I need a reliable and clean DC power supply for test rigs. - Page 1
Forum section: electronics / testgear

author: Steve Zarg
author_rank: Contributor
timestamp: December 01, 2014, 12:49:24 pm
content: Hi,I am not sure if placing this question on this section of the forum is stretching the definition of test equipment but I feel that the people here will appreciate my interest in selecting a good unit.I'd like to buy some sort of free standing DC power supply for use by both my wife and myself. I like to repair and diy audio gear and she has been making a bunch of Arduino projects.There seems to be hundreds of choices and I'm wondering if people can help me narrow down the choices. I like quality stuff and am willing to pay a bit extra if I know that the supply will be more stable, clean, and dependable.I am also wondering about voltage ranges and if there are great compromises made to provide wide ranges. Is it best to select a narrower range and then purchase a second supply unit for outside the range?I imagine the primary range would need to include 5vDC through 14vDC but I have a special interest in audio circuits so 24vDC and 48vDC seems useful too.I'd probably like to buy as much current capability as I can justify a budget for, but I don't have any idea what sort of price range I'll be considering until I learn some more about the more basic aspects of quality and dependability.I'll appreciate any info people can share on this subject.Thank You!

author: Steve Zarg
author_rank: Contributor
timestamp: December 01, 2014, 06:38:31 pm
content: Anyone?Any brands to consider, for example, on Amazon?Any brands to avoid?I'm looking at a variety of 0-30vDC 5A models that seem like they would be useful.What should I look for in an appliance like this? Linear power? Switching power?

author: Vgkid
author_rank: Super Contributor
timestamp: December 01, 2014, 06:43:49 pm
content: Where are you located?Linear power supplies are usually quieter than switchers.

author: Mr.B
author_rank: Unknown
timestamp: December 01, 2014, 07:07:51 pm
content: It largely depends upon your budget.I own:Tek PWS4323 (0-32v, 3A) ~USD 904.00Rigol DP831A (0-8v, 5A and +/-30v, 2A) ~USD 790.00Wun Hung Lo switcher (0-32v, 32A) ~USD 208.00These serve my requirements well - digital and audio tinkering.By the sounds of your requirements they would fit the bill.But they are not a cheap solution.As far as reliability...The Tek certainly is one of the best brands you can buy.The jury is still out on Rigol equipment so only time will tell.The Gopher brand... well the name and the price says it all. I have had mine for about a year and haven't had to repair it... yet.

author: rollatorwieltje
author_rank: Unknown
timestamp: December 01, 2014, 07:12:46 pm
content: If you have the budget, look for used HP/Agilent e36xx series power supplies. You can get those on eBay easily for between $100 to $300 depending on the features. I find it more useful to have multiple supplies, you often need multiple voltages anyway.

author: krivx
author_rank: Frequent Contributor
timestamp: December 01, 2014, 07:14:30 pm
content: Quote from: rollatorwieltje on December 01, 2014, 07:12:46 pmThis would be my vote. I have an e3615a and like it.

author: robrenz
author_rank: Super Contributor
timestamp: December 01, 2014, 07:16:10 pm
content: If you live in the USHP 6114AHP 6115APower Designs Precision 5020Unbeatable precision, stability and ripple.Inexpensive if you are patient on flebay and don't mind doing some contact cleaning.

author: rx8pilot
author_rank: Super Contributor
timestamp: December 01, 2014, 09:34:40 pm
content: I recently got an HP / Agilent / Keysight 6653A 0-35v @ 15A and it is great. SUPER quiet output. I am about to get another one.There are many options in this family with various voltage and current combos. They are also super ugly 1980's looking, but I wanted super clean and reliable and that is what I got. Very easy to fine adjust current and voltage smoothly without any spikes or noise from analog pots. Lots of eBay availability.

author: Steve Zarg
author_rank: Contributor
timestamp: December 01, 2014, 11:55:25 pm
content: Thank You.I am in the USA. I'll look around for a used example of some of the selections recommended here.

author: Electro Fan
author_rank: Super Contributor
timestamp: December 02, 2014, 03:13:20 am
content: Lots of people here will roll their eyesbut if you want to power circuits with pretty decent precision (within a few tenths of a volt and within a few milliamps) with a 30 Volt, 5 Amp linear power supply you should consider this:http://www.amazon.com/KORAD-KA3005P-Programmable-Precision-Adjustable/product-reviews/B0085QLNFM/ref=cm_cr_pr_btm_link_2?ie=UTF8&pageNumber=2&showViewpoints=0&sortBy=bySubmissionDateDescendingWhen this product was introduced it had some issues (but which manufacturer here doesn't have some product issues from time to time?). Since the introduction of the 3005 Korad made some changes to the product - it hasn't been perfect but overall it appears to have become reasonably stable and reliable over the last year and half or so. Read the reviews in the link (they go back a couple years); 2 out of 19 reviewers gave it 3 stars, 5 more gave it 4 stars, and 12 gave it 5 stars. All for under $150, maybe including shipping depending on where you are.I didn't write the review below and I don't know anything about the reviewer but note that he finds that his Fluke 179 and his Korad power supply match to 3 significant digits:---http://www.amazon.com/KORAD-KA3005P-Programmable-Precision-Adjustable/product-reviews/B0085QLNFM/ref=cm_cr_pr_top_recent?ie=UTF8&showViewpoints=0&sortBy=bySubmissionDateDescending5.0 out of 5 stars So far this is an awesome bench power supply, October 29, 2014By Tony Goodhew "TonyG" (Renton, WA USA) - See all my reviews(REAL NAME)Verified Purchase(What's this?)This review is from: KORAD KA3005P - Programmable Precision Variable Adjustable 30V, 5A DC Linear Power Supply Digital Regulated Lab Grade (Tools & Home Improvement)So far this is an awesome bench power supply. The voltage indicated on the unit with no load (I don't have a calibration load to give a detailed accuracy check) matches my Fluke 179 to 3 significant digits. I really like having the output on/off switch as I can bring the power supply up and let it stabilize before providing power to my project. Setting the values is easy with the buttons under the know letting you move the 'cursor' and then the knob allowing you to set them. It even takes care of the roll-over properly so that you don't have to set each individual value to get where you want to be.I don't really use the memory buttons as my current project is 5v but for someone working on multiple projects I think it would be valuable. The only thing I could have asked for was a second settable output but when I really need that I'll just buy another one.BTW This version is programmable but you can save yourself some money and get the 5D which isn't programmable - When I bought it the difference in price was only $5 so I went programmable in case I ever needed it.---Here is the same product minus the PC connectivity for a few dollars less:http://www.amazon.com/KORAD-KA3005D-Precision-Adjustable-Regulated/dp/B0084JFWNY/ref=sr_1_cc_3?s=aps&ie=UTF8&qid=1417488760&sr=1-3-catcorr&keywords=korad+3005- a couple of poor review sounds legitimate, but one user simply bought the wrong unit (no PC interface) and the other didn't like the sound. 5 others gave it 4 stars and 14 gave it 5 stars.http://sra-solder.com/korad-ka3005p-programmable-precision-variable-adjustable-30v-5a-dc-linear-power-supply-digital-regulated-lab-grade/- here is the vendor of choice (SRA Soldering Products); you can buy it directly from SRA or from SRA through Amazon; SRA stands behind their products with strong customer service.http://www.amazon.com/KORAD-KA3005D-Precision-Adjustable-Regulated/dp/B0084JFWNY/ref=sr_1_cc_3?s=aps&ie=UTF8&qid=1417488760&sr=1-3-catcorr&keywords=korad+3005#Ask- some Q&A about the product (and SRA)A Rigol will offer more features and probably better performance but it will cost 3 times as much. The Korad will take up considerably less bench space than a Rigol or any other power supply that anyone will recommend as being superior. It's not a professional grade power supply but for $150 or less it's hard to beat.YMMV, EF

author: 6E5
author_rank: Regular Contributor
timestamp: December 02, 2014, 03:37:32 am
content: I would go with an old HP. I see tons of pretty good 0-40v @ 2-5 amp HP supplies on eBay for less than $100. If you can do without digital or PC connectivity, then you can really reduce the cost. I suppose you could replace the meter with a digital one if you really wanted to.

author: HighVoltage
author_rank: Super Contributor
timestamp: December 03, 2014, 05:57:44 pm
content: Quote from: 6E5 on December 02, 2014, 03:37:32 amI totally agree.All my old HP power supplies are very reliable and stable and very low cost.

author: SharpEars
author_rank: Unknown
timestamp: December 03, 2014, 06:04:25 pm
content: Quote from: Mr.B on December 01, 2014, 07:07:51 pmHow can this tiny box put out 32 amps at 32 volts?That's 1024 watts we're talking here?

author: krivx
author_rank: Frequent Contributor
timestamp: December 03, 2014, 06:18:26 pm
content: Quote from: SharpEars on December 03, 2014, 06:04:25 pmIt's a switching supply. Probably doesn't hit both limits at the same time either.

author: SharpEars
author_rank: Unknown
timestamp: December 03, 2014, 06:23:57 pm
content: Quote from: krivx on December 03, 2014, 06:18:26 pmNope, theirweb siteclaims the full 1000+ watts, but can we trust Wun Hung Lo on his word? I mean look at that little fan in the back, there's no way it can cool the thing when at full load. Also, look at the noise figures, I don't believe them for a second:Ripple & Noise (Peak-Peak) <= 30mVRipple & Noise (r.m.s) <= 3mVNet Weight 3.0KGHow much should the transformer weigh on this thing, even if it is a switcher?

author: Mr.B
author_rank: Unknown
timestamp: December 03, 2014, 07:02:36 pm
content: Quote from: SharpEars on December 03, 2014, 06:23:57 pmTheir specs are very close to reality.The weight of my one is actually 3.05KgRipple and Noise (p-p) @ full load is ~32mV - measured on a Rigol DS2072AI have run it at full load for extended periods (>6 hours) with no problems, although the fan gets a little noisy and it does get a little warm.When I first received it I opened it up to do a safety visual and was fairly impressed with the build quality and there was no safety issues.Certainly no where near as bad as some other equipment we have seen here on the EEVB.I originally purchased it for testing my home brew DC load - works perfectly for that.

author: krivx
author_rank: Frequent Contributor
timestamp: December 03, 2014, 07:36:24 pm
content: Quote from: SharpEars on December 03, 2014, 06:23:57 pmIf the efficiency is high then it may only dissipate 100-200W.

author: Mr.B
author_rank: Unknown
timestamp: December 03, 2014, 07:55:12 pm
content: Without actually measuring it, I am guessing that it would not be near 200W, perhaps 100W.