Re: [time-nuts] Power Supplies

[Taka Kamiya via time-nuts]

Similar story
I was using one of those small modules abundant on Amazon and eBay.  Buck 
converter and drop out board.  It was noisy so I put a ferrite bead on output 
side.  One worked ok.  Added another and that put the board into full 
oscillation and it outputted 37V into a DUT destroying it.  (It was set to 5v)

--- 
(Mr.) Taka Kamiya
KB4EMF / ex JF2DKG
 

On Sunday, May 3, 2020, 12:26:30 PM EDT, Steve - Home  
wrote:  
 
 Thanks Ed, that was another solution I was considering. I’ve got a few LMs in 
a drawer, I’ll have to order a few LTs. 

Steve
WB0DBS



> On May 3, 2020, at 11:02 AM, ed breya  wrote:
> 
> If you have a supply with something north of 15V, and you'd like to make 12V 
> battery type voltage, it's easy to add an external solution with a low 
> dropout three-terminal regulator to take it down a bit and still get good 
> regulation. Look at LT1085 family, for example.
> 
> Ed
> 
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Re: [time-nuts] Power Supplies

[Steve - Home]

Thanks Ed, that was another solution I was considering. I’ve got a few LMs in a 
drawer, I’ll have to order a few LTs. 

Steve
WB0DBS



> On May 3, 2020, at 11:02 AM, ed breya  wrote:
> 
> If you have a supply with something north of 15V, and you'd like to make 12V 
> battery type voltage, it's easy to add an external solution with a low 
> dropout three-terminal regulator to take it down a bit and still get good 
> regulation. Look at LT1085 family, for example.
> 
> Ed
> 
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Re: [time-nuts] Power Supplies

[ed breya]

If you have a supply with something north of 15V, and you'd like to make 
12V battery type voltage, it's easy to add an external solution with a 
low dropout three-terminal regulator to take it down a bit and still get 
good regulation. Look at LT1085 family, for example.


Ed

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Re: [time-nuts] Power Supplies

[Steve - Home]

I bit the bullet and ordered a pair of 12V supplies. I’ll see what I can suss 
out for differences when I get them side by side on the bench. 

Steve
WB0DBS



> On May 3, 2020, at 9:39 AM, Bob kb8tq  wrote:
> 
> Hi
> 
> Unfortunately, there usually *is* a difference on each of these supplies. 
> They “fine tune” them for one specific voltage. Since the magnetics are 
> often done in house, there’s not much of a way to figure out everything 
> that they have done.
> 
> The risk with any switcher is that they can (and sometimes do) fail in a
> dramatic fashion. That may involve taking out the gear they are attached
> to when they fail. 
> 
> I had that happen with one about two years ago. The device cost $120 to 
> replace. What it killed was $400 and could have been up in the $10,000 range. 
> Obviously this was not on the bench in the basement …..
> 
> Bob
> 
>> On May 3, 2020, at 10:26 AM, Steve - Home  wrote:
>> 
>> Hi Bob,
>> 
>> Main reason was I already have a few 15V ones and would like to reuse them. 
>> I have a gut feeling there’s not a major difference between the 12V and 15V 
>> models. I may get one of the 12V ones and open it up and do a comparison. I 
>> thought maybe someone had been down that path before. 
>> 
>> Steve
>> WB0DBS
>> 
>> 
>> 
 On May 3, 2020, at 9:15 AM, Bob kb8tq  wrote:
>>> 
>>> Hi
>>> 
>>> If you want to do it and get full output, the change probably involves 
>>> nasty things
>>> like swapping out inductors …. Likely cheaper to just spend the $16 and buy
>>> a brand new one at the right voltage. 
>>> 
>>> https://www.trcelectronics.com/View/Mean-Well/LRS-100-12.shtml 
>>> 
>>> 
>>> Given the risks of getting a mod “almost right”, it’s probably worth the 
>>> piece of mind
>>> with a new one as well. 
>>> 
>>> Bob
>>> 
 On May 3, 2020, at 9:53 AM, Steve - Home  wrote:
 
 Has anyone found schematics for the Mean Well supplies? I have a couple of 
 15V 7A ones that will adjust down to 14.1 and I’d like to get them down to 
 the 12-13.8 range. 
 
 Steve
 WB0DBS
 
 
 
>> On May 3, 2020, at 8:43 AM, Bob kb8tq  wrote:
> 
> Hi
> 
> 
>> On May 2, 2020, at 8:10 PM, Perry Sandeen via time-nuts 
>>  wrote:
>> 
>> Learned Gentlemen,
>> I personally dislike equipment that uses *wall warts* due to quality 
>> concerns
>> One inexpensive way I've powered my Lucent equipment is using used 
>> laptop power supplies. They're easily found at HamFests or on ebay.  On 
>> Ebay prices very wildly.  If you buy 3 or 4 they can be $5 each shipped.
>> Another source to consider are the Mean Well SRPS at Jameco. 
> 
> If you are shopping for Mean Well supplies, TRC
> 
> https://www.trcelectronics.com/mean-well 
> 
> 
> is a good place to shop. They are a (if not the) factory direct US 
> distributor for the
> brand. That should eliminate the risk of getting one labeled Meen Well or 
> Men Well or ….
> That sort of thing is pretty common on eBay.
> 
> At least on the stuff I’ve shopped for, their prices are pretty good. 
> They deliver next 
> day on the cheap. Of course that’s probably because they are about 2 
> hours down the
> road from here :) 
> 
> Bob
> 
>> They run from 55 watts on up with a wide range of voltages.  They are 
>> have spec sheets.  Some SRPS's on ebay are cheap but their quality...
>> Regards,
>> Perrier
>> ___
>> time-nuts mailing list -- time-nuts@lists.febo.com
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>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>> and follow the instructions there.
> 
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>>> 
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> To 

Re: [time-nuts] Power Supplies

[Bob kb8tq]

Hi

Unfortunately, there usually *is* a difference on each of these supplies. 
They “fine tune” them for one specific voltage. Since the magnetics are 
often done in house, there’s not much of a way to figure out everything 
that they have done.

The risk with any switcher is that they can (and sometimes do) fail in a
dramatic fashion. That may involve taking out the gear they are attached
to when they fail. 

I had that happen with one about two years ago. The device cost $120 to 
replace. What it killed was $400 and could have been up in the $10,000 range. 
Obviously this was not on the bench in the basement …..

Bob

> On May 3, 2020, at 10:26 AM, Steve - Home  wrote:
> 
> Hi Bob,
> 
> Main reason was I already have a few 15V ones and would like to reuse them. I 
> have a gut feeling there’s not a major difference between the 12V and 15V 
> models. I may get one of the 12V ones and open it up and do a comparison. I 
> thought maybe someone had been down that path before. 
> 
> Steve
> WB0DBS
> 
> 
> 
>> On May 3, 2020, at 9:15 AM, Bob kb8tq  wrote:
>> 
>> Hi
>> 
>> If you want to do it and get full output, the change probably involves nasty 
>> things
>> like swapping out inductors …. Likely cheaper to just spend the $16 and buy
>> a brand new one at the right voltage. 
>> 
>> https://www.trcelectronics.com/View/Mean-Well/LRS-100-12.shtml 
>> 
>> 
>> Given the risks of getting a mod “almost right”, it’s probably worth the 
>> piece of mind
>> with a new one as well. 
>> 
>> Bob
>> 
>>> On May 3, 2020, at 9:53 AM, Steve - Home  wrote:
>>> 
>>> Has anyone found schematics for the Mean Well supplies? I have a couple of 
>>> 15V 7A ones that will adjust down to 14.1 and I’d like to get them down to 
>>> the 12-13.8 range. 
>>> 
>>> Steve
>>> WB0DBS
>>> 
>>> 
>>> 
> On May 3, 2020, at 8:43 AM, Bob kb8tq  wrote:
 
 Hi
 
 
> On May 2, 2020, at 8:10 PM, Perry Sandeen via time-nuts 
>  wrote:
> 
> Learned Gentlemen,
> I personally dislike equipment that uses *wall warts* due to quality 
> concerns
> One inexpensive way I've powered my Lucent equipment is using used laptop 
> power supplies. They're easily found at HamFests or on ebay.  On Ebay 
> prices very wildly.  If you buy 3 or 4 they can be $5 each shipped.
> Another source to consider are the Mean Well SRPS at Jameco. 
 
 If you are shopping for Mean Well supplies, TRC
 
 https://www.trcelectronics.com/mean-well 
 
 
 is a good place to shop. They are a (if not the) factory direct US 
 distributor for the
 brand. That should eliminate the risk of getting one labeled Meen Well or 
 Men Well or ….
 That sort of thing is pretty common on eBay.
 
 At least on the stuff I’ve shopped for, their prices are pretty good. They 
 deliver next 
 day on the cheap. Of course that’s probably because they are about 2 hours 
 down the
 road from here :) 
 
 Bob
 
> They run from 55 watts on up with a wide range of voltages.  They are 
> have spec sheets.  Some SRPS's on ebay are cheap but their quality...
> Regards,
> Perrier
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to 
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
 
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 time-nuts mailing list -- time-nuts@lists.febo.com
 To unsubscribe, go to 
 http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
 and follow the instructions there.
>>> 
>>> 
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>> 
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> 
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Re: [time-nuts] Power Supplies

[Steve - Home]

Thanks Bob, I’ll have a look at that. 

Steve
WB0DBS



> On May 3, 2020, at 9:23 AM, Robert LaJeunesse  wrote:
> 
> Steve, you shouldn't need a schematic. Look for a resistor between the 
> output + line and the pot that adjusts the voltage. Determine the value and 
> add a shunt resistor across it that is maybe 10x the value determined. See if 
> that drops it down enough. Adjust the shunt up or down to get the range you 
> want. Also note that if this is a linear supply setting it for a lower output 
> voltage range will increase dissipation at full load and possibly require 
> better / forced air cooling. 
> 
> Bob L.
> 
>> Sent: Sunday, May 03, 2020 at 9:53 AM
>> From: "Steve - Home" 
>> To: "Discussion of precise time and frequency measurement" 
>> 
>> Subject: Re: [time-nuts] Power Supplies
>> 
>> Has anyone found schematics for the Mean Well supplies? I have a couple of 
>> 15V 7A ones that will adjust down to 14.1 and I’d like to get them down to 
>> the 12-13.8 range. 
>> 
>> Steve
>> WB0DBS
> 
> 
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Re: [time-nuts] Power Supplies

[Steve - Home]

Hi Bob,

Main reason was I already have a few 15V ones and would like to reuse them. I 
have a gut feeling there’s not a major difference between the 12V and 15V 
models. I may get one of the 12V ones and open it up and do a comparison. I 
thought maybe someone had been down that path before. 

Steve
WB0DBS



> On May 3, 2020, at 9:15 AM, Bob kb8tq  wrote:
> 
> Hi
> 
> If you want to do it and get full output, the change probably involves nasty 
> things
> like swapping out inductors …. Likely cheaper to just spend the $16 and buy
> a brand new one at the right voltage. 
> 
> https://www.trcelectronics.com/View/Mean-Well/LRS-100-12.shtml 
> 
> 
> Given the risks of getting a mod “almost right”, it’s probably worth the 
> piece of mind
> with a new one as well. 
> 
> Bob
> 
>> On May 3, 2020, at 9:53 AM, Steve - Home  wrote:
>> 
>> Has anyone found schematics for the Mean Well supplies? I have a couple of 
>> 15V 7A ones that will adjust down to 14.1 and I’d like to get them down to 
>> the 12-13.8 range. 
>> 
>> Steve
>> WB0DBS
>> 
>> 
>> 
 On May 3, 2020, at 8:43 AM, Bob kb8tq  wrote:
>>> 
>>> Hi
>>> 
>>> 
 On May 2, 2020, at 8:10 PM, Perry Sandeen via time-nuts 
  wrote:
 
 Learned Gentlemen,
 I personally dislike equipment that uses *wall warts* due to quality 
 concerns
 One inexpensive way I've powered my Lucent equipment is using used laptop 
 power supplies. They're easily found at HamFests or on ebay.  On Ebay 
 prices very wildly.  If you buy 3 or 4 they can be $5 each shipped.
 Another source to consider are the Mean Well SRPS at Jameco. 
>>> 
>>> If you are shopping for Mean Well supplies, TRC
>>> 
>>> https://www.trcelectronics.com/mean-well 
>>> 
>>> 
>>> is a good place to shop. They are a (if not the) factory direct US 
>>> distributor for the
>>> brand. That should eliminate the risk of getting one labeled Meen Well or 
>>> Men Well or ….
>>> That sort of thing is pretty common on eBay.
>>> 
>>> At least on the stuff I’ve shopped for, their prices are pretty good. They 
>>> deliver next 
>>> day on the cheap. Of course that’s probably because they are about 2 hours 
>>> down the
>>> road from here :) 
>>> 
>>> Bob
>>> 
 They run from 55 watts on up with a wide range of voltages.  They are have 
 spec sheets.  Some SRPS's on ebay are cheap but their quality...
 Regards,
 Perrier
 ___
 time-nuts mailing list -- time-nuts@lists.febo.com
 To unsubscribe, go to 
 http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
 and follow the instructions there.
>>> 
>>> ___
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>>> To unsubscribe, go to 
>>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>>> and follow the instructions there.
>> 
>> 
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> 
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Re: [time-nuts] Power Supplies

[Robert LaJeunesse]

Steve, you shouldn't need a schematic. Look for a resistor between the output + 
line and the pot that adjusts the voltage. Determine the value and add a shunt 
resistor across it that is maybe 10x the value determined. See if that drops it 
down enough. Adjust the shunt up or down to get the range you want. Also note 
that if this is a linear supply setting it for a lower output voltage range 
will increase dissipation at full load and possibly require better / forced air 
cooling. 

Bob L.

> Sent: Sunday, May 03, 2020 at 9:53 AM
> From: "Steve - Home" 
> To: "Discussion of precise time and frequency measurement" 
> 
> Subject: Re: [time-nuts] Power Supplies
>
> Has anyone found schematics for the Mean Well supplies? I have a couple of 
> 15V 7A ones that will adjust down to 14.1 and I’d like to get them down to 
> the 12-13.8 range. 
> 
> Steve
> WB0DBS


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Re: [time-nuts] Power Supplies

[Bob kb8tq]

Hi

If you want to do it and get full output, the change probably involves nasty 
things
like swapping out inductors …. Likely cheaper to just spend the $16 and buy
a brand new one at the right voltage. 

https://www.trcelectronics.com/View/Mean-Well/LRS-100-12.shtml 


Given the risks of getting a mod “almost right”, it’s probably worth the piece 
of mind
with a new one as well. 

Bob

> On May 3, 2020, at 9:53 AM, Steve - Home  wrote:
> 
> Has anyone found schematics for the Mean Well supplies? I have a couple of 
> 15V 7A ones that will adjust down to 14.1 and I’d like to get them down to 
> the 12-13.8 range. 
> 
> Steve
> WB0DBS
> 
> 
> 
>> On May 3, 2020, at 8:43 AM, Bob kb8tq  wrote:
>> 
>> Hi
>> 
>> 
>>> On May 2, 2020, at 8:10 PM, Perry Sandeen via time-nuts 
>>>  wrote:
>>> 
>>> Learned Gentlemen,
>>> I personally dislike equipment that uses *wall warts* due to quality 
>>> concerns
>>> One inexpensive way I've powered my Lucent equipment is using used laptop 
>>> power supplies. They're easily found at HamFests or on ebay.  On Ebay 
>>> prices very wildly.  If you buy 3 or 4 they can be $5 each shipped.
>>> Another source to consider are the Mean Well SRPS at Jameco. 
>> 
>> If you are shopping for Mean Well supplies, TRC
>> 
>> https://www.trcelectronics.com/mean-well 
>> 
>> 
>> is a good place to shop. They are a (if not the) factory direct US 
>> distributor for the
>> brand. That should eliminate the risk of getting one labeled Meen Well or 
>> Men Well or ….
>> That sort of thing is pretty common on eBay.
>> 
>> At least on the stuff I’ve shopped for, their prices are pretty good. They 
>> deliver next 
>> day on the cheap. Of course that’s probably because they are about 2 hours 
>> down the
>> road from here :) 
>> 
>> Bob
>> 
>>> They run from 55 watts on up with a wide range of voltages.  They are have 
>>> spec sheets.  Some SRPS's on ebay are cheap but their quality...
>>> Regards,
>>> Perrier
>>> ___
>>> time-nuts mailing list -- time-nuts@lists.febo.com
>>> To unsubscribe, go to 
>>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>>> and follow the instructions there.
>> 
>> ___
>> time-nuts mailing list -- time-nuts@lists.febo.com
>> To unsubscribe, go to 
>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>> and follow the instructions there.
> 
> 
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Re: [time-nuts] Power Supplies

[Steve - Home]

Has anyone found schematics for the Mean Well supplies? I have a couple of 15V 
7A ones that will adjust down to 14.1 and I’d like to get them down to the 
12-13.8 range. 

Steve
WB0DBS



> On May 3, 2020, at 8:43 AM, Bob kb8tq  wrote:
> 
> Hi
> 
> 
>> On May 2, 2020, at 8:10 PM, Perry Sandeen via time-nuts 
>>  wrote:
>> 
>> Learned Gentlemen,
>> I personally dislike equipment that uses *wall warts* due to quality concerns
>> One inexpensive way I've powered my Lucent equipment is using used laptop 
>> power supplies. They're easily found at HamFests or on ebay.  On Ebay prices 
>> very wildly.  If you buy 3 or 4 they can be $5 each shipped.
>> Another source to consider are the Mean Well SRPS at Jameco. 
> 
> If you are shopping for Mean Well supplies, TRC
> 
> https://www.trcelectronics.com/mean-well 
> 
> 
> is a good place to shop. They are a (if not the) factory direct US 
> distributor for the
> brand. That should eliminate the risk of getting one labeled Meen Well or Men 
> Well or ….
> That sort of thing is pretty common on eBay.
> 
> At least on the stuff I’ve shopped for, their prices are pretty good. They 
> deliver next 
> day on the cheap. Of course that’s probably because they are about 2 hours 
> down the
> road from here :) 
> 
> Bob
> 
>> They run from 55 watts on up with a wide range of voltages.  They are have 
>> spec sheets.  Some SRPS's on ebay are cheap but their quality...
>> Regards,
>> Perrier
>> ___
>> time-nuts mailing list -- time-nuts@lists.febo.com
>> To unsubscribe, go to 
>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>> and follow the instructions there.
> 
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Re: [time-nuts] Power Supplies

[Bob kb8tq]

Hi


> On May 2, 2020, at 8:10 PM, Perry Sandeen via time-nuts 
>  wrote:
> 
> Learned Gentlemen,
> I personally dislike equipment that uses *wall warts* due to quality concerns
> One inexpensive way I've powered my Lucent equipment is using used laptop 
> power supplies. They're easily found at HamFests or on ebay.  On Ebay prices 
> very wildly.  If you buy 3 or 4 they can be $5 each shipped.
> Another source to consider are the Mean Well SRPS at Jameco. 

If you are shopping for Mean Well supplies, TRC

https://www.trcelectronics.com/mean-well 


is a good place to shop. They are a (if not the) factory direct US distributor 
for the
brand. That should eliminate the risk of getting one labeled Meen Well or Men 
Well or ….
That sort of thing is pretty common on eBay.

At least on the stuff I’ve shopped for, their prices are pretty good. They 
deliver next 
day on the cheap. Of course that’s probably because they are about 2 hours down 
the
road from here :) 

Bob

> They run from 55 watts on up with a wide range of voltages.  They are have 
> spec sheets.  Some SRPS's on ebay are cheap but their quality...
> Regards,
> Perrier
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to 
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
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[time-nuts] Power Supplies

[Perry Sandeen via time-nuts]

Learned Gentlemen,
I personally dislike equipment that uses *wall warts* due to quality concerns
One inexpensive way I've powered my Lucent equipment is using used laptop power 
supplies. They're easily found at HamFests or on ebay.  On Ebay prices very 
wildly.  If you buy 3 or 4 they can be $5 each shipped.
Another source to consider are the Mean Well SRPS at Jameco.  They run from 55 
watts on up with a wide range of voltages.  They are have spec sheets.  Some 
SRPS's on ebay are cheap but their quality...
Regards,
Perrier
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Re: [time-nuts] power supplies

[ed breya]

Power supplies are indeed mostly commodity items, but absolutely 
essential. I have a large collection of OEM open-frame units, in linear 
and SMPS, and a small collection of commercial bench supplies, and some 
home-made ones.


You can of course get a bunch of bench units and set them up for every 
possible need, and with a dazzling array of readouts and adjustments. 
What matters is what you mostly need to do, and what you want not to 
happen. If you have to work on one thing at a time, with one to a few 
voltages, it's pretty straightforward to set up and be ready to monitor 
what's going on. If you have a bunch of things that use standard 
supplies, that just need to run simultaneously, I think it's better to 
just have simple supplies that put out a bunch of standard voltages for 
them, with no fancy controls or measurement capability.


I've designed and built and used many SMPSs over the years, which is why 
I prefer good old-school linear supplies. If you don't need high power 
density or levels, you should go with linear, regardless of whether it's 
a commercial bench unit, OEM, or slapped together yourself. It will 
start out much cleaner, involving less grief when it comes to noise 
control - almost a guaranteed issue in time-nut type situations. You 
can't avoid SMPS noise entirely, since we're awash with their signals 
all around us, from PCs and equipment and appliances and practically 
everything else, but at least you can try to not add too much more right 
in the middle of your work. Don't get me wrong - I love SMPSs and 
related technology, and all the stuff they enable us to have and enjoy. 
Life would be a lot different and less fun (but quieter) without them.


If you just need an assortment of supply voltages at modest currents, 
one way is to put together an OEM linear supply like a standard +/-15V & 
+5V one, with some three-terminal regulator circuits at other desired 
voltages, and means to hook them up to the items. Refinements like 
OVP/RVP etc can be added, but of course add some complexity.


One thing I always do, especially carefully for high-value or 
one-of-a-kind items, is add intrinsic protection against any anticipated 
powering faults like over-voltage and reverse polarity. No matter how 
fancy your supplies are, it's still possible to make a mistake in hookup 
or settings, and ruin the device being powered.


The same applies to the power supplies themselves. With a bench supply, 
you don't necessarily know what would happen to it and its load, if you 
say, accidentally short a +12V supply to the +5V. Would it damage the 
supply and its load? If you fully know the characteristics and specs and 
what's behind the front panel, you can predict the outcome. If you built 
it yourself, you know that that you've (hopefully) anticipated the 
possibility and provided for this event, or, the supply may not be 
protected, but you've already added intrinsic protection to the load device.


So, it can get complicated, and as always, it depends...

Ed

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Re: [time-nuts] power supplies

[Poul-Henning Kamp]

In message <73bfcf33-8b29-38a6-d5a7-9192375d4...@earthlink.net>, jimlux writes:

>I suppose I can package a bunch of those up in a bigger box with banana 
>jacks or binding posts.

Use power-pole connectors, they are cheap and *so* much better.

I'm using a couple of fused West Mountain Radio distributors to
spread my 24VDC and 12VDC around the lab, highly recommended.

-- 
Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
p...@freebsd.org | TCP/IP since RFC 956
FreeBSD committer   | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.

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Re: [time-nuts] power supplies

[Steve - Home]

I’d give a “thumbs up” for the Acopian supplies, too. I have several and they 
get used regularly. I haven’t had one die on me yet (knocks on head)

Steve
WB0DBS



> On May 1, 2020, at 6:23 PM, jimlux  wrote:
> 
> On 5/1/20 12:07 PM, Tim Shoppa wrote:
>> Jim, when it comes to "bench supplies" - knobs for voltage and meters -
>> most of the commonly available Chinese bench supplies in the under 3A-range
>> are linear with series regulator.
>> This unit (HY1803D) is typical and has a transformer (relay-selected
>> winding depending on the voltage setting) and a 2N3055 heat sink on the
>> back.
>> http://www.mastechpowersupplies.com/variable-regulated-power-supply-hy1803d.html
>> After you get to the 5A range they start becoming switchers. There are only
>> a couple of common designs with different trim and brand names on the front.
>> Of course old-school (50's-80's era) regulated HP bench supplies are
>> commonly available on the surplus market and they are built like tanks and
>> pretty much infinitely repairable as long as the meters haven't been
>> smashed in.
> 
> 
> 
> True, but these days, I'd rather fool with oscillators and mixers than power 
> supply repair.  I've kind of gotten out of the "buy old surplus gear and make 
> do" phase. Although if you go somewhere like the San Bernardino Microwave 
> Society meetings, there's people there with literal truck loads of old test 
> gear, for which I would have sold my future children into bondage for, when 
> it was only 20 years old - of course, now it's 50 years old.
> 
> I'm past the thrill of running a 1980s sweeper or the venerable 8640 signal 
> generator.
> 
> Hence the question about "off the shelf bench power supplies"
> 
> 
> 
> 
> 
>> I would be reluctant to use a bench supply for long-term use because you
>> bump that knob and what was supposed to be 3.3V becomes 18V.
> 
> 
> Uh, no, I'd never do that, no, uh-uh.  At JPL we have bunches of overvoltage 
> protector widgets from some company I can't remember, banana plugs or wires, 
> external to the bench supply.  If you go over 5.25V, it crowbars.
> 
> 
>> Few to no current production wall warts are linear. Power-conserving
>> regulations around the world now pretty much require wall warts to be
>> switchers. Linear (including regulated) wall warts are still available from
>> the surplus outlets but they are less common than before.
> 
> yeah, i've got a box of those older linear warts - a transformer, a diode, 
> maybe a bridge, and maybe a capacitor.   Good for stuff like running LEDs or 
> small motors.
> 
> 
>> Few to no current production modular fixed-voltage supplies are linear.
>> With a handful of exceptions (I think a couple of the Lambda linear modules
>> are still available) they are almost all switchers.
> 
> Acopian is your friend for linear "bricks".
> 
> https://www.acopian.com/linear-regulated-power-supply-models.html
> 
> That familiar gold box is a common sight.
> 
> 
> 
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Re: [time-nuts] power supplies

[jimlux]

On 5/1/20 12:07 PM, Tim Shoppa wrote:

Jim, when it comes to "bench supplies" - knobs for voltage and meters -
most of the commonly available Chinese bench supplies in the under 3A-range
are linear with series regulator.

This unit (HY1803D) is typical and has a transformer (relay-selected
winding depending on the voltage setting) and a 2N3055 heat sink on the
back.
http://www.mastechpowersupplies.com/variable-regulated-power-supply-hy1803d.html

After you get to the 5A range they start becoming switchers. There are only
a couple of common designs with different trim and brand names on the front.

Of course old-school (50's-80's era) regulated HP bench supplies are
commonly available on the surplus market and they are built like tanks and
pretty much infinitely repairable as long as the meters haven't been
smashed in.




True, but these days, I'd rather fool with oscillators and mixers than 
power supply repair.  I've kind of gotten out of the "buy old surplus 
gear and make do" phase. Although if you go somewhere like the San 
Bernardino Microwave Society meetings, there's people there with literal 
truck loads of old test gear, for which I would have sold my future 
children into bondage for, when it was only 20 years old - of course, 
now it's 50 years old.


I'm past the thrill of running a 1980s sweeper or the venerable 8640 
signal generator.


Hence the question about "off the shelf bench power supplies"







I would be reluctant to use a bench supply for long-term use because you
bump that knob and what was supposed to be 3.3V becomes 18V.



Uh, no, I'd never do that, no, uh-uh.  At JPL we have bunches of 
overvoltage protector widgets from some company I can't remember, banana 
plugs or wires, external to the bench supply.  If you go over 5.25V, it 
crowbars.





Few to no current production wall warts are linear. Power-conserving
regulations around the world now pretty much require wall warts to be
switchers. Linear (including regulated) wall warts are still available from
the surplus outlets but they are less common than before.


yeah, i've got a box of those older linear warts - a transformer, a 
diode, maybe a bridge, and maybe a capacitor.   Good for stuff like 
running LEDs or small motors.





Few to no current production modular fixed-voltage supplies are linear.
With a handful of exceptions (I think a couple of the Lambda linear modules
are still available) they are almost all switchers.


Acopian is your friend for linear "bricks".

https://www.acopian.com/linear-regulated-power-supply-models.html

That familiar gold box is a common sight.



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Re: [time-nuts] power supplies

[jimlux]

On 5/1/20 1:11 PM, Mark Sims wrote:

Yes, Power Designs units are VERY good.  Some (their precision models) are 
insanely good.   They have a cult following and can be a bit pricey these days. 
 There are lots of posts on eevblog.com about them.  Dave did a video on one of 
the precision units.

https://www.eevblog.com/forum/testgear/power-designs-power-supplies-database/msg2801534/#msg2801534


Lots of PowerDesigns 2010, 2020, etc.  at JPL
Not in cal, some have broken features, but used all over the place.
(In fact, though we are teleworking, there's one powering a Wenzel 10MHz 
OCXO on my desk at work, right now. the current meter doesn't work for 
some reason, but that's what the DMM was for)



Seems they're $150-ish used


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Re: [time-nuts] power supplies

[Bob kb8tq]

Hi

You don’t have to get into the fancy versions to get a nice quiet supply. 
One of the guys at Frequency Electronics  (I forget who …) turned me 
on to them back in the 1970’s. I have not seen any of them selling for the
sort of prices some other supplies seem to command …. Maybe I just 
spend more time digging.

Bob

> On May 1, 2020, at 4:11 PM, Mark Sims  wrote:
> 
> Yes, Power Designs units are VERY good.  Some (their precision models) are 
> insanely good.   They have a cult following and can be a bit pricey these 
> days.  There are lots of posts on eevblog.com about them.  Dave did a video 
> on one of the precision units.
> 
> https://www.eevblog.com/forum/testgear/power-designs-power-supplies-database/msg2801534/#msg2801534
> 
> -
> 
>> Spend some time on eBay looking for Power Designs bench supplies. 
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[time-nuts] power supplies

[Mark Sims]

Yes, Power Designs units are VERY good.  Some (their precision models) are 
insanely good.   They have a cult following and can be a bit pricey these days. 
 There are lots of posts on eevblog.com about them.  Dave did a video on one of 
the precision units.

https://www.eevblog.com/forum/testgear/power-designs-power-supplies-database/msg2801534/#msg2801534

-

>Spend some time on eBay looking for Power Designs bench supplies. 
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Re: [time-nuts] power supplies

[Gerhard Hoffmann]

I love my R NGT20, I have several of them.
Reasonably clean, analog, uA741 technology, no switcher, knobs for 
everything.

3 independent, unconnected outputs:

2* 0-20V@1A for op amps etc

1*0-6V@5A for the digital stuff

for example:
< 
https://www.ebay.de/itm/Rohde-Schwarz-DC-Power-Supply-Stromversorgungsgerat-Typ-NGT-20/193258127587?hash=item2cff1500e3:g:v6wAAOSwlnVd9j7J 
  >



I have measured some of the devices I have here to see how much there

was to filter for my analog toys:


< 
http://www.hoffmann-hochfrequenz.de/downloads/Noise_Measurements_On_Some_Laboratory_Power_Supplies.pdf 
   >


For the NGT20 that was not much.

The HP6633B: OMG!!!

Cheers, Gerhard




Am 01.05.20 um 20:51 schrieb jimlux:
What with telework, I'm doing more timenuts-ey stuff at home, and the 
power supply conundrum has come up.


There's a plethora of interesting widgets scattered across my bench 
requiring variously, 5V, 8V, 12V, and 15V.


I've got a box full of various fixed voltage supplies, mostly linear, 
picked up over the years.
I suppose I can package a bunch of those up in a bigger box with 
banana jacks or binding posts.



And then there's some things where you'd like current limiting and/or 
variable voltage.


So I've started looking at inexpensive bench power supplies - there 
appear to be dozens, if not hundreds, of these available. There must 
be dozens that are all very similar - They're switchers for the most 
part, displays, etc. for $50-100, from different vendors, all similar.


Are they essentially commodity? Or are there particular brands that 
are good or bad?


Are they all noisy?

Weird UI problems (7 menu layers with a single knob)?



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Re: [time-nuts] power supplies

[Bob kb8tq]

Hi

Spend some time on eBay looking for Power Designs bench supplies. 
They went out of business years ago so they are not a popular item. 
Thus the price is usually pretty reasonable. I have never seen one that
was a switcher….

Bob

> On May 1, 2020, at 2:51 PM, jimlux  wrote:
> 
> What with telework, I'm doing more timenuts-ey stuff at home, and the power 
> supply conundrum has come up.
> 
> There's a plethora of interesting widgets scattered across my bench requiring 
> variously, 5V, 8V, 12V, and 15V.
> 
> I've got a box full of various fixed voltage supplies, mostly linear, picked 
> up over the years.
> I suppose I can package a bunch of those up in a bigger box with banana jacks 
> or binding posts.
> 
> 
> And then there's some things where you'd like current limiting and/or 
> variable voltage.
> 
> So I've started looking at inexpensive bench power supplies - there appear to 
> be dozens, if not hundreds, of these available.  There must be dozens that 
> are all very similar - They're switchers for the most part, displays, etc. 
> for $50-100, from different vendors, all similar.
> 
> Are they essentially commodity? Or are there particular brands that are good 
> or bad?
> 
> Are they all noisy?
> 
> Weird UI problems (7 menu layers with a single knob)?
> 
> 
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Re: [time-nuts] power supplies

[Tim Shoppa]

Jim, when it comes to "bench supplies" - knobs for voltage and meters -
most of the commonly available Chinese bench supplies in the under 3A-range
are linear with series regulator.

This unit (HY1803D) is typical and has a transformer (relay-selected
winding depending on the voltage setting) and a 2N3055 heat sink on the
back.
http://www.mastechpowersupplies.com/variable-regulated-power-supply-hy1803d.html

After you get to the 5A range they start becoming switchers. There are only
a couple of common designs with different trim and brand names on the front.

Of course old-school (50's-80's era) regulated HP bench supplies are
commonly available on the surplus market and they are built like tanks and
pretty much infinitely repairable as long as the meters haven't been
smashed in.

I would be reluctant to use a bench supply for long-term use because you
bump that knob and what was supposed to be 3.3V becomes 18V.

Few to no current production wall warts are linear. Power-conserving
regulations around the world now pretty much require wall warts to be
switchers. Linear (including regulated) wall warts are still available from
the surplus outlets but they are less common than before.

Few to no current production modular fixed-voltage supplies are linear.
With a handful of exceptions (I think a couple of the Lambda linear modules
are still available) they are almost all switchers.

Tim N3QE



On Fri, May 1, 2020 at 2:52 PM jimlux  wrote:

> What with telework, I'm doing more timenuts-ey stuff at home, and the
> power supply conundrum has come up.
>
> There's a plethora of interesting widgets scattered across my bench
> requiring variously, 5V, 8V, 12V, and 15V.
>
> I've got a box full of various fixed voltage supplies, mostly linear,
> picked up over the years.
> I suppose I can package a bunch of those up in a bigger box with banana
> jacks or binding posts.
>
>
> And then there's some things where you'd like current limiting and/or
> variable voltage.
>
> So I've started looking at inexpensive bench power supplies - there
> appear to be dozens, if not hundreds, of these available.  There must be
> dozens that are all very similar - They're switchers for the most part,
> displays, etc. for $50-100, from different vendors, all similar.
>
> Are they essentially commodity? Or are there particular brands that are
> good or bad?
>
> Are they all noisy?
>
> Weird UI problems (7 menu layers with a single knob)?
>
>
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Re: [time-nuts] power supplies

[Peter Loron]

If you are patient, you can find Sorensen/Xantrex/Ametek programmable power 
supplies on eBay for reasonable prices. Some of them are linear, some 
switching. High quality stuff. The XT series are linear bench supplies.

-Pete

> On May 1, 2020, at 11:51, jimlux  wrote:
> 
> What with telework, I'm doing more timenuts-ey stuff at home, and the power 
> supply conundrum has come up.
> 
> There's a plethora of interesting widgets scattered across my bench requiring 
> variously, 5V, 8V, 12V, and 15V.
> 
> I've got a box full of various fixed voltage supplies, mostly linear, picked 
> up over the years.
> I suppose I can package a bunch of those up in a bigger box with banana jacks 
> or binding posts.
> 
> 
> And then there's some things where you'd like current limiting and/or 
> variable voltage.
> 
> So I've started looking at inexpensive bench power supplies - there appear to 
> be dozens, if not hundreds, of these available.  There must be dozens that 
> are all very similar - They're switchers for the most part, displays, etc. 
> for $50-100, from different vendors, all similar.
> 
> Are they essentially commodity? Or are there particular brands that are good 
> or bad?
> 
> Are they all noisy?
> 
> Weird UI problems (7 menu layers with a single knob)?
> 
> 
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