Cheap bench power supply?

[nctnico]

What do you think of the measures shown in this video to reduce the noise?

He stole my idea from EEVblog! That is what I think  I did exactly the same (and more) to a similar PSU and posted the results here.

But the noise still is too high for use as a bench supply if you want to make measurements in a circuit

[Aldo22]

He stole my idea from EEVblog! That is what I think 

Then it can't be all that wrong. 

I did exactly the same (and more) to a similar PSU and posted the results here.

Where exactly is "here"?

Thank you.

[Wallace Gasiewicz]

You can also use a probe like that with a spectrum analyzer to locate source of a specific frequency that concerns you..  I do it all the time.  You can even use a probe that contacts a crystal to see its freq. Just touch the probe to the xtal can. The signal is too small for a scope but a spectrum picks it up.
Fix looks pretty good.   
But here you have how much test equipment and stock of parts to get a switching supply under control?   
Then you would have to test it with different loads and different power levels.To avoid this problem get a linear supply at first. Even an old one with analog meters.  You can always check your voltage with a voltmeter. 
Now, if you plan on using things that have USB power it would be nice to have these outputs on your PS.

[Randy222]

What about the Matrix line of PSU's? Some appear to look like the Korad's

And then, I always wondered what you can get from a kit like this, but you add in some filtering on the output.
https://www.aliexpress.us/item/3256801871857454.html

I am eyeballing this dc-dc set (style) because I might actually place the psu unit under my work desk, then cable to the controller using a shielded cable. I need small footprint on desk workspace.

[DaneLaw]

What about the Matrix line of PSU's? Some appear to look like the Korad's

And then, I always wondered what you can get from a kit like this, but you add in some filtering on the output.
https://www.aliexpress.us/item/3256801871857454.html

I am eyeballing this dc-dc set (style) because I might actually place the psu unit under my work desk, then cable to the controller using a shielded cable. I need small footprint on desk workspace.

Your link is sadly region-restricted.
A shame how Aliexpress gone bananas with their listing region-restrictions for certain continents here in 2024.

[shapirus]

Your link is sadly region-restricted.
A shame how Aliexpress gone bananas with their listing region-restrictions for certain continents here in 2024.

That's really weird, for me it opens, but says "This product can't be shipped to your address. Select another product or address. "

Anyway, it's not unique, search for "rd6006 kit" or "rd6006 set"

https://www.aliexpress.com/item/1005006144878911.html
https://www.aliexpress.com/item/1005006140421543.html
https://www.aliexpress.com/item/1005005902055333.html

etc.

(it's not exactly cheap though, when it includes the case and AC/DC PSU)

[Randy222]

Does this link work ?

https://www.aliexpress.com/item/1005002058172206.html?gatewayAdapt=4itemAdapt

They appear to ID a country source and then dump you through a "gateway".

[DaneLaw]

Does this link work ?

https://www.aliexpress.com/item/1005002058172206.html?gatewayAdapt=4itemAdapt

They appear to ID a country source and then dump you through a "gateway".

No it's the same, I think its an EU thing that got even more extreme here in 2024 and Aliexpress is locking out tons of listings.. though I have tried to log out of my account and then connect to Aliexpress through a VPN so my IP in theory should bounce in another continent, but even then many of these listings will simply not display and gives the screendumps above.

Its a shame as some of my saved items are here in 2024 behind this regionwall posted above, which gives no information about the product.
Even though a given seller could still ship it, with the purchase of another item at the same price-level, I still need to be able to see the listing.

Maybe if one made a new proforma account on Aliexpress, and put in a fake address in a given country, and just used that account solely for searching & looking around in Aliexpress.
But I don't know which country has the widest latitude for being able to see listings on Aliexpress, but this region's & censoring restrictions are problematic.

But I reckon it's sadly another EU-thing (unless other people in the EU can access links like the one above) weirdly many items on Aliexpress are now in 2024 forbidden to be displayed for people in my location (DK/EU)
Same with the seller I purchased the Rigol DG800PRO from in Nov. 2023 - here in the first weeks of 2024  90% of all his listings were suddenly behind this wall "not valid for people in your location"
He asked Aliexpress and they explained that there were new certification rules that took effect in 2024 for people in certain regions.. though he would try to counter that..

[Aldo22]

From Switzerland it is different.
I can see the products on all 4 links.
I can also order the products of the last 3 links.

Only the first one says:

This product can't be shipped to your address.
Select another product or address.

[orzel]

Anyway, it's not unique, search for "rd6006 kit" or "rd6006 set"

Dave did few videos about those, starting with this one i think: https://odysee.com/@eevblog:7/eevblog-1265-53-360w-lab-bench-psu:6

[DaneLaw]

From Switzerland it is different.
I can see the products on all 4 links.
I can also order the products of the last 3 links.

Only the first one says:

This product can't be shipped to your address.
Select another product or address.

Yep, but neither you [Switzerland] nor Shapirus [Ukraine] ain't based in the EU, and why I wonder if it's an EU restriction? or maybe it's simply country-based as its tragicomic how a quarter of my wishlists on Aliexpress with tech products that suddenly at the year turn is now being restricted to the point you can't see the listing anymore, only a locked-out to your region banner..
But in regards to links above, its solely this link from early posts - and if other users in the EU could access it. https://www.aliexpress.com/item/1005002058172206.html?

// VPN (Brazil) + incognito mode.. seems to do the job, same as Ukraine VPN + incognito.

[tautech]

He stole my idea from EEVblog! That is what I think 

Then it can't be all that wrong. 

I did exactly the same (and more) to a similar PSU and posted the results here.

Where exactly is "here"?

Thank you.

Probably this one:
https://www.eevblog.com/forum/testgear/cheap-variable-switching-power-supply/

[thm_w]

I haven't tried this one yet, but it looks interesting for people that need more voltage: https://www.amazon.com/dp/B0C89F4XJY/

Yeah it looks quite good, and it's btw a lot cheaper (about $35) on Ali. I might build a second unit to serve as a second channel, will see. However when you add the price of an AC/DC PSU... it may well be that getting the ready made one (I am sure they make ones already with a case and AC/DC supply) will cost the same, if not less, not to mention that it's easier. Building my first one was fun, but it was just enough of that particular kind of fun for me .

One of the major reasons to get these is if you have a spare PSU laying around. Usually at work or through friends you can find old laptop bricks (20V 10-20A) or server PSUs, etc. that are no longer used. I didn't bother with a case just mounted it on a flat sheet. But you could 3D print a case or just back cover I guess.

The Riden are way more expensive but offer proper battery charging relay + custom firmware. Wish some would come out with LXI though instead of dumb stuff like a handheld remote and weather screensaver .

https://www.aliexpress.us/item/3256803286017579.html 60V 12A Riden $100
https://www.aliexpress.com/item/1005003432603471.html 60V 12A WEGE $40
https://www.aliexpress.com/item/1005004945384897.html 60V 14A XY6014 $40

[Randy222]

These dc-dc front ends (choppers) are noisy though.
Most are buck type, be nice if some could be buck/boost types.

[thm_w]

These dc-dc front ends (choppers) are noisy though.
Most are buck type, be nice if some could be buck/boost types.

Riden is Buck->linear reg.. I don't have the other brands handy so not sure, but I assume would be similar.
You could get a generic buck/boost and put it before the Riden, but for me there is no point, just series a few scrap supplies together.

[shapirus]

Riden is Buck->linear reg..

Are you sure? Which one? The RD60xx series looks just like a usual adjustable DC/DC switching converter.

[slybunda]

I do have spare laptop power adapters lying around, some hp 65w ones and dell too

[Randy222]

Riden is Buck->linear reg..

Are you sure? Which one? The RD60xx series looks just like a usual adjustable DC/DC switching converter.

Even if it were, the chopper noise is fairly large, unless RD has made some changes to their ckt's.
However, from that Dave vid, the noise appears to be ringing from silicon on/off cycles, which can perhaps be mitigated with a designed snubber. Placing it onto the PCB might however be a challenge.

[thm_w]

Riden is Buck->linear reg..

Are you sure? Which one? The RD60xx series looks just like a usual adjustable DC/DC switching converter.

Yeah you are correct, its just buck, thought there was something else under the heatsink..

Even if it were, the chopper noise is fairly large, unless RD has made some changes to their ckt's.
However, from that Dave vid, the noise appears to be ringing from silicon on/off cycles, which can perhaps be mitigated with a designed snubber. Placing it onto the PCB might however be a challenge.

I also recall some of the noise was injected from the source PSU. As people had varying results depending on what was used.
You are right the ringing noise is large. I'll see about testing a snubber.

[Randy222]

Riden is Buck->linear reg..

Are you sure? Which one? The RD60xx series looks just like a usual adjustable DC/DC switching converter.

Yeah you are correct, its just buck, thought there was something else under the heatsink..

Even if it were, the chopper noise is fairly large, unless RD has made some changes to their ckt's.
However, from that Dave vid, the noise appears to be ringing from silicon on/off cycles, which can perhaps be mitigated with a designed snubber. Placing it onto the PCB might however be a challenge.

I also recall some of the noise was injected from the source PSU. As people had varying results depending on what was used.

Not in the Dave vid. Noise from the dc-dc lunchbox PSU showed no additional noise.
It however just looked like ringing when the silicon turns off, basic LC ringing which (I think) can be dealt with fairly easy with snubber. I had a similar issue of ringing from a fet that was sinking large inductive load. I managed to squash the ringing with correct snubber.

The dandy RD buck chopper is like buying a project even before you get to use it.

[nctnico]

He stole my idea from EEVblog! That is what I think 

Then it can't be all that wrong. 

I did exactly the same (and more) to a similar PSU and posted the results here.

Where exactly is "here"?

Thank you.

Probably this one:
https://www.eevblog.com/forum/testgear/cheap-variable-switching-power-supply/

Indeed but in the meantime I have decided to retire both power supplies I mentioned in this thread (I never even turned the 10A version on). I got a few Rek and Gophert power supplies for use as adjustable wall-warts: https://www.eevblog.com/forum/testgear/rek-kps6003-and-gophert-nps-1602-60v-3a-psu-hack-review/msg3336994/#msg3336994. The formfactor makes it easier to stack these.

But these are switchers as well so I don't recommend these for powering circuits where you are doing measurements on. Besides that the user interface is a bit clunky with the single rotate / select knob.

[bingo600]

The Korad KA3005PS is supposed to be an update on the prior "P model. I just got the new one for 100 euros to use for some radios while I check out my main POS supply I was using. Seems pretty ok, especially for the price.

Arrghhhh 
NOT NICE to reveal that (fine) price 

One Korad KA3005PS on the way from eleshop.eu 
Ended up in 122€ incl shipping to DK

/Bingo

I got my PSU today ....
Super fast (3 days) from NL 

  eleshop.eu

[shapirus]

Another decent lab (switching -- the usual caveats apply) power supply of the 60V/6A category, for which they offer an assembled unit with an AC/DC converter built in: https://www.aliexpress.com/item/1005005771018101.html

Same manufacturer as the one of the RD series discussed above, but this time it's a smaller and cheaper RK series. A winner in the sub-$100 category?

Not sure about how much noise will be added by the AC/DC unit, but the DC/DC converter looks pretty decent in that respect, and it also seems to be good in all that it has to do for its purpose. There's a review of the DC/DC unit in russian (google or whatever translate should make an acceptable translation for those who need it), which, importantly, has scope screenshots showing transient response and noise: https://www.kirich.blog/obzory/preobrazovateli/1165-novaya-model-reguliruemogo-preobrazovatelya-rk6006-ot-ruideng.html