Agilent Discontinues HP legacy E361x single output PSUs

[Christe4nM]

I just found out that all single output models of the E361x series are discontinued as of August 15th.    The dual and triple output models are still available.
They state the U8001A or E364x models as replacements. - Why? They either have higher noise levels, the E364x come with all the GPIB and programmable stuff I won't need, and the U8001A just doesn't instill a lot of confidence with me. They better come up with a replacement that really is a replacement. Although I cannot think of anything that replaces the E361x than another E361x. Black day for the industry in my opinion.

See Agilent's list of discontinued PSUs or for example the E3615A product page.

FYI, I definitely am not saying that I like older instruments over newer. In this case however the E361x series are proven to be very robust, reliably quality instruments. For decades they are were the industry standard design when it comes to linear power supplies. Simply discontinuing them instead of truly replacing them with a today's version just doesn't seem right.

[free_electron]

Its just harder to get parts to make em. The metal can transistors in em , the teledyne ad converter for the display ..

[rdl]

Don't worry, they will be available used for probably another 30 years.

[anotherlin]

Farnell list the E3610 at 376 euros without sales tax (add 20%), that's a lot for a single output, non programmable PSU.
I agree it's a well proven model with a long track record. But come on, we're in 2013, DC supplies are a "mature" technology.

I've never seen "factual" comparison between Agilent "classic" designs and current (cheaper) devices from other manufacturers.
But I don't think they can be so much worst to justify paying almost 400 euros for 15V at 2A.

[eevblogfan]

Hey

free electron - so what ? .. you don't need the original parts . HP/agilent's engineers know what they are doing , and they can find  the proper 2013's components ..

I really think they shouldn't  discontinued  that product ....

Anotherlin:  I am not sure what you tried to say ..

If I got you right . then I have to disagree with that ..

30~50$ cheap power supplies are suck , longevity , tempco , even the specs are fake ... 40W transformers are being used in 90W supplies ... that's bad ...

[robrenz]

I just got a glossy new 8 page Agilent flyer in the mail TODAY that is touting the E36xx series 

[free_electron]

free electron - so what ? .. you don't need the original parts . HP/agilent's engineers know what they are doing , and they can find  the proper 2013's components ..

Well .. there is retesting it, respin the board (because the new parts are not footprint compatible) , possibly having to redo the molding for the heatsink. ...
it would not be economically viable. especially since they already have a budget line that has a nice lcd display with rotary encoder and keypad ...

you can't keep on dragging along.

[plesa]

Does anybody know if Agilent has something in the power supply development pipeline?
Something which will replace the sigle or multiple output PSU's.

[Fsck]

I just got a glossy new 8 page Agilent flyer in the mail TODAY that is touting the E36xx series 

the entire 36xx? they're only cutting off the 361x, there's sitll 362x, 363x, 364x, and probably will be moar.

[robrenz]

I just got a glossy new 8 page Agilent flyer in the mail TODAY that is touting the E36xx series 

the entire 36xx? they're only cutting off the 361x, there's sitll 362x, 363x, 364x, and probably will be moar.

Their exact wording is the E3600 Series but they don't list what models are in the series.

[anotherlin]

Anotherlin:  I am not sure what you tried to say ..
If I got you right . then I have to disagree with that ..
30~50$ cheap power supplies are suck , longevity , tempco , even the specs are fake ... 40W transformers are being used in 90W supplies ... that's bad ...

I'm not saying to go for $50 supplies. At that price point you cannot expect any quality, it's not even enough money to buy the parts needed.
But almost 400 euros, that's just the way too much.

The technology is mature, just take a look at this 1965 application note from HP/Harrison (especially part A "power supply principles) : http://www.hpmemory.org/an/pdf/an_06-65.pdf
Now take a look at schematic of the E3610 on page 18 of : http://www.physics.fsu.edu/users/Wahl/labmanuals/instruments/ps/AgilentE361xAManual.pdf
Compare with a 60s HP 6209b I just scored on ebay, page 60 of : http://cp.literature.agilent.com/litweb/pdf/06209-90003.pdf
Or even a E3648 (https://www.eevblog.com/forum/testgear/agilent-e3648a-psu-schematic/msg218998/#msg218998) schematic, page 210 :  http://ridl.cfd.rit.edu/products/manuals/Agilent/power%20supplies/E3646AE2.pdf

If you compare the schematics : the 6209b is fully discrete no opamps, no ICs. The E3648 has complicated digital to analog circuit for remote programming.
Otherwise, it's really basically same theory of operation from the 60s : SCR pre-regulator followed power transistor series-regulator, with voltage and current sense feedback control.

So I don't see why a (somewhat) "cheaper" company (like let's Rigol) cannot achieve to design devices with specs and performance matching those of E361x or even E364x series.

[DaveW]

At least it now makes sense how the free DMM offer could be worthwhile for them; I got a free U1272A supply, listed at £295 by buying an E3610A supply, listed at £310. Just getting rid of stock about to go obsolete!

[alm]

So I don't see why a (somewhat) "cheaper" company (like let's Rigol) cannot achieve to design devices with specs and performance matching those of E361x or even E364x series.

In theory it's possible. In practice cheaper companies tend to use cheaper parts to save money, cut corners on design and add wank features like a color LCD and annoying menus to make it more attractive.

[Christe4nM]

The whole deal with a power supply is control systems engineering. A good power supply isn't in the first place about user interface, connectivity etc. It's all about the control loops for constant voltage and constant current. Although the basic principle is rather uncomplicated, finding the right implementation isn't. Its almost a quest of finding the right components, getting the loop to be stable in all circumstances, getting the CV and CC loops to have a very small cross-over region. Then try to make it fast while still maintaining stability. Oh wait, we want low noise too. Now add a bunch of protection circuitry and you've got a recipe on which each company creates their own solution.

Find amspire's topic on his power supply build in the projects subforum. That should give you an idea. He is going for his specific solution. Just copying his design but using another series transistor will most likely ruin your control loop stability.

The great thing about those HP 361x designs isn't in the components used, but how they got it all working together in a very great way. Present day of course the basic design has indeed matured. Still it requires a good understanding of the issues involved to achieve the same control loop stability, noise, speed etc.

[larry42]

It's a venerable design but wasn't there a post on the forum a few weeks ago about an instability with this supply if there is a low ESR capacitor connected across the terminals?

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