Let's talk about "Decent cheap Bench Power Supplies", OK?

[cvanc]

Well, it's time for me to buy a new power supply for the bench.  And the first question is always "new or vintage" for something like this.  Can I get some guidance here?

I'm looking for something that will provide dual opamp rails (up to at least +/-18V and maybe half an amp, more is better).  A triple output unit would be fine as well, even though I doubt I'd use the 3rd output much, as they are usually 5 Volts.

Good built in metering and adjustable current limit are musts.  Precision and noise are honestly secondary as long as they are 'good enough'.  I really want a useful and clear constant current mode; it would be helpful when troubleshooting shorts with my IR camera.

I have a Tek PS282 from a hundred years ago and it's been just fine, so I'm looking at old PS280's on eBay and I bet it would meet my needs well.  But what about something new?  I think Dave did some reviews of tiny bench supplies, but I have not found the old video yet.

All advice welcome, thank you.

[BillB]

What is "good enough" precision? 
Do you need timers, or remote programming?
Do you need 4 wire sensing?
Physical size - tiny?  Any actual physical size requirements?
Display requirements?
Most importantly, budget?

[bd139]

E36311A.

Get saving

[KaneTW]

R&S HMC/HMP series.

[Mr. Scram]

E36311A.

Get saving

That's decent but not cheap.

[DaJMasta]

So far, with your search criteria, the playing field is still very broad.

I would go with a triple output supply, at least, since a pair of isolated outputs can give you a split rail and even if the third output is just a logic level supply, that can really come in handy (and is good as a digital rail even when you're doing mostly analog work with the other channels).

There's the cheap ones, the sort of midrange cheap ones, and then the more expensive ones.  Plenty of reviews around on the first two broad categories, but I tend towards recommending a couple notches above the bottom of what's acceptable, so I'd look around at the SPD3303X-E and the DP832 (and of them, I personally think the Siglent is better value, though the third rail is less adjustable and does not have a current measurement).  If you want a bit less power noise/more accuracy, then the E3631A will suit your requirements (and is around the same price used), just with a fraction of the output power and a VFD display which only can show information about one channel at a time.

There are plenty of alternatives, and even some in that general price bracket.... so any further requirements?

[Fungus]

E36311A.

Get saving

That's decent but not cheap.

Around here? You only get to pick one of those.

[Mr. Scram]

Around here? You only get to pick one of those.

I don't agree, though it does depend on your specific demands. If you need to do precise measurements you'll end up with something else than when you just need power that's not super noisy and ballpark accurate without burning your place down.

[technogeeky]

I have been super happy with my GPD-3303s. It's 0-32 volts, 0-3.2 amps, with a selectable [2.5, 3.3, 5.0] volt, 3.0 amp output as the 3rd supply.



I got mine from eBay for $175. I've seen them go as low as $150 and as high as $225. It's pretty clean (though it does have thermal drift). The 3rd supply has some overshoot problems which can be fixed (there's a thread about this).

Dave did a video on essentially the same supply but with an updated display from Siglent here:

[Mr. Scram]

I have been super happy with my GPD-3303s. It's 0-32 volts, 0-3.2 amps, with a selectable [2.5, 3.3, 5.0] volt, 3.0 amp output as the 3rd supply.



I got mine from eBay for $175. I've seen them go as low as $150 and as high as $225. It's pretty clean (though it does have thermal drift). The 3rd supply has some overshoot problems which can be fixed (there's a thread about this).

Dave did a video on essentially the same supply but with an updated display from Siglent here:

One thing it lacks is remote sensing, which may be relevant if you require that accuracy.

[coromonadalix]

For the supplies i'm an old geek, i love any linear supply

Had fun trying an few switching models, but some of them lack inductive loads tolerance / acceptance, had this week an Mastech HY3010E-2 who had the main mosfets circuit blown because of the incredible build quality  pfff

I have an Kepco ate 75-8   who has been beaten a lot and never failed me, sure the linear supply are bulky and heavy,  but they are tougher for my need


@cvanc : Evaluate your needs, check feed backs and problems and get an service manual first before you buy something .... may help in the future, you never know.

[nctnico]

E36311A.

Get saving

I ended up buying the Keysight E36313A but the other one on the short list was a GW Instek GPE-2323. It depends on whether you need a lot of bells and whistles like remote control, voltage/current logging, step through current / voltage settings, etc.

[David Hess]

I like the old Tektronix PS503A but it requires a TM500 mainframe.  HP made a whole series of suitable power supplies like the E3620A and E3631A which would be suitable.

[rhb]

I bought an Instek GPE-4323.  Price was good for a linear supply, it's got 4 adjustable outputs.  Current limiting on C1 & C2.  Just voltage on C3 & C4.  My sole complaint is that setting the limits is fiddly because they used a pot rather than an encoder.  And the banana jacks are very close together.  So clamping a wire or lug is difficult.  But it's not an issue with banana plugs.

I've used it as a current source measured with a 34401A and it did a good job of holding the current I set to uA levels.  Not that I could set it that closely.  Just that it held what it was set to that closely.

[rsjsouza]

If you don't care for modernities, a TP340A or a TW5005T may fit the bill. Actually, most anything from Power Designs, really (2020, 2050, etc.)

[JXL]

Other vintage supplies which could work are HP6236B and HP6237B (my favorite) triple output power supplies.  They don't have current limiting, but the circuitry is in there and external pots can be easily added.
The 6236B has a "twin", Leader LPS-151 and it's higher output current sibling LPS-152.  These last 2 have current limiting controls on the front panel.
The manuals with circuit diagrams for them are available on the net.

[exe]

Let me be a rebel in this thread, I propose Rigol DP832. I myself don't have it, but reviews are positive. Not ideal, but I'd buy it if I needed a PSU. But I have three DIY power supplies and slowly building the forth one .

There are other options from siglent, gw-instek, etc, worth checking them. Just be sure to check for overshoot issues. Other things that worth paying attention: (acoustic) noise, power consumption when it's off, firmware stability, 115/230V switch (or 90-264V operation), ease of use (ergonomics), number of channels (I suggest not less than 2).

[nctnico]

By the way: I would recommend against getting a switching power supply unless you need a lot of power and/or small size / light weight. Their outputs are quite noisy and they usually inject some HF noise into the outputs as well.

[bd139]

Other vintage supplies which could work are HP6236B and HP6237B (my favorite) triple output power supplies.  They don't have current limiting, but the circuitry is in there and external pots can be easily added.
The 6236B has a "twin", Leader LPS-151 and it's higher output current sibling LPS-152.  These last 2 have current limiting controls on the front panel.
The manuals with circuit diagrams for them are available on the net.

Had both of those HP supplies before. Very nice units. Hard current limit is effective however. Didn't blow anything up with them

For many years I used a 7Ah 12V SLA as a power supply with a series resistor in circuit to limit TBH. Worked fine and if anything went wrong the resistor went up in smoke instead.

Worth looking out for Thurlby / TTi PL320QMD / PL330QMD as well. Big but run at full whack with just passive heatsink. I have two of the single units at the moment.

[Wolfgang]

Hi,

I have a lot of lab PSUs, and the Rigol DP832 is the one I use most. Reasons:

- good range (2x33V/3.3A, 1x5V5A)
- fairly stable and accurate (10mV)
- current mode works
- computer controllable if needed
- good readouts
- there is an "A" version if you need more gimmicks and precision

Why not try one ? My dealers offer a 30 days no reasons asked return policy.

[rstofer]

Let me be a rebel in this thread, I propose Rigol DP832. I myself don't have it, but reviews are positive. Not ideal, but I'd buy it if I needed a PSU. But I have three DIY power supplies and slowly building the forth one .

I bought the DP832 a while back and I like it a lot.  The current limiting alone is worth the cost of entry.  I was bringing up a little Z80 project and I had an address conflict causing two devices to drive the bus simultaneously.  Without current limiting, this would have been a disaster.  As it worked out, the supply limited, the voltage dropped and nothing was damaged.

It's a really nice supply but it isn't inexpensive.  However, when you consider the lifetime of the supply (multiple decades, I suppose), the cost per day is insignificant.  It's the 'ouch' to the cash flow that hurts.

Even with the cost, I think it is a better solution than trying to build up multiple DIY supplies.  The DIY supplies just don't have the features and a workable current limit is one feature I want, regardless of cost.

It's also nice to be able to see both the setpoints and the outputs.  There's a lot of information on the screen and it is all helpful.

[exe]

The DIY supplies just don't have the features and a workable current limit is one feature I want, regardless of cost.

Are you attacking my power supply? Ha-ha, not just my psu has a current limit, it also has just an 10uF output capacitor. Compare with what you have in dp832 .

[Wolfgang]

Yeah, agreed. Of yourse you can do better than a DP832, but not for the same bang for the buck.

450$ for a 185W power supply with 3 channels, a decent line transformer, coolers, an LCD, SCPI control, ... homebrew ?! Naah  You show me !   

[exe]

450$ for a 185W power supply with 3 channels, a decent line transformer, coolers, an LCD, SCPI control, ... homebrew ?! Naah  You show me !   

Depends if you take time and cost of prototypes into account .

[bd139]

You're not going to get a homebrew one for less than that. Even if you discount labour it's pushing it.

Heatsinks, transformer and enclosure are the most expensive bits TBH and I reckon for something equivalent you're looking at $300 min.

Build vs buy is an easy decision these days. Buy is 99.9% of the time cheaper.