Advice on cheap Lab Supply 30v 5amps seen all the stuff on ebay best quality?

[dssence]

 hi guys just wanted to know if you can help me a bit on which Lab supply unit to buy in 30v 5amps I've seen a couple supplies on ebay , but then I checked reviews and one or another ppl say they're shitty. honestly I was looking in 100U$s range.  What should be a priority construction wise Transformers, Capacitors inside? fets?  I'm like in the middle of nowhere with all these chinese units.
  Do all these ones have overprotection. And do they adjust amperage accordingly with the device it's being connected ? or I do have to set current, and if it exceeds it says overload?

- http://www.ebay.com/itm/ATTEN-PROGRAMMABLE-PRECISION-VARIABLE-30V-5A-DC-POWER-SUPPLY-DIGITAL-LAB-GRADE-/181237126136?pt=LH_DefaultDomain_0&hash=item2a329313f8

- http://www.ebay.com/itm/ATTEN-Variable-DC-Power-Supply-APS3005S-30V-5A-LAB-/160684423343?pt=LH_DefaultDomain_0&hash=item256989b8af

- http://www.ebay.com/itm/MASTECH-HY3005D-DC-Power-Supply-Lab-Grade-Precision-Adjustable-30V-5A-Backlit-/330939884523?pt=LH_DefaultDomain_0&hash=item4d0d8de3eb

 TNX!
-

[pickle9000]

I bought one of these a couple weeks ago, build quality seems ok but in all honesty ask me in 6 months.

http://www.ebay.ca/itm/Hantek-Programmable-High-Precision-Lab-Bench-DC-Power-Supply-PPS2116A-/221265590812?pt=LH_DefaultDomain_0&hash=item338474fa1c

The big issue with ebay stuff is you never know what you are going to get so a bit of a gamble. In this case I went for it because I need a spare (fast) so this looked like a good gamble. So far so good.

[Pasky]

http://www.circuitspecialists.com/bench-power-supply-csi530s.html

Someone did a tear down of their 3A model and it turned out to be pretty good for the price.

[dssence]

Hey thanks seems a nice supply that one.. but the only way to know if it's good it's to make a tear down and see the inside caps and so on. What are you using it for ? did you make any load tests? Fan noise ? does it have a passive heatsink on the back.
   How long did it take to arrive. 
   I was looking at here .  https://www.circuitspecialists.com/bench-top-power-supplies  any advice?

[Pasky]

I don't own it, but I have been eyeing it for a couple weeks.

[dssence]

http://www.circuitspecialists.com/bench-power-supply-csi530s.html

Someone did a tear down of their 3A model and it turned out to be pretty good for the price.

 Thanks seems nice that one , kind of solid. But I'm looking something with overload protection and a couple more functions. Like enable output or disable. short protection etc.

[Pasky]

The more you want, the more you need to pay.

[nanofrog]

Between Atten and Mastech, Mastech has a better reputation.

That said however, would you have an issue buying a used PSU?

I ask, as you can get some excellent supplies, such as a well built triple output unit within your budget. One example I found, would be a Power Designs TP343A. It can't quite do 30V@5A, but it gets close (up to 5A @ 20V / 2A @ 25V / 1A @ 50V when the upper two supplies are tied together via tracking mode). Then there's the third supply at the bottom (0-6V @5A, or 0-15V@2.5A). Also has current limiting (set by the flat blade screws). A lot of PSU for the money, and worth considering IMHO.

Just a thought anyway.

[rdl]

Do they still make that Korad KA3005P?

[dssence]

hmm I've heard some bad things about the korad.. having issues .. and so on . What would be a good choice from all these from the list  100 bucks range  30volts 5Amps or more (overload protectin short circuit as well)

https://www.circuitspecialists.com/bench-top-power-supplies

[jwm]

I have had the MASTECH one for a while, It works just fine but I have some issues with the interface.

The separate fine/course knobs are fairly annoying, you find yourself jumping back and forth between them and it's easy to mess up. I would have prefered a single knob.
The displays always show whatever current/voltage is currently going through your device, so there is no good way to actually set specific limits on current/voltage without diddling with the knobs live, or beforehand with an open circuit for voltage and across a load for current. Plus I'd like an easy way to turn on and off the channel.

And one more random nit, the protective plastic was left over the lcd screens and was all bubbly. I had to disassemble the thing to get it out, everything seemed fine inside, but QA issues like that worry me a little.

Do models such as the hantek http://www.ebay.com/itm/Hantek-Programmable-High-Precision-Lab-Bench-DC-Power-Supply-PPS2116A-/221265590812  or atten http://www.ebay.com/itm/ATTEN-PROGRAMMABLE-PRECISION-VARIABLE-30V-5A-DC-POWER-SUPPLY-DIGITAL-LAB-GRADE-/181237126136 fix this?

Anyone know a cheap triple supply that has the ability to independently see the max voltage/current independently of the actual instantanious voltage/current?

[dssence]

I have had the MASTECH one for a while, It works just fine but I have some issues with the interface.

The separate fine/course knobs are fairly annoying, you find yourself jumping back and forth between them and it's easy to mess up. I would have prefered a single knob.
The displays always show whatever current/voltage is currently going through your device, so there is no good way to actually set specific limits on current/voltage without diddling with the knobs live, or beforehand with an open circuit for voltage and across a load for current. Plus I'd like an easy way to turn on and off the channel.

And one more random nit, the protective plastic was left over the lcd screens and was all bubbly. I had to disassemble the thing to get it out, everything seemed fine inside, but QA issues like that worry me a little.

Do models such as the hantek http://www.ebay.com/itm/Hantek-Programmable-High-Precision-Lab-Bench-DC-Power-Supply-PPS2116A-/221265590812  or atten http://www.ebay.com/itm/ATTEN-PROGRAMMABLE-PRECISION-VARIABLE-30V-5A-DC-POWER-SUPPLY-DIGITAL-LAB-GRADE-/181237126136 fix this?

Anyone know a cheap triple supply that has the ability to independently see the max voltage/current independently of the actual instantanious voltage/current?

That's the one I was also taking into account the atten supply. Is it good?. So the mastech HY3005D doesn't work quite well..
   do these lab supplies provide amperage to the device it's drawing towards it.. automatically? or you have to set up the current and if the device draws way more amperage than what you have setted it overprotects?

[pickle9000]

With the Hantek you can adjust voltage and current on the fly and before hookup without shorting the supply to set the current. It has an output on off switch. It also has overcurrent and overvoltage protection.

Main faults, electrolytics are not brand name so need replacing. Knob on case is not the best quality.

Pluses, very nice looking transformer, fan is temp controlled, case is very heavy gauge steel, grounding and soldering are good. 

[dssence]

With the Hantek you can adjust voltage and current on the fly and before hookup without shorting the supply to set the current. It has an output on off switch. It also has overcurrent and overvoltage protection.

Main faults, electrolytics are not brand name so need replacing. Knob on case is not the best quality.

Pluses, very nice looking transformer, fan is temp controlled, case is very heavy gauge steel, grounding and soldering are good.

 hey that's a really nice built and assembled supply from what I could see . But again I don't understand the following. Say I connect a device to the supply requiring 5amps and 5volts. If I set 5 volts on the supply and it starts requiring more than 5amps what's going to happen it overprotects? Or It starts auto adjusting the extra amperage required.
   Something else do you know if these units ship from Canada to the US through USPS ? Can you post me another supply as well but from the us itself. Tnx!

[pickle9000]

If your device tries to draw more current than what the supply is set for (lets say 1 amp) one of two things will happen. This again depends on the settings. First, in current limiting mode the supply will limit the draw to 1 amp. Overcurrent protection is a setting that act like a circuit breaker and turns disconnects the output. 

In the case of 5 amps the supply would limit the output to 5 amps because that is the maximum is can supply. Overcurrent is a separate setting and need not apply.

In a real life situation let's say you are testing a new circuit and you think it needs 200ma at 5 volts. You set your supply to say 240ma at 5 volts and the overcurrent protection for 300ma. You turn on the power and instantly it goes into overcurrent protection and the power is shut off. You have a problem, time to check the board and look for a short or other issue. If you had the current set to 5 amps and no overcurrent protection you would probably see some magic smoke.

[dssence]

If your device tries to draw more current than what the supply is set for (lets say 1 amp) one of two things will happen. This again depends on the settings. First, in current limiting mode the supply will limit the draw to 1 amp. Overcurrent protection is a setting that act like a circuit breaker and turns disconnects the output. 

In the case of 5 amps the supply would limit the output to 5 amps because that is the maximum is can supply. Overcurrent is a separate setting and need not apply.

In a real life situation let's say you are testing a new circuit and you think it needs 200ma at 5 volts. You set your supply to say 240ma at 5 volts and the overcurrent protection for 300ma. You turn on the power and instantly it goes into overcurrent protection and the power is shut off. You have a problem, time to check the board and look for a short or other issue. If you had the current set to 5 amps and no overcurrent protection you would probably see some magic smoke.

 I see ,so if I had a device drawing say 500ma 5volts, and I set the supply to 5volts ..then current to 600ma. and overcurrent protection at 700ma and the device draws 800ma , supply will protect itself cause I have setted overcurrent to 700ma?

[pickle9000]

Exactly.

[grumpydoc]

You set your supply to say 240ma at 5 volts and the overcurrent protection for 300ma

If you want the over-current protection to turn the supply off and protect your prototype from design or implementation cock-ups you need to set the overcurrent level lower than the current limit. Otherwise the voltage will collapse a bit but you'll still put 240mA (in this example) into your design - which might not be healthy for it.

[jwm]

Erf... I tried to read the manual of the Hantek one to figure out how it's max current/voltage interface works. this is what I found.

Open the power switch, set the voltage, press the VOL voltage adjust selection key, shows the digital voltage regulator tube is selected, the selected digital tube status in the flickering, spinning move ADJUST switch, variable voltage value of the size, again press the VOL voltage adjust selection keys can be selected to change the location of digital tube.

I guess the audiophiles will appreciate that there are not just tubes, but digital tubes!

[mrflibble]

curious. tube is chinglish for segment display or something? 

[rdl]

tube is chinglish for segment display or something?

Seems that way. They often refer to 7 segment LEDs as "digital tube display", very common to see this on eBay.

[pickle9000]

It takes about 60 seconds to learn how to operate, similar to Japanese style temp controllers. One handed operation.
Actual interface operation is fast, no complaints.



Interface Operation Instructions

Hantek PPS2116A Power Supply

Indicators

- A single flashing 7 segment digit indicates you are in set/adjust mode for that item (current or voltage adjust).
- M1-M6 are the memory storage indicators

Set knob / wheel

- When in set/adjust mode (single flashing digit) you can increase/decrease the set point. For example if 0.100 is displayed and the 1 is flashing you can adjust by .1 volts (up or down to the maximum or minimum voltage). One rotation of the knob is about 10 steps so in this case 1 rotation is about 1 volt.

VOL/CUR buttons

- Push once to enter set mode, push repeatedly to change the digit adjust position (1v,1/10th a and so on) then use the knob to adjust. I like to adjust by 1/10th of a volt so I leave it there. Same for current.

SHIFT

- Push SHIFT before M1-M5 to store settings.
- Push SHIFT before Output for overvoltage overcurrent store.

M1-M5

- Load stored settings.

OUTPUT

- Turn output on/off

[Pasky]

So is the general consensus here that the Hantek is the best linear power supply for the price at < $100?  I've been in need of a 3A-5A DC power supply and not sure what to get myself.

[GiskardReventlov]

I've been sort of looking for a power supply and I read this thread. I don't see any consensus here. But I know I will not get one of these Hantek or Atten or Other re-badged supplies.  It seems more risky to buy a new one of these then a used, known brand on ebay.  I've noticed that Dave has a Rigol dp832 but that has a serious issue that Rigol has ignored fixing (and a different price range). He also has a BK on his bench.  You can check his ebay store (or amazon?) and see what stuff he sells off it might be a indicator of what he considers a keeper.

ebay has thousands of PS listed, you can filter by location in miles to keep shipping cost down.

[pickle9000]

The Hantek:

The price is actually about 120 bucks shipping included (in Canada). If you expect to add 10-15 bucks to get a few good electrolytics you are at 135 bucks (CDN). It does have optically isolated usb control as well.

Will it last? I can't say time will tell, is it worth the money? Yes. Does it beat the other 100.00 chinese specials? For sure.

If you compare this to the Atten in the first post shipping in cost makes it 165.00 It does have a serial connection on it, requires install by the user, don't know about isolation. It beats it by virtue of the usb connection.

Will I recommend it? No, I think it's worth the money but that's as far as I will go.