop end brand name equipment has been shown to have defects and issues as well, both when brand new and after years of use. The new Keysight power supplies turned out to have quite a few rather relevant bugs in it and it's not the first time that happened to them. Besides, it's not a new HP versus new Rigol discussion. It's a 20 or 30 year old and often beaten up HP versus brand new Rigol with warranty discussion. What's your cup of tea depends on your needs and wishes, but it's not as clear-cut as you make it seem here. Especially a lot of the HP branded stuff is now getting so old that it really needs to be treated on an as-is basis.

author: Wolfgang
author_rank: Super Contributor
timestamp: February 26, 2019, 09:07:19 pm
content: ... and dont forget RIGOL and maybe others in fact *made* some low-end HP/Agilent/Keysight equipment as OEMs.

author: Inno_Dim
author_rank: Newbie
timestamp: March 23, 2019, 04:00:28 pm
content: Well I'm a newbie here, so please be kind to me.It happens to own a korad KA3005P, so far so good. But when I use it to recharge lithium batteries voltage drops across my crappy-long wires, so I had to adjust every now and then, the output voltage in order I have fixed voltage across my load (i.e. batteries)To overcome this issue I decided to add remote sensing feature in my korad. What I did is described here:https://www.instructables.com/id/Remote-Sensing-for-Korad-Power-Supply/So now if anyone goes to buy a korad, should have in mind that with virtually no cost, and with some labor time can add remote sensing capability to korad.Feel free to ask me any question about this modification and/or suggest me ways to improve it.

author: rstofer
author_rank: Super Contributor
timestamp: March 23, 2019, 07:01:34 pm
content: Quote from: Calvin on February 23, 2019, 02:13:18 pmManufactured shorting links and shorting jumpers assume a connector spacing of exactly 3/4". So do dual plugs.Dave was very critical of a piece of equipment where the manufacturer deviated from this standard.https://www.pomonaelectronics.com/products/hardware/double-banana-plug-solderless

author: Jwillis
author_rank: Super Contributor
timestamp: March 23, 2019, 11:12:09 pm
content: Quote from: Moriambar on February 19, 2019, 07:37:19 pmMany bells and whistles tend to be unused by average hobbyists.Although the Siglent is nice ask yourself if you need data linking. That's an extra that brings up the price.Data linking is used in an assembly line environment so all your workers are running the voltages they need for the station they are at.Memory is nice if your a total klutz because you can lock in a parameter and not worry as much. But do you really need it.2 or more channel supplies can be paralleled or put in series so a 2 channel 0- 3 amp 0-30v configured for parallel will give 6amps 0-30v. and series will give 3amp at 0 -60v.Personally I find that the less complex something is the less likely things go wrong and easier to repair.400 euro here is over 600 dollars .Heck I would buy 2 simple power supplies instead of one fancy one.But hey its your money.

author: james_s
author_rank: Super Contributor
timestamp: March 23, 2019, 11:29:58 pm
content: I feel the same way, for hobby bench use nothing beats old fashioned analog knobs on a power supply. Simple, reliable, easy to use, the computerized bells & whistles just add more complexity and more to go wrong.