ebay, weird bench supply

[6PTsocket]

I am looking for a linear bench supply and I came across this one that said "linear" but reading further it said " PWM voltage stabilization. I emailed the seller to find our which it was and got this answer:
"Thanks for your letter and your interests in our product.
The item uses PWM switching voltage stabilizer and MOS linear adjustment mode."
Is this double talk for a switching power supply by a seller repeating the blurb that came from China with the PS or is it some hybrid technology I am unaware of? Are they talking about the DC output that is fed back to the PWM controller to regulate the supply? Thanks.
I have since found another candidate Mastech/Voltq that is definitely linear, less than a mv of noise and 4 digit neters that resolve to 1ma. Nice for general use but I am curious about the first ad.



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[JackJones]

What's the manufacturer and model?

Maybe they are using switching supply for preregulation to a linear one or something?

[6PTsocket]

What's the manufacturer and model?

Maybe they are using switching supply for preregulation to a linear one or something?

Brand: YeacomUSA, Model: YES2990. Output: 0-30volts, 10A. Price: around 56 bucks.
I don't even see a name on the front panel.  It is clearly a Chinese generic. The brand is just the California importer. They did invite me to call for more info. It HAS to be a switcher at that price.

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[6PTsocket]

What's the manufacturer and model?

Maybe they are using switching supply for preregulation to a linear one or something?

Brand: YeacomUSA, Model: YES2990. Output: 0-30volts, 10A. Price: around 56 bucks.
I don't even see a name on the front panel.  It is clearly a Chinese generic. The brand is just the California importer. They did invite me to call for more info. It HAS to be a switcher at that price.

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Oops! Typo. That is YescomUSA

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[6PTsocket]

I just googled the brand and they also import dance (stripper) poles and tents. Glad I didn't bother to call. LOL!! Can you imagine trying to get tech support?

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[JackJones]

Definitely a rebranded one, I found dozens of different brands for the exact same looking model. It's pretty common to see them rebranded even with the better quality ones.

The specs seem to be 50mV of ripple, given they promise 10A in such a compact looking size I bet it's purely a switchmode supply.

I did find a picture of one in a review: https://ae01.alicdn.com/kf/UTB8j_i6H8ahduJk43Jaq6zM8FXav.jpg

Doesn't look linear to me!

[ArthurDent]

As mentioned, some power supplies use a switching mode preregulator to increase efficiency then a linear final regulator so there is a low voltage drop across the linear stage for low heat dissipation and you get the added advantage of lower noise and probably better regulation.

[strawberry]

Definitely a rebranded one, I found dozens of different brands for the exact same looking model. It's pretty common to see them rebranded even with the better quality ones.

The specs seem to be 50mV of ripple, given they promise 10A in such a compact looking size I bet it's purely a switchmode supply.

I did find a picture of one in a review: https://ae01.alicdn.com/kf/UTB8j_i6H8ahduJk43Jaq6zM8FXav.jpg

Doesn't look linear to me!

Too large capacitance at output terminals.