Current favorite bench DC power supply? - Page 1
Forum section: electronics / testgear

author: IDEngineer
author_rank: Super Contributor
timestamp: August 21, 2017, 09:15:20 pm
content: I've been putting this off for too long. I'm about to buy a Siglent SDG2042X and figure I'll get a bench supply at the same time.My most important requirement is that it goes down to a TRUE 0.0VDC. I've got a variable supply but it only goes down to ~0.7VDC, which is still too much for some analog work.Clean DC out is a must. Multiple independent outputs would be nice but not a requirement; ditto a fancy LCD display. Need at least 15V max out, 1-2 amps is plenty.There's everything from <$100 Chinese unknowns on eBay to multi-kilobuck supplies from Keysight, etc. I'm thinking a few hundred dollars feels just about right.Any experience out there with today's offerings? Thanks!

author: bd139
author_rank: Super Contributor
timestamp: August 21, 2017, 09:34:07 pm
content: If I could get one I'd grab a second hand HP/Agilent/Keysight E3611A. The things take up little space, are very reliable, no nasty load transients etc and there are tonnes of them available in the US for not much cash. You either get a Chinese POS with a fancy display or a basic high quality supply with LEDs. I'd go for the latter. It's more important with power supplies than anything else.Hardly ever turn up in the UK though so I opted for a Thurlby TS3022S (dual 30v 1a). The display sucks though. LEDs are better.

author: Dubbie
author_rank: Unknown
timestamp: August 21, 2017, 09:45:05 pm
content: Those Chinese POS you denigrate are actually mostly very nice.I'm talking about name brands like Rigol and Siglent etc, not the no name aliexpress SMPS.I'd way rather have a few extra nice features like an informative screen, LXI control and linking outputs rather than some mythical "American" quality voodoo.

author: nctnico
author_rank: Super Contributor
timestamp: August 21, 2017, 09:46:15 pm
content: I'm still very tempted to get a Keysight E36312A. I've looked at Rigol's and Siglent's offerings but they just don't get anywhere near it when it comes to accuracy (and there are the usual issues) and I really like the low current measurement feature on the E36312A.

author: tautech
author_rank: Super Contributor
timestamp: August 21, 2017, 09:56:49 pm
content: Quote from: IDEngineer on August 21, 2017, 09:15:20 pmThose that have the latest Siglent PSU seem pretty happy with it.Some reading, links and vids for you to check out:https://www.eevblog.com/forum/testgear/siglent-spd3303x-e/

author: trophosphere
author_rank: Frequent Contributor
timestamp: August 21, 2017, 10:03:45 pm
content: I bought aKeithley 2280S-32-6and it has been my favorite power supply as I do embedded systems development and like having the ability to immediately see precise dynamic current consumption in graphical form. It is also very good for sensors and analog circuitry requiring a low noise power source with the added benefit of programming levels/ramp times to test latchup and glitches. There is also the ability to discharge a power source but I haven't used it. It is on though expensive side though.

author: DaJMasta
author_rank: Super Contributor
timestamp: August 21, 2017, 10:32:06 pm
content: Quote from: nctnico on August 21, 2017, 09:46:15 pmThey're sort of in a different class, even the upgraded SPD3303X or DP832 are half the price of the Keysight, and more than double the output. There are certainly applications that can require very fine regulation and very low noise.... but how often are you going to be powering them on your bench without any local regulation or power conditioning on board? If I power up an RF board or a ADC board that's very sensitive to noise... won't the boards have local regulation or LC filters on the rails or both? Won't they be operating in a noisy environment when uncovered anyways? A quick bench test shows that a couple of power resistors in an unshielded rats nest shows me <7mV voltage error including the initial warm up of the supply and ~15mV RMS of noise with the 20M bandwidth limit in place on the scope, which is almost all introduced in the wiring (34461A and DS4024 measuring a SPD3303X-E), and that's on the "economy" version of the PSU (that's less than 1/4 the price of the Keysight) that only shows you 10s of mV and mA.On the inexpensive side of that estimate, I think used gear is the right approach, and especially if you're doing analog work, having something with two or more output channels to give you a split rail is probably best... though getting decent capacity on three rails at around $100 is a tough order. If you're fine with half an amp on the higher voltages, there's the E3630A. If a single rail is fine, maybe the 66311/66312 fits the bill (but tends to be a bit more). If you don't mind analog readouts, there are a number of choices in that ballpark. As the pricepoint increases, you get into Rigol and Siglent's current offerings, the DP711 or 712 as a single rail option with a higher voltage capability, then the SPD3303X-E is another notch pricier but with triple outputs, then the DP832 is another notch and has a fully adjustable third rail. Both the Siglent and Rigol triple supplies have high resolution options (software only) to give you another digit of set resolution and readout.From looking around, I haven't been wowed by any of BK's recent offerings, but I imagine they're at least on part with the cheaper supplies and at least have a brand name with potential support behind them.

author: IDEngineer
author_rank: Super Contributor
timestamp: August 21, 2017, 10:39:39 pm
content: QuoteI'm willing to spend a few hundred bucks:Quote...and the comments so far are giving me several options to consider. I have no problem with used gear in good condition, so I think a trip to eBay with some HP/Agilent/Keysight part numbers is a must.I did like one of the screenshots of a Siglent supply, though... it implied that the unit plots voltage/amperage on its LCD. I have current probes and such for really accurate measurements, but it might be nice to have a "quickie" display like that. Just another thing to think about.

author: DaJMasta
author_rank: Super Contributor
timestamp: August 21, 2017, 10:43:53 pm
content: Sorry, misread but edited before that post - the info is about the same, just framed in a way that actually reflects the initial post betterAnyways, the SPD3303X and X-E variants as well as the Rigol supplies offer waveform displays, for the Siglent, you press a button to toggle it and can have each channel toggled separately. I don't see an easy way to scale the graphs (and they will not show fine detail because of how far they're zoomed), but you still have access to changing the setting in graph mode. Probably sufficient to see detail in a variable load or with a programmed variable configuration, but not to show very small adjustments made by the supply or load.

author: IDEngineer
author_rank: Super Contributor
timestamp: August 21, 2017, 10:46:44 pm
content: Quote from: DaJMasta on August 21, 2017, 10:43:53 pmRight - I'm thinking here of large-scale changes such as turning on selectively powered subsystems on an embedded system, that sort of thing.Now if they wanted to bring out a BNC with voltage or (especially!) current info that could be dropped into a DSO, that would be incredible....

author: IDEngineer
author_rank: Super Contributor
timestamp: August 21, 2017, 10:59:39 pm
content: Quote from: trophosphere on August 21, 2017, 10:03:45 pmLove Keithley's stuff. Just looked at that unit based on your recommendation... ouch, that's a pricey^H^H^H^H^H^H really nice unit! A bit more money than I'm able to spend right now though, especially since I'm also picking up a Siglent SDG2042X at the same time.

author: tautech
author_rank: Super Contributor
timestamp: August 21, 2017, 11:00:52 pm
content: Quote from: IDEngineer on August 21, 2017, 10:39:39 pmDon't be misled by the SPD3303X or X-E imagery shown on the Siglent websites, it shows a previous FW version of the display GUI that doesn't have the real-time actual output shown.And yes, I've asked them to update the images as the GUI doesn't represent the product as it's shipped today.Websites have very recently beeen updated:

author: JXL
author_rank: Regular Contributor
timestamp: August 21, 2017, 11:11:08 pm
content: QuoteTry HP6237B (0-18V @ 1A and +/-20V @ 0.5A) or if you prefer lower voltage/higher current (6V @ 3A), look at it's sibling HP6236B. If bench space is not an issue you can try the larger Leader LPS-151 or LPS-152. These last 2 have current limiting and the schematics are almost identical to HP6236B. I have both the HP6237B and LPS-151, and they are my most used bench supplies. You can find these supplies for <<$100 on eBay.

author: IDEngineer
author_rank: Super Contributor
timestamp: August 21, 2017, 11:17:48 pm
content: Another thread mentioned the Instek GPE-x323 series. Nice clean display and you can get 3+1 channels for under $400. Has separate rotary voltage adjustments for the channels too, whereas some "share" a single rotary control across all channels (at least that's better than the "press the +/- buttons as fast as you can" designs). Have to search for reviews on the Instek stuff, haven't ever used it before.EDIT: Just found the GPE-4323 four channel unit for $318 at TEquipment, and that'sbeforethe EEV discount. Quite compelling....

author: Macbeth
author_rank: Super Contributor
timestamp: August 21, 2017, 11:56:26 pm
content: My HP6632B has a ~ -2mV for 0V DC (yes, minus - it can sink as well as source current). If I set it to 0.001V it gives +3mV. These are the steps in its DAC/ADC.Riglol DP832 CH1 output OFF is ~ 4.5mV, output ON at 0.000 is ~ 4.4mV and 0.001V ~ 5.4mV, the PSU itself reporting 00.006V and 00.007V respectively.mV DC measured with my Keithley 2000.

author: rdl
author_rank: Super Contributor
timestamp: August 22, 2017, 01:10:33 am
content: These do the job for me. No fan, quiet, and solid as a rock, but some would consider the 10 mA meter resolution a shortcoming. Jellybean parts, so easily fixable. The E3611A is basically the same except higher voltage at lower current.There were some revisions, so the later Agilent versions are probably preferable. I know my HP version of the E3610A has a bit of turn-on voltage overshoot, but the Agilent does not.

author: steven4601
author_rank: Contributor
timestamp: August 22, 2017, 06:07:33 am
content: For the past 3 or 4 years I have been enjoying various 1-6 channel output power supplies.Somehow I default to this nice 2.5 channel digital programmable bench supply for all quick experiments.2 channels 0-30V 0-3A, and the 3rd is with a switch option for low voltage aux supplies.What makes it handy is the quick and easy setting of the outputs with 1mv & 1mA resolution.

author: plazma
author_rank: Frequent Contributor
timestamp: August 22, 2017, 07:01:38 am
content: My favourite atm. is this DIY unithttps://www.eevblog.com/forum/projects/dps5005-portable-mini-lab-psu/msg1285206/#msg1285206Larger Thurlby Thandar and HP units are in the garage lab.

author: nctnico
author_rank: Super Contributor
timestamp: August 22, 2017, 07:46:28 am
content: Quote from: DaJMasta on August 21, 2017, 10:32:06 pmIt is not just about noise but also about accuracy and resolution. The E36312A's low current measurement can show current accurate to tens of uA.

author: IDEngineer
author_rank: Super Contributor
timestamp: August 22, 2017, 04:45:16 pm
content: Spent a lot of time reviewing the E36000A series. Very tempting! But with discount the GPE-4323 is under $300, a full $1100 less than the 5A version of the Keysight. $1100 buys a lot of test equipment, and nothing I'm doing requires the additional precision to be embedded in the power supply. Then again, I tend to keep test equipment for a very long time so it's never a bad investment. (I still have a Phillips PM3214 analog scope on my bench, works great and is still holding calibration!)Decisions, decisions....

author: nctnico
author_rank: Super Contributor
timestamp: August 22, 2017, 05:10:22 pm
content: IMHO the GPE-4323 is also a good choice if you don't need all the bells and whistles but it still has (IIRC) 1mV / 1mA resolution. What I'm missing in my current bench power supply is accurate readout of voltage and current.

author: cdev
author_rank: Super Contributor
timestamp: August 22, 2017, 05:17:41 pm
content: Quietness is a very important attribute for a "favorite" bench power supply.

author: nctnico
author_rank: Super Contributor
timestamp: August 22, 2017, 05:32:17 pm
content: Quote from: cdev on August 22, 2017, 05:17:41 pmI couldn't agree more. Unfortunately many of the interesting older HP/Agilent power supplies have loud fans so they are not very pleasant to work with.

author: bd139
author_rank: Super Contributor
timestamp: August 22, 2017, 05:53:46 pm
content: This is why I like the E36xx supplies. Small, quiet, reliable, no fancy shit to go wrong.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: August 22, 2017, 07:40:46 pm
content: They look like direct descendants of the Harrison HP 6284A style supplies.

author: bd139
author_rank: Super Contributor
timestamp: August 22, 2017, 09:24:05 pm
content: They are indeed that. The internal construction is very similar.

author: jpb
author_rank: Super Contributor
timestamp: August 22, 2017, 09:44:05 pm
content: Quote from: bd139 on August 22, 2017, 05:53:46 pmI've recently bought a E3631A power supply off ebay. It is nice but the fan is very noisy - I perhaps might change it. My other power supply is a TTi PL320QMD which though big and bulky is completely quiet as it has no fan at all.

author: IDEngineer
author_rank: Super Contributor
timestamp: August 22, 2017, 09:50:08 pm
content: Quote from: nctnico on August 22, 2017, 05:32:17 pmI second that opinion. I spend a lot of time building my lab PC's so they are whisper quiet. Really annoying when the new DSO's have fans that remind me of wind tunnels, but you dare not reduce the CFM because the heat coming off those A/D's is very noticeable if you put your hand in the exhaust airstream. Difficult problem.I suspect it's the same with power supplies. Do you optimize for the user experience, or for technical specs? This latest offering from Keysight appears to go for a balance - quiet with pretty good specs - but it carries a high price tag.How long before we start building our labs with cooling water connections in the walls, so we can plug in the cooling like we do the power cord? Transfer the heat AND the noise to "somewhere else".

author: bd139
author_rank: Super Contributor
timestamp: August 22, 2017, 11:29:25 pm
content: Everything is a compromise. I want small, quiet with real controls rather than encoders for power supplies. Power supplies are just about the only kit which has gone completely backwards in the last few years. Shiny shit is all we're greeted with.Quote from: jpb on August 22, 2017, 09:44:05 pmYeah that's one of the fancier later units. Not a fan of them.I've got a TTi TS3022S and a PL310. No complaints here other than they're huge compared to the HP/Agilent/Keysight units.

author: IDEngineer
author_rank: Super Contributor
timestamp: August 23, 2017, 12:32:51 am
content: After evaluating everything, I pulled the trigger on the Instek GPE-4323. Four channels, rotary knobs, isolated outputs, 1mA resolution, new so it comes with a warranty, reasonable reviews, and $298 *delivered* from TEquipment with the EEV discount.The new Keysight units were a strong temptation but in the end I decided they weren't worth over 4X as much money. I couldn't find them for less than $1400 and while that included a free DMM, I already have a nice Fluke unit so that wasn't a huge incentive.Used HP/Agilent/Keysight units risked noisy fans and the possibility of my needing to work on them sooner rather than later. I'm buying a power supply to design NEW things, I don't need to be spending time servicing my test equipment. That sounds like a fun hobby for later in life but right now I'm busy enough!I have a Rigol scope and like it, and the people behind the company, but just too many compromises and issues with their power supplies.I gave some thought to buying multiple single-output power supplies but decided the resulting daisy-chaining of grounds and such would just further clutter the bench. Plus they'd consume more bench real estate than a single four channel unit, and I might be dealing with multiple fans instead of one.Absolute worst case, I'm out $300 and can revisit my decision later.

author: coromonadalix
author_rank: Super Contributor
timestamp: August 23, 2017, 01:19:01 am
content: Try Kepco ATE 75-8, a 0-75v at 8 amps cc and cv 3/4 rack sized psu for a very loud fan loll, i'll beat all of you in a pinch, had to put an scr controlled speed dial in it, it has an 5 inch 120v ac fan blower.It has an 120 v dc preregulator section in it with an really huge wire wound resistor who looks like an dryer element with ceramic holders, when you short this psu at full power, this resistor will heat your room really fast loll.Modded it with isolated grounds 4.5 digits panel meters ... an incredible Ebay bargain 120$ shipped, it was the rear shorting/programmation connector who was missing.Could not find one at a good/reasonable priceHad Lambda LLS series variable smps who where very noisy too ...

author: cdev
author_rank: Super Contributor
timestamp: August 23, 2017, 03:28:52 am
content: Simply having heatsinks and being "silent" does you no good if your transformers hum. I have a triple Sorensen XL power supply buit in the 1980s that is still a current model (!!!) It has very nice, large digital LED readout for voltage and current and a 10 turn pot for voltage on each one. It weighs at least 30 lbs. I got it in an auction and repaired it. Were it not for this hum, it would otherwise be ideal.I suspect, it being 40 years old, that its transformers have just dried out. Anybody have any suggestions? It runs within spec, ripple is low. Digital voltage and current display is still quite accurate.Hums loudly.Out of desperation I bought a GW Instek GPC-3020 since they were very cheap. The fan on it however, is quite loud and noisy. Looking into replacement (of the fan) with one that has a thermal switch so it only goes fast when its actually hot. The current 24v, 80 cm fan is running at full blast all the time and it doesn't get hot no matter what I throw at it.So I often find myself back to using my littlesilentHP 6217A.

author: innkeeper
author_rank: Unknown
timestamp: August 23, 2017, 04:45:53 am
content: I'm quite happy with my GW Instek GPD-3303S - i picked up on eBay as one of those ITT Tech school bankruptcy sales.fully digital, 3 channel output all 0-3A+- 0-30v with 3 decimal place precision on the voltage and on the current limiting / reading ( 1mv / 1ma resolution). plus has tracking, series and parallel output modes.The 3rd output can be 2.5V, 3.3V and 5.0VIt has memory save and recall for your settings.USB interface, for pc control and monitoring, with software, and with labview drivers.outpout is very clean.and no fan noise unless i am drawing up near 3A and even then its reasonable.nabbed one for 100 bucks off ebay, normally around 400 retailTE

author: Deridex
author_rank: Regular Contributor
timestamp: August 25, 2017, 02:11:46 pm
content: My favorite PSU at my home is a HP 6632B which has been eqipped with front panel connectors. Even though i think about replacing the fan inside to make it less noisy.At work i prefer the Rohde&Schwarz HMP2020 but they are to expensive to buy one for my hobby.

author: HKJ
author_rank: Super Contributor
timestamp: August 25, 2017, 04:07:37 pm
content: Depending on application it is either the Keithley 2280S or the TTi QL355P (I have four of these).The 2280S has very precise voltage and current readouts and can also sink current, for some of my work this is very useful.For more general usage the QL355P works fine.Both have keyboard and encoder, I generally uses both. Keyboard to set the initial voltage and encoder for doing adjustments during tests.And with my test I also use the computer link nearly all the time.

author: b_force
author_rank: Super Contributor
timestamp: August 25, 2017, 04:14:39 pm
content: I sometimes don't get the comments about fan noise.What prevents you from modifying the fan or even designing a better thermal solution?

author: bd139
author_rank: Super Contributor
timestamp: August 25, 2017, 04:27:25 pm
content: The big warranty sticker that stops you getting into it.

author: b_force
author_rank: Super Contributor
timestamp: August 25, 2017, 04:35:19 pm
content: Quote from: bd139 on August 25, 2017, 04:27:25 pmFor equipment that is that old?There are also techniques to removes these stickers

author: bd139
author_rank: Super Contributor
timestamp: August 25, 2017, 04:46:54 pm
content: Old kit gets ripped up here instantly. Problem is I've got a lot of new stuff

author: b_force
author_rank: Super Contributor
timestamp: August 25, 2017, 04:48:58 pm
content: Quote from: bd139 on August 25, 2017, 04:46:54 pmAnd you don't trust the 'new stuff' enough that you will need the warranty?

author: bd139
author_rank: Super Contributor
timestamp: August 25, 2017, 05:05:27 pm
content: Spot on. It's all Rigol stuff

author: IDEngineer
author_rank: Super Contributor
timestamp: August 25, 2017, 05:43:15 pm
content: Quote from: b_force on August 25, 2017, 04:14:39 pmThat presumes a "better" fan is available in that size/voltage. But there are many tradeoffs in fan selection: Size, voltage, current, CFM, and noise are the biggies. You'll notice most small equipment fans like these emphasize two specs: CFM and noise. The two are almost always directly related. Within the same size envelope it's really hard to get more CFM without more noise. You can get more CFM at the same or less noise by going larger, but test equipment doesn't usually have a lot of open unused space waiting for a bigger fan.Fan noise, especially the annoying high frequency content, is related to the RPM of the impeller. IIRC it's like a second or third order function which means the noise goes up FAST with increased RPM. But you dare not decrease the RPM because that decreases CFM and might let things get too hot. And so it goes.One reasonable alternative for older, "less intelligent" supplies might be the same fan, but with intelligent thermal control such that it only comes on (or increases its speed) when the supply actually needs that much cooling (i.e. you're drawing lots of current). Presumably that would keep the fan off/quiet the vast for most of the time for all but the highest power situations.

author: nctnico
author_rank: Super Contributor
timestamp: August 25, 2017, 05:50:47 pm
content: Quote from: IDEngineer on August 25, 2017, 05:43:15 pmIt is not black & white like that. Usually a better/more expensive fan (thicker/longer) can move more air at a higher pressure at the same noise level compared to a cheap one.

author: IDEngineer
author_rank: Super Contributor
timestamp: August 25, 2017, 06:01:53 pm
content: Quote from: nctnico on August 25, 2017, 05:50:47 pmI agree, and stated that a larger (in your words, "thicker" or "longer") fan certainly enables that. But within the same physical envelope - since most test equipment doesn't have lots of extra space inside - it's hard to decrease noise without also decreasing CFM. If you go back far enough that the existing fan isn't using the more recent impeller fin designs, then a upgrade might be possible. But for anything remotely modern, the physical size of the fan imposes some harsh limits.If your piece of test equipment has the room, by all means install a larger fan optimized for same CFM at lower noise!

author: b_force
author_rank: Super Contributor
timestamp: August 25, 2017, 06:36:24 pm
content: Larger fan or two fans.Fan noise goes (roughly) with a 50*log(delta RPM)(I have done quite some work in field of acoustics with this)My experience is that in many cases there ARE (much) better fans available.You can clearly see that companies safe money on this (or on thermal design in general IMO)In many cases the fan is also over designed.By that I mean that a lower RPM can be used without overheating everything.Mostly you can simply add a 'smart' fan circuit that keeps an eye on the temperature, so the fan always turns on the lowest speed.

author: texaspyro
author_rank: Super Contributor
timestamp: August 25, 2017, 06:40:56 pm
content: A lot of older equipment comes from a time when fan choices were limited, fan noise was not a consideration, or designers chose what was available or already in use at the company. I've replaced fans in older equipment that went from "air raid siren" to "is it on?" and the temperature in the box changed by maybe a couple of degrees.Also a lot of equipment has fans sized for a spec'd large, industrial temperature range. Most people only use equipment in an office environment so you probably have quite a bit of headroom for a lower performance fan. You should do before / after temperature checks when replacing a fan.Oh, and my current favorite power supply is the EEZ PSU H24005:https://www.crowdsupply.com/envox/eez-h24005

author: IDEngineer
author_rank: Super Contributor
timestamp: August 25, 2017, 06:42:21 pm
content: Certainly, if the OEM went ultra-cheap on the fan, something better may be available.Since this fan discussion is (loosely) based on using older supplies from the likes of HP, though, I would be surprised to learn that HP went cheap on their fans. They certainly didn't go cheap on much else! That was the basis for my comment about a more modern fan design... if the supply you're trying to resurrect is decades old, you have a better chance at a more modern fan design. Maybe the likes of Rigol went cheap on fans in their current offerings too. But a recent Agilent/Keysight/R&S supply with a "cheap" OEM fan? Considering their retail price, I hope not.

author: IDEngineer
author_rank: Super Contributor
timestamp: August 25, 2017, 06:43:28 pm
content: Quote from: texaspyro on August 25, 2017, 06:40:56 pmTHIS is an excellent observation!

author: b_force
author_rank: Super Contributor
timestamp: August 25, 2017, 06:53:28 pm
content: Quote from: IDEngineer on August 25, 2017, 06:42:21 pmThe opposite of cheap (expensive) is NOT equal to performance!!I have done research for a company about fan noise.In most cases manufactures just put in a beefy expensive fan, with the idea that it will be good enough.Or because it's a reliable manufacturerIt still doesn't mean it will be the optimum fan for the design.I have seen thermal constructions from HP, and I can't really say that they put a lot of thinking or effort in optimizing it.Thermal design is a bit of a after thought in most electronics to be very honest.Must be adequate enough to reach the specs and cheap.Also, in old equipment fans are noisier than nowadays fans.If it's being used for years, the first thing I always do is replacing them.Quote from: texaspyro on August 25, 2017, 06:40:56 pmAnother reason why temp controlled fan is a good idea

author: bd139
author_rank: Super Contributor
timestamp: August 25, 2017, 06:54:58 pm
content: Indeed. My HP 5328A counter had to go in the end because it was too damn noisy. It actually sounded like a hoover going.

author: anotherlin
author_rank: Frequent Contributor
timestamp: August 25, 2017, 07:26:41 pm
content: Quote from: Deridex on August 25, 2017, 02:11:46 pmMy home bench power supply is a HMP2020, love it, works just perfect.If you check buy/sell forum, TopLoser has some nice deals on Hameg/R&S stuff.I got mine from him last year, I paid 525 euros VAT + shipping included.As for noise, as I've never been higher than 500mA (I usually have -15V/+15V for analog electronics), the fan doesn't spin fast, so it never has been a problem.Regarding performance, the output is very clean, not noisy. Even if it's a "dual stage" design: switch mode pre-regulator followed by a linear post-regulator.It has huge power capability 2 channels at 30V, channel 1 at 10A max, channel 2 at 5A, for grand total of 188W max.The only drawback is that the readback is only precise at 0.5mA. This may make it less useful for very low power design work.

author: Mr. Scram
author_rank: Super Contributor
timestamp: August 25, 2017, 10:57:25 pm
content: Quote from: cdev on August 22, 2017, 05:17:41 pmSwapping out a fan is not that hard. Selecting one that has similar cooling capabilities is a little more complex, but there are a few quality go to brands that supply good fans that do not make a lot of noise, but will still provide a solid airflow and static pressure.

author: nctnico
author_rank: Super Contributor
timestamp: August 25, 2017, 11:02:56 pm
content: Quote from: Mr. Scram on August 25, 2017, 10:57:25 pmThere are more ways to do this. In several of my HP power supplies I added a circuit which controls the fan based on temperature. In the lower power models I leave the fan off until it is needed in others I have it running at half speed (or less). In both cases the fans never get to full speed even at high load conditions.

author: innkeeper
author_rank: Unknown
timestamp: August 25, 2017, 11:46:34 pm
content: Quote from: steven4601 on August 22, 2017, 06:07:33 amfor the GPD-3303Sits wht i use 90% of the time.plus it can be pc controled / monitored and has labview drivers. and its quiet.

author: nidlaX
author_rank: Frequent Contributor
timestamp: August 26, 2017, 12:52:39 am
content: The Siglent SPD-3303D has a very aggressive fan control profile that keeps it quiet. From my measurements, temperatures are well controlled even under heavy load.Recommended!

author: David Hess
author_rank: Super Contributor
timestamp: August 26, 2017, 01:33:32 am
content: My favorite power supply? That would be the Tektronix PS503A because it provides floating current limited tracking outputs up to +/-20 volts in any ratio or a single floating output up to 40 volts. It has full documentation making maintenance easy. HP makes some similar power supplies.If I was designing a bench power supply, that is the minimum feature set I would duplicate.The photograph below shows one of my PS503As on the very right.

author: texaspyro
author_rank: Super Contributor
timestamp: August 26, 2017, 01:47:28 am
content: I also like the PS503. I have a bunch (but you only get full output current in the rightmost slot). I built some 3.3 / 3.6V regulators that plug into the 5V bananas... damn young 'uns these days and their teeny weenie voltages. Real he-man logic runs at 5V like Cthulhu intended.The main failure mode on the PS503 seems to be 741A op amps in the regulator circuits. And the incandescent lamps... those get replaced by LEDs. I've only had one that needed the main caps replaced. Oh, and the usual dipped tantalum caps... Tek gear from that era used particularly failure prone ones.... Oooh, that smell... don't ya just love that smell...

author: cdev
author_rank: Super Contributor
timestamp: August 26, 2017, 01:55:49 am
content: I think I have one picked out, just need to do a little more research.Quote from: Mr. Scram onTodayat 16:57:25>Quote from: cdev on 2017-08-22, 11:17:41Swapping out a fan is not that hard. Selecting one that has similar cooling capabilities is a little more complex, but there are a few quality go to brands that supply good fans that do not make a lot of noise, but will still provide a solid airflow and static pressure.

author: cdev
author_rank: Super Contributor
timestamp: August 26, 2017, 02:00:45 am
content: You burn in your tantalums so that if they fail, they will fail then?Or is it just because they are old. I have a bunch of old tants and I have just been using them at basicallyhalftheir rated voltage or less. So far not a single failure. they are mil-spec.They are very heavy for their size.Quote from: David Hess onTodayat 19:33:32

author: anotherlin
author_rank: Frequent Contributor
timestamp: August 26, 2017, 02:33:48 am
content: Quote from: David Hess on August 26, 2017, 01:33:32 amYou should also stress that each output can do 1A max, and the additionnal 5V/1A output.The TM504 rack is fanless, so basically you can have 20V/2A (parallel connection) completely silent.They are classic design linear supply so the output is very clean, no switching noise.And they can be had for very cheap, I paid mine 50 euros with the TM504 included!The biggest drawback is that there's no readback.

author: texaspyro
author_rank: Super Contributor
timestamp: August 26, 2017, 03:12:29 am
content: Quote from: anotherlin on August 26, 2017, 02:33:48 amThere can be... if you have a volt meter in the rack and wire to the backplane. I set up a rack that way. I added a switch to select... uhhh something... I was many years ago... voltage / current?

author: David Hess
author_rank: Super Contributor
timestamp: August 26, 2017, 03:31:39 am
content: Quote from: texaspyro on August 26, 2017, 01:47:28 amOne of mine had a bad input capacitor so I refurbished them all replacing the input and output capacitors.The 741s, and one of my PS503As has 301As instead apparently from the factory, should not be failing however there may be a failure mode when the capacitors go bad where oscillation or overshoot causes problems. If I ever have to track that down, I will make some improvements.Quote from: cdev on August 26, 2017, 02:00:45 amA local electronics store here has inexpensive NOS (new old stock) dipped tantalum capacitors in bins but since I am unsure of their heritage, I burn them in for a couple days before they go into my parts collection. This might be a waste of time since I have yet to have one fail.Quote from: anotherlin on August 26, 2017, 02:33:48 amThe rare TM504A included a fan and the larger mainframes include fans but they all still only have one high power slot.The tracking outputs from a single PS503A cannot be placed in parallel limiting the floating output current to 1 amp or 400 milliamps in a low power slot. In practice I have not found the 1 amp limitation to be a problem in most cases. If I need more current, then I use a different power supply.QuoteBeing a linear design with full documentation, they are also easy to maintain.I would rather have the tracking current limited floating outputs than read back and I can always add a couple of TM500 multimeters if necessary as shown in the photograph.Another thing I like are the separate coarse and fine voltage controls for each side.

author: IDEngineer
author_rank: Super Contributor
timestamp: August 26, 2017, 03:38:05 am
content: Quote from: texaspyro on August 26, 2017, 01:47:28 amYou forgot the minus sign!REAL men run their logic on a -5.2V supply and enjoy 500pS gate delays. Why use anything but ECL?I guess you could use slower logic if you needed a delay line....

author: IDEngineer
author_rank: Super Contributor
timestamp: September 06, 2017, 12:30:23 am
content: The Instek GPE-4323 power supply has arrived and is now on the bench. I have to report my first impression: Whomever laid out the screen didn't talk to whomever laid out the knobs!On the screen, CH1 has its voltage display on the left and its current display on the right; in other words, the displays are arranged horizontally. But the knobs that control CH1 are arrangedvertically, with voltage on the top and current on the bottom! Twice already I've reached up to adjust CH1 current, only to be adjusting CH2's voltage instead, because that's the visually obvious place that corresponds to the screen display.C'mon, folks. Designing decent human interfaces isn't that hard. You almost have to TRY to screw it up this badly.

author: texaspyro
author_rank: Super Contributor
timestamp: September 06, 2017, 12:44:24 am
content: Quote from: IDEngineer on September 06, 2017, 12:30:23 amNEVER underestimate the (in)abilities of a Chinese UI designer... you'll lose every time.

author: montemcguire
author_rank: Regular Contributor
timestamp: September 06, 2017, 05:35:12 am
content: I'm using the Agilent/Keysight E3631A as my main bench supply, and after a couple of years, I like it a lot. It's extremely reliable, it does what it says it's doing, and it does that very well, with a good bit more accuracy than I'd expect. It's also pretty easy to use, despite the less than verbose display. I really like the "all-on / all-off" button - definitely essential for a bench supply when stupid things might crop up and require a quick shutoff and load down-programming! I have a pile of older HP 6627A and similar system supplies, which are great performers, but they're clumsy to use on a bench without some magical GPIB assistant - they're hard to set up and control only through the front panel. The E3631A is not clumsy at all, as it was designed as a bench supply, and not a system supply.I bought mine used and refurbished, and while the newer Keysight models seem very nice, this older unit performs well enough, and does what I need very well. For me, making sure that I don't blow up a 'sacred' DUT is very important, so I don't mind paying a little more for proven reliability and performance. In short, I paid more than I had to, but I think it was worth it. There seem to be a number of these units available used, so definitely consider this series of bench supplies. I'd buy another if I needed another!

author: MadTux
author_rank: Frequent Contributor
timestamp: September 06, 2017, 11:14:38 am
content: HPAK E3614/3615/3616/3617 and Keithley 236/237Fluke 332/335D for accurate and high voltagesHPAK 66311B is also nice, although voltage adjustment isn't as nice as in the E36xx series.HPAK 6269/6274 is great for beefy stuff.Stay away from HPAK E3610/3611/3612 if you don't have 120VAC line voltage, about the only HPAK instument that has a fixed transformer inside

author: Mr. Scram
author_rank: Super Contributor
timestamp: September 06, 2017, 04:42:58 pm
content: Quote from: texaspyro on September 06, 2017, 12:44:24 amI think there might be some cultural differences in play too. Back when feature phones were the standard, there often was quite a distinct difference in UI experience when it came to phones designed by western companies and eastern ones. These were large companies too, which spend considerable time and effort developing the phones, so I'm hesitant to declare the UI more suitable to my liking actually better, as opposed to being used to something different. Especially considering research has shown that we tend to prefer inferior systems that we know over superior systems that we're unfamiliar with, until the performance disparity is sufficiently huge.

author: IDEngineer
author_rank: Super Contributor
timestamp: September 06, 2017, 05:21:19 pm
content: Fine, but we're all humans everywhere on the planet. I suspect it's common to humans worldwide that when you're looking at a display divided into quadrants, and there are four knobs in the same arrangement immediately to the right that adjust those four values, you'd expect a 1:1 mapping of quadrant to quadrant.The mapping doesn't even correlate to the arrangement of the binding jacks along the bottom. Maybe, if the jacks for CH1 and CH2 were vertically arranged below their respective displays, it would make more sense. But there's no correlation there either.Let's give them the benefit of the doubt and say that the pots had to be in that arrangement for noise or other reasons. Why not just rearrange the display? What demanded that the display have its quadrants be set up like that?And the worst part is this isn't a dot matrix display, so this problem can't be fixed (or made a user selectable option) in firmware.

author: Mr. Scram
author_rank: Super Contributor
timestamp: September 06, 2017, 08:18:27 pm
content: Quote from: IDEngineer on September 06, 2017, 05:21:19 pmI'm just saying the most basic assumptions can go awry. Very simple, technical basics can cause relevant differences. Westerners will mostly read left to right, but other languages will read right to left or top to bottom. This leads to simple assumptions where the most prominent or most used UI elements should be, scrolling in which direction is intuitive and more. The way sentences are structured in languages familiar to us can be very different to that of character based languages, or even a language like Classical Latin, where the position of each word is mostly irrelevant.That's not even taking much more subtle cultural cues and what's assumed to be common knowledge into account. I'm not saying your example isn't just bad design, but I've learned to be very cautions of what you bring with you without ever realizing it and consider to be normal, but is completely alien to others.

author: IDEngineer
author_rank: Super Contributor
timestamp: September 07, 2017, 01:03:21 am
content: Quote from: Mr. Scram on September 06, 2017, 08:18:27 pmI acknowledge your point, but still... we're talking basic eye-hand coordination in this case, not cultural differences. I can't imagine any cultural difference that would make it seem logical to have two directly related quadrants rearranged like the front of this power supply. Maybe if you were viewing the display through a mirror?

author: texaspyro
author_rank: Super Contributor
timestamp: September 07, 2017, 01:21:13 am
content: My favorite Chinese UT screw up was a function generator. It had an encoder to change settings. But the encoder was only active if you turned the output off... two button presses... and then another two to turn the output back ON. WTF were they smoking when they thought this was a good idea.Another was a sig gen that had a touchscreen. You could call up a keyboard to enter values (no twirly knob for you!). You also had to enter leading or trailing zeroes... the field had to be fully populated... also there was no backspace or abort entry key!!! The keyboard used less than 20% of the already small screen. You had to use a very fine stylus and the Hubble space telescope to use it.I could go on about software UI's but the duct tape keeping my head from exploding is at its limit.

author: Neomys Sapiens
author_rank: Super Contributor
timestamp: September 07, 2017, 01:24:13 am
content: Oltronix B703DTZentro-Elektrik 7941Rohde & Schwarz NGSM32/10TTi CPX400DP(as far as 'normal' voltage/current ranges are the thing)

author: cdev
author_rank: Super Contributor
timestamp: September 07, 2017, 10:24:59 pm
content: Stupidity (or inscrutability) knows no borders. Ability to design a nice, usable UI is likely 100% based on the amount of experience somebody has doing it, and nowadays, software tools they have to do it with, tools that might be pricey and not available to firms and/or engineers who are just starting out.And of course.. often reasons that I am sure are 100% economics. Especially with hardware, They may not make sense to us, leaving out some important $2 part that turns an implementation from good to dangerous.. but they happen.- "For want of a nail a kingdom is lost."Quote from: Mr. Scram onYesterdayat 10:42:58>Quote from: texaspyro on 2017-09-05, 18:44:24I think there might be some cultural differences in play too. ...

author: bd139
author_rank: Super Contributor
timestamp: September 07, 2017, 10:40:30 pm
content: Got to be honest, the moment I see Times New Roman on the UI on some futuristic bit of kit I slightly facepalm.

author: rdl
author_rank: Super Contributor
timestamp: September 08, 2017, 12:21:04 am
content: Quote from: bd139 on September 07, 2017, 10:40:30 pmYou're not the only one. I also can't tolerate power toggle/rocker switches that operate side to side. Up is on down is off. Anything else just seems wrong to me.

author: cdev
author_rank: Super Contributor
timestamp: September 08, 2017, 12:32:00 am
content: I have a Sorensen XTT triple bench supply that would be close to perfect if it just didn't hum. It was manufactured in the 1980s and the varnish on the transformers must have dried out or something and so the transformers in it hum loudly.

author: IDEngineer
author_rank: Super Contributor
timestamp: September 08, 2017, 05:08:25 pm
content: Quote from: texaspyro on September 07, 2017, 01:21:13 amOK, those beat my complaints about the Instek unit. Wow, just wow.I think I still need a single DC power supply with straightforward, separate coarse and fine voltage adjustment knobs. Some of the stuff I'm working with requires me to play with offset voltages in the millivolt range and these single turn pots just aren't getting me there....

author: nctnico
author_rank: Super Contributor
timestamp: September 08, 2017, 05:18:23 pm
content: I hate power supplies with single turn pots and/or seperate fine & course pots. In some cases I have replaced a single turn pot with a multi-turn one. You have to realise though that cheap power supplies may not have a good enough temperature stability for milli-Volt adjustments.

author: HKJ
author_rank: Super Contributor
timestamp: September 08, 2017, 05:34:04 pm
content: Quote from: IDEngineer on September 08, 2017, 05:08:25 pmNo way, I hate the fine and coarse pot supplies. At one time I bought a PS with a 0-15V knop and changed the pot to a multiturn pot. I used that PS for years, before I got one with an encoder where I could select to adjust voltage on 0.001 , 0.01 or 0.1 volt steps.In my "work" I have to adjust the PS in small voltage steps quite often and multiturn works, but encoder is better. Keyboard or two pots are hopeless for it.

author: IDEngineer
author_rank: Super Contributor
timestamp: September 08, 2017, 05:35:11 pm
content: Quote from: nctnico on September 08, 2017, 05:18:23 pmWhy the hate for coarse+fine? Maybe it's application specific. If you need fine resolution across a wide range, a single multiturn would be better. But if you need fine resolution in a narrow range, it's nice to use the coarse to set the midpoint and then apply the dynamic range of the fine pot to that small adjustment range.QuoteTotally true. But I can't even get started if the adjustments don't give the resolution to get there!

author: IDEngineer
author_rank: Super Contributor
timestamp: September 08, 2017, 05:37:03 pm
content: Quote from: HKJ on September 08, 2017, 05:34:04 pmI've never used one where I could select the step increment like that. I agree that would be the best of all worlds. Any recommendations for such a unit, say 0-15VDC? Low amps is fine, anything that needs millivolt accuracy won't be pumping 10's of amps.

author: HKJ
author_rank: Super Contributor
timestamp: September 08, 2017, 05:39:14 pm
content: Quote from: IDEngineer on September 08, 2017, 05:35:11 pmBecause I need to adjust the coarse very precise to get a usable range for the fine adjustment. I may be a bit application specific, but I would expect many people want to test supply voltage over a specific range.

author: HKJ
author_rank: Super Contributor
timestamp: September 08, 2017, 05:45:56 pm
content: Quote from: IDEngineer on September 08, 2017, 05:37:03 pmI can do that one all my most used supplies: TTi QL355P, TTi QPX1200SP, Keithley 2280S-32-6It took me some years, but over time I have removed equipment I do not like and added more equipment that I like, I have retired a couple of power supplies that did not work as described above, including the one where I replace the pot with a 10 turn (It is only semi replaced, sometimes I still use it).

author: IDEngineer
author_rank: Super Contributor
timestamp: September 08, 2017, 06:15:31 pm
content: Quote from: HKJ on September 08, 2017, 05:45:56 pmOuch... the cheapest encoder knob supply I can find is >$400. That probably explains why I didn't run across any during my recent search! You (don't) get what you (don't) pay for.Looks like I might be retrofitting some multiturns into my Instek.

author: HKJ
author_rank: Super Contributor
timestamp: September 08, 2017, 06:32:05 pm
content: Quote from: IDEngineer on September 08, 2017, 06:15:31 pmI would expect that to be a very good idea. Any time you need more resolution on your voltage pot, a multiturn is an easy fix.