Seeking advice on programmable power supply. - Page 1
Forum section: electronics / testgear

author: adauphin
author_rank: Unknown
timestamp: March 09, 2020, 03:16:54 am
content: I'm looking to add a DC PSU to the bench, will compliment a Rigol 1054Z, and Siglent SDG2042X. I would like to stay under $400 new or used, I would think I could find something capable of at least 5A but not sure what to look for in terms of options.Not sure if I should go with a linear or switching.I've looked at the SPD3303X-E, adequate amperage but I would like more however this will likely increase with cost, having 2 or more outputs is also ideal.Testing and building small projects is fine for 3A, I just want to speculate having 5-6A would offer more flexibility.I would think being able to be more accurate in the mV range is preferred over going over 3-4A and that I get.Not brand loyal, any input and criticism is greatly appreciated.

author: tautech
author_rank: Super Contributor
timestamp: March 09, 2020, 04:19:28 am
content: IMO having a SMPS as your main PSU is a mistake.SPD3303X and X-E outputs can be seriesed or paralleled for higher voltages or current. Check the datasheet.All outputs are also isolated for further flexibility. X-E can be 'improved' to X models for the higher resolution X models offer.

author: adauphin
author_rank: Unknown
timestamp: March 09, 2020, 06:15:16 am
content: Quote from: tautech on March 09, 2020, 04:19:28 amI was thinking linear was the way to go but had to ask.Quote from: tautech on March 09, 2020, 04:19:28 amGood to know, thank you. I will read over the datasheets.

author: electricMN
author_rank: Regular Contributor
timestamp: March 10, 2020, 06:56:15 pm
content: I got this linear power supply from Amazon for $210 a couple of years ago.https://www.amazon.com/gp/product/B012LMOI84/ref=ppx_yo_dt_b_asin_title_o08_s00?ie=UTF8&psc=1I've had no problems with it.

author: MarkF
author_rank: Super Contributor
timestamp: March 10, 2020, 07:14:32 pm
content: If you can live with a SINGLE output power supply, I have my eye on theSiglent SPD1305X 30V / 5A.

author: Plasmateur
author_rank: Regular Contributor
timestamp: March 10, 2020, 08:32:48 pm
content: Quote from: adauphin on March 09, 2020, 03:16:54 amYou are only missing one instrument for the perfect home tinkering setup. And it happens to be the power supply below.Code:Rigol DS1054Z 4CH O-ScopeSiglent SDG2042X 2CH AWGInstek GPP-4323 4CH DC power supply

author: gslick
author_rank: Frequent Contributor
timestamp: March 11, 2020, 01:09:48 am
content: Someone currently has a couple of HP/Agilent 66332A 0-20V/0-5A supplies for sale for $125 each. Single output, but doesn't get too much higher quality than that, if that is the sort of voltage/current range you need.https://www.eevblog.com/forum/buysellwanted/for-sale-(us)-trove-of-hpagilent-tektronix-wavetek-equipment/A new one of those from Keysight would cost you almost $3000.

author: J-R
author_rank: Super Contributor
timestamp: March 11, 2020, 09:21:00 pm
content: I picked up a great condition 66332A a while back for around that price. But then had to pay that much again for shipping.After some minor repairs, cleanup and full calibration, it's nice to have around. I like that it can both source and sink.Rated programming accuracy is 10mV, but after calibration I've found mine to be closer to 3mV with a display accuracy of +/- 1mV.Some negatives are that it's big, heavy, noisy and old. I couldn't get Keysight's bench software to work with it over the serial port (unsupported), although the sample program kind of works.

author: nctnico
author_rank: Super Contributor
timestamp: March 11, 2020, 10:24:10 pm
content: I can recommend replacing the fan from the 66332A with one from Noctua.

author: thm_w
author_rank: Super Contributor
timestamp: March 12, 2020, 12:54:56 am
content: SPD3303X $389 seems like the one.DP832 is $470, a bit above budget, unless it has something you'd really like.Quote from: Plasmateur on March 10, 2020, 08:32:48 pmIts $560 though.

author: Joel_l
author_rank: Frequent Contributor
timestamp: March 12, 2020, 01:30:16 am
content: I bought the SPD3303X-E and did the mod to make it an X ( don't remember what that was at the moment ). Been very happy with it.

author: nctnico
author_rank: Super Contributor
timestamp: March 12, 2020, 10:32:29 am
content: Quote from: thm_w on March 12, 2020, 12:54:56 amBut the GPP-4323 does have several advantages over the Rigol and Siglent which make it worth spending the extra money.

author: Gandalf_Sr
author_rank: Super Contributor
timestamp: March 12, 2020, 10:43:52 am
content: DP832 has a fully adjustable Ch3 which the SPD3303X-E does not; it only allows 3 voltages and a fixed3.2Acurrent limit. DP832 has a common ground for channels 2 & 3 which is a slight downside.I prefer the DP832 (which can easily be convinced that it's a DP832A) and feel it's worth the extra money.

author: thm_w
author_rank: Super Contributor
timestamp: March 12, 2020, 09:25:41 pm
content: Quote from: nctnico on March 12, 2020, 10:32:29 amIt very well may be, but suggesting a product 40% over budget without any justification would tend to be ignored.

author: adauphin
author_rank: Unknown
timestamp: March 13, 2020, 09:08:09 am
content: Sorry for the late reply, I appreciate the input. I'll try to address the replies.Quote from: electricMN on March 10, 2020, 06:56:15 pmI appreciate the link.Quote from: MarkF on March 10, 2020, 07:14:32 pmI think I want to go with 2 or more outputs, thanks though.Quote from: Plasmateur on March 10, 2020, 08:32:48 pmThat is a nice unit, but the 4323 is stretching the budget.... I waskindaconsidering upping the ante, but the SPD3303X-E having the option of the "X" is also looking good. With regards to my budget and my line of reasoning, is just the fact of encroaching on $600 right now with those models I feel it puts me in a different category to explore even higher-end models. In that case it would almost come down to the "X" model or the 4323 as the price is very close. So do I stay under $400, or when we're talking the 4323, do I look at models under $750-800? I honestly don't know if the 4323 would be the higher end of the under $600, or the lower end of the under $750..if that makes sense. Might be a whole other line of research on models.I do understand that the 4323 or the 3303X would be the last PSU I would likely need for some time. I don't mind if someone throws these ideas out, most times in this hobby I don't know what's comparable even if it's quite obvious.Quote from: gslick on March 11, 2020, 01:09:48 amI almost want to have it just for a secondary PSU, tempting. I feel it would satisfy many of my needs, but having those modern PSU's staring at me makes it difficult....Quote from: thm_w on March 12, 2020, 12:54:56 amI just wish the 832 had a normal 10-digit keypad and a large rotary dial independent of each other. Not a deal-breaker but I don't know why they designed it like that.I would like to have at least 2 outputs, 4 outputs with parallel dual channels is very appealing.I also looked at the GPP 3323 and 2323, but the price is so close I would just go with the 4323 between those 3.I'll look over all of these and try to come to a sensible conclusion....lol. Thanks again.

author: Gandalf_Sr
author_rank: Super Contributor
timestamp: March 13, 2020, 09:50:47 am
content: I have owned an SPD3303X-E and I still have aDP832DP832A. The round keypad is a non-issue IMHO, it works and I am not at all irritated by it; I also like the 'pie chart' display screen which is now my default. I didn't like the binding posts on the SPD3303X-E which were loose when using many common banana plugs - Siglent claim that was fixed but I'm not convinced, they sent me updated binding posts but they were the same as the ones already fitted - I sold the SPD3303X-E at a loss and don't miss it. The DP832 is a quality power supply, if my retirement savings account wasn't circling the bowl, I might buy another.

author: PTR_1275
author_rank: Frequent Contributor
timestamp: March 13, 2020, 10:00:25 am
content: The 66332A as mentioned previously is very similar to the 6632B. Hardware is the same, but the 66332a has some better measuring functions.I really like these supplies because they can sink or source current. Use 2 of them connected to a computer and you can program them to sweep voltage and current ranges to find efficiency of dc-dc converters for example.Also in the low current mode, very low current resolution. Great for measuring low currents without needing to get the multimeter out.If you buy one and get it shipped, make sure to ask the seller to pack lots of foam around it and cut a hole out for the knob on the front panel. Push that in with enough force and it smashes the VFD during shipping.

author: tautech
author_rank: Super Contributor
timestamp: March 13, 2020, 10:16:22 am
content: Quote from: Gandalf_Sr on March 13, 2020, 09:50:47 amWith common not isolated channels.From previous posts:Quote from: Gandalf_Sr on August 13, 2017, 10:23:09 am

author: Gandalf_Sr
author_rank: Super Contributor
timestamp: March 13, 2020, 10:44:54 am
content: But then I got buyers remorse...Quote from: Gandalf_Sr on March 06, 2018, 09:49:54 am

author: Gandalf_Sr
author_rank: Super Contributor
timestamp: March 13, 2020, 10:50:23 am
content: Quote from: tautech on March 13, 2020, 10:16:22 amI already observed that a bad point for the DP832 is that Ch2 and CH3 share the same ground but, as I've said before, it has yet to present a situation to me where I needed 3 rails and couldn't make it do what I wanted. Having a 3.2 Amp current 'limit' on Ch3 of the SPD3303X is far worse IMHO. There's also no display of Ch3 data on the SPD3303X-E display. For CH3 controls, you have a switch to select 2.5,3.3, or 5V and then an on/off button for the channel but the only 'protection' is 3.1A of circuit-frying current.

author: Gandalf_Sr
author_rank: Super Contributor
timestamp: March 13, 2020, 11:08:04 am
content: Quote from: blueskull on March 13, 2020, 10:49:07 amI believe you that that PSU is good but it's $287 for 1 channel.

author: k8byp
author_rank: Newbie
timestamp: March 13, 2020, 04:49:58 pm
content: "accurate in the mV range"What circuits will be used with this that require mV accuracy? My 'sense' (and pardon me if thats wrong..) is that you wont need much better than a couple tenths accuracy. If not, youll have a lot more to worry about that buying a brick - like lead lengths and room noise.Get a GOOD modern SMPS. Realize there is a lot of false information / beliefs out there about SMPS are inefficient/noisy/ etc. that are based on OLD SMPS designs.Modern SMPS are NOT walwarts these days, since, especially EU emission regulations have forced SMPS makers to much more tightly control their designs as far as noise goes.Notice the advices to not use SMPS are solely based on opinion- no reasons have been givenMeanwell is what I use. Darn good stuff. Made in very high quantity, including medical industry.Do linear PS have feedback networks to stabilize voltage to tenths of a volt? mV? Generally not. Linear supplies are often 'bulk" supplies. Very fast over-current limits? (thats important in design and testing!)If you want a real trick setup, get an AWG and use a power supply to amplify it. AWGs can output DC or various waveforms and if you want to simulate PS ripple or problems then an amplified AWG would allow that to be done. Use the AWG output to control the SMPS control input.

author: nctnico
author_rank: Super Contributor
timestamp: March 13, 2020, 05:22:43 pm
content: Quote from: k8byp on March 13, 2020, 04:49:58 pmMilli Volt accuracy is very necessary. Modern chips specify their supply voltages in tens of mV. If you want to power a 1.8V chip you'll want to make sure that the suppy voltage is within 10mV of what you set. And core voltages for processors are even lower. In one of my recent designs the core voltage switches between 0.9V and 1V depending on the processing load.If a PSU has accurate voltage and current measurements then you don't need extra DMMs to measure it. This is one of the reasons I got the expensive Keysight E36313A: it comes which 6 4.5 digit DMMs built in (with low and high range for the current).QuoteYou are wrong here. You can try it yourself by measuring sensitive signals from a circuit (with an oscilloscope for example) which is powered from a bench SMPS. Ground loops will make the noise from the SMPS show up on your oscilloscope. So for a generic bench PSU a switching power supply is not the best option. I have several lab grade switching bench PSUs which are great when I need a lot of power but when I need to measure small signals a linear power supply is necessary.

author: thm_w
author_rank: Super Contributor
timestamp: March 13, 2020, 09:27:25 pm
content: Quote from: adauphin on March 13, 2020, 09:08:09 amYep, I get it, its odd. If you don't think you will like it, I wouldn't buy one without demo'ing it.RD6006 has a normal laid out keypad:- Rigol: type in 1, ., 2, hit Volts- RD6006: press v-set, 1, ., 2, hit EnterNeither is clearly better or worse.Although I have 4 different keypad layouts in front of me right now so don't trust me (789, rigol round, 123, 123456)

author: Mr. Scram
author_rank: Super Contributor
timestamp: March 13, 2020, 09:37:10 pm
content: Quote from: nctnico on March 12, 2020, 10:32:29 amUnless you want people to assume you're just recommending a GW-Instek device due to being a fanboy you may want to elaborate on what these advantages actually might be. I can't seem to find reviews or people actually using one.

author: nctnico
author_rank: Super Contributor
timestamp: March 13, 2020, 11:00:52 pm
content: Quote from: Mr. Scram on March 13, 2020, 09:37:10 pmThis has been explained before: The Siglent PSU mentioned in this thread doesn't have a numeric keypad and a 3rd channel with a couple of fixed voltages and no adjustable current limit. The Rigol DP832 doesn't have fully isolated channels. The GPP-4323 has neither of these limitations. Second hit from Google:https://www.electrobob.com/gpp-4323-power-supply-review/BTW: If you really read my posts more carefully then you'd know I don't do fanboy-ism. You have brought that up several times now; it starts to look like some kind of personal vendetta.

author: Gandalf_Sr
author_rank: Super Contributor
timestamp: March 13, 2020, 11:20:49 pm
content: Methinks the nctnico doth protest too much

author: Mr. Scram
author_rank: Super Contributor
timestamp: March 14, 2020, 12:48:46 am
content: Quote from: nctnico on March 13, 2020, 11:00:52 pmEssentially every recommendation you make is some kind of GW-Instek kit and that happens in almost every thread asking for recommendations. Someone asks about a certain device and before long there's nctnico recommending a GW-Instek device. It's predictable to the point of being comedic. You also tend to discuss supposed disadvantages of devices of other brands ad nauseum, usually with a few other usual suspects pushing "their" brand. I don't care about you or your preferences but I do care about every thread being treated as a personal challenge and proving ground by a few people who consequently spam the thread with the same old preferences and discussion. At least one of the other usual suspects has learnt to behave and I'd hope the others can follow suit. The endless same discussion in endless threads is of no use to anyone. Not to the person asking and not to the rest of the visitors. I'm sorry for being blunt but I've grown tired of the brand turf wars.

author: aristarchus
author_rank: Regular Contributor
timestamp: March 14, 2020, 01:13:17 am
content: Just my opinion here.Got the DP832, since three years now.So far it does the job just fine, never seen the need for separate gnd on ch2, ch3.Also, although got accustomed using it via its front panel keys the first couple of years, nowadays using it via the UltraPower PC application find it really easy.(Changed it to DP832A already)Just my 2c

author: nctnico
author_rank: Super Contributor
timestamp: March 14, 2020, 01:38:18 am
content: Quote from: Mr. Scram on March 14, 2020, 12:48:46 amAnd? Point me to a thread where my recommendation is off-topic. Lots of threads where I recommend different brands. You won't find me recommending a GW Instek function generator for example. And I wasn't even the first to mention the PSU from GW Instek in this thread. FFSNo, this is just your personal vendetta based on... well, I don't care.