Have $350US to Spend on a Bench Power Supply

[thakidd]

First of all, thanks goes out to Dave and the community. I have learned a lot just catching up on the forums and videos!

Trying to complete my bench so I can get serious with what I have been up to. Long story short, I have been screwing with C#/C++/VB/PHP and Java for the past 6 years in an IT/devel capacity. When I was a kid 20+ years ago, I started with Radio Shack electronic kits and then moved on to playing with parts my dad brought home from his job. Lost focus for 15 years and then discovered the BS2 > Arduino > Make Controller > and a few embedded Linux boards.

I am getting pretty good at prototyping projects but feel I really haven't had quality tools to advance farther. Bought some stupid $120 meter/12v psu/soldering iron combo a year ago and have had no luck what so ever with SMD. Thanks to this forum and Dave's videos, I bit the bullet and purchased the Rigol 1052E (i've needed a scope for 9 months or so) and a Hakko 936-12. I also have an Ideal 61-361 digital multimeter that I purchased a few years ago, drills, drill press, glue gun, dremel, and a panavise circuit board holder...think it does 0 to 10".

I see myself primarily tackling digital circuits. I have one more item currently on my list; I need a good PSU. I was reading the forums and noticed a few people said good things about Instek. I have been looking at their GPS-3030DD, GPS-6030D, and my favorite reading the specs, the GPS-2303.

Wondered if I could get some feedback on PSUs...Would those models work well and last a while or should I be looking in a different direction. Again the budget for a PSU is topped out at $350US and I do not feel comfortable building my own yet as my bench is in a town home man cave/bedroom.

I would also love any additional pointers on any other tools you think I might need for my workbench besides lots of components!

Thanks for the help.

[Bored@Work]

$350 is more than enough for a PSU, especially if you don't want one from big brands like Agilent.

In fact, the market is swamped with Made in China PSUs, of OK quality (and of course some dangerous junk). Although prices have gone up a little bit in recent month. These PSUs are usually advertised as "lab grade". Don't take this to serious, they are OK, but "lab grade" is an  entirely different game, a game you don't need.

The GPS-2303 you mentioned is a dual power supply, isn't it? As an example I randomly picked a typical Chinese power supply from ebay http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=370436827930

This is a triple one (two adjustable outputs, one fixed), for $162. Don't get confused by the label. PSU's looking like this are all from China and come under hundreds of different "brands". Just order enough of them from the factory, and the factory will put whatever label you want on the front.

I can't guarantee that this particular one will last long, and I encourage you to look around. However, these PSUs are usually pretty robust, because they have rather simple technology, and are often build around common regulators that are on the market for decades.  

My example is at the lower end of the scale, still I regard this PSU as OK. If you spend more you often just get a PSU with a nicer front plate, but the same guts. You can pay more if you change the technology, SMPS instead of linear regulation, remote control, more fine grained adjustments, more precision.

[slburris]

If you are in the US, you might look over some of the Mastech power supplies at
http://www.mastechpowersupply.com/

They have been happy to send me schematics of power supplies I've been
interested in.  Have the schematic is important to me, because it gives me a
decent chance to repair the supply if something goes wrong.  The Mastech
ones I've looked at are pretty much all off the shelf parts, quite repairable.

I have a power supply from Circuit Specialists:

http://www.circuitspecialists.com/level.itml/icOid/8613

that I got off of Ebay, and I've been quite happy with it as well.

Scott

[KTP]

For smt, the single most important tool I have other than my weller iron is a cheap ebay binocular microscope (10x, 30x, 50x).  I actually solder while looking through the microscope at 10x, then flip to 30x to inspect the joints (for something like TSSOP38 or TQFP64).  A good flux pen and some really thin solder helps too.

[thakidd]

@KTP: Didn't think about that addition but that completely makes sense. Just out of curiosity, what 'model' did you grab? I do need to up my soldier and flux pen (fat soldier and brush flex here...bad stuff). Anything you recommend soldier size wise and type of pen?

@slburris: I was wondering about the Mastech. Why did you go with the Circuit Specialists though?

@ BoredAtWork: That makes complete sense. I will look into those. Got to love China...if you are consuming.

[sonicj]

mod a old computer power supply and put the $$$ towards other gear on your wish list. you get 3.3v, 5v & 12v +/- with plenty of amperage. they can be had for cheap or free!
-sj

[KTP]

@KTP: Didn't think about that addition but that completely makes sense. Just out of curiosity, what 'model' did you grab? I do need to up my soldier and flux pen (fat soldier and brush flex here...bad stuff). Anything you recommend soldier size wise and type of pen?

Just make sure the microscope is the kind with the large diameter low power objective.  I don't know what model mine is...just some China garbage that works.

Something like this: http://cgi.ebay.com/NEW-DISSECTING-BINOCULAR-STEREO-MICROSCOPE-10X-30X-/200523954282?pt=LH_DefaultDomain_0&hash=item2eb028b86a

[TopherTheME]

mod a old computer power supply and put the $$$ towards other gear on your wish list. you get 3.3v, 5v & 12v +/- with plenty of amperage. they can be had for cheap or free!
-sj

I've got a PC power supply on my bench and it works great, especially for amount I paid for it ($0). The -12V and -5V rails really come in handy for powering op-amps.

[FreeThinker]

Just bought this off fleabay

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=190448067151&ssPageName=STRK:MEWAX:IT

not a very good pic but seems a decent unit from what i've read.Picking it up on Saturday.

[FreeThinker]

Just bought this off fleabay

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=190448067151&ssPageName=STRK:MEWAX:IT

not a very good pic but seems a decent unit from what i've read.Picking it up on Saturday.

Picked it up Saturday, does what it says on the tin...also got a Isotech ISR650 50mhz scope thrown in for an extra £13.50.Result!!!!. Plugged in and both work ok Any one got an operators/service manual? Thanks in advance

[thakidd]

Thx for all the replies!

Manson...that is an interesting choice in name. Glad they worked out for you.

I went to Fry's Electronics (haha, great name for a Wal-Mart kind of electronics shop...teehee!) and picked up a Mastek HY3003F-3 for $150US. Brought it home and immediately hooked it up to the Rigol scope to check it out. So far it seems pretty stable. Broke into it and was disappointed with the design quality. All in all, I cannot complain too much as it has turned out to be a pretty good piece of equipment. I just hope it lasts a while.

[slburris]

Thx for all the replies!

Manson...that is an interesting choice in name. Glad they worked out for you.

I went to Fry's Electronics (haha, great name for a Wal-Mart kind of electronics shop...teehee!) and picked up a Mastek HY3003F-3 for $150US. Brought it home and immediately hooked it up to the Rigol scope to check it out. So far it seems pretty stable. Broke into it and was disappointed with the design quality. All in all, I cannot complain too much as it has turned out to be a pretty good piece of equipment. I just hope it lasts a while.

Can you post some photos of the quality problems?

I picked up a Circuit Specialists power supply on Ebay a few months ago, and it's worked
just fine.  But if you look inside, there's plenty of evidence of sloppy hand soldering
of surface mount components.

Scott

[FreeThinker]

Thx for all the replies!

Manson...that is an interesting choice in name. Glad they worked out for you.

Rebadged by the likes of Rapid,Maplin,RS in the UK but manson is the name under the sticker.May change the pots to 10 turn ones as the selectivity is not great, or may add a second fine tune pot in series but will do fine for now.Not a top of the range unit but more than enough for my needs.Next on my list is a cheap DSO.Off to give Ebay search a good work out 

[Bored@Work]

Broke into it and was disappointed with the design quality.

That's the way they are. Rather simple technology, OK, but not more.

[Feanor]

Used Manson http://www.altronics.com.au/index.asp?area=item&id=M8226. No complaints at all, opened it up all looks pretty good inside.

[SuperMiguel]

Is it worth it to build a power supply using a computer power supply, and using resistor to control the current?

[MrPlacid]

Is it worth it to build a power supply using a computer power supply, and using resistor to control the current?

From what I've heard, no. It seemed that people who go this route sooner or later break down and buy a real power supply.

[SuperMiguel]

this one any good: http://www.circuitspecialists.com/prod.itml/icOid/10180 or http://www.mastechpowersupply.com/dc-power-supply/linear-power-supply/mastech-regulated-variable-dc-power-supply-hy1503d-15v-3a/prod_64.html

or i should ask whats the best Power supply i can buy for around $50-$100 ?

[Bored@Work]

this one any good: http://www.circuitspecialists.com/prod.itml/icOid/10180 or http://www.mastechpowersupply.com/dc-power-supply/linear-power-supply/mastech-regulated-variable-dc-power-supply-hy1503d-15v-3a/prod_64.html

Let me repeat almost word for word what I wrote before. Maybe you care to read it this time.

... the market is swamped with Made in China PSUs, of OK quality (and of course some dangerous junk). Although prices have gone up a little bit in recent month. These PSUs are usually advertised as "lab grade". Don't take this to serious, they are OK, but "lab grade" is an  entirely different game, a game you don't need.

...

...  Don't get confused by the label. PSU's looking like this are all from China and come under hundreds of different "brands". Just order enough of them from the factory, and the factory will put whatever label you want on the front.

I can't guarantee that this particular one will last long, and I encourage you to look around. However, these PSUs are usually pretty robust, because they have rather simple technology, and are often build around common regulators that are on the market for decades. 

My example is at the lower end of the scale, still I regard this PSU as OK. If you spend more you often just get a PSU with a nicer front plate, but the same guts. You can pay more if you change the technology, SMPS instead of linear regulation, remote control, more fine grained adjustments, more precision.

or i should ask whats the best Power supply i can buy for around $50-$100 ?

Asking for "the best" is usually a stupid move. Every piece of equipment is a compromise, usually of many factors. In fact, if you go into a shop and ask for "the best" the shop assistants immediately know they can rip you off, since you haven't clear requirements and can be lied to.

[saturation]

I have just finished evaluating a Mastech linear power supply.  I had to get hold of high power resistors to load it down to maximum and I was surprised it did better than its specification; it also did not blow.  I don't have time to post the pics and raw data, but if you're looking for a great linear PSU for under $100, Mastech is very competitive, for this model:

Load regulation: maximum load, 3A, 30Vdc, ripple was in the microvolt

under lower voltages it was fairly constant at under 1mV, down to 0.1Vdc, a bit concerning but good, when using it to drive low voltage circuits

Did not test line regulation

Power draw quiescent was 8W, at maximum load it drew 140W

CONS:

The amp meter is quite accurate, the voltmeter is not.  This is because it measures Vdc out including the internal resistance drop of the PSU, so under load the voltmeter reading is off as high as 10%.  

You can recalibrate both meters, it has its own adjustments screws under the meters, and is not mentioned in the manuals.  However, the internal resistance wont' change the accuracy of the voltmeter.

The voltmeter is non-linear, and even with zero load there is a 1-0.5% error reading 0-30V.

The voltmeter is most accurate the lower the loads are.  its not a problem driving modern circuit designs that draw in the mA, but if you're near 1A, its best to get a separate DMM to monitor the supply.

The fan is always on.  Its unnecessary under 1A loads, but it would be best if it had a small thermal cutoff switch since it is noisy.  It is definitely needed once 1A loads are used, and the unit starts to get hot internally.

See discussion here:

https://www.eevblog.com/forum/index.php?topic=683.15

My unit:



The Hi/Lo switch doubles the current output for the current current knob setting.  A strange switch but the main advantage is that the total power consumption of the whole PSU is lower slightly if this switch is LO for the same output volt-amps, in other words if you output 1A at 30V with this switch at LO, the power consumption is lower that if you switch it to HI and still output 1A, 30V.

So default, leave it at LO until the amps provided are no longer sufficient.

The fine adjustment is terrific!  You can adjust millivolts and milliamps with easy stable precision.

The lowest price Mastech is $50, its a steal.




 

If you are in the US, you might look over some of the Mastech power supplies at
http://www.mastechpowersupply.com/

They have been happy to send me schematics of power supplies I've been
interested in.  Have the schematic is important to me, because it gives me a
decent chance to repair the supply if something goes wrong.  The Mastech
ones I've looked at are pretty much all off the shelf parts, quite repairable.

I have a power supply from Circuit Specialists:

http://www.circuitspecialists.com/level.itml/icOid/8613

that I got off of Ebay, and I've been quite happy with it as well.

Scott

[SuperMiguel]

is 3A enough?

[saturation]

For electronics work, yes.  Most electronics today are very low power devices and driving voltages are far under 10V, they are often designed to work with just batteries or brick supplies.  A typical cellphone battery is 1500mAH at 3.7V, so at full power this unit can supply 1.5A at 3.7V for only 1 hour, far within the capacity of the cheapest Mastech supply.

A common use for high current are in radio transmissions or audio amps, but digital has reduced power consumption markedly compared to analog radio.  As for designing audio amps, well, sky's the limit!

What is more common to use today for general electronics are multiple supplies, that is having 2-5 PSU variable supplies.  I typically use 2 at one time, one to power the project, another to provide variable input.  Once I've tested it with variable DC, then I switch to a function generator.  Thus, you often find dual supplies built into one unit.

2 Mastech 15V supplies will cost you $100, plus s&H, far under your budget.  If you're just starting, just get one to check it out, you'll always have a need for just 1 variable PSU.

A minimum voltage to have is about 15V, this is typical for driving analog op amps, usually 10V and up.  Since op amp supplies are often split, such as  15V and -15V, 2 15V supplies can power such circuits easily.  These are typically uses for dual tracking supplies, which roughly cost about the same as 2 single units.

Many folks opt to get single PSU with dual/triple/quad supplies built into one unit, but I prefer to buy them separate.  If the unit fails, you lose all those multiple supplies simultaneously, and if you check the cost, its near the same to buy separate Mastech than a single multi-supply.

Programmable or computer controlled supplies are rarely needed for home or individual use.  They are very useful in production work, when even the time to twiddle knobs takes too long, and you want to dial in a precise A or V, or have it controlled to do multiple QC tests on a production line.  

is 3A enough?

[SuperMiguel]

this one : http://www.mastechpowersupply.com/dc-power-supply/linear-power-supply/mastech-regulated-variable-dc-power-supply-hy1503d-15v-3a/prod_64.html

[saturation]

Which 15v you recommend?

http://www.mastechpowersupply.com/dc-power-supply/linear-power-supply/mastech-regulated-variable-dc-power-supply-hy1503d-15v-3a/prod_64.html

If you do want one, email Sean and get CONFIRMATION BEFORE you order on the ff:

The unit is in stock
When will it ship
Finalize the price

The website automated ordering system works, but the stock and final price maybe different.  Sean will answer email about orders very quickly.

[SuperMiguel]

Whos sean? Whats his email?

wow shipping is $20

so the final price on the site is $69.99 with shipping

also does this power supply ship with the probes?