Author Topic: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown  (Read 46216 times)

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Offline RupertGo

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Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #50 on: December 10, 2015, 09:37:04 AM »
You have to grasp a rotary switch and turn it (less so for rotary encoders with large knobs). A protruding side switch is a lot easier to accidentally activate - adjust the PSU, go to frob whatever equipment's to the right of it on the bench, and zap. On most test equipment, hitting something by accident is an inconvenience at worst - on the thing that's powering your logic, you really want more, not less, protection from fumbles.

I speak from bitter experience. Also, when the BBC went from rotary mixing pots to linears on its desks, it made them fade down when you pushed them up - so that if you caught them on the cuff of your jacket when you were reaching up for the controls above them, you'd fade to silence at worse, rather than fading up something to be accidentally broadcast.
 

Offline Armxnian

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Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #51 on: December 10, 2015, 09:39:53 AM »
Nice $350.00US power supply.
It's going to cost more for your family to pay for your funeral when you get killed by the soon to be exposed mains wiring.

Seriously though, nothing has changed from the old siglent design practices. All the negatives mentioned in the video will just piss you off every time you think about it. Knowing siglent's programming prowess, setting 2v probably outputs 32.
 

Offline Lukas

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Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #52 on: December 10, 2015, 09:57:39 AM »
Why there are still people making linear power supplies besides these really high end SMUs?

Why not SMPS+post regulator architecture? ... comparable noise and ripple.

Comparable? To an all-linear? I'd like to see you pull that off.

Who gives a damn about efficiency in a lab supply?
Size. Not needing a loud fan.
Besides an SMPS you can go oldschool like keysight did with the E36100 series and use a SCR pre regulator instead of switching relays. I'm wondering why so few are doing it, since placing a dimmer on the primary side of the transformer isn't rocket science.
 

Offline Salas

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Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #53 on: December 10, 2015, 09:58:49 AM »
- Deceptive Corporate practices
 - Non standard width banana plugs
 - Crap quality banana plugs
 - Shit caps

And the shorted turn of the toroidal transformer. The mounting screw doesn't seem to be isolated. Rust, again. The bodged ethernet. Build quality is the same like my Mastech clone. I wouldn't pay more than €300 for that Lab PSU.

I have the big three channel Mastech with the LCD panel meters, a single channel Tenma branded Korad, and the Siglent. The Mastech after two years of use stays nowhere put for voltage setting. As faithful as Runaround Sue. Having to short the outputs to set CC & lack of output disengage button is stone age ergonomics. Frustrating. The Korad is setting fine, has memories and output button, but its back panel fan is idling out like a coffee grinder. When running some class AB amplifier 1kHz at couple of amps as load, the Korad's control loop ripples too badly. The Siglent is rock stable, has a very quiet fan that will rev up once in a blue moon, displays results in spec. Big colorful digits are great, I can always see what's going on at a distant glimpse. Got it because the Rigol is too big for my space and it screams. I hate fan noise building up when various stuff is running, it makes me wanna shut down the development work and leave. Careful testing is like reading to comprehend. It demands silence. My model (3303S) has only 0.1V or finer step through the knob firmware by now but the binding posts are fine. Exactly the same looking binding posts with the X. Can use its PC interface to punch in any setting but I would prefer 1V jumps added. I don't want to engage the PC all the time for everything.
« Last Edit: December 10, 2015, 10:23:55 AM by Salas »
 

Online blueskull

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Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #54 on: December 10, 2015, 10:00:11 AM »
Why there are still people making linear power supplies besides these really high end SMUs?

Why not SMPS+post regulator architecture? ... comparable noise and ripple.

Comparable? To an all-linear? I'd like to see you pull that off.

Who gives a damn about efficiency in a lab supply?
Size. Not needing a loud fan.
Besides an SMPS you can go oldschool like keysight did with the E36100 series and use a SCR pre regulator instead of switching relays. I'm wondering why so few are doing it, since placing a dimmer on the primary side of the transformer isn't rocket science.

Probably regulatory requirements? If my memory serves me correctly, there is an EU direction that power supplies outputting >=60W must have low THD and high PF.
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Offline mikerj

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Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #55 on: December 10, 2015, 10:14:25 AM »
26:30 -- If you have the output physically shorted, the voltage you choose is irrelevant. It's in constant current mode. So there's no point in settings it to 1V or whatever to make it maximally stressful, you've already achieved that with the shorted outputs.

It's only irrelevant if the PSU selects a voltage tap based on measured output voltage rather than the voltage setpoint.
 

Offline c4757p

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Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #56 on: December 10, 2015, 10:29:33 AM »
Who gives a damn about efficiency in a lab supply?
Size. Not needing a loud fan.

Meh, I don't get it. If it's going on a workbench you've probably got room for a real power supply, and I never understood why fan noise bothered people. But whatever floats your boat, I guess.

Probably regulatory requirements? If my memory serves me correctly, there is an EU direction that power supplies outputting >=60W must have low THD and high PF.

Oh for chrissake, I should have figured there was some stupid EU regulation, there usually is.

It's only irrelevant if the PSU selects a voltage tap based on measured output voltage rather than the voltage setpoint.

Selecting based on the setpoint would be completely brain-damaged design.
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Offline FrankBuss

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Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #57 on: December 10, 2015, 10:52:42 AM »
Nice $350.00US power supply.
The SPD3303X costs more than $600.

Online AF6LJ

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Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #58 on: December 10, 2015, 10:59:25 AM »
Nice $350.00US power supply.
The SPD3303X costs more than $600.

I know that post was a commentary on what I thought it was worth.
I don't see anything to justify the list price for that power supply.
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Online AF6LJ

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Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #59 on: December 10, 2015, 11:08:23 AM »
Nice $350.00US power supply.
It's going to cost more for your family to pay for your funeral when you get killed by the soon to be exposed mains wiring.
It wouldn't be the first piece of gear I opened up and repaired what should have fixed when it was built.
Quote
Seriously though, nothing has changed from the old siglent design practices. All the negatives mentioned in the video will just piss you off every time you think about it. Knowing siglent's programming prowess, setting 2v probably outputs 32.
The binding posts were just the beginning.
And that would be the second thing that would get fixed.
The laser cut chassis reminded me of those crap computer cases that I have lacerated my hands on so many times in years past.

I'm not impressed with a number of items I have seen coming out of China. They have a ways to go before they actually can build world class gear, even low end gear.
Sue AF6LJ
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Online AF6LJ

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Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #60 on: December 10, 2015, 11:11:54 AM »
Why there are still people making linear power supplies besides these really high end SMUs?

Why not SMPS+post regulator architecture? ... comparable noise and ripple.

Comparable? To an all-linear? I'd like to see you pull that off.

Who gives a damn about efficiency in a lab supply?

9110 HAS a linear regulator, follows a DC/DC, which is fed from an offline SMPS.

Their datasheet stats 2mV ripple at worst case, while the worst case ripple for a GW Instek GPS series is 1mV. The new Siglent one stats 1mV too. Both RMS values.

If these things have ripple that is that bad, then linear power supplies have got way crappier since the nice 60s-80s PDI ones I'm used to. :scared:

Nice $350.00US power supply.


Nice? You'd spend $350 to get some shoddy banana jacks that don't hold plugs and some mains wiring that's going to short to the chassis in a few years?

Nah. This PSU put Siglent back on my shit list, actually. Releasing a product with mains wiring like that is practically malicious.

I would repair that stuff, and debur the sheet metal.
I would also do a video on it and send a link to siglent as well as post it here.
As far as the wiring goes, putting plastic tubing over the wires isn't the answer, cleaning up the edges is.
There is no excuse for that.
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Offline langwadt

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Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #61 on: December 10, 2015, 11:22:03 AM »
Why there are still people making linear power supplies besides these really high end SMUs?

Why not SMPS+post regulator architecture? ... comparable noise and ripple.

Comparable? To an all-linear? I'd like to see you pull that off.

Who gives a damn about efficiency in a lab supply?

9110 HAS a linear regulator, follows a DC/DC, which is fed from an offline SMPS.

Their datasheet stats 2mV ripple at worst case, while the worst case ripple for a GW Instek GPS series is 1mV. The new Siglent one stats 1mV too. Both RMS values.

If these things have ripple that is that bad, then linear power supplies have got way crappier since the nice 60s-80s PDI ones I'm used to. :scared:

Nice $350.00US power supply.


Nice? You'd spend $350 to get some shoddy banana jacks that don't hold plugs and some mains wiring that's going to short to the chassis in a few years?

Nah. This PSU put Siglent back on my shit list, actually. Releasing a product with mains wiring like that is practically malicious.

I would repair that stuff, and debur the sheet metal.
I would also do a video on it and send a link to siglent as well as post it here.
As far as the wiring goes, putting plastic tubing over the wires isn't the answer, cleaning up the edges is.
There is no excuse for that.

a simple zip tie would have fixed it, just zip tie it to the bundle right next to it and it never get near that sharp edge

 

Offline c4757p

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Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #62 on: December 10, 2015, 11:30:19 AM »
I would repair that stuff, and debur the sheet metal.
I would also do a video on it and send a link to siglent as well as post it here.
As far as the wiring goes, putting plastic tubing over the wires isn't the answer, cleaning up the edges is.
There is no excuse for that.

Fair enough, but I'd totally flunk it in a review (yeah, I know, this was a teardown, not a review, but it gave opinions) if you had to open it up, voiding the warranty, and modify it yourself to make it safe and usable. It's supposed to be a power supply, not a power supply kit!
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Offline BUkitoo

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Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #63 on: December 10, 2015, 11:32:18 AM »
I have the SPD3303D and I noticed that the user interface is not the best (Is just the same you are showing).

When you set the parallel mode or the serial mode happens that the user interface keeps splitted in two (as two independent supplies) but, let say, in parallel mode you really want a more current capable supply, so I would prefer to have a uniffied "one channel" screen configuration. But no, you have to sum both channels maximum current to know the maximum current capability.  The same happens with serial mode (summing voltages).

OK, is just a software matter.
« Last Edit: December 10, 2015, 11:54:34 AM by BUkitoo »
 

Online tautech

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Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #64 on: December 10, 2015, 11:50:26 AM »
I have the SPD3303D and I noticed that the user interface is not the best (Is just the same you are showing).

When you set the parallel mode or the serial mode happens that the user interface keeps splitted in two (as two independedn supplies) but, let say, in parallel mode you really whan a more current capable supply, so I would prefer to have a uniffied "one channel" screen configuration. But no, you have to sum both channels maximum current to know the maximum current capability.  The same happens with serial mode (summing voltages).

OK, is just a software matter.
We've asked them to fix that a while back, maybe they couldn't hence the new X model.  :-//
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Offline Smokey

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Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #65 on: December 10, 2015, 01:06:38 PM »
If this is a new production model, So much for the "Atten isn't Siglent" argument.  I can't decide if it's better or worse if it's a Siglent design rebadged as Atten or Atten design rebadged as Siglent.
 

Offline Brumby

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Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #66 on: December 10, 2015, 02:39:31 PM »
The spacing of the binding posts would be irritating, but their sloppiness is a fail.  For a 1mV accuracy, it seems kinda dumb to not have sense wires.  I have mixed feelings about multi-purpose knobs - but I will reserve any criticism until after having tried it out (which isn't likely)

I did empathise with Dave when he reached the maximum voltage and this stupid window pops up on the screen.  EXTREMELY annoying and totally unnecessary.  One would assume that anyone using a lab supply would understand its limitations and work out very quickly that the maximum has been reached by the display no going any higher.  If they couldn't, then I'd be anxious about them being anywhere near the gear.  If Siglent really want to throw up a notification, then do it with a little indicator that flashes up somewhere NOT over the active information areas of the screen - and even then, only when the knob is turned to the right plus, maybe half a second.  It mustn't impede operation in any way.

Q. Dave: When this window pops up -
1. Does it lock out any adjustment until it closes? (if so, it could find itself flying out the window real quick)
2. If not, does adjusting the voltage down cause the window to disappear immediately?


As for the metalwork...


As far as the wiring goes, putting plastic tubing over the wires isn't the answer, cleaning up the edges is.
There is no excuse for that.


Absolutely.  Just get rid of the knife.
 

Online @rt

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Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #67 on: December 10, 2015, 04:16:07 PM »
I'm just a scumbag, and know better than that.
You should have unbolted the toroid and see what happens.
It doesn't look like the work of 100 engineers to me.
It would hace been interesting to open it in the presence of Yolo.
 

Offline bitwelder

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Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #68 on: December 10, 2015, 06:10:13 PM »
As Trio supplied this PSU, who know if it was fiddled with before Dave got his hands on it, as these have just been released it was probably their demo unit.
Sometimes can be useful to check the status of the hated 'warranty void' sticker before doing a teardown  ;)
 

Online Bud

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Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #69 on: December 10, 2015, 06:24:40 PM »
Cant wait for excuses, 'we let flesh college graduate design this supply and source bottom of the barrel components'?

Yes it was a new young female employee who designed it when she had spare time between filing wrongful trademark claims to ebay.
 

Offline Salas

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Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #70 on: December 10, 2015, 06:47:08 PM »
GW Instek looks like having some similar functionality traits also. A cross between the X and the Hantek

 

Offline Smokey

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Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #71 on: December 10, 2015, 07:10:24 PM »
That select switch on the fixed voltage output is stupid.  It's just stupid.  There is an Arm processor on the thing and it has a Mechanical switch to select voltage outputs?  Really? 
 

Offline FrankBuss

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Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #72 on: December 10, 2015, 07:15:44 PM »
GW Instek looks like having some similar functionality traits also. A cross between the X and the Hantek
Even the same 2.5V, 3.3V, 5V fixed voltage outputs. I bet it looks very much the same inside.

Would be interesting to hear know who copied it from whom and if they were allowed to do this, or if it is all OEM from one manufacturer. At least the channel 1 and channel 2 numbers are swapped on the GW Instek :-DD

Offline Salas

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Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #73 on: December 10, 2015, 07:22:13 PM »
Could be. Siglent has its own digital control and firmware solution for the two fully fledged channels though.
 

Offline station240

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Re: EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown
« Reply #74 on: December 10, 2015, 07:45:16 PM »
a simple zip tie would have fixed it, just zip tie it to the bundle right next to it and it never get near that sharp edge

Yes that's the only real fix, or glue down nylon tie points. Tubing solves nothing, as you can still trap the cable in the case when you close it.
 


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