Author Topic: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown  (Read 77073 times)

0 Members and 1 Guest are viewing this topic.

Offline Zbig

  • Frequent Contributor
  • **
  • Posts: 903
  • Country: pl
Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #100 on: December 11, 2015, 07:20:33 pm »
Even the hard disk manufacturers stopped with that racist stuff back in the IDE days when they renamed Master and Slave to Primary and Secondary. (Where's mojo to back me up on this one?)  :palm:

Not exactly. There were two channels: Primary and Secondary, each of them supporting up to two devices on a single cable: a Master and a Slave, for a total of four devices. So you had a "Primary Master", "Primary Slave", "Secondary Master" and "Secondary Slave" in a maxed-out configuration.
 

Offline Zbig

  • Frequent Contributor
  • **
  • Posts: 903
  • Country: pl
Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #101 on: December 11, 2015, 07:37:19 pm »
Isn't it that the main justification for a standard-spaced terminals on a PSU is the ability to use a shorting bar for parallel serial/symmetrical connection? On Siglent, you don't do that as there are internal relays for that.
« Last Edit: December 11, 2015, 08:03:53 pm by Zbig »
 

Offline jnissen

  • Regular Contributor
  • *
  • Posts: 63
Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #102 on: December 11, 2015, 08:22:48 pm »
Mmmm,

 - Deceptive Corporate practices
 - Non standard width banana plugs
 - Crap quality banana plugs
 - Shit caps

Seriously, those banana plugs?  Entire instrument is a complete fail.


 :palm:


100% agree!
 

Online Messtechniker

  • Frequent Contributor
  • **
  • Posts: 532
  • Country: de
  • Old analog audio hand - No voodoo.
Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #103 on: December 12, 2015, 11:23:41 am »
Thanks, Dave, for the teardown of the Siglent SPD 3303X. As far as I’m concerned
there is no need for a full review of this thing at the moment. I admit, I was for a
while thinking about buying it, but after these results ….  :palm:
This would have been my first purchase of semi-serious kit made in China.
I will now forget it for the next 10 years or so.

I’m looking now at the Hameg HMC 8043. I know, quite a different animal also price wise.

Yours - Messtechniker
Agilent 34465A, Siglent SDG 2042X, Hameg HMO1022, R&S HMC 8043, Voltcraft VC 940 M-Audio Audiophile 192, R&S Psophometer UPGR, 3 Transistor Testers
 

Offline mjt

  • Supporter
  • ****
  • Posts: 10
Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #104 on: December 12, 2015, 07:05:05 pm »
So if there's only one AD7792 and the three outputs are isolated, how are they coupling the signal to get 5 digit precision?

I'm not an electronics expert, but I thought to get good linearity through an optoisolator you need the type with two matched photodiodes (so you can do feedback) which the pc817 isn't.

Or am I missing something? Do they have an ADC for each channel, or some feedback arrangement that doesn't need both photodiodes to be in the same package, or something?
 

Offline Macbeth

  • Super Contributor
  • ***
  • Posts: 2562
  • Country: gb
Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #105 on: December 12, 2015, 08:25:46 pm »
I’m looking now at the Hameg HMC 8043. I know, quite a different animal also price wise.

Yours - Messtechniker
The only real gamechanger I found (without an actual review of how it really performs) are the binding posts. Now I know the Rigol DP832 also had an issue with a batch of them with binding posts being the other way - too narrow. Perhaps this is a bad sample? The non standard spacing would be an issue if it had sense terminals that you use standard spaced shorting bars on I guess. Surely nobody uses those fixed space banana to BNC converters on PSUs?

The Hameg is an instant fail because, like my Tenma 72-83xx PSUs it uses those recessed "safety" banana sockets. That is utter fail on a low voltage PSU.
 

Offline Smokey

  • Super Contributor
  • ***
  • Posts: 1655
  • Country: us
Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #106 on: December 13, 2015, 12:27:43 am »
 

Offline c4757p

  • Super Contributor
  • ***
  • Posts: 7805
  • Country: us
  • adieu
Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #107 on: December 13, 2015, 12:39:59 am »
Surely nobody uses those fixed space banana to BNC converters on PSUs?

I do. It's nicer to have one (thin) coax on the bench than two leads - especially when it's more than one. And why wouldn't I? That's a "standard" I thought no power supply maker would be dumb enough to go against... :palm:
No longer active here - try the IRC channel if you just can't be without me :)
 

Online Monkeh

  • Super Contributor
  • ***
  • Posts: 7144
  • Country: gb
Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #108 on: December 13, 2015, 02:15:48 am »
Surely nobody uses those fixed space banana to BNC converters on PSUs?

I use a lot of double banana plugs.
 

Offline Macbeth

  • Super Contributor
  • ***
  • Posts: 2562
  • Country: gb
Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #109 on: December 13, 2015, 03:17:00 am »
Guess I'm wrong? I never would have thought of powering stuff up using a BNC RG58 cable and no doubt another BNC at the other end to whatever convertor going into the DC input of DUT, but it takes all sorts...?

Really the wrong diameter banana sockets are of more concern. And these new EU Elfen Safety PSUs are utter shite. No binding posts at all, shrouded recessed sockets.  :palm:
 

Offline John Coloccia

  • Super Contributor
  • ***
  • Posts: 1194
  • Country: us
Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #110 on: December 13, 2015, 04:02:26 am »
I use banana to BNC all the time on a power supply, if only to monitor the voltage on a scope vs some other thing I'm looking at. I power with BNC all the time too. Most of what I do only draws a handful of milliamps...enough to fly to the moon, don't you know.  :) It's pretty ridiculous that they can't get the binding posts and the spacing correct. I've never even given this a second thought on any other equipment I've ever used. It's just how you do it. Baffling, amateur hour kind of nonsense.
 

Offline Tothwolf

  • Regular Contributor
  • *
  • Posts: 95
  • Country: 00
Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #111 on: December 13, 2015, 04:05:27 am »
The unprotected mains wiring near sharp metal is inexcusable. How much would a small section of clear PVC tubing really add to the overall cost?

The Rubycon capacitors in this power supply are decent parts. The ZLH series is a long life low ESR part somewhat similar to the Nichicon HE series. Rubycon's YXA series is probably closer to a Nichicon PJ or PS series and are also not bad parts.

While the Lelon capacitors used as main input filters will probably last quite awhile (100Hz or 120Hz), I don't like seeing the smaller Lelon parts on the other boards. Even though 5mm or 6.3mm Lelon parts will probably last the 5 year design life of this instrument, they still aren't the high quality parts I would expect to see in a precision power supply.
« Last Edit: December 13, 2015, 04:09:08 am by Tothwolf »
 

Offline SL4P

  • Super Contributor
  • ***
  • Posts: 2163
  • Country: au
  • There's more value if you figure it out yourself!
Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #112 on: December 13, 2015, 07:06:35 am »
You mentioned the TO-220 flapping in the breeze...
I also noticed the electrolytics on the front-panel PCB... some were already 'sagging' from vibration / gravity / whatever motivation.
Some white epoxy-snot would fix that for virtually no effort.

Added: the channel-3 switch seems  a bit flimsy - perhaps a pull & slide or other mechanism would be a bit safer - esp as it's directly below the primary controls.
« Last Edit: December 13, 2015, 07:12:16 am by SL4P »
Don't ask a question if you aren't willing to listen to the answer.
 

Online Messtechniker

  • Frequent Contributor
  • **
  • Posts: 532
  • Country: de
  • Old analog audio hand - No voodoo.
Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #113 on: December 13, 2015, 08:01:11 am »
The Hameg is an instant fail because, like my Tenma 72-83xx PSUs it uses those recessed "safety" banana sockets. That is utter fail on a low voltage PSU.

Why this? Just did a 4 wire measurement on a safety banana socket*
with an ordinary banana plug* inserted. Measured 2.5 milliOhms.  8)
What's wrong with that?

*) Used items - laying the the box for ages.
Agilent 34465A, Siglent SDG 2042X, Hameg HMO1022, R&S HMC 8043, Voltcraft VC 940 M-Audio Audiophile 192, R&S Psophometer UPGR, 3 Transistor Testers
 

Offline rs20

  • Super Contributor
  • ***
  • Posts: 2247
  • Country: au
Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #114 on: December 13, 2015, 11:51:32 am »
The Hameg is an instant fail because, like my Tenma 72-83xx PSUs it uses those recessed "safety" banana sockets. That is utter fail on a low voltage PSU.

Why this? Just did a 4 wire measurement on a safety banana socket*
with an ordinary banana plug* inserted. Measured 2.5 milliOhms.  8)
What's wrong with that?

Recessed banana sockets are a compromise -- they're less versatile, but you're nominally safe from touching the terminals. If the terminals can't reach a dangerous voltage, then that's a fail, they're less versatile, but __________________.
 
The following users thanked this post: squeakyfeet

Offline dr.diesel

  • Super Contributor
  • ***
  • Posts: 2211
  • Country: us
  • Cramming the magic smoke back in...
Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #115 on: December 13, 2015, 12:10:36 pm »
I’m looking now at the Hameg HMC 8043. I know, quite a different animal also price wise.

I have one on order.

Surely nobody uses those fixed space banana to BNC converters on PSUs?

I use them all the time as well.

Online NiHaoMike

  • Super Contributor
  • ***
  • Posts: 7269
  • Country: us
  • "Don't turn it on - Take it apart!"
    • Facebook Page
Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #116 on: December 13, 2015, 06:58:22 pm »
Recessed banana sockets are a compromise -- they're less versatile, but you're nominally safe from touching the terminals. If the terminals can't reach a dangerous voltage, then that's a fail, they're less versatile, but __________________.
Could the output be floated at a high voltage? For example, you could use a 15V bench supply to run the gate drive circuit for a motor drive that is running from a mains level supply.
Cryptocurrency has taught me to love math and at the same time be baffled by it.

Cryptocurrency lesson 0: Altcoins and Bitcoin are not the same thing.
 

Offline German_EE

  • Super Contributor
  • ***
  • Posts: 2399
  • Country: de
Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #117 on: December 13, 2015, 08:40:02 pm »
Try it, we'll watch from over here  :popcorn:
Should you find yourself in a chronically leaking boat, energy devoted to changing vessels is likely to be more productive than energy devoted to patching leaks.

Warren Buffett
 

Offline c4757p

  • Super Contributor
  • ***
  • Posts: 7805
  • Country: us
  • adieu
Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #118 on: December 13, 2015, 09:15:43 pm »
Instead of having to be "protected" from your banana jacks, how about, y'know, not touching them? This isn't handheld equipment. Just don't bloody touch them while it's turned on. We can save the stupid recessed jacks for handheld devices and the Hello Kitty editions.
No longer active here - try the IRC channel if you just can't be without me :)
 

Offline SL4P

  • Super Contributor
  • ***
  • Posts: 2163
  • Country: au
  • There's more value if you figure it out yourself!
Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #119 on: December 13, 2015, 09:17:53 pm »
go have a coffee, while a trainee or your kids come into your work area.
Don't ask a question if you aren't willing to listen to the answer.
 

Offline c4757p

  • Super Contributor
  • ***
  • Posts: 7805
  • Country: us
  • adieu
Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #120 on: December 13, 2015, 09:27:41 pm »
So? Your kids could stick their fingers in a toaster or lamp socket too. Don't be a fool and leave things powered up while you walk out, if you're working with dangerous voltages.

As for the trainee... what are you training for, the circus? If he doesn't understand not to touch bitey voltages he needs to repeat school, or otherwise learn the hard way |O
« Last Edit: December 13, 2015, 09:29:32 pm by c4757p »
No longer active here - try the IRC channel if you just can't be without me :)
 

Offline Brumby

  • Supporter
  • ****
  • Posts: 11054
  • Country: au
Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #121 on: December 14, 2015, 01:23:24 am »
My take on all these 'protective protocols' is that it is not intended to protect from deliberate stupidity, but to minimise the risk of accidental contact.

For example, I have never in my life ever known of an instance where something conductive has slipped between a mains plug and a wall socket shorting out the active and neutral - but obviously there have been.  So we now have insulated active and neutral pins.  I don't really mind this because it makes sense AND that it doesn't affect usage (unlike the earlier 'shroud' on line sockets, which caused me problems with a couple of things.)

My only gripe about recessed sockets is that you don't get the terminal post option, useful for securing bare wire connections.  If they are trying to say we should only use 'properly terminated' cables, then I would be miffed.  Trading off significant functionality for an incremental improvement in safety really rubs me up the wrong way.
 

Offline Brumby

  • Supporter
  • ****
  • Posts: 11054
  • Country: au
Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #122 on: December 14, 2015, 01:44:14 am »
Oh, if anyone is still unsure about the question of a shorted turn on the toroidal - here's a snapshot from Dave's video:



I see what looks like a nylon spacer with a moulded rim to ensure the washer nut is kept centred and right away from the mounting disc.  I suspect this spacer will have a cylindrical protrusion at the rear, separating the bolt shaft and any other metalwork.  In short, there is no shorted turn.

Dave did point this out.
 

Offline madires

  • Super Contributor
  • ***
  • Posts: 6091
  • Country: de
  • A qualified hobbyist ;)
Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #123 on: December 14, 2015, 10:05:00 am »
I see what looks like a nylon spacer with a moulded rim to ensure the washer nut is kept centred and right away from the mounting disc.  I suspect this spacer will have a cylindrical protrusion at the rear, separating the bolt shaft and any other metalwork.  In short, there is no shorted turn.

Yup, you're right! But it would be still an interesting experiment to find out what the impact (in numbers) of a shorted turn in the middle of the toroid would be.
« Last Edit: December 14, 2015, 10:10:15 am by madires »
 

Offline Kleinstein

  • Super Contributor
  • ***
  • Posts: 9216
  • Country: de
Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #124 on: December 14, 2015, 06:22:59 pm »
The recessed safty conectors are useful (and in the EU required for a lab supply that deserves it's name) for low voltages too.
Its not about isolation of the connectors itself, but compatibitly with new safety plugs with a fixed insulation tube.

So even if the supply is low voltage this alows you to use the better cables as well and thus no more need to have the unsafe old style banana plugs or the plugs with movable shield.
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf