Old(er) vs new(er) bench power supplies?

[gsrokmix]

Hello all,

This is my first post here on this forum. I have been lurking here, and watching Dave's videos for a while.

I am 46 years old, and am returning to school to get an AS in electronics engineering technology. I had a successful career as a recording engineer for over 20 years. With the business drying up quite a bit after 9/11, I had to take a job in a factory (which I hate) about 5 years ago. Having always been fascinated by electronics, I've decided to learn seriously, and hopefully make a new career out of my passion.

I am putting together my bench at home. I have a decent scope (Tek 2236), DMM (Fluke 87-V), function generator, and tools ect...I am now looking for a bench power supply.

I have read a million posts, and seen lots of reviews about specific units. The factory I work at has probably a couple of hundred supplies in use. They are all BK. I've been looking at some used models such as the BK 1760 triple output supply, and BK 1735 single output supply. These can be had on average for about $150 each.

My question (yes finally there is one.....) is are the older supplies still sufficient (assuming they are working properly) for general work? For about the same price as a new Mastech or other "cheap" supply on Amazon, I can get one of these older "lab quality" supplies.

Am I missing something basic? The triple output supplies interest me because they can be chained for more voltage / current. I don't know that I would need more than 30V & 3A for awhile?

I know this, or a very similar question(s) has been asked a million times, but I really would appreciate any advice or thoughts from those more experienced than myself (which is pretty much everyone here).

Thanks for your time. I am excited to be a part of this community which is so rich with information!

George

[nanofrog]

...Are the older supplies still sufficient (assuming they are working properly) for general work?

Yes, IME.

I've gotten better quality as well as more value for money by purchasing used. You do have to be careful of course, and do your homework (risk increases as you move down in price <untested, for-parts/not working, ...> vs. refurbished + calibrated + warranty type listings).

The triple output supplies interest me because they can be chained for more voltage / current. I don't know that I would need more than 30V & 3A for awhile?

Some single output PSU's can be connected in series/parallel as well (i.e. HP 62xx series can IIRC). That said, I've found the multiple output models are a better value, so I'm a bit biased towards them. 

[BillW50]

I have one of these power supplies and I love them. Variable 32VDC, 5 amp supply for $57.88.

http://www.banggood.com/CPS-3205-0-32V-0-5A-Portable-Adjustable-DC-Power-Supply-110V220V-p-934530.html

And since the output is isolated, you can chain them without a problem.

[gsrokmix]

That Gopher unit looks interesting. Is it a switching supply?

It looked like the multiple output supplies are a good value. I haven't read about a lot of people using them though?

Thanks for the replies.

George

[nanofrog]

That Gopher unit looks interesting. Is it a switching supply?

Yes, it's a switch mode design.

There's an entire thread on it actually; Switching power supply Gopher CPS-3010 30V 10A $0.35/W, and even a a video review:



Regarding multiple output PSU's, it seems there's plenty of people that have them (lots of photos in the Show your favorite and most used benchtop PSU thread). FWIW, mine would be a Power Designs TP343B.

[JoeN]

Go linear or go home.   

[nanofrog]

Go linear or go home.   

I much prefer linear as well.

And FWIW, older, quality used units available tend to be linear. 

[oldway]

I recommend old HP power supplies.
I have one 6236B triple output power supply and two 6296A (0-60V 3A).

[george graves]

I am 46 years old, and am returning to school to get an AS in electronics engineering technology. I had a successful career as a recording engineer for over 20 years.

Welcome.  I transitioned from video editing - so kinda the same deal (but started school for ME) For someone starting out, I would not recommend a used PS(or building your own PS).  Reason?  You won't have a clue how to repair it - once you've have a lot more knowledge, you will, but starting out, the best thing to do is to keep your barrier to entry low, and the frustration level manageable (cause it will be frustrating!)

I like my little Korad units(KA3005P - I have 2 - might pick up a 3rd as a back up).  Linear, really decent little guys - When I was starting electronics, I wish an entry level PS was as nice.

Yes, older stuff will have higher quality....And when you get to that point that you know what you'll need, well, then you'll know that you need it.  My 2 cents.

Not to mention size.  Do you have a huge desk that can take a 19" wide , 18" deep old PS?  So yea, sometimes smaller is better.

[rf-loop]

Go linear or go home.   

For normal lab use.
There are three possibilities, linear, linear and linear
1. Linear (conservative without any digital noise sources)
2. Linear (with perhaps digital display (some times noise source, depends...)
3. Linear using microproseccors control, TFT's ets digital noise sources but many times acceptable if know limits)
.
.
10. Very good lab grade "silent techcnology" primary switch mode, secondary analog.
.
.
~~. crap cheap primary/secondary switch mode "laboratory" shit power supply

[Rolo]

I had the same dilemma, if funds were no issue I would go for a Keysight U8001A or U8002A. I find this very attractive PSU's, linear and compact. While saving/waiting a used delta PSU showed up here (NL) on a second hand goods site.
I made a digital meter for it and replaced the 20 turn pot. Now it's working fine and it fits my hobby needs perfectly.
It's 0 to 30V, 3 Amps, linear. So it shows old ones can be good, if you can find a decent one to start with.

[Joule Thief]

I recommend old HP power supplies.
I have one 6236B triple output power supply and two 6296A (0-60V 3A).

I agree with the 62xx series from HP. A few squirts of contact cleaner on the VOLT / AMP selectors and maybe a filter capacitor or two in the reference power supplies and you have pure gold.

Don't overlook the Power Design TP343A series. Years of use and the only items needing replacement are the VOLT / AMP switches and possibly a 10 turn voltage control pot.

These are all absolutely silent runners and are a pleasure to work with.

[GreyWoolfe]

Don't forget the HP/Agilent/Keysight 36XX series power supplies.  I have a 3610 that I like a lot.

[BravoV]

Since the OP live in US, if I were him, for start I'd stalk for HP 6114A or 6115A adj power supply.

[Vgkid]

The 6114/6115 are pretty expensive, overkill for 99.9% of stuff. Plus they are sitting on my watch list...

[zapta]

Don't forget the HP/Agilent/Keysight 36XX series power supplies.  I have a 3610 that I like a lot.

I have a E3610A in a good condition but switched to a compact Tenma switch mode power supply.

Will not refuse a reasonable offer (US only). Established eevblog users can pay after delivery. It's just sitting there.

[Vgkid]

Another thumbs up for those compact Tenma linear psu's. I have one powering a few ocxo's for several months. Just need to replace those caps.

[gsrokmix]

Thanks guys for all of the replies.

The HP 6236B's look interesting. There are a few on ebay right now, but none look like they were tested.

The Agilent 3610's look good as well.

Will I really need 30V vs 20V out of a single supply?

I appreciate all of the advice.

Thanks,

George

[fivefish]

My 2 cents to this discussion.

What kind of projects do you think you'll be working on?
If opamp based, then you need a dual power supply.
500mA max of the HP 6236 (for the 0-20V sections) seems limiting/too low but will probably be enough for most opamp based projects.
If you'll be mostly working on digital stuff (5V, 3.3V sufficient high amps... 3A-5A) will probably be more to your liking.

I have a 6205C and used that for a long time, mostly on opamp based projects. But for other projects that require higher power, it goes into current limiting.
I bought a GW Instek GPS-3303 power supply. All analog design, dual 0-30V, plus a dedicated 5V output, all 3Amps capable. I liked it so much, I bought (2) more dead PSUs on eBay for $50 each and for additional $10 in parts, fixed them all. So I have (3) of these GPS units in my lab, plus (2) HP power supplies (6205C, E3620A).

There's currently one on eBay for $200. I suggest make an offer. http://www.ebay.com/itm/Nice-Instek-GPS-3303-Triple-Output-DC-Power-Supply-/131562897156?hash=item1ea1c27f04



This sucker weighs in at 16lbs. Huge transformer, and will easily deliver it's rated output. I've load tested them, it's truly 6Amp capable @ 30V (180Watts) + (5V x 3A = 15W).  Very easy to fix (jelly bean, cheap parts), and pretty robust.

It doesn't have fancy push-button, set your output voltage, or USB connection. If you're after that, and you think you need those features, then look into  something else. Maybe a new Rigol PSU.

YMMV. Good luck.

[c4757p]

My $0.02: my school has a couple labs stocked with that model power supply. They survive students. Perfectly good PSU.

[gsrokmix]

Eventually I would like to build my own mic pre-amps, and other audio gear. I don't know what industry I may find work in once I get out of school. For the foreseable future I will be mainly using it to power pretty basic circuits I will be building to learn from. I am also starting to collect broken gear to be able to practice trying to repair.

What do you feel the benefit of the Instek would be over an older unit such as a BK 1760?

Thanks,

George

[gsrokmix]

Which one you referring to, the Instek?

[c4757p]

Yes

[fivefish]

What do you feel the benefit of the Instek would be over an older unit such as a BK 1760?

Right now, you can get the GPS unit for $200 on eBay (probably even less as the seller is asking for a Best offer price). Instek wins.

I don't see a cooling fan on the BK psu, just a couple of big heatsinks at the back (maybe internal or none? I don't see a fan exhaust). The Instek has internal heatsinks, and an internal fan blowing hot air out (kicks in as temperature rises). So maybe the BK will be quieter than the Instek. or maybe the cooling fan of the Instek is a good sign of longevity? But then again, the BK is only 2amps per channel + 5Amps (9A total), while the Instek is 3Amps per channel x 3 outputs (9A total) -- draw(?) or slight win for Instek because of the fan.

The BK doesn't have a separate current meter. The Instek have separate   current and voltmeter for both outputs.  (No voltmeter/currentmeter on fixed 5V output though). Instek for the win.

More digits/resolution on the BK PSU LED display. BK for the win.

The BK does have adjustable 3rd rail output (but no voltmeter), the Instek only has fixed 5V output (so voltmeter not needed). -- BK for the win.

The BK only goes to 2 Amps on outputs A & B, the Instek to 3Amps on all outputs. Instek for the win.

BK weighs at 21lbs, Instek at 16lbs. (as scrap metal, BK for the win. Carrying it around, Instek for the win)

BK has coarse and fine voltage adjustments. The Instek needs light-finger touch if you want to set voltage/current to exactly 15.00 (so you don't get 14.99, or 15.01). BK wins.

Bigger LED displays for the Instek. And the separate current meter is a big-PLUS for me. I can monitor voltage and current at the same time at a glance.  Instek for the win.

Sorry, but it's an ugly power switch on the BK PSU It looks so out of place with the rest of it's knobs and buttons.

Both PSUs can do independent, series or parallel connection of it's dual outputs. -- draw.

** The only thing I don't like about the Instek is their use of single-turn potentiometers for the voltage and current setting. A multi-turn potentiometer would have been nice since it doesnt have fine/coarse adjustments.

Both seems a good pick for a lab PSU. Overall, my *personal* bias is towards the Instek because of that separate current meters, higher 3A+3A+3A capability... plus I know how to fix these things if ever they die out on me.

[gsrokmix]

Thanks fivefish. You made some good points. Thanks for taking the time to makethe comparisons.

I suppose the age of both could be considered too. Many more hours of run time on the older BK units I would have to assume?