Rigol DP832 vs Agilent E3631a

[exe]

The Agilent has a VFD display, which would be a no-go for me. There are many on ebay with a faded display, some are completely unreadable.

Also, I think they are not as robust as people think, imho, there some broken on ebay . I agree with people who say it is over-engineered (https://gerrysweeney.com/agileent-e3631a-power-supply-teardown-repair/). It uses a multi-layer pcb, ridiculously thin traces (that tend to break after years of thermal cycling), custom ICs.... The mosfet (IRFP044) on +6V rail seems not specified for linear operation...

[SMB784]

The Agilent has a VFD display, which would be a no-go for me. There are many on ebay with a faded display, some are completely unreadable.

Also, I think they are not as robust as people think, imho, there some broken on ebay . I agree with people who say it is over-engineered (https://gerrysweeney.com/agileent-e3631a-power-supply-teardown-repair/). It uses a multi-layer pcb, ridiculously thin traces (that tend to break after years of thermal cycling), custom ICs.... The mosfet (IRFP044) on +6V rail seems not specified for linear operation...

Robust is a funny word open to interpretation.

Are these devices robust on the scale of 50 years worth of rough use? Probably not.  Are they robust to the point that they turn on and give stable, accurate output every time after two decades of constant use? You bet.

The alternatives to the HP/Agilent power supplies on the market today haven't been around for multiple decades, and thus their reliability cannot be assessed in the long term. These HP supplies have been around that long, and while some show up broken on eBay (mostly due to egregious error on behalf of the previous owner), I would wager that for every 1 that is broken after 20 years of use there are another 5 that will sit on a rack somewhere plugging away without a single complaint for another 20.

[bd139]

The Agilent has a VFD display, which would be a no-go for me. There are many on ebay with a faded display, some are completely unreadable.

Try replacing a DP832 power supply LCD in ten years.

[exe]

Try replacing a DP832 power supply LCD in ten years.

TBH I can't find one even now (didn't try hard). But this wouldn't turn me away from it. It's not a part that fails often (unless abused) and it doesn't fade (okay, backlight can, but often be repaired).

[Wolfgang]

... and if you try to replace the VFD in the HP supply, the repair cost will be probably a new DP832. In ten years the eBay will be flooded with used DP832s because the sold so many already ... A short look today listed a used DP832 for less than 200$ in working condition.

VFDs as such are no selling argument in 2018.

[exe]

Yeah, the thing is, E3631a is a phasing out product, while DP832 is still on sale.

There are still VFDs on ebay for E3631a, but for how long? About a year ago I bought a display for my K2000, now they are unobtanium. I can't even buy "an old broken unit for parts" because chances are it will have worn-out display.

[bd139]

Buy one now and put it away.

[exe]

Buy one now and put it away.

Sounds like a plan, but adds ~$50-100 to the price. Although, people say if VFD in a good condition it will last for quite some time, just don't leave it always on.

[bd139]

They last 8-10 years left on 24/7. A lot of the supplies you see were part of test systems etc so we’re on 24/7

[Zucca]

Don't be fooled by a simple VFD...

https://www.eevblog.com/forum/repair/hp-34401a-dmm-with-leaking-segments/msg1745069/#msg1745069

A PSU needs to delievers good quality current and voltage... and be easy to use, the rest comes after...

[exe]

A PSU needs to delievers good quality current and voltage... and be easy to use, the rest comes after...

Displaying multiple channels at the same time doesn't come after for me...

[bd139]

Spend a few weeks with a cheap Mastech power supply with a sticky tap relay and you'll change your mind. Oh Mr Pass Transistor has blown up and gone C-E short. 50V into my 3.3V device-o-clock. 

Rigol is somewhere between the Mastech and the E3631A.

If you look at the E3633A for example it has OCP and OVP that actually work. DP832 overshoots like fuck. Long enough to cost you a nice board full of AD and LT ICs.


Priority stack for me: Performance > Reliability > Interface > Price

[Zucca]

Ohhh Mastech, I was a young EE and I got a triple output PSU Mastech from Amazon. Arrived open the box, plugged in, turned on and did not work. DOA. Opened it up to check for a quick repair, and my liver contracted. Blind students can solder better than Mastech. I never returned a new item so fast, it lasted litteraly 10min.

Anyway between Agilent and Rigol, I go for Agilent. OP has enough material to decide, at the end it's a personal taste.

PS: I gave my old hy3005dx to my father  :
https://www.eevblog.com/forum/testgear/mastech-dc-power-supply-hy3005dx-cheap-and-very-impressing!/
now I am Mastech free, and life is beautyful.

[bd139]

I never owned a mastech just fixed them for people . I’ve got TTi PL supplies here. Cheap, well engineered and reliable.

To be fair the design is pretty neat but the problems are usually the quality of the construction which is dire, the quality of the parts used, the preregulator implementation and the lack of safety features.  An SCR preregulator as per HP supplies costs only slightly more than a wun hung low 20 cent relay and actually stays working. Also a tracking crowbar at the very least. Reckon I could add both for $5

[exe]

Mastech

Okay, when I say interface is important to me it doesn't mean about other parameters at all . I play a lot with analog circuits and for me ability to easily change parameters and see them is crucial for productivity. Although, an external DMM can solve this...

DP832 overshoots like fuck. Long enough to cost you a nice board full of AD and LT ICs.

Really? I was under impression it is quite good and doesn't do it, except may be when turned on. Where did you get this data? BTW, people report here that E36313A also overshoots at power on (and yes, they discuss issue with dp832 as well, but that's a single report, I'd like to have confirmation from other people): https://www.eevblog.com/forum/testgear/rigol-dp832-ovp-overshooting-with-huge-delay/ .

[rsjsouza]

Interesting; I have a 16 year-old Mastech clone that is very well built and is a workhorse. The only problem is reported below:

https://www.eevblog.com/forum/reviews/instrutherm-fa3005-(mastech-hy3005)-fix-and-teardown/

Between a HP and a Rigol, I think the HP is guaranteed to give you more years of service, while the Rigol still remains to be seen. IMHO the VFD is the biggest drawback for the HP, but perhaps it can be replaced with some engineering (just like other HP gear that people revived with alternative displays)

[Wolfgang]

... cant complain so much about the RIGOL DP832As. I got 4 of them, up to 4 years old, and they are all still alive and kicking.
I need to measure the overshoot issue (never saw it personally), however.
SCPI programmability is OK, it got USBTMC connectivity, the A version can play some tricks with external switch ports, cycling, graphs and other stuff,

... There is more bang than the RIGOLs, yes ... but not for the same buck.