Siglent SPD3303X-E vs GW Instek GPP-4323 or other recommendations - Page 1
Forum section: electronics / testgear

author: FPdesign
author_rank: Contributor
timestamp: May 28, 2022, 07:07:29 am
content: Looking into a new programmable linear DC power supply for pro audio designs..Important to have at least 3 isolated outputs, quiet operation, series/parallel modes, to name a few..The Siglent SPD3303X-E is almost the perfect choice for me.. it has all that, plus it's quite compact and it seems relatively quiet (please correct me if I'm wrong here).. not a fan of noisy fans.. would be nice if the third output was bit more flexible but isn't a dealbreaker..Now I've heard a few users talk positive about the GW Instek GPP-4323.. I really like having the extra output, all outputs programmable.. and most importantly you also can use two as load functions.. downside it is next price category up (but ok due to extra output and load function), it seems noisier than the Siglent, and from some topics it might not quite deliver the promised specs.. question @ users: is the load of the GPP-4323 also programmable or just the outputs? (checked the manual but couldn't find any info on this)If anyone would have experience with either or even both would be great to give me some feedback.. other options are also welcome.. preferable closer to the price range of the Siglent SPD3303X-E.. (I've already excluded the Rigol as an option for now)

author: AVGresponding
author_rank: Super Contributor
timestamp: May 28, 2022, 08:36:09 am
content: I don't have any experience of the GW Instek but I have an RS Pro rebranded SPD3303X-E, and it was very easy to "hack" it to the 3303X using the firmware updater (extra digit of resolution for current).It's pretty good, quiet, much quieter than my old school HPAK supplies for sure!The only marginal issue I have is that the display sometimes has a momentary glitch, where it flicks from the set voltage to full. The output is not affected, and maybe mine just has a bad cap in the metering circuit somewhere or something (it was a used purchase from a bulk reseller).

author: nctnico
author_rank: Super Contributor
timestamp: May 28, 2022, 10:52:11 am
content: IMHO the biggest advantage of the GPP-4323 is having a numeric keypad to set values. I find this is a must have on a bench PSU; it makes life much easier.

author: mawyatt
author_rank: Super Contributor
timestamp: May 28, 2022, 01:59:50 pm
content: We have 3 of the SDP3303X-E all "enhanced" as mentioned for the extra resolution, and a GPP-4323. All are very quiet and good low noise outputs, excellent for lab use with precision circuits.The SDP3303X-E is our workhorse and generally the "Goto" supply for quick use, once you learn the idiosyncrasy of the controls.Value-wise it's hard to beat the SDP3303X-E, but if you actually required 4 isolated fully settable outputs then the GPP-4323 is likely the best value. Haven't used the load function on the GPP-4323 yet, so can't comment on this feature.We've mentioned before IF your intended use is in advanced electronics development use, don't discount your lab supply!! Folks often go on the cheap for the lab supply and suffer the consequences later. Things like overshoot on startup/shunt down, unstable outputs/settings, inaccurate settings, high noise and so forth should not be considered for precision lab supply use. For our work we require a very accurate current limit at low levels into the "ma" area (also very accurate voltage levels). Here you set the current limit slightly above the expected supply nominal circuit current demand so any abnormal current demand is limited, which is important in limiting the potential damage during testing/evaluation/troubleshooting of new circuits/chips, and this feature has saved our butt quite a few timesBest,

author: mawyatt
author_rank: Super Contributor
timestamp: May 28, 2022, 02:58:59 pm
content: BTW related to lab supply use is a common mistake everyone makes, the use of more shunt decoupling capacitance on the supply lines to reduce supply noise.Back in the late 70's tests were conducted to determine how much energy it takes to cause a chip failure/damage when the energy source is from the supply into the chip supply pin. These tests were conducted to help determine chip survivability during a nuclear event where pn junctions become forward biased and recall the result was 0.01 Joules. So this provides a limit on the direct capacitance on the supply pin near the chip.Using this criteria (likely even lower today) for example with a circuit using a 15 volt supply.Energy =< (C*V^2)/2C =< 2*Energy/V^2C =< 2*(0.01J)/15^2C needs to be less than 89uF with a 15 volt supply to have less than 0.01J of available energy.So where is this is going and how does it relate to lab supply use? We've all been guilty of just hanging more and more capacitance off the supply line to reduce supply noise, well beyond the required energy storage to damage the circuit/chip under test/evaluation. First off, we shouldn't be using a noisy supply where the supply noise needs serious filtering, and second we should use in-line decoupling to help the shunt capacitor, where in-line refers to series impedance. Adding a small series resistor in-line with the supply can provide a much larger impedance for the decoupling capacitor to work into, and thus require a smaller capacitor to achieve acceptable noise reduction. Of course there is a voltage drop across the series resistor which must be accounted for, but often if small this can be ignored or just bump the supply voltage up to compensate.Anyway, hope this helps from a long career of "been there done that" and suffered the consequences, so no need for others to fall into these trapsBest

author: nctnico
author_rank: Super Contributor
timestamp: May 28, 2022, 04:15:41 pm
content: In addition: IMHO it is very important that a bench PSU has an output enable/disable button or switch. That way the load can be powered up with the power supply being fully in control of voltage and current. I have modified quite a few power supplies to add such a switch.

author: Hexley
author_rank: Regular Contributor
timestamp: May 28, 2022, 04:58:23 pm
content: Quote from: FPdesign on May 28, 2022, 07:07:29 amSome comments by an owner of the GPP-4323:It is **very** quiet.It is also quite compact.I have not found it to miss any spec that I can recall. And its out-of-box calibration was excellent.It can be fully controlled remotely. You might take a look at "TestController" software by forum member HKJ. There is an extensive interface for the GPP-4323. See the attached screen shot for a picture of Channel 1 set to constant-resistance load mode using TestController, for example.I have been very pleased with the product.

author: FPdesign
author_rank: Contributor
timestamp: May 28, 2022, 05:27:58 pm
content: thanks everyone for your feedback so far!.. keep 'em coming..will be replying individually shortly.. have couple follow up questions on some of your responses but got to pop into meeting shortly..talk soon and thanks again

author: mawyatt
author_rank: Super Contributor
timestamp: May 28, 2022, 06:43:05 pm
content: Quote from: nctnico on May 28, 2022, 04:15:41 pmYes indeed, a single large Output ON/OFF Button is essential, and this is NOT the Mains Power On Switch!!In use, turn the Mains ON, set the desired Voltage/Current, then Turn the Output ON.Having a ALL OUPUT ON/OFF Single Button is also very important, especially when using multiple supply channels.Both the Single Channel and ALL Channel ON/OFF buttons are important as removing the Output(s) ASAP under"Emergency" conditions!!Both the supplies under discussion have both these important featuresBest,

author: FPdesign
author_rank: Contributor
timestamp: May 29, 2022, 02:25:14 am
content: @AVGresponding.. I will be doing the "upgrade" too for better resolution if I go with the Siglent@nctnico.. I don't need to change voltage as often as I'm working within same specs most of time (parameter recall will do the trick for most), so not having the numeric keypad wouldn't be a big loss.. plus it will be attached to my network and I still can use the remote app.. and yes I agree regarding enable/disable channel output options.. luckily both options listed have this..@mawyatt.. from reviews I hardly ever noticed the fan from the Siglent SPD3303X-E.. where on the GPP-4323 it was more noticeable.. obviously it's always hard to tell from videos (even when mics were used to test noise).. what is your personal experience here side by side?..with the Load function, I really need it to be programmable for load testing (over network at least, if not possible on device direct) otherwise I would have to get a dedicated DC load.. which would make the GPP-4323 less interesting, since I can do with only 3 outputs and spend the money on the extra device instead.. I'm hoping to get an answer from GW Instek soon.. or one of the other users.. should you have an update on this feel free to let me know..@Hexley.. thanks for that.. I am actually looking for a programmable load function for testing purposes.. I know the PP-4323 has a handy remote app and the DC outputs are programmable/sequencing (even running scripts over network), but I couldn't find anything mentioned regarding the Load function being programmable...thanks again for everyones input so far..

author: 2N3055
author_rank: Super Contributor
timestamp: May 29, 2022, 08:31:24 am
content: Quote from: FPdesign on May 29, 2022, 02:25:14 amWhile the load on GPP-4323 is interesting addition and can be useful for static testing, there is no dynamic testing capabilities and it is quite limited with capabilities. If you need to do some more elaborate testing you need to get a dedicated load instrument.

author: mawyatt
author_rank: Super Contributor
timestamp: May 29, 2022, 12:25:40 pm
content: Quote from: FPdesign on May 29, 2022, 02:25:14 amBoth are very quiet under light load.Haven't used the load function nor done any programming with the GPP-4323.2N3055 has a good recommendation, get the lower cost SDP3303X-E and a dedicated Electronic Load.Edit: Think Korad has some inexpensive Electronic Loads that OP might find useful, altho we've never used any Korad product.Best,

author: luudee
author_rank: Frequent Contributor
timestamp: May 29, 2022, 01:59:20 pm
content: Have you considered to use multiple RD6006P/RD6012P with a toroidal transformer(s)?Might be interesting home project. There is a group here that talks about those and variousways to implement them ...luudee

author: nctnico
author_rank: Super Contributor
timestamp: May 29, 2022, 02:39:16 pm
content: Quote from: luudee on May 29, 2022, 01:59:20 pmNot just no, hell NO! The OP specifies needing a low noise bench power supply. A switching power supply doesn't fit that bill at all. Been there, done that.Switching PSUs are great if you need lots of power / high currents for projects that need that or as an adjustable wall-wart. But for doing development of low power (analog) circuits the only way to go is a low noise linear power supply.

author: Hexley
author_rank: Regular Contributor
timestamp: May 29, 2022, 04:40:59 pm
content: Quote from: FPdesign on May 29, 2022, 02:25:14 am@FPdesign -When you say "the Load function being programmable", are you referring to something other than setting the load mode (CC/CV/CR) and adjusting the corresponding load parameter (load current/load voltage/load resistance)? Because all of that can be done either from the front panel or via SCPI commands remotely.If you are looking for ways to set load pulse timing and amplitude, those are of course not available intrinsically since the load is a DC load as noted by 2N3055 and Matt. You could probably send network commands to simulate that function, though the maximum speed allowed by the network/script would probably limit the function to millisecond resolution.Having said that, it is worth noting that the GPP-4323 has a sequencing function that lets it generate stepped control values. Perhaps those could be used to change load parameters automatically. But frankly, the instruction manual's description of the function is, to put it mildly, opaque. Making your own Python script to do the same thing over the network would probably be just as quick to implement. Maybe quicker.Finally, for reference -- the SCPI commands used to control the load are described on page 133 of the GPP-4323 user manual. To enable a constant voltage load on channel 2, for example, the command is :LOAD2:CV ON. Then the actual voltage level is set with VSET as described on page 130 -- for example, to set the load voltage to 10.000 on channel 2, the SCPI command is VSET2:10.000 . Similar commands are used to set up a CC load or a CR load.Hope that helps.

author: FPdesign
author_rank: Contributor
timestamp: May 30, 2022, 05:06:22 pm
content: @N3055.. yeah looks like I might just have to go with a dedicated DC Load.. would have been great an all-in-one device to save some desk space.. but no use if it is missing features I need..@mawyatt.. I'm leaning towards the SDP3303X-E now too.. 3 outputs is all I need for now, but I do need more from a DC Load than the PP-4323 seems to offer, so I rather safe the money and buy a dedicated device instead..@luudee.. I have looked into some of those budget options as well.. but I do need better specs than they can deliver.. and after buying multiple of them for the amount of outputs I need, I'm near the price of the Siglent anyway..@Hexley.. I'm talking about programming a sequence as you can do with the DC Output.. either on the device itself or via script over network (the later is what I usually do).. I have also been browsing through the manual but couldn't find anything further on the Load function besides "set and forget".. so one must assume programming/sequencing DC Load isn't an option on this device.. I did contact GW Instek but have yet to hear back from them..thanks everyone for your further input.. as always much appreciated!