Recommended Quality Triple Channel Power Supply? - Page 1
Forum section: electronics / beginners

author: SpannersToSparks
author_rank: Regular Contributor
timestamp: January 25, 2017, 03:21:42 am
content: HiI recently saw the EEV Blog reviews of the Rigol DP series power supplies. I am kitting out an electronics lab for myself, and though I know the recommendation is always "build one yourself", I have the cash and want to invest in something that will last me down the line. As they are also recommended in the Art of Electronics, which I intend to work through, I am looking at a triple channel PSU.After having looked at the poor review of the vaguely similarly priced Siglent model on EEV, and seeing the high cost of Keysight, I am at a bit of a loss to know what to look at. What is the current recommended unit in the price range up to around £400?NB I am not averse to building my own PSU, but 1) I am new to it, and don't want to be relying on something I built at my most incompetent for any length of time especially for something like a power supply and 2) it looks like building a triple channel with built in protection would probably cost about as much as buying a decent one.Cheers

author: bitseeker
author_rank: Super Contributor
timestamp: January 25, 2017, 05:07:14 am
content: Welcome to the forum.As you've probably seen in the Art of Electronics, the HP/Agilent/Keysight E3630A triple-channel is a recommended power supply. However, it's important to note that that model does not have an adjustable current limiter. It does have short-circuit protection (i.e., a fixed current limit).Stepping up to the E3631A will get you adjustable current limiting, higher power delivery, GPIB control, configuration memories, and more. So, depending on availability and pricing in your locale, it may be a good option. TTi power supplies are also a popular choice.Although DIY is a popular recommendation, it's also prudent to have a good lab power supply that you can rely on.

author: JXL
author_rank: Regular Contributor
timestamp: January 25, 2017, 06:05:01 am
content: I have an Hantek PPS2320A (2 * 0-32V@3A & fixed 2.5/3.3/5.0V@3A) which is USB programmable. My goto supply is an HP6237B (0-18V@1A & +/-(0-20V)@0.5A) modded with 10-turn pots for voltage control and added pots for adjustable current limiting. The HP schematics are available on-line.

author: rstofer
author_rank: Super Contributor
timestamp: January 25, 2017, 06:08:17 am
content: There is a Test Equipment forum here that is more focused on equipment.Look at the Rigol DP832. with a little hack (details elsewhere) you can upgrade it to a DP832AI bought one a couple of months ago and it's pretty slick.

author: SpannersToSparks
author_rank: Regular Contributor
timestamp: January 25, 2017, 04:51:42 pm
content: Quote from: bitseeker on January 25, 2017, 05:07:14 amHi bitseeker,Cheers for the reply. The Keysight sounds good, but is a little over my budget, especially as I am also hoping to pick up a decent function generator. I am going to have a good browse through the TTI models, so thank you for the suggestion.Yeah agreed on the homebrew PSU thing. I can see it being worth it maybe AFTER I've completed LTAoE

author: SpannersToSparks
author_rank: Regular Contributor
timestamp: January 25, 2017, 04:53:38 pm
content: Quote from: JXL on January 25, 2017, 06:05:01 amHowdy JXLThose are some nice looking supplies. I take it those would only be available as second hand or refurbished? I must admit I rather like the analogue displays. My only concern as a new guy is what to do if something goes wrong, especially if its been imported. Do you know of any reputable dealers? I am based in the UK, which may complicate matters a little.Thanks again

author: SpannersToSparks
author_rank: Regular Contributor
timestamp: January 25, 2017, 04:56:06 pm
content: Quote from: rstofer on January 25, 2017, 06:08:17 amThanks rstoferI am not sure about the DP832 after the issues Dave pointed out in his EEVBlog reviews. If Rigol have fixed them I would feel more comfortable, especially as I have one of the scopes, but the common ground and inaccurate current reading on the binding posts was a bit of a concern. I have posted over in the test equipment forum as you suggested, so perhaps some light will be shed over there.I was super happy with Rigol's customer service when I bought the scope, so I would be happy to buy from them again.

author: JPortici
author_rank: Super Contributor
timestamp: January 25, 2017, 05:55:43 pm
content: if you are on the cheap, the US ebay is currently flooded with GWI triple channel programmable power supplies (though i'm not sure of the extent of the "programmable" as i failed to see a communication connector)i got myself one for 110$ + shipping + import duties... about 250 euros.it's currently on its way to my home so i can't comment on the instrument itself

author: jpb
author_rank: Super Contributor
timestamp: January 25, 2017, 06:20:29 pm
content: Quote from: SpannersToSparks on January 25, 2017, 03:21:42 amAs you're in the UK, I'd recommend TTi as being robust and well made if a little bulky. They are not as expensive as Keysight or R&S but probably a bit more than Siglent. My double PL320QMD only cost £160 as new-old stock but the place I bought it from has run out of stock. I bought my counter from TTi direct at a reduced price as an ex-demo model but I don't know if they will do power supplies on the same basis.There is often TTi supplies on ebay but they are very variable in age and quality (from looking at the photos).The more basic triple model is within budget new:http://uk.farnell.com/aim-tti-instruments/el302rt/power-supply-3ch-30v-2a-adjustable/dp/1670782?mckv=_dc|pcrid|78108461709|&gross_price=true&CATCI=aud-132163472949:pla-141994879269&CAAGID=20220726789&CMP=KNC-GUK-GEN-SHOPPING-AIM_TTI_INSTRUMENTS&CAGPSPN=pla&gclid=CPHvq4z03dECFYOfGwodI6UHXQ&CAWELAID=120173390000406516

author: grouchobyte
author_rank: Regular Contributor
timestamp: January 25, 2017, 06:32:01 pm
content: If you can afford it....

author: slurry
author_rank: Regular Contributor
timestamp: January 25, 2017, 07:06:53 pm
content: I would say a two-channel PSU and a separate 1-channel, that's what i prefer as i can have to projects running at the same time at different places.I like Aim-TTi a lot, although the cheapset series (EL...) have a very plastic feeling to them and the levels of ripple can be a bit much.If you can spend the money, i would recommend the mx100 which shows P as well as I and U:http://uk.farnell.com/aim-tti-instruments/mx100tp/power-supply-3ch-70v-6a-programmable/dp/2457410At a budget i would check this out:http://uk.farnell.com/aim-tti-instruments/pl303qmd/power-supply-2ch-30v-3a-adjustable/dp/1510524Elektro-automatik have some quite good PSU's, but i do like the older series way better than these new ones, i have this one on the bench right now:http://uk.farnell.com/ea-elektro-automatik/ea-ps-2384-05b/power-supply-3ch-84v-5a-adjustable/dp/2097196

author: oldway
author_rank: Super Contributor
timestamp: January 25, 2017, 07:34:31 pm
content: This one if you can find one for cheap.

author: nanofrog
author_rank: Super Contributor
timestamp: January 25, 2017, 09:40:25 pm
content: As you're in the UK, I'd second looking forusedTTi or even Farnell branded supplies.For example:Single OutputDual Output (Thurlby-Thandar)Dual Output (Farnell)Triple OutputThere's other brands too, such as Rhode & Schwartz, but I don't think they're as common as TTi or Farnell in the UK.Good luck.

author: rstofer
author_rank: Super Contributor
timestamp: January 25, 2017, 09:45:34 pm
content: Quote from: SpannersToSparks on January 25, 2017, 04:56:06 pmYup, I replied over there as well. Here I just want to talk about the heatsink issue and the fact that it has been resolved. The common ground simply doesn't matter (to me).

author: Vtile
author_rank: Super Contributor
timestamp: January 25, 2017, 09:56:50 pm
content: Get one that have atleast two of those three lines floating. It does allow you to connect the lines then 2x30V@2A, 1x+-30V@2A 1x60V@2A, 1x30V@4A. (For in example 30V/2A + 0..6V/5A triple output unit) In old linear Lab PSUs that were the thing, but I'm not sure about the new swithing mode supplies. If the PSU is good enough (manual informs the isolation voltages to ground etc.) you can also stack several units parallel or in series. How much amperage you really need? Would you get two units one for high output, poor stability and one high regulation low output?Then comes the sinking ability some units allow to be a sink and some do not. I have one HP 20V@5A that is both sink and source, while not handy at all as a workbench supply, since it is one of those "type in the values and press set to apply" type of things. You do want rotary knob control of both voltage and current in the long run for your "Do it all" powersupply, that is just so good and quick to use UI.

author: tggzzz
author_rank: Super Contributor
timestamp: January 25, 2017, 10:26:00 pm
content: Personally I'd spend as little as possible on bench PSUs, and more on other test equipment. And youwillfind you need more equipmentIf your circuit will have a life "away from the bench", then it will need its own stand-alone PSU - so why not simply use that stand-alone PSU during testing instead of the bench PSU?I wouldn't recommend building your own PSU, becausewhensomething goes wrongtwocircuits will suffer. The reason so many 60s and 70s power supplies were so trouble-prone is that often the PSU design was given to the newest least experienced engineerI strongly recommend a PSU where each rail's voltage and current limit can be set independently of the others.Apart from that, you need to define some ofyour"use cases", so that you will be able to work out what's important for you.You will need to define the minimum acceptable voltage and current for your purposes. If all outputs are floating then you can put them in series to get a higher voltage, e.g. 2*0->30V = 1*1->0-60V.You will need to define whether you have integral meters or rely on front panel knobs plus external meters, whether one meter for voltage and one for current or one meter switchable between voltage and current, analogue or digital. In my experience it is sufficient to set the voltage, and then to continuously monitor the current. If accuracy is important, you will need to use an external meter anyway.You will need to define whether the voltage/current controls need to be analogue or digital. There are advantages and disadvantages to each, and both are usable. Generally I prefer analogue controls and meters for PSUs, but when I'm measuring DC linearity it is convenient to be able to increment the voltage in 0.1V or 1V steps with digital inputs.Consider getting three separate units or a dual plus a single; that will give you far more choice.Consider getting cheap old PSUs; I seem to pick them up for £10-£20 at local auctions. They will probably work; if not you haven't lost much. Many may require the pots are cleaned with IPA or Craig Deoxit, some will require replacing some electrolytic capacitors. Both those things are much simpler/faster/cheaper than building you own PSU from scratch!

author: FlyingHacker
author_rank: Frequent Contributor
timestamp: January 25, 2017, 10:52:21 pm
content: I would suggest getting an older used supply, like a LAMBDA LPT-7202-FM for many reasons.Definitely get a supply with an adjustable current limit. This will save your components, and it will let you test other things like meters and Zener diodes easily. It will let you experiment with Ohm's law with real components as well without fear of sending too much current through something if you get the math wrong.Get a floating supply if you can (Hwere negative is not tied to earth ground unless you hook them together yourself).Very few people ever use the fancy features in a new digital supply.Memory settings are about worthless. How hard is it to dial the voltage and current limit?An On/Off for the different outputs is useful, but how hard is it to pull one banana lead out? Works great (assuming you know if your supply is floating or grounded and understand that just pulling one lead may leave your project grounded through the supply).I see a lot of people spend way too much money on a fancy power supply. Put that money towards a better scope, a better DMM, more breadboards, components, etc.More equipment does not a better engineer make. More experimentation and problem solving to make do with what you have will result in a lot more learning.

author: mmagin
author_rank: Frequent Contributor
timestamp: January 25, 2017, 11:49:47 pm
content: Quote from: JPortici on January 25, 2017, 05:55:43 pmI got one of these, GPC-3020 much cheaper than that. It's a reasonable power supply. Seems to behave correctly under load and has reasonably low ripple.

author: bitseeker
author_rank: Super Contributor
timestamp: January 26, 2017, 02:58:59 am
content: Quote from: JPortici on January 25, 2017, 05:55:43 pmIt has memory for, I think it was, four different setups. That's all the programmability that I'm aware of it having.QuoteBeware of significant overshoot on channel 3. See the following thread for more info (there are a couple of other related threads, too).https://www.eevblog.com/forum/testgear/instek-gpd-3303s-power-supply-overshoot-opinion-wanted/

author: mmagin
author_rank: Frequent Contributor
timestamp: January 26, 2017, 04:40:03 am
content: The GPC-3020 doesn't seem to have an overshoot problem at all, so far as I can tell.

author: bitseeker
author_rank: Super Contributor
timestamp: January 26, 2017, 07:37:24 am
content: Quote from: mmagin on January 26, 2017, 04:40:03 amThat's good. It's the one with analog meters, correct?Although digital meters are sought after, I have many power supplies with analog ones. After all, if you need precise values for a circuit, you still have to use a DMM to measure at the circuit, unless the power supply supports external sense leads.

author: mmagin
author_rank: Frequent Contributor
timestamp: January 26, 2017, 03:52:20 pm
content: Quote from: bitseeker on January 26, 2017, 07:37:24 amYes, mine has the analog meters.