3 channel PSU without problems - Page 1
Forum section: electronics / testgear

author: Jan Audio
author_rank: Frequent Contributor
timestamp: March 13, 2019, 04:30:30 pm
content: I have this Peaktech 1 channel PSU ( 6225a ).The display was showing all LEDS flashing, so the shop repaired it, and got no new warranty.It has been broken again, if i had new warranty they should have repaired it.This is against my rules, so i am advicing you : NEVER BUY ANY PEAKTECH.Ok the display is flashing, the PSU is still working, it would be easy to take another chance and buy 1 more of the same PEAKTECH 6225a to form a dual supply.I need a 3 channel PSU from high quality.I need -15v, +15v and switchable 5v or 3,3v.The only thing i like to buy is a R&S HMC8043, it cost very much.For the rest i only see problems, i youtubed some cheaper brands, and i only get error movies, i dont want these chinese shit again.The thing is i dont use all the fancy stuff in the HMC8043, i only like to power my circuit and have the milliamps readable per channel.Those newer R&S ( made in malaysia ) had also big problems, they are not really cheaper either.What type 3channel PSUdo you advice is worth the money ?

author: rsjsouza
author_rank: Super Contributor
timestamp: March 13, 2019, 05:01:32 pm
content: Despite the initial hurdles that were fixed by Keysight and their firmware, my Keysight E36312A has been quite a great performer.It has some nuisances, such as the fan that runs continuously, but I can live with that as long as I power down my bench after a day of work.

author: maginnovision
author_rank: Super Contributor
timestamp: March 13, 2019, 05:05:01 pm
content: My only 3 channel PSU is the rigol dp832A. My only problem so far is the inability to completely lock down the front panel. Results in people sometimes turning channels off or on that shouldn't be.

author: Jan Audio
author_rank: Frequent Contributor
timestamp: March 13, 2019, 05:23:56 pm
content: ThanksThe Keysight E36312A is as pricey as the R&S HMC8043, and im not a fan fan.The rigol dp832A is also pricey, and not trustworthy for me.For that money (i dont have) i would buy the HMC8043.I really like my peaktech 6225a exept that its broken,its small, makes no noise, decent looking.Why is it crap ?

author: rsjsouza
author_rank: Super Contributor
timestamp: March 13, 2019, 06:13:26 pm
content: Quote from: Jan Audio on March 13, 2019, 05:23:56 pmI agree the Keysight is very expensive, but its fan is not noisy at all.According to reports from experienced users around here, the Rigol is a great performer, has very reasonable quality and is quite inexpensive for the amount of features and power.Quote from: Jan Audio on March 13, 2019, 05:23:56 pmIt is crap because some minimal level of quality and reproducibility across a production run costs money. The design may even be good, but the quality erodes during production of such units.I think you need to better set your expectations. You ask which 3 channel power supplies are worth the money but I think you wanted to ask which 3 channel power supplies can have good quality and be had for cheap. If you don't have access to the used market, you will be hard pressed to fulfill all the conditions.

author: colorado.rob
author_rank: Frequent Contributor
timestamp: March 13, 2019, 06:25:38 pm
content: Siglent SPD-3303X-E?https://store.siglentamerica.com/product-category/dc-power-supply/spd3303x-series/

author: tautech
author_rank: Super Contributor
timestamp: March 13, 2019, 07:53:52 pm
content: Quote from: colorado.rob on March 13, 2019, 06:25:38 pmYep, good fit.To the OP, if watching any old videos on these please be aware the main LCD readout information was changed in firmware to give better info to the user.Only one of the Siglent websites shows how it looks now on their webpage:

author: kripton2035
author_rank: Super Contributor
timestamp: March 13, 2019, 07:56:06 pm
content: old used hameg 7042 or 8042 are rock solid. you can get some on ebay quite often in europe.

author: nctnico
author_rank: Super Contributor
timestamp: March 13, 2019, 08:52:00 pm
content: Quote from: Jan Audio on March 13, 2019, 04:30:30 pmI like my Keysight E36313A. The first batch did had a problem but Keysight took all of them back and fixed it for free. It has a fan but you can't hear it. What tipped the scale for me is that the E36313A (like the E36312A) has two current measurement ranges and the readout for both current and voltage is very accurate. The low current range is accurate to about +/-10uA with a 1uA resolution.

author: Jan Audio
author_rank: Frequent Contributor
timestamp: March 14, 2019, 02:47:18 pm
content: I did not see any second hand, exept still expensive.I buy second hand for lower then half the cheapest new price, i better not buy second hand at all, always buying broken stuff.I dont buy any siglent for sure, and this time also no chinese stuff no more, i almost forgot, thanks for reminding.

author: Jan Audio
author_rank: Frequent Contributor
timestamp: March 14, 2019, 02:49:30 pm
content: Quote from: rsjsouza on March 13, 2019, 06:13:26 pmSo i could take another gamble for €75,-Do you expect i will receive another soon broken unit ?

author: rsjsouza
author_rank: Super Contributor
timestamp: March 14, 2019, 05:35:27 pm
content: Quote from: Jan Audio on March 14, 2019, 02:49:30 pmJan, I really can't tell for sure. As you said, it is a gamble.However, depending on where you purchased it you could potentially see if there is the ability to issue free returns. If the power supply fails under the same conditions, you could always return it.I recall an old thread where folks discuss a very similar power supply as yours (at least it has the same looks) and it is highly regarded there.https://www.eevblog.com/forum/testgear/cheap-variable-switching-power-supply/https://www.eevblog.com/forum/testgear/mch-k305d-cheap-switching-lab-power-supply/The OEM is different, and that may make a difference in quality: MCH K305D, also seen as LW-K305D.

author: nctnico
author_rank: Super Contributor
timestamp: March 14, 2019, 07:29:05 pm
content: Quote from: rsjsouza on March 14, 2019, 05:35:27 pmCalling it 'highly regarded' isn't exactly the truth. Some are outright dangerous due to poor wiring and it pushes out a lot of EMI noise.

author: rsjsouza
author_rank: Super Contributor
timestamp: March 14, 2019, 07:39:24 pm
content: Quote from: nctnico on March 14, 2019, 07:29:05 pmI missed your post in the first thread. I guess you are right; the high frequency noise is not that great. The other factors are not that terrible, provided you inspect the supply beforehand.To the OP, I also have the AFR PS3005 - a clone of theQJE PS3005power supply. It is ok for general purpose work and I frequently stress it closer to its limit, although under these conditions I am not too concerned about ripple and noise.

author: AlanS
author_rank: Unknown
timestamp: March 15, 2019, 02:12:45 am
content: I too like my Keysight E36313A - I needed it urgently after a lightning strike took out my H24005 and they are not being made anymore. As testament to their value, I've only seen one come on to the used market since the strike.I understand that cost issue and would recommend the H25005 that Prasimix is working on. But I suspect it's a ways away. I'm sure it will be worth the wait though - the H24005 is fantastic.

author: 0culus
author_rank: Super Contributor
timestamp: March 15, 2019, 02:18:15 am
content: I like the Keithley 2231A, got it new. It doesn't have quite as many features as the highest model so it was considerably cheaper. It gives you 30V/3A out of channels 1 and 2, 5V/3A out of channel 3. Can connect 1 and 2 in series or parallel to get 60V or 6A, respectively. Easy to save and recall configurations too.

author: nctnico
author_rank: Super Contributor
timestamp: March 15, 2019, 03:03:48 pm
content: Quote from: blueskull on March 15, 2019, 02:23:21 amI don't think Dutch people are included in Wave2019.

author: bd139
author_rank: Super Contributor
timestamp: March 15, 2019, 06:25:06 pm
content: Don't know how much current you need but look at second hand HP/Agilent/Keysight E3630A.Silent, reliable, digital readout.

author: nctnico
author_rank: Super Contributor
timestamp: March 15, 2019, 06:41:56 pm
content: Quote from: bd139 on March 15, 2019, 06:25:06 pmBut it doesn't have current limiting. IMHO that is a crucial feature for a bench power supply. When I bring up a new circuit I set the limit to a low value to prevent any damage due to whatever error.

author: bd139
author_rank: Super Contributor
timestamp: March 15, 2019, 07:01:56 pm
content: As I said in another thread a lot of the time your DUT is dead from the output cap before the power supply feedback loop does anything about it. Have destroyed a few things with current limits turned on even to low values.Also it does have a hard current limit and foldback as well.

author: nctnico
author_rank: Super Contributor
timestamp: March 15, 2019, 07:23:42 pm
content: Quote from: bd139 on March 15, 2019, 07:01:56 pmNo. Not if you switch the PSU output on with the load attached. That way the current limit tracks the voltage ramp-up. I never attach a DUT to a PSU output which is on. First connect the DUT then switch the output on. All my PSUs have output enable switches (except one which I have not modified yet).

author: 2N3055
author_rank: Super Contributor
timestamp: March 15, 2019, 07:30:22 pm
content: How about TTi PL303QMT? Does anybody have it?

author: colorado.rob
author_rank: Frequent Contributor
timestamp: March 15, 2019, 07:44:39 pm
content: Quote from: 2N3055 on March 15, 2019, 07:30:22 pmI have the TTi MX100TP and am very happy with it. Certainly well worth the money to me. I suspect it it out of OP's budget but little has been said of budget other than the Hameg PSU being too expensive. If the R&S 8043 is outside of the budget, then I suspect the AIM/TTI ones are as well.

author: Jan Audio
author_rank: Frequent Contributor
timestamp: March 16, 2019, 02:18:58 pm
content: Quote from: nctnico on March 15, 2019, 06:41:56 pmIndeed, this i forgot to mention.I also looked and some models have the 5v channel also no current limiting.I like to have all 3 channels current limiting.Those TTi are very expensive also.

author: bd139
author_rank: Super Contributor
timestamp: March 16, 2019, 02:37:09 pm
content: Look at second hand PL320/PL330 supplies. They are dirty cheap and come in single double and triple varieties.

author: Jan Audio
author_rank: Frequent Contributor
timestamp: March 16, 2019, 03:23:41 pm
content: Quote from: 0culus on March 15, 2019, 02:18:15 amI assume it has current limiting.Looking good this one, i would go for that one now instead of the R&S.

author: ebastler
author_rank: Super Contributor
timestamp: March 16, 2019, 03:37:23 pm
content: @Jan Audio, you seem to be looking exclusively at the two far ends of the spectrum: el cheapo "Peaktech" on the one end, and expensive established brands (R&S or Keithley) on the other end.Nothing wrong with the established US and European brands, of course -- but you have already stated clearly that you cannot afford them. Hence, I think you should have closer look at the Chinese mid-range brands, like Rigol and Siglent. The Siglent SPD3303X-E, for example, should easily meet your requirements and is about half the price of the established brand models you have mentioned.

author: Jan Audio
author_rank: Frequent Contributor
timestamp: March 16, 2019, 03:59:32 pm
content: That is my problem : i checked all the cheaper ones on youtube and i get errors and failures.btw : the keithley is cheaper then the rigol or siglent.+ most stuff is also very very big.edit : I dont want to talk much more about how good the keithley is so the price dont go up.Now i have to save some money, in maybe 3 month i can buy, it cost 770 euros.

author: 0culus
author_rank: Super Contributor
timestamp: March 16, 2019, 04:13:40 pm
content: Quote from: Jan Audio on March 16, 2019, 03:23:41 pmYes it does. The current is limited to the number you set, from 0A to the rated output.

author: ebastler
author_rank: Super Contributor
timestamp: March 16, 2019, 04:22:44 pm
content: Quote from: Jan Audio on March 16, 2019, 03:59:32 pmHmm... which "errors and failures" did you see mentioned for the Siglent SPD3303X-E?(Honest question, since I am pondering buying one myself!)QuoteHow would 770 Euros for the Keithley be cheaper than 440 Euros (or 370 excl. VAT) for the Siglent?

author: Jan Audio
author_rank: Frequent Contributor
timestamp: March 16, 2019, 04:37:11 pm
content: You are right, the siglent with the 1milliamp resolution is € 610,00For 160 more you have a better brand.Just dont want any more chinese gambling.

author: 0culus
author_rank: Super Contributor
timestamp: March 16, 2019, 04:40:00 pm
content: The Keithley branded stuff is manufactured in China, but I have no complaints about the one I have.Manufacturing in China is highly dependent on how much oversight is given. If you don't give them careful oversight, they can and will find the absolute cheapest way to satisfy your requirements.

author: ebastler
author_rank: Super Contributor
timestamp: March 16, 2019, 04:42:35 pm
content: Quote from: Jan Audio on March 16, 2019, 04:37:11 pmYour choice, of course. But equating your Peaktech experience with Rigol and Siglent is misleading.Regarding the pricing: Since I am looking for a power supply for hobby use, I am considering Siglent's -E model with 10mV resolution, with the firm intent of applying the firmware "upgrade" to 1mV.

author: 2N3055
author_rank: Super Contributor
timestamp: March 16, 2019, 04:43:27 pm
content: Those Keithleys are basicaly Itech...They are not better deal than Siglent .But whatever you like..

author: Jan Audio
author_rank: Frequent Contributor
timestamp: March 16, 2019, 04:50:26 pm
content: Quote from: ebastler on March 16, 2019, 04:42:35 pmAh, that changes alot, €440,-

author: 0culus
author_rank: Super Contributor
timestamp: March 16, 2019, 04:50:35 pm
content: Either one is probably better than any of the "el cheapo" ones. To get a much higher end *new* power supply costs significantly more than I want to spend as a hobbyist. The EE department at my school has some of the Keithleys for grad students and researchers to use (undergrads have to use cheap ones haha) and they have apparently done well in service. I bought mine on recommendation from the guy who runs their labs.

author: Jan Audio
author_rank: Frequent Contributor
timestamp: March 16, 2019, 04:52:07 pm
content: Quote from: 2N3055 on March 16, 2019, 04:43:27 pmHi, what is the exact type-number for this one ?Do you have a link maybe.thanks

author: Jan Audio
author_rank: Frequent Contributor
timestamp: March 16, 2019, 04:55:21 pm
content: Quote from: 0culus on March 16, 2019, 04:50:35 pmIndeed, i cant justify the cost exept that i need it.It is not a oscilloscope with more advanced software, why does it cost so much ?

author: Jan Audio
author_rank: Frequent Contributor
timestamp: March 16, 2019, 04:58:14 pm
content: The siglent dont have the third channel milliamps limited.

author: 0culus
author_rank: Super Contributor
timestamp: March 16, 2019, 05:05:31 pm
content: Quote from: Jan Audio on March 16, 2019, 04:55:21 pmDesigning a power supply that won't explode isn't trivial, but clearly it can be done for affordable prices or the siglents/keithleys wouldn't exist. I don't have any experience with a really high end supply, but perhaps they are better calibrated? I don't know. There is a higher Keithley model than mine that has fancier remote control capabilities and costs about twice as much for the trouble. I didn't need those, so the choice was obvious.Quote from: Jan Audio on March 16, 2019, 04:58:14 pmI recommend getting the keithley, then. I got mine through ebay seller valuetronics_international. They are an authorized Keithley/Tektronix distributor as well as used test equipment and they are pretty flexible on price. They accept my best offer every time I've bought from them.

author: 2N3055
author_rank: Super Contributor
timestamp: March 16, 2019, 05:07:00 pm
content: https://www.welectron.com/ITECH-IT6302-Benchtop-Power-SupplyAnd PSU are more expensive to make because components are just expensive..

author: 0culus
author_rank: Super Contributor
timestamp: March 16, 2019, 05:11:39 pm
content: Or get the OEM one, that's fine too. Either way it's a major step up from the cheap shitty ones. I especially hate ones that have knob control that is super jumpy and makes it hard to set.

author: nctnico
author_rank: Super Contributor
timestamp: March 16, 2019, 05:12:10 pm
content: Looking at the Keithley / Tektronix PSU line-up I wonder which ones are designed by Keithley/Tektronix. I'm spotting other rebadges as well from GW Instek.

author: Jan Audio
author_rank: Frequent Contributor
timestamp: March 16, 2019, 05:19:06 pm
content: If the parts used inside are exactly the same, then i dont mind the brand.More links are welcome Nico.509,- i would buy the itech over siglent + hack for 440,-both chinese.Just need to be sure about the parts inside.

author: 2N3055
author_rank: Super Contributor
timestamp: March 16, 2019, 05:42:21 pm
content: for +- 30 V 2A and isolated 0-6V 5A you also have DP831 from Rigol...easy unlock to full res an all functions

author: bd139
author_rank: Super Contributor
timestamp: March 16, 2019, 06:32:19 pm
content: Or buy some Korads!

author: 2N3055
author_rank: Super Contributor
timestamp: March 16, 2019, 06:38:39 pm
content: Quote from: bd139 on March 16, 2019, 06:32:19 pmDespite your sarcasm, not even close...

author: bd139
author_rank: Super Contributor
timestamp: March 16, 2019, 06:41:27 pm
content: Worth a try

author: 2N3055
author_rank: Super Contributor
timestamp: March 16, 2019, 06:44:05 pm
content: Quote from: bd139 on March 16, 2019, 06:41:27 pmI wouldn't want it any other way..Have a good one..

author: Jan Audio
author_rank: Frequent Contributor
timestamp: March 17, 2019, 02:17:56 pm
content: Looks like the front panel buttons has the feel of a telefunken remote control, not very solid.

author: colorado.rob
author_rank: Frequent Contributor
timestamp: March 17, 2019, 05:20:58 pm
content: So,what exactly is your budget and what are your requirements? So far it sounds like you don't know what you require, just that you have opinions about what you dislike.

author: rsjsouza
author_rank: Super Contributor
timestamp: March 17, 2019, 05:46:57 pm
content: Jan, as I mentioned on the first page, an uncompromised solution does not exist, especially on a budget. If the Keithley's problem is on how its buttons look or feel, I think that is the least of your problems.

author: Jan Audio
author_rank: Frequent Contributor
timestamp: March 18, 2019, 03:28:08 pm
content: I,m going for this one if i have money.If this one is somewhere else cheaper then €509,- or from any brand, then i,m intrested.This one meet my requirements, i would like to pay 300, it seems this one is the best deal for 509.

author: rsjsouza
author_rank: Super Contributor
timestamp: March 18, 2019, 06:56:11 pm
content: Jan, given your restrictions have you thought about getting a good design and building one yourself? Although you may not have all the details figured out in your first design pass, you can always add modifications and features over time, which will save you from spending a great deal of money from the start.I did this a long time ago with my father, where we started with a somewhat basic design (18V 1A, single channel, no current limiting) and upgraded it over the years with additional features.

author: Jan Audio
author_rank: Frequent Contributor
timestamp: March 19, 2019, 02:33:55 pm
content: Ah that is a very nice reply.The problem is : i dont do 220 volt.I really would like to make such a thing, it can not be done without 220 volt ?If there is a way, maybe with a wall adapter that has 18 volt or more, i would like to do so.I dont mind if it has max 0,5A per channel when using a 1,5A wall adapter.My requirements :wall adapter input design0 to 15 volt for 2 channels0 to 5 volt for 1 channeldigital adjustablecurrent limitingexact readoutFirst i would try make a 1 channel version to get started.

author: rsjsouza
author_rank: Super Contributor
timestamp: March 19, 2019, 05:15:37 pm
content: Jan, the 220V portion of alinearpower supply is quite simple (switching power supplies are quite difficult and much more dangerous). It is basically a transformer in series with a fuse, a switch and both connected to the outlet.From that point and on, the rest of the circuit where the electronics part of the power supply will be located is quite safe - the transformer fully isolates you from the mains.If you want to embark in this adventure, I suggest you to read some of the references on the web about the theory of operation and design/assembly of linear power supplies. Two that I found interesting are:https://www.circuitlib.com/index.php/lessons/91-basic-linear-power-supply-circuits-designhttps://rsdacademy.net/textbooks/AnalogCircuits/Part1/PageSetup.php?Page=3There is also the alternative to start with an inexpensive 24V wall wart, where all the high voltage electronics are enclosed, and use linear or switching voltage regulators to generate the various voltages you need - the two references above have design examples of linear voltage regulators, but you can always find other designs or expand at a later time when you find yourself confident enough to experiment other topologies.Just be sure the wall wart has enough output power to provide for the output channels plus the inefficiencies of the voltage regulators.

author: Jan Audio
author_rank: Frequent Contributor
timestamp: March 19, 2019, 05:57:47 pm
content: Even if its simple and safe i always have bad luck and want no risk with 220v.I looked at the schematics and dont see how it measures the milliamps.i made a new topic here :https://www.eevblog.com/forum/projects/tripple-limited-bench-psu-(-digital-)-from-wall-adapter/