Looking for a good power supply under $600 - Page 1
Forum section: electronics / beginners

author: jimjam
author_rank: Regular Contributor
timestamp: May 30, 2014, 12:50:10 pm
content: I was almost convinced in getting a Rigol DP832 but then I read about all these issueshttps://www.eevblog.com/forum/testgear/rigol-dp832-firmware-updates-and-bug-list/While the specs seem pretty nice, the reality with all the bugs seem to be annoying.What other alternatives are there that is of a good quality? I especially don't like the sound of "spike at power up".Wish list:- good quality (and all that entails)- short circuit protection, over voltage/current protection is a must have- stable / accurate to 10-100mV / mA under load- I should be able to type in the voltage / current- A dial would be nice too for minor adjustments- nice lcd/graphical display- Should remember the last settings when powered on- No spikes on power on / off- 2-3 channels would be niceI don't currently need:- Hi-resNice to have:- Ability to parallel for higher current- Has a customisable "preset" voltage/current feature would be nice e.g. 5V, 3.3V, 6V, 9V, 12V, etc- Not too expensive (under $600, or definitely under $1k)- Available in AustraliaHave I missed any important criteria?

author: saturation
author_rank: Super Contributor
timestamp: May 30, 2014, 02:03:04 pm
content: If what you want is functional, clean, dependable, even metrology grade power, I'd strongly consider an all analog PSU such as Power Designs reviewed on this forum and do a robrenz refurbishing on it.

author: robrenz
author_rank: Super Contributor
timestamp: May 30, 2014, 02:59:35 pm
content: If you are in the US (please set your country in your profile so we know where your from) I have a PD 2005Aherethat is very nice. If you are looking for accuracy notice the calibration results using a 24ppm meterhere.

author: KJDS
author_rank: Super Contributor
timestamp: May 30, 2014, 03:01:40 pm
content: If you're in the UK or Europe then I'd buy one or more of my pre-owned HP6632B

author: jimjam
author_rank: Regular Contributor
timestamp: May 30, 2014, 06:09:04 pm
content: Thanks for the tip on setting my country. I'm in Australia. I think I'd prefer a digital power supply like Rigol. I'm not sure if precision is what I'm really after at this point. I just want something foolproof/reliable/quick to use so I can get on with my projects. The other alternative seems to be the Siglent, however I prefer the ability to type in the voltage rather than having to turn the knob all the time, which brings me back to Rigol.Two things I'm not sure of about Rigol:- The power on spike- Fan noiseHave they fixed the power on spike issue?A DP832 costs around $500 here in Australia.

author: nanofrog
author_rank: Super Contributor
timestamp: May 30, 2014, 07:08:22 pm
content: Willing to consider used?FWIW, there's aGrundig PN300available on eBay for example (located in the US, but ships to AU and fits in your budget). Might seem really expensive for used at first glance, but keep in mind it's a triple output unit, not a single; it has 2x programmable outputs (0-32V, 0-2.3A), and 1x fixed (5V, 2A). Decent enough BIN price for the US market actually, and there is a "Make Offer" option enabled.Still in production, and the MSRP of new is 629GBP, which converts to ~1134AUD using xe.com. So about half the cost of new one based on the BIN price.DatasheetManualAlso,this threadmight be of interest (one of the members that owns one, posted some tear down pics).

author: Swake
author_rank: Frequent Contributor
timestamp: June 02, 2014, 02:32:50 pm
content: Quote from: KJDS on May 30, 2014, 03:01:40 pmA year ago I purchased an HP6632A from ebay. It was about 200€ including shipping. Stable as no other. Accurate too. Dial in the voltage and/or current you want and that is what you get.A week later I purchased 2 more for 350€. Best buy ever.Parallel or serial connection is supported.I added front panel connections. Easy and cheap mod because it ones was an option and thanks to this the aluminium front panel has 2 holes on the right behind the sticker and on the PCB 2 connections are soldered to connect the wires.Heavy. Very heavy. Make sure you have a sturdy shelveModel HP6632Bhas slightly better specs but may suffer from dimmed cfl display issues. I prefer LCD screens. A few different models exist with other voltage/current combinations, some with multiple power supplies in one box.

author: Swake
author_rank: Frequent Contributor
timestamp: June 02, 2014, 02:39:44 pm
content: Forgot to mention: On the 6632A the fan is loud!I 'upgraded' putting a temperature dependent voltage supply in between the 12V source and the fan. (just a FET + NTC glued to the heatsink)

author: Fsck
author_rank: Super Contributor
timestamp: June 02, 2014, 02:58:24 pm
content: I agree with @Swake , if you can, go with 3x used 6632a's .if the shipping makes it too expensive, can use an e3620 and a 6632a or another one of the e361* series. or hell, two e3620s.or if more size-restricted, could look for a 6622a, 6623a, 6624a or 6627a.loud is a typical characteristic for high power, high stability supplies.

author: Dave
author_rank: Super Contributor
timestamp: June 02, 2014, 06:36:32 pm
content: Quote from: Swake on June 02, 2014, 02:39:44 pmYou do know that you can manually lower the fan speed in the menu, right?Pressing 9 and 0 at the same time grants access to a hidden menu. You first set the fan mode to manual and then set the fan speed to 0%. It doesn't actually stop the fan, but it does make it a whole lot quieter.

author: Corporate666
author_rank: Unknown
timestamp: June 02, 2014, 06:40:33 pm
content: Quote from: jimjam on May 30, 2014, 06:09:04 pmHonestly, you should get the DP832, IMO. The issues were blown out of proportion - not to say they were not serious, but Rigol stepped up and fixed them. Granted, sending your PSU back for repair is a pain in the ass, but it's not like there is any other option - and Rigol did fix them at no cost to buyers. And if you buy now, it's a fixed unit. I think engineers tend to be way too demanding and critical and analytical, so they often focus on a small issue that will never affect them and get genuinely upset about it - as if you kicked their dog in the nuts.The fan noise... I have a DS2072 and the fan in that is quite a bit louder than the DP832. I have various other PSU's which are also at least as noisy at the DP832, if not louder. If I load up the DP832 to the max, the fan kicks into high gear which can be a bit loud, but there are not many times I am pulling 100+ watts from the PSU, and all my PSU's have fans that crank up in speed when you approach medium to high loads.As for the power spike at turn on, that is the thing I dislike most about this PSU, however it is NEVER good practice to have a circuit connected when you turn on the main switch. It doesn't do it when you turn on and off the channels, just when you first power up the PSU - and regardless of brand, you should never have a circuit attached at power-up. I have other supplies that are much worse than the DP832 for power on spikes, but it's not such an issue that I've put all my PSU's on the scope to check if they do it... it's just not a problem once you know about it.Other than those issues, honestly I love the DP832. I think Dave would tell you he likes his also. I don't think many owners would tell you they dislike theirs, especially for the price. I have several Agilent, HP, Sorensen, Philips and other brand PSU's and the DP832 is my daily go-to PSU because I find it extremely convenient to use... and if something isn't easy and convenient to use, it tends not to get used... so big thumbs up for the DP832 from me.

author: Swake
author_rank: Frequent Contributor
timestamp: June 03, 2014, 07:24:13 am
content: Quote from: Dave on June 02, 2014, 06:36:32 pmNo, I did not know... First thing I will try this evening :-) Thanks for the tip.Is this mentioned in the service manual? Do you know of any other hidden / secret features?

author: Swake
author_rank: Frequent Contributor
timestamp: June 03, 2014, 09:46:06 am
content: Let me give you another killer feature:An hp 6632A/B power supply is able to sink current as well. This effectively makes it an electronic load. Very handy to test battery packs or another power supply.

author: jimjam
author_rank: Regular Contributor
timestamp: June 03, 2014, 02:29:35 pm
content: @Corporate666 what do you like about DP832? What features do you use often? You are swaying me back towards Rigol now. I guess I can live with the spike and always disconnect before powering up. I'm glad you clarified about channel on/off vs PSU power on because I didn't realise that.Did you short the two common (or was it negative) with a big wire like some other people did?I had a look at HP6632A - the cheapest one on ebay is $108 + $84 shipping.

author: Swake
author_rank: Frequent Contributor
timestamp: June 03, 2014, 04:51:12 pm
content: Quote from: Dave on June 02, 2014, 06:36:32 pmChecked and can't activate the hidden menu on the HP6632A. Probably for a more recent model, maybe the B version?

author: Corporate666
author_rank: Unknown
timestamp: June 03, 2014, 05:52:33 pm
content: Quote from: jimjam on June 03, 2014, 02:29:35 pmI am really busy every day, so for me, having things that work and do what I want is important, since I don't like wasting time working around the quirks of a piece of equipment. I find the DP832 is a great PSU for that reason. I guess the things I like most...1) It is 3 channel, so I can always have a 3.3V or 5V on channel 3 for my logic, and channel 1 and 2 are both high voltage/high amperage (relative to, say, a 12V or 20V PSU) so I can use those for higher power circuits. Actually most of my stuff runs at 12V-24V but sometimes I am testing bare boards and sometimes boards with wires attached, so I have alligator test leads in channel 1 and probe test leads in channel 2. This is actually a huge time saver for me since I no longer have to keep swapping out my leads depending on if I am testing panelized boards or finished boards. Using probe leads in the power supply allows me to apply power to test pads on boards very easily2) The voltage and current settings are very accurate and OCP/OVP work very well. I can set the voltage to 5 and current to 0.010A and probe individual LED's on a board to see which ones are working without fear of damage. Then I can turn voltage up to 30 and test a chip-on-board white LED with a voltage of 28 with the same setup and just a few key presses.3) I use the keypad about 75% of the time to set volts and amps, and the dial 25% of the time. But having both is very good, especially since you can move the cursor on the dial to increment in 1A, 0.1A, 0.01A or 0.001A steps, great for slowly ramping up volts or amps and seeing if things work in your circuit before you turn it on full power4) A couple of times I have connected the channels in serial to increase voltage... I had an array of siz 9V Cree COB LED's I wanted to test... it was really nice to be able to actually get 54V @ 350mA from this PSU. Ordinarily I would have had to head over to the Sorensen for higher voltage or the Agilent for higher amperage, but the Rigol can put out enough of both that I only end up using the others for specialized testing (Sorensen is 150V/10A, Agilent will do 20V/120A). I had a nice Philips programmable PSU that I pretty much never use anymore.I did not bother shorting the negatives with a big wire... honestly, that's one of those things where I think a lot of people complain too much about it. Most people won't use both positives with one negative and also be in a situation where the voltage drop is mission critical. If you are, well, just use an interconnect between negatives... or just install it from the get-go and no longer worry about it. Some PSU's come with this from the factory - so it's not a hack IMO, it's just something Rigol should have included in the box.I also like that the PSU has a lot of other features I could use if I wanted... like monitoring circuits over time, external control, being able to make programs/scripts for testing and all of that. I'll probably never really use it, but it's nice to know it's there if I ever do.At the end of the day - the heat issue is fixed, the common-negatives issue is a trivial solution, so what really are the issues with the DP832? I think it is just one - a small and low energy power spike at initial power on. Well, I have other PSU's that do the same thing... honestly, anyone passing over this PSU for that reason is a fool. I think there is a lot of irrational indignation among engineers, as if Rigol somehow betrayed or cheated them on this PSU... so they buy old clunky PSU's with 1/10th the features and capabilities just so they can pride themselves on it not having any flaws. Personally, I'd rather have a Lamborghini that has a quirk where the washer fluid light comes on as I operate the windshield washer than a 1988 Honda Civic that everything works correctly in. But to each their ownAll I can tell you is that I have a bunch of PSU's, some of which were a lot more expensive than the DP832, and on the shelf above my desk with the leads always attached and usually powered on is my DP832. Then I have a rolling cart with 5 other "high end" PSU's that I only ever plug in if I need something specific.If you have the $$$ available, buy the DP832 and something else from somewhere and see which you like better - then return the one you don't like. I'd bet my bottom dollar you'd keep the 832.

author: Dave
author_rank: Super Contributor
timestamp: June 03, 2014, 10:30:39 pm
content: Quote from: Swake on June 03, 2014, 04:51:12 pmOops.That trick works on my 6632B, I thought the A model also had it.

author: jimjam
author_rank: Regular Contributor
timestamp: June 04, 2014, 02:35:45 am
content: @Corporate666 thanks so much for your detailed explanation. I really appreciate it. What you're saying makes a lot of sense and I agree with it. One more question, is there a spike when powering off the DP832 or does it just happen on power on?

author: Corporate666
author_rank: Unknown
timestamp: June 04, 2014, 04:47:44 am
content: Quote from: jimjam on June 04, 2014, 02:35:45 amI read your post just as I was leaving work, so I figured I'd check it for you.I have a fixed (sent back to Rigol) unit with the latest firmware. When I turn it on, it drops to -75mv then spikes up to 650mv, so we're talking a total delta of just over 700mV.When I turn it off, I get a spike of 150mV which lasts for a couple of seconds (cap discharging, presumably).I don't remember what Dave measured, but I seem to remember it was a few volts? Anyway, perhaps others will disagree but I don't think a 750mV spike at turn on is an issue, nor is 150mV at turn off. Of course, this is only when using the main power switch. When the unit is on and I turn on or off the channels, there are no spikes at all - it doesn't overshoot at all.

author: saturation
author_rank: Super Contributor
timestamp: June 04, 2014, 11:53:39 am
content: Corporate666 makes a very good case for the value of this PSU. In fact, what is mentioned are the general benefits of T&M equipment that justify its high price by combining equipment into one box, or even just reduce the size and weight and keep the functionality the same. Or, it may be a better value because it measures at a faster rate yet has the same accuracy or precision as an older model.In a production setting, to quickly move to set parameters like V or A, it could even be strictly specified by production engineers so it can be locked into the PSU and programmed, and if errors occur traced to the test station, it can later be retrieved and verified. With finite space and work time, reduce parts count of devices on the test bench and higher throughput just easily justify $400 for a new tool as ROI, probably even more. If said device only lasted 1 year, it may pay for itself in less time, given labor costs, and easily justify a repurchase and not a repair of the PSU, just trash it to eBay or an auction.For the type of work being done, a turn on spike of 1V or more may not matter.The question to the OP is if this your use too. If a bench lab PSU is not production, but for design or limited testing such as for prototypes or one-off repairs, what matters is clean battery-like power, high accuracy and precision, and extreme reliability. It really comes down to how you spec out your device as in the first message in this thread and its intended use.

author: jimjam
author_rank: Regular Contributor
timestamp: June 04, 2014, 12:31:01 pm
content: @saturation - aside from the spikes (if they are indeed only 650mv it should be a non issue), I thought this DP832 is clean, battery-like, high accuracy / precision. Are you saying that it is not, and for that purpose there are better options? I do think that for $400 ($500+ in Australia), it's quite a bargain for an equipment packed with high-end features.

author: robrenz
author_rank: Super Contributor
timestamp: June 04, 2014, 02:00:03 pm
content: He means something like the Power Designs precision supplies or the HP 6114A or 6115A supplies. These are in another realm of precision and stability compared to the DP832. THAT DOES NOT MEAN THEY ARE THE BEST SUPPLY FOR YOU. If you don't need ultra precision or stability IMO the DP832 will definitely be a more useful supply.

author: jimjam
author_rank: Regular Contributor
timestamp: June 05, 2014, 05:18:19 pm
content: OK I'll get a DP832Thanks for the answers / info. While I'm at it, I'll also get a scope. That's for another thread I suppose

author: saturation
author_rank: Super Contributor
timestamp: June 06, 2014, 04:23:20 pm
content: Tequipment.net has this model listed as a best seller and backordered. To Rigol's credit, I rarely seen a "rush" for T&M equipment except for some of their brand products such as the 1052e, the SA815 and now this.Just comments on reading about this PSU to date.Firmware issues are resolving/resolved? but if new ones arise one is beholden to Rigol for a fix. A competing Instek version is $415 and offers less features but has none of the bugs Rigol faced; Instek has a reputation of having better software, interfaces and work as expected. All analog ones are easiest to DIY fix, as needed, so weigh the value of programmability over your control of the device.http://www.tequipment.net/product-comparison/?Items=403182,420326"High" accuracy: ~ 0.01% at best, a new "Mastech" type non-programmed linear supply is ~ 0.02% but can have variable quality[ some hacking maybe needed]. A used "precision" supply robrenz mentions are ~ 0.002% or better, with resolution to the uV. Current is as precise too. Both alternatives are ~$60-100/channel.Only 2 channels of 832 are isolated, 1 vs 2or3. Most bench multi supplies have all channels fully isolated.The Rigol has no reverse input protection and sinking current risks damage, there is a simple fix that adds diode drop to the output. The Instek cannot sink but its protected and most all analog linear supplies can sink for finite time.The sink issue also suggests output issues when the Rigol is used in parallel mode if voltages are not set the same, and by how much can they differ? I'll ask the forum about it. Until then best to use a blocking diode.Higher accuracy with low ripple, isolation and some sinking capacity make PSU more "battery" like than a PSU that lack such features.When channels are "OFF" they are not "OFF" but output set to 0.0 V. This means the PSU is still electrically connected to a circuit.Many built in instruments: volt, ammeter, timers analyzers are handy, but they fall short in design and troubleshooting issues but are great in production testing issues.When something 'off' happens isolated instruments give better assurance the measurements read true because they are separate instruments independent of the PSU, the DUT and even from each other [particularly battery operated ones].Many of the analysis functions of the 832 are built into some bench DMMs or e-loads.e-loads are often devices used for cycling power on-off or varying current flow but cannot do programmed variable output voltage, if that is needed.Quote from: jimjam on June 04, 2014, 12:31:01 pmEnjoy! Please review it for us when you get it, including your purchase experience from the seller. Given your options for quality T&M in Oz, including what's available on the eBay market, the Rigol is a good unit, so long as you know and need its pros and are aware of its flaws.Quote from: jimjam on June 05, 2014, 05:18:19 pm

author: robrenz
author_rank: Super Contributor
timestamp: June 06, 2014, 04:57:28 pm
content: Better order quickTequipment noticehere

author: sacherjj
author_rank: Frequent Contributor
timestamp: June 06, 2014, 05:26:53 pm
content: I just got my DP832 after a multi month wait. Unfortunately, it has 1.09 stock, so I can't hack in the features I don't need now, but would like to play with. My only negative so far is this thing is LONG. I didn't build my equipment shelf quite deep enough for it, so my front feet are just off the shelf. No complaints other than that.

author: jimjam
author_rank: Regular Contributor
timestamp: June 06, 2014, 05:43:48 pm
content: Rigol should give Dave 10% commission!I hope they have stock in Australia! I am still waiting until I decide on a scope because if I want to get a rigol I can order at the same time and ask for a discount

author: robrenz
author_rank: Super Contributor
timestamp: June 06, 2014, 05:52:08 pm
content: Quote from: robrenz on June 06, 2014, 04:57:28 pmSorry I forgot you were in Australia

author: jaxbird
author_rank: Frequent Contributor
timestamp: June 06, 2014, 06:02:45 pm
content: Not wanting to upset anyone, but you might want to consider a couple of the super cheap/good value Korad supplies, likes the one Dave reviewed, but the fixed versions of course.They will pretty much cover all your needs, plus they are more powerful than the Rigol (5A vs 3A) that is useful depending on what projects you work on.The best part is that they are so cheap that with your budget you can always keep a couple of spares if you need even more voltages.

author: jimjam
author_rank: Regular Contributor
timestamp: June 06, 2014, 06:24:34 pm
content: Quote from: jaxbird on June 06, 2014, 06:02:45 pmIt seems that in Australia "Triotest" is no longer selling Korads. Amazon's price is $116 - so, In Australia..... it would be around.... $160 - $200 + 10%GSTWhen I looked at this:http://www.jaycar.com.au/productResults.asp?MID=3&SSUBID=821&SUBCATID=999&keyform=CAT2#3It really makes Rigol DP832 seem like an absolute bargain compared to those power supplies they are selling at Jaycar.The instek - lacks the ability to punch in the voltage. This model which is nowhere near Rigol's features, sells for almost the same price as rigol:http://au.element14.com/gw-instek/gps-1850d/power-supply-dc-18v-5a-90w/dp/2147730We don't have a lot of choice here unless willing to import, and importing doesn't work well for heavy / bulky stuff. Ah well

author: jaxbird
author_rank: Frequent Contributor
timestamp: June 06, 2014, 06:37:16 pm
content: Quote from: jimjam on June 06, 2014, 06:24:34 pmThat's too bad, it does indeed limit your choices, always the problem with power supplies, if you can't get them locally, shipping will be significantJust be careful, many of the cheaper PSUs are switchmode, if you need fairly low noise linear is a must.

author: G0HZU
author_rank: Super Contributor
timestamp: June 06, 2014, 11:16:21 pm
content: QuoteOne of the best features of the Rigol is that it can be remotely programmed and I think that this would be the only reason I would want the Rigol on my bench.Otherwise I don't see anything I like about this PSU. I guess we all have different opinions on what makes a good PSU but here's a few things I don't like about the Rigol 832.The display is too small and cramped and the VA info is not above the relevant PSU output. I don't want to be looking at a tiny cramped and offset display.It looks like you have to manually select control for each PSU by pressing a button to enable each in turn. I would not like this. It's bad enough having to look at the cramped and fussy display but to have to move my hands across several buttons just to trim each PSU supply manually would drive me mad. I'm used to old school supplies with touchy feely controls and big displays for voltage and current that you can see from across the room at a glance.One minor gripe is that there is only one 4mm socket per terminal. I've kind of grown up using TTI supplies where you get the extra 4mm socket for the sense connection and this makes life easy when making multiple connections.In the UK it costs about £320 so it scores very highly (in terms of bang per buck) for the fact that it is remotely programmable but I don't see much else to like when compared to buying a nearly new TTI PSU for a fraction of the price.

author: sacherjj
author_rank: Frequent Contributor
timestamp: June 07, 2014, 01:57:47 am
content: Quote from: G0HZU on June 06, 2014, 11:16:21 pmWhile you do have to enable each channel to change it, there is an all on button for toggling all of them.

author: Corporate666
author_rank: Unknown
timestamp: June 07, 2014, 02:44:14 am
content: Quote from: G0HZU on June 06, 2014, 11:16:21 pmIt's not really realistic to have a separate keypad for each channel, so if you get a keypad and multiple channels, you'll always need to have a way to identify which channel you're setting.Having the display for the channel be directly above the connections is a non-issue, IMO... the display matches 1-2-3 left to right, same as the terminal layout - and the fact that you always have test leads going from the PSU to whatever you're powering already abstracts the display from whatever is connected anyway.I also am a bit shocked anyone would say the display is cramped and small - one of the things I like about the 832 is the display is big and really easy to instantly see what's going on. Maybe there are PSU's out there with 10" LCD's on them that I'm not aware of, but coming from single line LCD or dual line VFD PSU's like my Philips/Fluke/Agilents, I find the 832 to have a huge and really clear display.I don't think TTI makes any models with more than 2 displays, so if you get one of their triple output units that matches channels with the DP832, there must be a switch to change what one of the displays is showing, or that output has no display. I also don't see anything but volts/amps on the TTI's... so setting any of the dozens of features that the DP832 has must either be a chore, or those features don't exist on the TTI (which I think is the case) - stuff like OCP/OVP, tracking, timing, analysis, saving configs, etc.Not to mention 3-channel TTI is, what, about double or triple the price? Does the TTI have LAN/USB/RS-232, etc?

author: WarSim
author_rank: Frequent Contributor
timestamp: June 07, 2014, 03:40:59 am
content: I am not saying anything about bang for the buck etc.I have my own opinion and criteria and have chosen TTi.Yes I did research Rigol first mainly because of the reviews here.Unfortunately, close scrutiny caused them to not meet my specific criteria.If Rigol meets your criteria I agree they are great options.I am responding to mention:Yes some triple output TTis have three displays.Yes all TTis I researched can be purchased with LAN/USB/RS232 etc.Yes all TTis I researched had fixed or adjustable OCP/OVP.Yes all dual/triple TTis I researched had tracking features.Some of TTis I researched had profile storage.It is true I did not find a TTi that didn't require a computer for sequencing.Sent from my iPad using Tapatalk

author: G0HZU
author_rank: Super Contributor
timestamp: June 07, 2014, 11:34:42 am
content: QuoteIt was the height of the characters on the numerical display and the fact that they are clumped so closely together that I wasn't keen on. I'm used to TTI displays with approx 15mm characters with bright red 7 seg LEDs. I do like to have a display that can be read at a casual glance from way across the room. Note: I also have some TTI supplies here with old school black on grey LCD readouts and I don't like using them as much because the display is so gloomy. It's hard to read at an angle despite the 15mm character size. I kind of regret buying the LCD TTI PSUs for this reason.

author: saturation
author_rank: Super Contributor
timestamp: June 07, 2014, 04:59:06 pm
content: If anyone owns a DP832, can they test the parallel configuration of this PSU? Are both channels stable when they are connected in parallel? What happens if you make one channel differ by 1 V? In theory, the channel with the lesser voltage setting becomes the output voltage of both channels, and the channel with the higher voltage setting will match that voltage setting and go into constant current mode. This is a stress test, but any linear CVCC supply can perform that test without instability [ albeit not advised in the long term as one channel is 'overworked', ideally each channel shares the work equally.]The Rigol application note:http://www.batronix.com/pdf/Rigol/DP8_DP1_ActiveLoads.pdfStates no 'active loads' should be applied to any channels as it could damage the 'powered device.' It implies its not advised to parallel even its own other powered channel.But what I think Rigol means is you cannot connect a fixed voltage source to any channels such as a fixed voltage wall wart supply, a battery or a solar cell. A CVCC device adapts dynamically until an equilibrium is reached, and both devices are in a steady state.Finally, an 'active load' means something like an electronic load, which clearly can be used on the DP832 so I think the wording they chose is not ideal.

author: ScottyAU
author_rank: Contributor
timestamp: June 23, 2014, 03:59:06 am
content: JimJam - did you end up deciding/ordering a Bench supply? (i'm in the same boat looking at the 832 too aswell).Cheers,Scott

author: jimjam
author_rank: Regular Contributor
timestamp: June 23, 2014, 04:59:47 am
content: Scotty,I am going to get a Siglent DP3303D from Triotest. I haven't ordered it yet though.About Rigol, I called Emona and they said they don't have the stock for DP832 and they're coming in July, possibly mid july. They have one DP832A in stock. My main worry about Rigol are the fan noise and the fact that they seem to have lots of issues.I don't know, I might regret getting a siglent but I have a feeling either one will do just fine, except that I'll have to live with a noisy fan with Rigol, or the lack of keypad for Siglent. I'll only change the voltage / current occasionally but the fan runs constantly.Yep the fan can be replaced - but technically that'll void warranty on principle, even if I could possibly circumvent it by being careful with the warranty seal.

author: ScottyAU
author_rank: Contributor
timestamp: June 23, 2014, 09:29:35 am
content: Do you know if the stock with Triotest is the latest revision of the hardware with the bugs fixed?The physical foot print of the Siglent suits my bench a lot better than the depth of the Rigol.I'd emailed the local Emona guy but hadn't heard back - interesting to know they won't have stock for so long.Cheers,Scotty

author: jimjam
author_rank: Regular Contributor
timestamp: June 23, 2014, 10:59:16 am
content: Try calling Emona. That's how I got hold of them. I'll let you know about Triotest/siglent once I've heard back from them.

author: ScottyAU
author_rank: Contributor
timestamp: June 23, 2014, 11:22:49 am
content: I've dealt with the local Emona guy here in Brisbane (Richard) in the past - he's a top bloke. I'm sure he's just a bit snowed under. And i've got the stock answer i needed now anywayI'll be quite interested to see what Triotest have to say ( i also emailed them this afternoon).Cheers.

author: ScottyAU
author_rank: Contributor
timestamp: June 24, 2014, 06:10:37 am
content: I spoke to Triotest today - they said that they weren't aware of the issue, which was a little bit disappointing.They did say though that there stock is only a few weeks old though - so they will be whatever the current model is.So i've placed an order for a SPD3303D. Will post back when it arrives.Looking forward to having something other than a ATX breakout power supply!As an aside i also have a Re:Load Pro coming in a month or so (https://www.kickstarter.com/projects/nickjohnson/re-load-pro-a-dc-active-load) so i'll do some testing with it as well.Scotty

author: ScottyAU
author_rank: Contributor
timestamp: June 24, 2014, 06:37:10 am
content: Triotest heard back from Siglent - they said they fixed the issue in December.Triotest assure me the current stock will include this fix!Scotty