wall wart + LT3045?

[jabbr]

13 hours ago, Superdad said:

My post this afternoon was more a reaction to mansr's suggestion--via his posting of the LT3045's PSRR graph--that a DC regulator would block common-mode AC currents. 

 

Perhaps it’s terminology but the common mode currents can sail around the regulator ie on the ground plane, rather than through the regulator — which is why I’m saying that the schematics are important. These leakage currents are currents like any other that flow in a closed path. The regulator does block AC currents per the PSRR but if the leakage current path doesn’t go through the regulator, then it’s not blocked. 

 

But consider the diagram “Common mode noise” in the link I posted. Now consider the impedance of the block marked “Circuit” ... consider what happens to the current flows as the impedance is raised. This will reduce common mode current flow at the expense of differential mode flow, and indeed the regulator does reduce leakage current. Right?

 

Alternatively the regulator shunts the AC currents to ground — the leakage current loop is before the output and might not pass through the down line circuit. 

 

Again the details of theentire schematic are critical to answer to answer this question. 

[Ralf11]

my qualified statement: the schematic is important to consumers, only if they can read it...

[jabbr]

 

You don’t need to read a schematic — watch this — note that the SMPS does not supply what’s being tested !!

[the_doc735]

the wall wart + LT3045 seems to have pro's and con''s. Thanks for all your advice and info. As it stands I don't think it is a worthwhile venture overall. It makes it much more difficult when you have a low budget to work with. Even a separate radius power supply from the CU seems to be in doubt as even this leads back to a common rail in the CU where contamination occurs.

So, I have made a diagram of my power configuration, so that anyone can give advice as a way forward. Trouble is; dozens of LPSU's cost a small fortune! Even just fitting-up the Player PC with LPSU (s) is expensive to me.

 

 

...Power Banks (for moby)?

"FWIW, most people don't realize that these USB batteries and power banks use DC-to-DC boost converters internally (a switch mode power supply) to achieve various voltages from their internal lithium-ion batteries. Google 'boost converter'. "
 

[the_doc735]

Is this 'better' than a SMPS (wall wart)?

 

UK 9V 1A AC-AC Linear Power Supply

 

 

....it's linear and cheap!

[the_doc735]

FYI:

 

power-inspired

[sandyk]

3 hours ago, the_doc735 said:

Is this 'better' than a SMPS (wall wart)?

 

UK 9V 1A AC-AC Linear Power Supply

 

 

....it's linear and cheap!

It's also useless without at least  Bridge rectifier diodes and a filter capacitor after it  , and without a voltage regulator the Output voltage will vary considerably under load, and the actual output voltage will also depend on the regulation of the transformer inside it.

 Even the cheap 9V DC  versions with just basic rectifier diodes and a filter capacitor inside the case as well can have as high as 14V DC OUT in some cases !!!

[mansr]

8 hours ago, the_doc735 said:

Is this 'better' than a SMPS (wall wart)?

 

UK 9V 1A AC-AC Linear Power Supply

 

 

....it's linear and cheap!

That outputs 9V AC, not DC. It's mostly likely just a simple transformer. Calling it "linear" is meaningless.

[jabbr]

16 hours ago, Ralf11 said:

my qualified statement: the schematic is important to consumers, only if they can read it...

 

Yeah it gets fairly technical. The topics of leakage currents, common mode noise, EMI are related and can appear like voodoo but aren’t. Switch mode power supplies can be designed to work in low noise environment — but really cheap wall warts have issues that involve all the above. 

 

There are “cheap” SMPS which are really bad and then there are those which are very cost effective. Hard to tell the difference without learning a bit. I advocate for power supply manufacturers to provide measurements/spec sheets.

 

This presentation is worth spending a considerable amount of time understanding. Henry Ott: http://www.hottconsultants.com/pdf_files/APEC-2002.pdf

[Foggie]

11 hours ago, the_doc735 said:

Is this 'better' than a SMPS (wall wart)?

 

UK 9V 1A AC-AC Linear Power Supply

 

 

....it's linear and cheap!

 

These Jameco have been recommended by many here as a great wall wart - in a pinch/short or long term as well. 

 

 

[the_doc735]

9 hours ago, mansr said:

That outputs 9V AC, not DC. It's mostly likely just a simple transformer. Calling it "linear" is meaningless.

Ooo...hps! Sorry, meant to show a AC/DC version/example. Well spotted.

[the_doc735]

6 hours ago, Foggie said:

 

These Jameco have been recommended by many here as a great wall wart - in a pinch/short or long term as well. 

 

 

please note: I would require 220-240v (UK). I wonder if these have the rectifier diodes, a filter capacitor & voltage regulator?

[the_doc735]

Does anyone know if this LPSU would be suitable for a TP-LINK MC220L?

(i.e. rectifier diodes, a filter capacitor & voltage regulator?)

...gets rid of the switching problem?

 

https://www.ebay.co.uk/itm/DC-Linear-Power-Supply-Regulator-PSU-DC-9V-for-DAC-Low-noise-Replace-switch-psu/132640010957?hash=item1ee1f5f2cd:g:cmwAAOSwgcVbCnut

 

GOOD PRICE!  

 

I know Voltage and amperage are OK.

 

[sandyk]

45 minutes ago, the_doc735 said:

I know Voltage and amperage are OK.

 

 Not according to the datasheet for the TP LINK !  You would need to ask for the 5V 2.5A model.

 

Power: 5VDC/1A (AC/DC adapter incl.)

http://images10.newegg.com/UploadFilesForNewegg/itemintelligence/TP-LINK/L13111470376071800.pdf

[the_doc735]

21 minutes ago, sandyk said:

 

 Not according to the datasheet for the TP LINK !  You would need to ask for the 5V 2.5A model.

 

Power: 5VDC/1A (AC/DC adapter incl.)

http://images10.newegg.com/UploadFilesForNewegg/itemintelligence/TP-LINK/L13111470376071800.pdf

 

this is the label on the back of the unit:

[sandyk]

44 minutes ago, the_doc735 said:

 

this is the label on the back of the unit:

 

If that is what you already have, then no problems.

 The one at the link must be a different version.

[Ralf11]

10 hours ago, jabbr said:

 

Yeah it gets fairly technical. The topics of leakage currents, common mode noise, EMI are related and can appear like voodoo but aren’t. Switch mode power supplies can be designed to work in low noise environment — but really cheap wall warts have issues that involve all the above. 

 

There are “cheap” SMPS which are really bad and then there are those which are very cost effective. Hard to tell the difference without learning a bit. I advocate for power supply manufacturers to provide measurements/spec sheets.

 

This presentation is worth spending a considerable amount of time understanding. Henry Ott: http://www.hottconsultants.com/pdf_files/APEC-2002.pdf

 

Thanks - I never thought of the different modes being correlated with antenna shapes...

 

I started a thread on whether a consumer could look at design features for any help in narrowing their listening choices:

 

 

[jabbr]

2 hours ago, the_doc735 said:

Does anyone know if this LPSU would be suitable for a TP-LINK MC220L?

(i.e. rectifier diodes, a filter capacitor & voltage regulator?)

...gets rid of the switching problem?

 

https://www.ebay.co.uk/itm/DC-Linear-Power-Supply-Regulator-PSU-DC-9V-for-DAC-Low-noise-Replace-switch-psu/132640010957?hash=item1ee1f5f2cd:g:cmwAAOSwgcVbCnut

 

 

 

Fine ... the ones I have and refer to as the "Ultra el-cheapo" are similar to: https://www.ebay.co.uk/itm/30W-Hifi-Ultra-low-noise-Linear-Power-supply-DC5V-2-5A-R-core-transformer-L6-37/123286410738?hash=item1cb47155f2:g:gtUAAOSwJslbK4AI -- they have different VA ranges, and some are similar to the Sigma 11 design with a discrete current-mirror MOSFET pass transistor, zener diode design. Thanks to @look&listen for pointing out the similarities to me.

 

Great compromise for that particular application.

 

[Ralf11]

Superphonica needs an "El Cheapo Audio Mart" storefront 

[jabbr]

17 minutes ago, Ralf11 said:

Thanks - I never thought of the different modes being correlated with antenna shapes...

 

 

Yep, the "common mode noise" and EMI issues are largely the same.

http://www.hottconsultants.com/pdf_files/image_plane.pdf

I could post a whole page of references dating back 40+ years describing the effects of various shielding techniques and configurations on radiated EMI ... of course this remains all the rage to this day

 

Regarding DAC#2 above -- no it doesn't do what it claims ... ask for data...

[the_doc735]

1 hour ago, jabbr said:

 

Fine ... the ones I have and refer to as the "Ultra el-cheapo" are similar to: https://www.ebay.co.uk/itm/30W-Hifi-Ultra-low-noise-Linear-Power-supply-DC5V-2-5A-R-core-transformer-L6-37/123286410738?hash=item1cb47155f2:g:gtUAAOSwJslbK4AI -- they have different VA ranges, and some are similar to the Sigma 11 design with a discrete current-mirror MOSFET pass transistor, zener diode design. Thanks to @look&listen for pointing out the similarities to me.

 

Great compromise for that particular application.

 

your choice looks pretty good valve too! R-Core etc. And still a decent price as well. many thanks!

[sandyk]

1 hour ago, Ralf11 said:

Superphonica needs an "El Cheapo Audio Mart" storefront 

 

 Are you thinking of selling your Oppo 205 ?

[the_doc735]

Can anyone confirm what I have read; that any devices in the system chain BEFORE the FCoE cable doesn't need any special processing, Linear PSU's etc. etc. (i.e. the devices I have highlighted in pink, in the pic.)?

 

...apparently only the signal gets through the optic cable (no rubbish)?

[the_doc735]

the 'TV' (hdmi) link with soon be removed from the equation as I am thinking of making the PLAYER PC - 'headless' and using

remote desktop via my domestic/general purpose laptop. Good idea? ?

 

 

 

[the_doc735]

more detail: