Author Topic: Choosing a PSU, what should I look for  (Read 3484 times)

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Offline Moriambar

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Choosing a PSU, what should I look for
« on: February 19, 2019, 07:37:19 pm »
Hey there.
I am in need of a PSU. The old unit that was gifted me (it has at least 30 years) is not enough anymore.
I usually do not do much power-stuff, and also am kinda on a budget (I can spend up to around 400€ if the benefits are so huge to justify that, but perhaps I do not need expensive things).

I basically need:
  • at least two outputs
  • at least two of the outputs should be able to go to ~20/30V
  • 2A are enough, although I know that 3A is usually quite standard. I normally do not need more than 1A
  • short circuit protection is ESSENTIAL since otherwise I would blow up everything after the first 10 minutes
  • perhaps, as a beginner, there's something else I need that I do not know
  • best if seller is europe-based

After gathering all these requirements, I found (on a seller website) the following products. I actually do not know how to choose because basically I cannot justify the price difference in any way. Also, albeit on a budget, I do not want to buy absolute crap. So here we are

Number one is a KORAD KD3305D (never heard of KORAD before) https://www.welectron.com/Korad-KD3305D-Labornetzteil_1 Datasheet. It's really cheap, and it seems to have everything I need, although I do not know whether it is ok/reliable.

Next is another KORAD, KA3305P https://www.welectron.com/Korad-KA3305P-Benchtop-Power-Supply Datasheet. It costs a little more. No clue what the difference is, apart from having a single knob instead of one knob per channel…

Now I've got a SIGLENT, SPD3303C https://www.welectron.com/Siglent-SPD3303C-Benchtop-Power-Supply . It costs almost 100€ more than the first Korad. Apart from the siglent brand, I do not know why since it delivers less power than the korad at a lower resolution too.

Finally, the monster, which is basically kinda an overbudget thing (but if it's remarkably better than the others I'm willing to make), the Siglent SPD3303X-E, which costs 2.5 times the first korad; https://www.welectron.com/Siglent-SPD3303X-E-Benchtop-Power-Supply datasheet. It seems that the price is justified by a nicer interface and a better connectivity which I do not care about, but perhaps there's more to it I'm missing.


So after all of this I actually do not know. Is there anything better out there for my purpose, that I simply ignored just going to one seller? Which one do you think is best for my needs?

Thanks to anyone who will help me choose and understand better. Cheers
 

Online KL27x

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Re: Choosing a PSU, what should I look for
« Reply #1 on: February 19, 2019, 09:19:04 pm »
The Korad "P" is programmable.

I use a Korad PSU. There's some overshoot when you first turn it on. That's a complaint that is common. Also, you can't instantly switch between two different voltage settings without cutting power. The relay turns off, and you have to turn it back on.


I broke my Korad, because the stupid encoder stopped working. I took it apart and put a drop of mineral oil in the encoder. But I decided to test it before putting it back together and shorted something on the front panel. (There are like 4 different PCB all screwed and plugged together, and when out of the housing hindsight shows there is one point that can short when the pcb's flop around in the headers).

After replacing the obviously burned out shift register, i find the encoder works perfectly, again. All the display and controls works, but something else broke and there's no output. I bought another... mostly because it proved good enough for me and I don't feel like re-learning how to use a new bench PSU. But my needs are very modest and this is the fanciest PSU I have ever used, so compared to the two other POS i have purchased that burned THEMSELVES up, I'm easy to please.
« Last Edit: February 19, 2019, 09:22:15 pm by KL27x »
 
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Offline sambonator

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Re: Choosing a PSU, what should I look for
« Reply #2 on: February 20, 2019, 12:03:37 am »
Some of the latest reviews on Amazon are negative.

https://www.amazon.com/KORAD-KA3305P-Programmable-Precision-Adjustable/dp/B012LMOI84

I opted to get a used GW Instek GPD-3303S instead. 
 

Offline Mr. Scram

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Re: Choosing a PSU, what should I look for
« Reply #3 on: February 20, 2019, 12:26:13 am »
Some of the latest reviews on Amazon are negative.

https://www.amazon.com/KORAD-KA3305P-Programmable-Precision-Adjustable/dp/B012LMOI84

I opted to get a used GW Instek GPD-3303S instead.
That GW-Instek is pretty sweet, but it's also in a different class and price bracket.
 

Offline MarkF

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Re: Choosing a PSU, what should I look for
« Reply #4 on: February 20, 2019, 01:03:43 am »
Here is a quick look at the GwInstek GPE-3323 and a short comparison to the Siglent SPD-3303X-En at the end.

   
 

Online Wolfgang

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Re: Choosing a PSU, what should I look for
« Reply #5 on: February 20, 2019, 01:21:31 am »
Hey there.
I am in need of a PSU. The old unit that was gifted me (it has at least 30 years) is not enough anymore.
I usually do not do much power-stuff, and also am kinda on a budget (I can spend up to around 400€ if the benefits are so huge to justify that, but perhaps I do not need expensive things).

I basically need:
  • at least two outputs
  • at least two of the outputs should be able to go to ~20/30V
  • 2A are enough, although I know that 3A is usually quite standard. I normally do not need more than 1A
  • short circuit protection is ESSENTIAL since otherwise I would blow up everything after the first 10 minutes
  • perhaps, as a beginner, there's something else I need that I do not know
  • best if seller is europe-based

After gathering all these requirements, I found (on a seller website) the following products. I actually do not know how to choose because basically I cannot justify the price difference in any way. Also, albeit on a budget, I do not want to buy absolute crap. So here we are

Number one is a KORAD KD3305D (never heard of KORAD before) https://www.welectron.com/Korad-KD3305D-Labornetzteil_1 Datasheet. It's really cheap, and it seems to have everything I need, although I do not know whether it is ok/reliable.

Next is another KORAD, KA3305P https://www.welectron.com/Korad-KA3305P-Benchtop-Power-Supply Datasheet. It costs a little more. No clue what the difference is, apart from having a single knob instead of one knob per channel…

Now I've got a SIGLENT, SPD3303C https://www.welectron.com/Siglent-SPD3303C-Benchtop-Power-Supply . It costs almost 100€ more than the first Korad. Apart from the siglent brand, I do not know why since it delivers less power than the korad at a lower resolution too.

Finally, the monster, which is basically kinda an overbudget thing (but if it's remarkably better than the others I'm willing to make), the Siglent SPD3303X-E, which costs 2.5 times the first korad; https://www.welectron.com/Siglent-SPD3303X-E-Benchtop-Power-Supply datasheet. It seems that the price is justified by a nicer interface and a better connectivity which I do not care about, but perhaps there's more to it I'm missing.


So after all of this I actually do not know. Is there anything better out there for my purpose, that I simply ignored just going to one seller? Which one do you think is best for my needs?

Thanks to anyone who will help me choose and understand better. Cheers

Why no RIGOL DP832 on your list ? Does more than you asked for, fully programmable, long enough on the market for the bugs to be gone. I like it !
 

Offline sambonator

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Re: Choosing a PSU, what should I look for
« Reply #6 on: February 20, 2019, 01:46:59 am »
Some of the latest reviews on Amazon are negative.

https://www.amazon.com/KORAD-KA3305P-Programmable-Precision-Adjustable/dp/B012LMOI84

I opted to get a used GW Instek GPD-3303S instead.
That GW-Instek is pretty sweet, but it's also in a different class and price bracket.
Yes... so I qualified it with the word "used"  ;)
 

Offline Calvin

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Re: Choosing a PSU, what should I look for
« Reply #7 on: February 20, 2019, 02:34:59 am »
Hi,

I recently bought me the Siglent SPD3303C and I'm very happy with it.
It,s accurate, stable and well behaved.
So far I haven't seen any overshoot or glitches that may be a danger to the load.
Output voltages remain comfortably stable under load (for a non remote sense supply) and noise is low.
It certainly is short circuit proof .... the manual asks You to short the supply rails when testing OCP function.
It's easy and intuitive to handle ... the front face layout is arranged logically.
I prefer to have a knob to easily and quickly change values instead of keypads .
I also prefer good old 7-segment displays ... possibly in different colors for voltage and current .... easy to read at a short glance ... keep it clean and simple ... You want information, not a light show.
The afore mentioned Rigol for me is a prime example of how not to design the UI of a 'tool'.
The cooling fan of the Siglent remains quite low in volume until You draw considerable power.
It offers some basic programming capability through a couple of front face buttons and a bit more refined ones via the web control.
The Siglent does cost more than the Korad, but I've the feeling, that below it's budget Youre taking the risc of buying too expensive .... i.e chances are growing You buy an accident-to-happen instead of a decent device ... quality comes at a price.

regards
Calvin

 
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Offline Moriambar

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Re: Choosing a PSU, what should I look for
« Reply #8 on: February 20, 2019, 07:12:00 am »
Some of the latest reviews on Amazon are negative.

https://www.amazon.com/KORAD-KA3305P-Programmable-Precision-Adjustable/dp/B012LMOI84

I opted to get a used GW Instek GPD-3303S instead.
Wow that costs 3x the base Korad and 2x the Siglent... at least in Europe I only found that at farnell for 500€ (excl VAT). That's way out of budget

As per the "used" bit: I don't know: I kinda need it quick and do not have the time to wait for an used offer (and also pray that it works!)
Thanks anyway
« Last Edit: February 20, 2019, 07:15:06 am by Moriambar »
 

Offline Moriambar

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Re: Choosing a PSU, what should I look for
« Reply #9 on: February 20, 2019, 07:13:27 am »
Hey there.
I am in need of a PSU. The old unit that was gifted me (it has at least 30 years) is not enough anymore.
I usually do not do much power-stuff, and also am kinda on a budget (I can spend up to around 400€ if the benefits are so huge to justify that, but perhaps I do not need expensive things).

I basically need:
  • at least two outputs
  • at least two of the outputs should be able to go to ~20/30V
  • 2A are enough, although I know that 3A is usually quite standard. I normally do not need more than 1A
  • short circuit protection is ESSENTIAL since otherwise I would blow up everything after the first 10 minutes
  • perhaps, as a beginner, there's something else I need that I do not know
  • best if seller is europe-based

After gathering all these requirements, I found (on a seller website) the following products. I actually do not know how to choose because basically I cannot justify the price difference in any way. Also, albeit on a budget, I do not want to buy absolute crap. So here we are

Number one is a KORAD KD3305D (never heard of KORAD before) https://www.welectron.com/Korad-KD3305D-Labornetzteil_1 Datasheet. It's really cheap, and it seems to have everything I need, although I do not know whether it is ok/reliable.

Next is another KORAD, KA3305P https://www.welectron.com/Korad-KA3305P-Benchtop-Power-Supply Datasheet. It costs a little more. No clue what the difference is, apart from having a single knob instead of one knob per channel…

Now I've got a SIGLENT, SPD3303C https://www.welectron.com/Siglent-SPD3303C-Benchtop-Power-Supply . It costs almost 100€ more than the first Korad. Apart from the siglent brand, I do not know why since it delivers less power than the korad at a lower resolution too.

Finally, the monster, which is basically kinda an overbudget thing (but if it's remarkably better than the others I'm willing to make), the Siglent SPD3303X-E, which costs 2.5 times the first korad; https://www.welectron.com/Siglent-SPD3303X-E-Benchtop-Power-Supply datasheet. It seems that the price is justified by a nicer interface and a better connectivity which I do not care about, but perhaps there's more to it I'm missing.


So after all of this I actually do not know. Is there anything better out there for my purpose, that I simply ignored just going to one seller? Which one do you think is best for my needs?

Thanks to anyone who will help me choose and understand better. Cheers

Why no RIGOL DP832 on your list ? Does more than you asked for, fully programmable, long enough on the market for the bugs to be gone. I like it !

More than 100€ out of budget, that's why. It costs around 500 + VAT
 

Online Wolfgang

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Re: Choosing a PSU, what should I look for
« Reply #10 on: February 20, 2019, 11:00:27 am »
OK, thats the list price. With 20% off, you would be in target, almost.
 

Offline Moriambar

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Re: Choosing a PSU, what should I look for
« Reply #11 on: February 20, 2019, 12:11:36 pm »
OK, thats the list price. With 20% off, you would be in target, almost.
500+VAT in italy is 610€ (albeit on ebay I find it for over 600€); so it would be 488 with 20% off (if one can find that: do you have any hints on where to look for it?). It's still over my budget by almost 100€.
It could be nice, I trust you, but it's simply too expensive unfortunately. I could do with about 40% off!

Thanks for the idea. But let me renew the question: do you know where to find PSUs with 20% off?

Cheers
 

Online Wolfgang

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Re: Choosing a PSU, what should I look for
« Reply #12 on: February 20, 2019, 01:07:41 pm »
... one of the good occasions is the Ham Radio Fair in Friedrichshafen. RIGOL has a big stand there ...
And they gave 20% off to all purchases done there. I bought quite some stuff from them, and I am satisfied with most of their equipment.
 

Offline Moriambar

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Re: Choosing a PSU, what should I look for
« Reply #13 on: February 20, 2019, 01:11:32 pm »
... one of the good occasions is the Ham Radio Fair in Friedrichshafen. RIGOL has a big stand there ...
And they gave 20% off to all purchases done there. I bought quite some stuff from them, and I am satisfied with most of their equipment.

Well, I'm not exactly near it (around 600Km trip) but still it would cost too much for me, as I pointed out before. That's unfortunate, I know, but I'm poor  :-//
I'm open for donations though :D
 

Online Wolfgang

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Re: Choosing a PSU, what should I look for
« Reply #14 on: February 20, 2019, 01:21:20 pm »
another try would be Batronix. Full price is about 500€, but you could ask for an offer. And shipping in Europe is free.
 

Offline Moriambar

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Re: Choosing a PSU, what should I look for
« Reply #15 on: February 20, 2019, 03:04:14 pm »
another try would be Batronix. Full price is about 500€, but you could ask for an offer. And shipping in Europe is free.
Well, perhaps I will, but I doubt they will say "look: an unknown Italian customer wants a single unit! Let's give this to him with a 25% discount!"
But one can never know :)
 

Offline Calvin

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Re: Choosing a PSU, what should I look for
« Reply #16 on: February 21, 2019, 06:17:33 am »
Hi,

The Rigol simply doesn´t look like a decent tool, but rather like "Transformers-meet-Hello-Kitty".
If I were CEO and had two little Kids, a girl and a boy and asked them to design a power supply front face .... I think something looking like the Rigol could emerge.  :-DD
Hey Rigol ... keep it clean and simple ... we need tools not toys!  :box: :box:

jauu
Calvin
 

Online Wolfgang

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Re: Choosing a PSU, what should I look for
« Reply #17 on: February 21, 2019, 11:21:11 am »
... I would rather not buy electronic equipment based on aesthetics. For the purists there is a monochrome version (DP832 without A).
 

Online rstofer

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Re: Choosing a PSU, what should I look for
« Reply #18 on: February 21, 2019, 07:57:59 pm »
... I would rather not buy electronic equipment based on aesthetics. For the purists there is a monochrome version (DP832 without A).

And also without the extra digit of resolution.
I think the 832 can be unlocked to get that extra digit of resolution but I don't know if that allows for the color display.  Probably not.
I simply don't care enough about the extra digit to unlock mine nor do I care enough to pay more than twice as much.
 

Online rstofer

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Re: Choosing a PSU, what should I look for
« Reply #19 on: February 21, 2019, 08:29:03 pm »
Hi,

The Rigol simply doesn´t look like a decent tool, but rather like "Transformers-meet-Hello-Kitty".
If I were CEO and had two little Kids, a girl and a boy and asked them to design a power supply front face .... I think something looking like the Rigol could emerge.  :-DD
Hey Rigol ... keep it clean and simple ... we need tools not toys!  :box: :box:

jauu
Calvin

Ever used one for any length of time?

I can enter voltage and current values with the keypad in terms of mV, V, mA, A depending on a button push.  I can tweak these values with the rotary encoder.

I can select which of the 3 channels gets adjusted and I can set voltage, overvoltage limit, constant current and overcurrent shutdown values.  There is a difference between constant current setting and overcurrent shutdown.  If the DUT hits the overcurrent or overvoltage limit, all channels shut down immediately.  And I can see all 12 of these settings at all times.  Further, I don't have to short the output to make the current settings with some kind of potentiometer, all values are set digitally.  12 settings...

I also get a larger display of output voltage, current and watts.  For all 3 channels simultaneously.
So, we have 21 different values constantly displayed, try that with 7 segment displays.

The only thing I find objectionable is the fact that I have to confirm with a second button press that I want to turn on all 3 channels simultaneously.  Not a big deal but, gee, I just pushed the All on/off button, let's get it done already!  I understand why it is done so I will get over it.

In any event, the DP832 is probably out of the price range so it really doesn't matter.


 
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Offline Moriambar

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Re: Choosing a PSU, what should I look for
« Reply #20 on: February 21, 2019, 08:35:31 pm »
In any event, the DP832 is probably out of the price range so it really doesn't matter.
Exactly.
Albeit it's interesting to see other units (and get envious for not being able to afford them), really there's no way for me to get that psu, so for this topic is immaterial how good it is.

Anyway, in a couple of days I'll decide, but I probably will choose the SPD3303C, because it seems the best I can afford apparently (and especially among the ones I suggested), unless something else pops up.

Cheers
 

Online rstofer

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Re: Choosing a PSU, what should I look for
« Reply #21 on: February 22, 2019, 01:22:57 am »
It should be fine!
 

Online james_s

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Re: Choosing a PSU, what should I look for
« Reply #22 on: February 22, 2019, 04:47:12 am »
If I were going to spend that much, I'd be looking at a nice used HP/Agilent, Tektronix, etc rather than low end Chinese brands.
 

Offline Moriambar

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Re: Choosing a PSU, what should I look for
« Reply #23 on: February 22, 2019, 07:20:51 am »
If I were going to spend that much, I'd be looking at a nice used HP/Agilent, Tektronix, etc rather than low end Chinese brands.
Well, apart from finding the used ones (much easier in the us than in europe), one never knows how good the conditions of used stuff is.
I am surely not capable of a repair, and I think that buying a used unit for 300€ and then find out that is broken is basically throwing away the money (and I cannot afford it).
Also I wouldn't be able to choose the specs.
BUT.
If you want and can help me regarding used stuff I can think about it, although I feel it risky since it's basically all the money I got.
The baseline is: I need an at least dual channel psu. I cannot afford more than 300-400€ max all included.

Cheers
 

Online rstofer

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Re: Choosing a PSU, what should I look for
« Reply #24 on: February 22, 2019, 08:20:18 am »
At some point, choosing equipment by consensus is a waste of time.  Everybody likes what they have, they dislike what they just got rid of (with reason) and it all breaks down with no definitive answers.  There is always something just a little better for a little more money.  And buying used is truly a risk.  Sometimes it works out, sometimes not so much.  Sellers almost never pay return shipping so you are out money even if you can send it back.

Drive a stake in the ground, buy something and don't look back.  Years from now, if you need something else, sell what you have and buy it.   In the meantime you will have gotten years of usage and gained a real awareness of what you like or dislike in some type of equipment.

 
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