Looking for good bench PSU - Page 1
Forum section: electronics / testgear

author: tehjrow
author_rank: Contributor
timestamp: May 12, 2015, 06:51:37 pm
content: I've done a bit of researching and the one thing I have learned is that there are TONS of different companies making bench power supplies.Here's what i'm looking for:Linear power supplyVoltage and current control (large and fine adjustments)Digital voltage and current displaysProgrammable memoryWilling to spend up to $200 (I know I probably don't need to spend nearly that but thought I would put this here in case something really fancy was mentioned)I was looking at the KORAD KA3005D or KA3005P (not sure what the difference is) but I noticed it got a bad review here as it failed:How about this one?http://www.circuitspecialists.com/bench-top-power-supply-csi3003x-5.html

author: Muxr
author_rank: Super Contributor
timestamp: May 12, 2015, 09:43:17 pm
content: there is a followup video that covers the fixed version of the Korad power supply:

author: nanofrog
author_rank: Super Contributor
timestamp: May 12, 2015, 09:53:52 pm
content: First off, where are you located?If you go into your user profile and set your country, your nation's flag will display beneath your userID. Makes things a lot easier for everyone, particularly regarding links to products & pricing.------------------------Regarding the cheap Chinese PSU's, I'd advise skipping them if possible as they're not the best performers, or that well made as a general rule (~$300 & lower range). On the other end of the spectrum however, is Rigol, who makes some decent PSU's for the money. But they start at $450 here in the US, so more than 2x your stated budget.Fortunately, you may be able to do a lot better used (highly dependent on your location). For example, if you live in the US, you can get a used quality linear PSU easily, and very inexpensively as well. Even a triple output is feasible on your budget, and offers the most bang-for-the-buck IME.Tested Triple Output Supplysearch on eBay (US site).An HP 623x series supply would be within budget as well (x = 4, 5, 6, and 7; also multiple output).HP 6237Bfor example. Try searching for these by P/N (i.e. "HP 6237"; can usually find more units listed this way).

author: SaabFAN
author_rank: Frequent Contributor
timestamp: May 12, 2015, 10:16:40 pm
content: I think, if you want to stay below 200€, the best bet would be to build one yourself. I don't think, you'll find a programmable PSU inside that pricerange.In one of his earlier videos, Dave demonstrated how it is done.My suggestion would be to build one with switching regulators though. You will have some noise on the Output, however, which wouldn't concern me though. Might even be better when testing.The LTC3600 from Linear Technology looks like a fine candidate. You can select current, Voltage and easily parallel them for higher currents. Just keep in mind to keep the Voltage at the RUN-Pin below 12V, or you'll break the chip, like I did (missed that spot in the datesheet).This design should give you a reasonably small board that you should be able to also fit a StepUp-Converter and a sub-10Ah Lead-Acid Battery inside the case that in turn can be charged by a normal charger available from camping-stores, keeping the voltages inside your design below 50V.

author: nctnico
author_rank: Super Contributor
timestamp: May 12, 2015, 11:06:39 pm
content: I just bought this PSU as an extra one:www.ebay.com/itm/281663049598Forum member Tautech is over the moon about this one...

author: GoneTomorrow
author_rank: Regular Contributor
timestamp: May 12, 2015, 11:40:19 pm
content: The Korad PSU's aren't actually that bad, possibly even reasonably good. Dave's review was on an early production run that had incorrect output transistors installed, which caused the problem. They quickly fixed that, and AFAIK there haven't been any more issues. Many people have been using them for years with no issues.Obviously not as good as a $500+ bench PSU but that's to be expected. I tore down my Tenma 10480, which is basically a 3A version of the Korad 3005 and it's built quite well, and actually has Rubycon caps throughout.BTW, the difference between P and D is that the P version has the USB programming connector, the D just has internal programming via the memory slots, no communication.

author: tautech
author_rank: Super Contributor
timestamp: May 13, 2015, 12:03:42 am
content: Quote from: nctnico on May 12, 2015, 11:06:39 pmNot really, they're just a sound and cheap little SMPS PSU that has not given any issues for me or my customers.Here's a recent thread about them:https://www.eevblog.com/forum/testgear/cheap-variable-switching-power-supply/msg665180/#msg665180

author: drakke
author_rank: Regular Contributor
timestamp: May 13, 2015, 01:37:53 am
content: http://www.amazon.com/KORAD-KA3005P-Programmable-Precision-Adjustable/dp/B0085QLNFMhttp://www.amazon.com/KORAD-KD3005D-Precision-Adjustable-Regulated/dp/B00FPU6G4E/ref=pd_sim_328_3?ie=UTF8&refRID=0ESRCKQ77FHMAADHS9ZKhttp://www.amazon.com/KORAD-KA3005D-Precision-Adjustable-Regulated/dp/B0084JFWNY/ref=pd_sim_328_2?ie=UTF8&refRID=0ESRCKQ77FHMAADHS9ZKThere seems to be lots of choices.

author: tehjrow
author_rank: Contributor
timestamp: May 13, 2015, 01:39:07 am
content: Thanks for all the replies, I think i'll go with the Korad KA3005P.

author: drakke
author_rank: Regular Contributor
timestamp: May 13, 2015, 03:09:21 am
content: If you decide to take to cover off people here might be interested in pictures of the interior.I'm interested in how difficult it would be to replace the potentiometer with a precision 10-turn one.Also since it is programmable, if you have an oscilloscope you check how well it responds.

author: Huluvu
author_rank: Regular Contributor
timestamp: May 13, 2015, 05:11:53 am
content: As already mentioned the actual KORADs aren't bad and listed by a very good Price.I recently opened a KD3005D Model which was surprisingly showing Rubicon Caps inside....if there are genuineKORAD KD3005D

author: GoneTomorrow
author_rank: Regular Contributor
timestamp: May 13, 2015, 06:04:25 am
content: Quote from: drakke on May 13, 2015, 03:09:21 amAre you talking about the Korad? It has a rotary encoder, not a potentiometer.

author: nctnico
author_rank: Super Contributor
timestamp: May 13, 2015, 08:27:54 am
content: What I hate about PSUs with a rotary encoder is that they (usually) forget the settings when powered off/on. That gets annoying quickly.

author: GoneTomorrow
author_rank: Regular Contributor
timestamp: May 13, 2015, 09:35:41 am
content: The Korad doesn't

author: pascal_sweden
author_rank: Super Contributor
timestamp: May 13, 2015, 09:55:12 am
content: Interesting to read that Korad is using Rubicon caps. This builds up confidence for sureThe Korad 3005P seems a very good option for a single output power supply.I was wondering if Korad has also a triple output power supply with all outputs isolated from each other, not a common ground between two grounds like on the Rigol, and at least 30V on two outputs, and the third output can be fixed to 5V.BTW: Is the Korad power supply using relays inside? Some power supplies are without relays, so there is no risk of spikes on the output when switching between another part of the secondary winding. If it has relays, did somebody verify that there are no spikes in voltage on the output when it switches? It is not only when you power it on, or when you power it off, that there is a potential risk of a spike on the voltage output. There is also a risk of a spike on the voltage output when the relay switches between the different secondary windings.

author: BFX
author_rank: Frequent Contributor
timestamp: May 13, 2015, 07:13:47 pm
content: I got this one from ebay for 200$ as wrong ... but it works well

author: SaabFAN
author_rank: Frequent Contributor
timestamp: May 13, 2015, 09:04:50 pm
content: Quote from: SaabFAN on May 12, 2015, 10:16:40 pmHuh... I stand corrected. Should've researched the matter more: Korad KA3005P costs 89€ here in Germany!http://www.pollin.de/shop/dt/ODE0ODQ2OTk-/Stromversorgung/Netzgeraete/Regelbare_Netzgeraete/Programmierbares_Netzgeraet_mit_USB_Interface_KORAD_KA3005P_30_V_5_A.html?utm_source=google&utm_medium=pvgl&utm_content=351581&gclid=CjwKEAjw7MuqBRC2nNacqJmIpT0SJABQXAOtQBnJA5DUlFo4yyDWEDqrnQqyi45-0m4nv1S7To64bBoCja3w_wcB

author: richard.cs
author_rank: Super Contributor
timestamp: May 13, 2015, 10:33:56 pm
content: A little off the top of your price range but I bought a load of these for work a couple of years back and was pretty pleased with them.http://www.rapidonline.com/electrical-power/thurlby-thandar-single-power-supply-0-15v-0-5a-pl155-517133They're nice to use and the remote programming just works. They make a bench DMM that's utterly dire though.

author: Electro Fan
author_rank: Super Contributor
timestamp: May 14, 2015, 12:22:01 am
content: If the price is the same I think the Thurlby is probably the better PS but I'm betting that for new units the Korad will be less expensive in almost any region of the world. A used Thurlby in good condition for the price of a new Korad would be a thinker - but it's probably in favor of the Thurlby. These are just my impressions from studying the TTI product line. Having said that I have been a very happy Korad user for a couple years (knock on wood) and have no hesitation in recommending a KA3005P or KA3005D. The Korad 3005 is easy to use, reasonably accurate, pretty quiet, compact, and the price is right. If you can, buy one from SRA-Solder on Amazon. BTW, regarding the rotary encoder, the KA3005 doesn't forget the last setting - it always comes back on power up, with the output off. Just hit the output on button and it's ready to go where you left off.

author: tehjrow
author_rank: Contributor
timestamp: June 04, 2015, 12:29:23 pm
content: I got the Korad KA3005P and I love it so far, thanks guys!