Re: [time-nuts] potential low-RFI power supply

[ed breya]

Taka,

You can set up a mini conducted-EMC lab with a few additional items that 
can be purchased, and some that you can make yourself, if you have the 
right parts.


The most important item is a wideband AC current probe or transformer. A 
commercial clip-on type is most convenient, and ideally it should have 
jaws big enough to clip around fairly large conductors, like an entire 
power cord. I have some nice Tek P6021s, but they are too small for 
large conductors - they only go up to about 3-4 mm diameter wire. I 
don't know what's available out there that would work for bigger stuff, 
but there may be some. It's not that you need a high current capability, 
but that it's very convenient to go around large cable assemblies or 
even components. In the old days, EMC labs would use nice big shielded 
split-toroid HF current transformers to clamp around the big stuff - I 
would imagine it's the same nowadays. When I need such measurements, I 
just wind up a transformer on a ferrite core. What you don't want is one 
of those big clamp-on amp meter type things - they are for measuring 
high currents at line frequency, and can't reach SMPS type frequencies. 
About 20-50 MHz or so BW is plenty, and you don't need to worry about 
the low end response like at line frequency, although that would be nice 
too.


I'm guessing you won't find such a probe with all these characteristics 
commercially, unless you get a high precision, professional type one 
made for EMC or SMPS design use, and likely very spendy. So, it's an 
opportunity to make your own. I'll explain later how to make some, but 
at this point it's necessary to know what you have available, 
ferrite-wise. Many people have nice collections of magnetic cores and 
parts, new or salvaged, so already may have plenty of pieces to play 
with. For SMPS/EMC use, it's good to have some nice ferrite power 
toroids - the bigger (like 2-3" ID) the better - for winding 
transformers with a hole big enough for a one-turn pass-through loop of 
big stuff, like a power cord, or even its plug too. For clamp-ons, you 
can use any un-gapped two-piece core like E-I, C-I, C-C, etc, again, the 
bigger the better, for putting around cords and such. If you have a 
bunch, that's great. Also, if you have some junker equipment with SMPS 
stuff in it, you can likely salvage many pieces that you can use.


Remember, all this current probe/transformer stuff is about measuring 
high speed common-mode currents, not operating loop currents in 
circuits. You'll want to first explore the time domain with a scope, 
then later an SA.


The next category of ferrites is more of the same stuff, but for 
steering the currents away from where they're not wanted, to where they 
don't bother anything, or can be dissipated. Lots of smaller cores are 
handy for this too, especially the split-toroid (or box) types that are 
commonly used and encountered on cords and internal wiring for EMC noise 
suppression. These are commonly called "prayer beads," for good reason.


I'll have more to say about all this next time.

Regarding your SA, you won't really need it to make any measurements on 
the DC output, until maybe later. The best use will be to look at the CM 
currents via the probe/transformer, which is an isolated AC measurement, 
and will have protection (I'll explain if necessary) against excessive 
signal power.


If you already know about thoroughly protecting your 50 ohm gear when 
making any measurements with DC present, then good. Just in case, I've 
included a couple of links to recent pertinent discussions in the hp and 
tek groups. This subject comes up every so often, and I always have 
something to say about it. Please read both threads all the way up and 
down, for context, and you'll have a pretty good idea of what's involved.


https://groups.io/g/HP-Agilent-Keysight-e quipment/message/106348

https://groups.io/g/TekScopes/message/166344

That's all for now. Good luck in finding lots of good ferrites, and 
maybe even a nice current probe.


Ed

___
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.

Re: [time-nuts] potential low-RFI power supply

[jimlux]

On 5/18/20 11:27 AM, Taka Kamiya via time-nuts wrote:

I bought one the moment information about this PS was posted here.

Will you gentlemen come up with a testing method?  I have an audio FFT, 
spectrum analyzer up to 26.5GHz, O'scope of various kind, measuring receiver, 
frequency counters, 6 1/2 DMM and other assorted stuff to play with.  I, 
however, lack the experience and technique most of folks here have.
I'll be glad to run any test and post a result.


Ed Breya had a pretty comprehensive list.

What I would start with is getting some big resistors to serve as a load.



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


 On Monday, May 18, 2020, 1:49:04 PM EDT, jimlux  
wrote:
  
  On 5/18/20 10:19 AM, Joseph Gwinn wrote:

On Mon, 18 May 2020 12:00:02 -0400, time-nuts-requ...@lists.febo.com
wrote:
Re: time-nuts Digest, Vol 190, Issue 30


Message: 1
Date: Sun, 17 May 2020 12:53:42 -0600
From: Eric Scace 
To: Time Nuts email list 
Subject: [time-nuts] potential low-RFI power supply
Message-ID: 
Content-Type: text/plain;    charset=utf-8

Pro Audio Engineering announced a sale (through Friday) on its
nominal 14 Vdc 4A switching supply
<https://proaudioeng.com/products/pae-kx33-low-rfi-ac-power-supply/>.
The test results
<https://proaudioeng.com/products/pae-kx33-low-rfi-ac-power-supply/>
webpage compares noise on the DC output and noise frequency spectrum
under a variety of conditions with a lead-acid battery, an Astron
linear supply, and a variety of switching supplies from other
manufacturers.

I have not used this and can?t vouch for its performance. Given
recent discussions here on supplies, the analysis might be
interesting. At least the supplier has attempted to quantify the
performance of its power supply and make that information available
to the prospective purchaser.

It would be interesting to see comparable (or more suitable)
measurements made by others posted here.


Given that this power supply is intended for audio applications such as
mixer boards, if the switching frequency exceeds say 200 KHz, none of
the ripple spurs will matter, as they are far above the band.  Hmm.
Unless that get too close to the sampling rate of some delta-sigma
converter I suppose.


Actually, it's intended as a power supply for HF transceivers, so noise
in the HF band is of interest. Especially if it's radiated from the
power cable.

___
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.




___
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.

Re: [time-nuts] potential low-RFI power supply

[Taka Kamiya via time-nuts]

I bought one the moment information about this PS was posted here.  

Will you gentlemen come up with a testing method?  I have an audio FFT, 
spectrum analyzer up to 26.5GHz, O'scope of various kind, measuring receiver, 
frequency counters, 6 1/2 DMM and other assorted stuff to play with.  I, 
however, lack the experience and technique most of folks here have.
I'll be glad to run any test and post a result.
--- 
(Mr.) Taka Kamiya
KB4EMF / ex JF2DKG
 

On Monday, May 18, 2020, 1:49:04 PM EDT, jimlux  
wrote:  
 
 On 5/18/20 10:19 AM, Joseph Gwinn wrote:
> On Mon, 18 May 2020 12:00:02 -0400, time-nuts-requ...@lists.febo.com
> wrote:
> Re: time-nuts Digest, Vol 190, Issue 30
> 
>> Message: 1
>> Date: Sun, 17 May 2020 12:53:42 -0600
>> From: Eric Scace 
>> To: Time Nuts email list 
>> Subject: [time-nuts] potential low-RFI power supply
>> Message-ID: 
>> Content-Type: text/plain;    charset=utf-8
>>
>> Pro Audio Engineering announced a sale (through Friday) on its
>> nominal 14 Vdc 4A switching supply
>> <https://proaudioeng.com/products/pae-kx33-low-rfi-ac-power-supply/>.
>> The test results
>> <https://proaudioeng.com/products/pae-kx33-low-rfi-ac-power-supply/>
>> webpage compares noise on the DC output and noise frequency spectrum
>> under a variety of conditions with a lead-acid battery, an Astron
>> linear supply, and a variety of switching supplies from other
>> manufacturers.
>>
>> I have not used this and can?t vouch for its performance. Given
>> recent discussions here on supplies, the analysis might be
>> interesting. At least the supplier has attempted to quantify the
>> performance of its power supply and make that information available
>> to the prospective purchaser.
>>
>> It would be interesting to see comparable (or more suitable)
>> measurements made by others posted here.
> 
> Given that this power supply is intended for audio applications such as
> mixer boards, if the switching frequency exceeds say 200 KHz, none of
> the ripple spurs will matter, as they are far above the band.  Hmm.
> Unless that get too close to the sampling rate of some delta-sigma
> converter I suppose.

Actually, it's intended as a power supply for HF transceivers, so noise 
in the HF band is of interest. Especially if it's radiated from the 
power cable.

___
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.

Re: [time-nuts] potential low-RFI power supply

[jimlux]

On 5/18/20 10:19 AM, Joseph Gwinn wrote:

On Mon, 18 May 2020 12:00:02 -0400, time-nuts-requ...@lists.febo.com
wrote:
Re: time-nuts Digest, Vol 190, Issue 30


Message: 1
Date: Sun, 17 May 2020 12:53:42 -0600
From: Eric Scace 
To: Time Nuts email list 
Subject: [time-nuts] potential low-RFI power supply
Message-ID: 
Content-Type: text/plain;   charset=utf-8

Pro Audio Engineering announced a sale (through Friday) on its
nominal 14 Vdc 4A switching supply
<https://proaudioeng.com/products/pae-kx33-low-rfi-ac-power-supply/>.
The test results
<https://proaudioeng.com/products/pae-kx33-low-rfi-ac-power-supply/>
webpage compares noise on the DC output and noise frequency spectrum
under a variety of conditions with a lead-acid battery, an Astron
linear supply, and a variety of switching supplies from other
manufacturers.

I have not used this and can?t vouch for its performance. Given
recent discussions here on supplies, the analysis might be
interesting. At least the supplier has attempted to quantify the
performance of its power supply and make that information available
to the prospective purchaser.

It would be interesting to see comparable (or more suitable)
measurements made by others posted here.


Given that this power supply is intended for audio applications such as
mixer boards, if the switching frequency exceeds say 200 KHz, none of
the ripple spurs will matter, as they are far above the band.  Hmm.
Unless that get too close to the sampling rate of some delta-sigma
converter I suppose.


Actually, it's intended as a power supply for HF transceivers, so noise 
in the HF band is of interest. Especially if it's radiated from the 
power cable.


___
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.

Re: [time-nuts] potential low-RFI power supply

[Bob kb8tq]

Hi



> On May 18, 2020, at 1:19 PM, Joseph Gwinn  wrote:
> 
> On Mon, 18 May 2020 12:00:02 -0400, time-nuts-requ...@lists.febo.com 
> wrote:
> Re: time-nuts Digest, Vol 190, Issue 30
> 
>> Message: 1
>> Date: Sun, 17 May 2020 12:53:42 -0600
>> From: Eric Scace 
>> To: Time Nuts email list 
>> Subject: [time-nuts] potential low-RFI power supply
>> Message-ID: 
>> Content-Type: text/plain;charset=utf-8
>> 
>> Pro Audio Engineering announced a sale (through Friday) on its 
>> nominal 14 Vdc 4A switching supply 
>> <https://proaudioeng.com/products/pae-kx33-low-rfi-ac-power-supply/>. 
>> The test results 
>> <https://proaudioeng.com/products/pae-kx33-low-rfi-ac-power-supply/> 
>> webpage compares noise on the DC output and noise frequency spectrum 
>> under a variety of conditions with a lead-acid battery, an Astron 
>> linear supply, and a variety of switching supplies from other 
>> manufacturers.
>> 
>> I have not used this and can?t vouch for its performance. Given 
>> recent discussions here on supplies, the analysis might be 
>> interesting. At least the supplier has attempted to quantify the 
>> performance of its power supply and make that information available 
>> to the prospective purchaser.
>> 
>> It would be interesting to see comparable (or more suitable) 
>> measurements made by others posted here.
> 
> Given that this power supply is intended for audio applications such as 
> mixer boards, if the switching frequency exceeds say 200 KHz, none of 
> the ripple spurs will matter, as they are far above the band.  Hmm.  
> Unless that get too close to the sampling rate of some delta-sigma 
> converter I suppose.

If it was only that simple …..

Switchers go into a variety of modes depending on what state they are in. 
One common mode “burps” the output when the load current is low. This 
significantly improves efficiency. It also takes the “crud frequency” way down. 

We often use one of these devices at a load well below the rated max. That
makes getting into these sorts of modes a fairly common thing. 

Bob


> 
> Joe Gwinn
> 
> ___
> 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.

Re: [time-nuts] potential low-RFI power supply

[Joseph Gwinn]

On Mon, 18 May 2020 12:00:02 -0400, time-nuts-requ...@lists.febo.com 
wrote:
Re: time-nuts Digest, Vol 190, Issue 30

> Message: 1
> Date: Sun, 17 May 2020 12:53:42 -0600
> From: Eric Scace 
> To: Time Nuts email list 
> Subject: [time-nuts] potential low-RFI power supply
> Message-ID: 
> Content-Type: text/plain; charset=utf-8
> 
> Pro Audio Engineering announced a sale (through Friday) on its 
> nominal 14 Vdc 4A switching supply 
> <https://proaudioeng.com/products/pae-kx33-low-rfi-ac-power-supply/>. 
> The test results 
> <https://proaudioeng.com/products/pae-kx33-low-rfi-ac-power-supply/> 
> webpage compares noise on the DC output and noise frequency spectrum 
> under a variety of conditions with a lead-acid battery, an Astron 
> linear supply, and a variety of switching supplies from other 
> manufacturers.
> 
> I have not used this and can?t vouch for its performance. Given 
> recent discussions here on supplies, the analysis might be 
> interesting. At least the supplier has attempted to quantify the 
> performance of its power supply and make that information available 
> to the prospective purchaser.
> 
> It would be interesting to see comparable (or more suitable) 
> measurements made by others posted here.

Given that this power supply is intended for audio applications such as 
mixer boards, if the switching frequency exceeds say 200 KHz, none of 
the ripple spurs will matter, as they are far above the band.  Hmm.  
Unless that get too close to the sampling rate of some delta-sigma 
converter I suppose.

Joe Gwinn

___
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.

Re: [time-nuts] potential low-RFI power supply

[ed breya]

Trying to look at the junk on the output voltage won't tell the story 
you need. Just connect a scope (1 meg) input to the DC output ground, 
and you'll begin to see the common-mode current situation. The actual LF 
and HF ripple on the DC out can be dealt with by sufficient filtering or 
post-regulation, and hardly matter compared to the common-mode currents, 
which will pervade everything connected.


First, put only a scope probe tip or direct input connection on the DC 
out ground or plus - shouldn't matter too much either way if the output 
floats. Do not connect the scope's ground to the PS yet - let its ground 
return to earth via its mains cord. This will likely indicate a very 
large signal, including the noises of the power supply and the scope and 
other local ground loop sources, against the high measuring impedance. 
This is the gross (in size and disgusting-ness) available CM driving 
voltage in your measurement setup, including line leakage, especially if 
the PS is fed by a two-wire cord.


With this setup, you should be able to see a pretty good representation 
of the actual signal on the main switching device in the PS. This is 
usually by far the biggest, fastest signal inside, and the cause of most 
EMC grief. Set up the scope triggering for LF Reject, and speed up the 
sweep to observe where the SMPS runs, say 20 kHz to maybe 300 kHz for 
newer type products, then play with the trigger level and hold-off. 
There should be plenty of crap available to trigger on - the trick is to 
get the right part. A dual timebase may help, but shouldn't be necessary.


You'll be able to tell if the PS runs in burst mode at no load, 
evidenced by chirping at low frequency, on the scope and maybe audibly. 
Now add some load, say 10 percent, and it will likely leave burst mode, 
and go to regular PWM at the proper frequency, which you now can 
measure. This frequency is the fundamental, for figuring out 
interference issues.


With a small load, depending on the topology, the PS may be running in 
discontinuous mode, evident on the switch waveform when the device shuts 
off, and a large ringing voltage appears, higher than the fundamental 
frequency. This represents energy in the tank circuit - transformer L 
and device and parasitic C all over the place. The resonant frequency 
and decay can change dramatically with conditions, and is not dependent 
on the fundamental, but is triggered by it, so imagine all the mixing 
products involved. This, plus line harmonics mixed in, tends to make 
what appears to be broadband noise, but a lot of it is actually finely 
spaced spurs that may move around with different loads and other 
conditions - what a mess..


As you increase the load, the PS may transition to continuous mode, and 
the big rings will disappear, since current through the energy storage 
inductance never goes to zero. Always present, are the very fast, 
smaller rings on all the sharp edges, due to leakage inductances and 
other device parasitics. These make up the very high frequency harmonic 
content, and easily escape into the environment.


As you can imagine, the EMC/spectral content can change a lot under 
different conditions. It's good to know as much as you can about what 
it's doing inside. Then it may be possible to avoid certain problems by 
operating in conditions where it's least offensive to your situation.


It's pretty slick to be able to see somewhat inside a black box, if you 
know what to look for. There's no guarantee this will work in any 
particular situation, but I'd say there's a very good chance of getting 
lots of details - or at least to see a lot of ugly waveforms that won't 
trigger properly. If you hardly see anything, then that means the device 
and you ambient environment are extremely clean - or more likely that 
your setup or scope have a problem.


The next step is to see some of your measurement limits. Now connect the 
scope ground (via BNC outer) or probe's ground clip to the signal point, 
which ideally results in no apparent signal, even with the sensitivity 
cranked way up. If this happens, then you're in great shape, 
ground-loop-wise. However, I'd guess or predict that you'll see plenty, 
because there is no true ground. The minimum signal is with the input 
shorted, and no connection to anything. When you hook it up, everything 
changes. Remember also, that a lot of noise will be around that's not 
from the DUT, so you need to determine what's what and where.


There are more measurements that can be made, of course, especially when 
you can think inside as well as outside the box. I'll have a bit more to 
say next time.


Ed



___
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.

Re: [time-nuts] potential low-RFI power supply

[Dana Whitlow]

IIRC the HP3561A goes to 100 kHz.  It's a well-built FFT analyzer at heart.

Dana


On Sun, May 17, 2020 at 4:12 PM Taka Kamiya via time-nuts <
time-nuts@lists.febo.com> wrote:

> I have an HP audio FFT that starts from sub 1Hz so I can do that when I
> get mine.  What kind of load shall I use for this?  Purely resistive load?
> What kind of power?  Near 100%, 50% or??  I don't know off the top of head
> what the available RBW is.  It's HP3561A
>
> ---
> (Mr.) Taka Kamiya
> KB4EMF / ex JF2DKG
>
>
> On Sunday, May 17, 2020, 4:12:03 PM EDT, jimlux 
> wrote:
>
>  On 5/17/20 11:53 AM, Eric Scace wrote:
> > Pro Audio Engineering announced a sale (through Friday) on its nominal
> 14 Vdc 4A switching supply <
> https://proaudioeng.com/products/pae-kx33-low-rfi-ac-power-supply/>. The
> test results <
> https://proaudioeng.com/products/pae-kx33-low-rfi-ac-power-supply/>
> webpage compares noise on the DC output and noise frequency spectrum under
> a variety of conditions with a lead-acid battery, an Astron linear supply,
> and a variety of switching supplies from other manufacturers.
> >
> > I have not used this and can’t vouch for its performance. Given recent
> discussions here on supplies, the analysis might be interesting. At least
> the supplier has attempted to quantify the performance of its power supply
> and make that information available to the prospective purchaser.
> >
> > It would be interesting to see comparable (or more suitable)
> measurements made by others posted here.
> > ___
> > 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.
> >
>
>
> Interesting.. It would have been nice to see spectrum analyzer plots
> from, say, 0 to 1 MHz with a much narrower resolution BW.  1 MHz/div
> with 300 kHz RBW isn't going to show the "row of discrete spurs" that
> the switchers put out.
>
> 4mV ripple isn't bad, or at least, it's better than most of the other
> switchers.  The Astron linear is given as 5mV, but the scope photo
> doesn't seem to show anything. At 5ms for the whole screen, you should
> see some variation for over the 8.33 ms ripple period.
>
>
> I get that they're demonstrating the performance with a specific
> transceiver load - but I'd be interested in seeing measurements at zero,
> 50%, and 100% load on a switcher.
>
>
>
> ___
> 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.
>
___
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.

Re: [time-nuts] potential low-RFI power supply

[Taka Kamiya via time-nuts]

I have an HP audio FFT that starts from sub 1Hz so I can do that when I get 
mine.  What kind of load shall I use for this?  Purely resistive load?  What 
kind of power?  Near 100%, 50% or??  I don't know off the top of head what the 
available RBW is.  It's HP3561A

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

On Sunday, May 17, 2020, 4:12:03 PM EDT, jimlux  
wrote:  
 
 On 5/17/20 11:53 AM, Eric Scace wrote:
> Pro Audio Engineering announced a sale (through Friday) on its nominal 14 Vdc 
> 4A switching supply 
> . The 
> test results 
>  webpage 
> compares noise on the DC output and noise frequency spectrum under a variety 
> of conditions with a lead-acid battery, an Astron linear supply, and a 
> variety of switching supplies from other manufacturers.
> 
> I have not used this and can’t vouch for its performance. Given recent 
> discussions here on supplies, the analysis might be interesting. At least the 
> supplier has attempted to quantify the performance of its power supply and 
> make that information available to the prospective purchaser.
> 
> It would be interesting to see comparable (or more suitable) measurements 
> made by others posted here.
> ___
> 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.
> 


Interesting.. It would have been nice to see spectrum analyzer plots 
from, say, 0 to 1 MHz with a much narrower resolution BW.  1 MHz/div 
with 300 kHz RBW isn't going to show the "row of discrete spurs" that 
the switchers put out.

4mV ripple isn't bad, or at least, it's better than most of the other 
switchers.  The Astron linear is given as 5mV, but the scope photo 
doesn't seem to show anything. At 5ms for the whole screen, you should 
see some variation for over the 8.33 ms ripple period.


I get that they're demonstrating the performance with a specific 
transceiver load - but I'd be interested in seeing measurements at zero, 
50%, and 100% load on a switcher.



___
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.

Re: [time-nuts] potential low-RFI power supply

[jimlux]

On 5/17/20 11:53 AM, Eric Scace wrote:

Pro Audio Engineering announced a sale (through Friday) on its nominal 14 Vdc 4A switching 
supply . The test 
results  webpage 
compares noise on the DC output and noise frequency spectrum under a variety of conditions 
with a lead-acid battery, an Astron linear supply, and a variety of switching supplies from 
other manufacturers.

I have not used this and can’t vouch for its performance. Given recent 
discussions here on supplies, the analysis might be interesting. At least the 
supplier has attempted to quantify the performance of its power supply and make 
that information available to the prospective purchaser.

It would be interesting to see comparable (or more suitable) measurements made 
by others posted here.
___
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.




Interesting.. It would have been nice to see spectrum analyzer plots 
from, say, 0 to 1 MHz with a much narrower resolution BW.   1 MHz/div 
with 300 kHz RBW isn't going to show the "row of discrete spurs" that 
the switchers put out.


4mV ripple isn't bad, or at least, it's better than most of the other 
switchers.  The Astron linear is given as 5mV, but the scope photo 
doesn't seem to show anything. At 5ms for the whole screen, you should 
see some variation for over the 8.33 ms ripple period.



I get that they're demonstrating the performance with a specific 
transceiver load - but I'd be interested in seeing measurements at zero, 
50%, and 100% load on a switcher.




___
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.

Re: [time-nuts] potential low-RFI power supply

[Taka Kamiya via time-nuts]

Looks promising!  I went ahead and purchased a piece.  With new switching 
supply COMPONENTS targeting audio market from various chip manufacturers, it is 
indeed a hopeful and promising development.  Now I'm wishing someone to make a 
piece one order of noise level less for "time-nuts" market.
A bit off topic but I've been playing with various time-nuts sources with 
internal regulation with various power sources, including bottom of the rung 
switchers.  (100mV +/- noise)  I'm finding perform surprisingly well.

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

On Sunday, May 17, 2020, 2:54:28 PM EDT, Eric Scace  wrote: 
 
 
 Pro Audio Engineering announced a sale (through Friday) on its nominal 14 Vdc 
4A switching supply 
. The test 
results  
webpage compares noise on the DC output and noise frequency spectrum under a 
variety of conditions with a lead-acid battery, an Astron linear supply, and a 
variety of switching supplies from other manufacturers.

I have not used this and can’t vouch for its performance. Given recent 
discussions here on supplies, the analysis might be interesting. At least the 
supplier has attempted to quantify the performance of its power supply and make 
that information available to the prospective purchaser.

It would be interesting to see comparable (or more suitable) measurements made 
by others posted here.
___
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.

[time-nuts] potential low-RFI power supply

[Eric Scace]

Pro Audio Engineering announced a sale (through Friday) on its nominal 14 Vdc 
4A switching supply 
. The test 
results  
webpage compares noise on the DC output and noise frequency spectrum under a 
variety of conditions with a lead-acid battery, an Astron linear supply, and a 
variety of switching supplies from other manufacturers.

I have not used this and can’t vouch for its performance. Given recent 
discussions here on supplies, the analysis might be interesting. At least the 
supplier has attempted to quantify the performance of its power supply and make 
that information available to the prospective purchaser.

It would be interesting to see comparable (or more suitable) measurements made 
by others posted here.
___
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.