EEVblog #1173 - Rohde & Schwarz Power Supply Bonanza

[EEVblog]

Rohde & Schwarz were offended at the quality of the power supplies in the EEVblog lab, so sent in some "real" lab power supplies!
Unboxing and first look at the Rohde & Schwarz HMP4040, HMP2020, and NGE103 programmable lab power supplies.

Comparisons with other brand PSU's: There are some comparisons with other brand PSUs:
https://www.rohde-schwarz.com/brochure-datasheet/hmp/

https://www.rohde-schwarz.com/au/product/hmp4000-productstartpage_63493-47360.html

https://www.rohde-schwarz.com/au/product/nge100-productstartpage_63493-387267.html

[Mr. Scram]

Hey Rohde & Schwarz, the power supply situation in my lab is outright outrageous. Luckily for you, I don't have a problem with that being corrected at all. I'd even throw in a review!

Getting sent kit like that is certainly one of the perks of being a Youtube personality. Thought leader? Influencer? Whatever. I don't know what it is about R&S equipment, but the slightly understated and fairly German design always appeals to me in ways I can't quite explain. Nothing flashy or attention grabbing, just a measured "Want to get work done? Let's get going".

[nctnico]

IMHO the binding posts and keypad are bit of a hit & miss. I'd like binding posts AND a keypad (to enter voltage and current) but none of the power supplies shown in the video seem to have both. Using a keypad is much quicker and precise than turning a knob.

[EEVblog]

I don't know what it is about R&S equipment, but the slightly understated and fairly German design always appeals to me in ways I can't quite explain. Nothing flashy or attention grabbing, just a measured "Want to get work done? Let's get going".

Agreed. Even their new stuff which is trying to be "trendy" still manages to pull that off.

[Fungus]

Accepting freebies from big companies...? 

[Fungus]

Clever use of the foam in the packaging, saves foam and no need to glue anything!


At 23 minutes I think you mean "convection", not "radiation". If heat is radiating out of the holes in the case then you've got a big problem. 

[johnlsenchak]

But   Dave  we  didn't  get  any tear downs , that's what people want to see !!! Bloody  hell !   

[Mr. Scram]

Agreed. Even their new stuff which is trying to be "trendy" still manages to pull that off.

Their recentish oscilloscope is a device I lust after. I don't even care how good it is, even though it is. It's a perfect example of how to make what is still a tool attractive without falling in to the boy racer trap of flashy LEDs or over designed shapes. Of course, the attention to detail and fit and finish are another part of the appeal. Shahriar calling the internals "beautiful" is some of the highest praise I can imagine.

[NikkiC]

But   Dave  we  didn't  get  any tear downs , that's what people want to see !!! Bloody  hell !

Give the bloke a chance to make em mate.   

[MT]

Soooo, the Rigol is now just a very distant memory from the past!

[mariush]

I don't like the direction buttons with weird shape around the rotary knob, they just seem hard to press and use.  There is room to add the buttons to the right of the knob like you have them on keyboards.

There's an issue with the smaller psu ... the usb connector in the front is not centered properly and when you pressed on the power button, the connector also moved inside... almost like maybe the circuit board is locked with only one screw, or maybe locked in place with friction (pcb slid between some plastic channels)

I don't like the way they soldered those wires to the outputs. With a bit of routing on the circuit board, they could have used bus bars between the main circuit board and the board with the connectors.
Same for that main wire and the wire connecting the usb shielding ... they could have used a bus bar bent a specific way to keep the clearance instead of a wire on the other side.  They could even dip the whole bar in some enamel or use some heatshrink, if they wanted insulation.

Also not a fan of how they screwed the fans to the metal case, they could have used some rubber things to reduce vibrations and maybe glue some rubber spacers on the corners of the fan so that if you press down on the case, the metal won't hit the fan.

[Brumby]

But   Dave  we  didn't  get  any tear downs , that's what people want to see !!! Bloody  hell !   

Back it up there....  Teardowns HAVE been done and are available: EEVblog #1174 - Rohde & Schwarz PSU Teardowns

[Fungus]

Back it up there....  Teardowns HAVE been done and are available: EEVblog #1174 - Rohde & Schwarz PSU Teardowns

I think Dave needs to put one of his couch feet on the end of that bolt through the transformer.


(maybe that's the reason he has so many - they're really toroidal transformer condoms!)

[Romain]

Anybody knows where are the hi-res pictures of the teardown?
I'm looking for the digital isolator used for each channel.

[maginnovision]

I don't like the direction buttons with weird shape around the rotary knob, they just seem hard to press and use.  There is room to add the buttons to the right of the knob like you have them on keyboards.

There's an issue with the smaller psu ... the usb connector in the front is not centered properly and when you pressed on the power button, the connector also moved inside... almost like maybe the circuit board is locked with only one screw, or maybe locked in place with friction (pcb slid between some plastic channels)

I don't like the way they soldered those wires to the outputs. With a bit of routing on the circuit board, they could have used bus bars between the main circuit board and the board with the connectors.
Same for that main wire and the wire connecting the usb shielding ... they could have used a bus bar bent a specific way to keep the clearance instead of a wire on the other side.  They could even dip the whole bar in some enamel or use some heatshrink, if they wanted insulation.

Also not a fan of how they screwed the fans to the metal case, they could have used some rubber things to reduce vibrations and maybe glue some rubber spacers on the corners of the fan so that if you press down on the case, the metal won't hit the fan.

I don't think vibration from the fan is a problem at all, everything is very rigid. Nothing rattles(not sure about nge) They have pretty much always used wires, not bus bars, so asking them to change that is 100% futile.

[electronic_eel]

I'm a bit puzzled about their architectural choice of the big-ass, custom-wound mains transformer and a buck preregulator afterwards.

Why didn't they use a common flyback or forward regulator directly from mains as preregulator for each channel? That way they wouldn't need the big and probably expensive transformer but still had individual isolated channels with preregulation. The transformers for a flyback or forward can be much smaller and thus cheaper because of the higher frequency.

[Cnoob]

No scoping the outputs? to see how the voltage rises when switched on.
Standard test I thought.

While I'm envious it's a piece of lab equipment I like to be simple no frills and no spills.

I have a Tenma Duel psu. apart from the memories (which I don't like.) It has everything I need.

[sorenkir]

The big one would perfectly stack on my 1996 vintage Hameg HM8142 !

[IanMacdonald]

I'm a bit puzzled about their architectural choice of the big-ass, custom-wound mains transformer and a buck preregulator afterwards.

Why didn't they use a common flyback or forward regulator directly from mains as preregulator for each channel? That way they wouldn't need the big and probably expensive transformer but still had individual isolated channels with preregulation. The transformers for a flyback or forward can be much smaller and thus cheaper because of the higher frequency.

There's always a fair amount of capacitive coupling through a SMPS transformer. Not a problem if the secondary is earthed either directly or capacitively but would be in a floating output application as it might induce tens of volts of common-mode noise. A 50Hz transformer would be less problematic in this respect.

[luzotug]

Every manufacturer this days do "overpriced" software options, the NGE102/103 options are (in Europe) :

• NGE-K101 ethernet : 120 EUR
• NGE-K102 wireless lan : 180EUR
• NGE-K103 four digital I/O : 90EUR

If you take all the options the unit is more expensive than the older brother HMC8042/HMC8043 :

• HMC8042 without GPIB : 980 EUR / NGE102 with full option : 650+390 EUR
• HMC8043 without GPIB : 1100 EUR / NGE103 with full option : 790+390 EUR

Sure you get the new feature wireless and four digital I/O but the HMC8042/8043 have better spec, sense line on the back, 1 analog modulation input on the back, data logging (NGE only use USB for screenshot and firmware update) and the key panel can also be used as a keypad.

[ergya]

Young player Beginner fanboy here who likes any fancy puppies like these. I think I understand what (offical) calibration means just could not find any information on the net how often do you need to calibrate things like this? You just walk in to any calibration firms (if I am correct Dave was doing this for living, sorry if not ) and tell them "hey fella here is my R&S little puppy please make it great again" or the have to be R&S certified or something or they can just calibrate it? If you don't calibrate a fancy toy like this, how off they can go in 1/5/10 years (in average, I know ot varies from device to device)?

[electronic_eel]

There's always a fair amount of capacitive coupling through a SMPS transformer. Not a problem if the secondary is earthed either directly or capacitively but would be in a floating output application as it might induce tens of volts of common-mode noise.

Isn't that mostly an issue of the design of the SMPS transformer? I guess you can get rid of most of the common mode noise with a separate shield winding around the primary winding. That reduces efficency a bit, but that wouldn't be an issue here.

[Fungus]

No scoping the outputs? to see how the voltage rises when switched on.
Standard test I thought.

Yeah, but, "Hameg". You really think...?

[floobydust]

Can anyone confirm if these have a massive output capacitor? This is frequently used to cover for the lag in the digital (MCU) control loop. When a PSU switches from CV to CC there is a large current overshoot until the O/P cap discharges or the MCU backs off.

You can can set current limit to say 0.01A and output voltage to 25V, repeatedly short the PSU output and do spot welding! Some PSU's have huge i.e. >680uF output caps that make CC mode kind of a joke.

I used a popular manufacturer's fancy digital PSU and it was so bad I had to laugh and go back to using a 30 year old analog PSU. I've never seen specs on CV->CC response time.

[Cnoob]

Yeah, but, "Hameg". You really think...?

It would be nice to see how  smooth and clean the output rises including the switch mode one or is there something wrong.

I would of expected to see a rubber cap on the toroidal even before Dave rasied the issue, it was that obvious.