Go Back   Home > Forums > >

Mean well vs generic power adapter vs  audio oriented smps
Mean well vs generic power adapter vs  audio oriented smps
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools
Old 27th August 2020, 07:46 AM   #21
Sangram is offline Sangram  India
diyAudio Moderator
 
Sangram's Avatar
 
Join Date: Sep 2002
Location: India
Mean well vs generic power adapter vs  audio oriented smps
Yes, but those have quite a bit more noise and you have issues because there are now two noise sources in series. Depending on your DAC's current requirements, a simple TL431-based series regulator will be much better. Or an LM317, which is a much simpler circuit - at the expense of a bit of performance (almost negligible).
  Reply With Quote
Old 27th August 2020, 08:08 AM   #22
auriga2001in is offline auriga2001in  India
diyAudio Member
 
Join Date: Nov 2013
Location: Bangalore
Yes, LM317 for the DAC maks sense due to the low power requirements. But, can I still use the buck converter for other 5V applications like USB hub, chargers, etc? Basically, my question was regarding series connecting anything with input capacitors (like the buck converter) to the Meanwell smps.
Thanks.
  Reply With Quote
Old 27th August 2020, 08:11 AM   #23
Sangram is offline Sangram  India
diyAudio Moderator
 
Sangram's Avatar
 
Join Date: Sep 2002
Location: India
Mean well vs generic power adapter vs  audio oriented smps
Yes, using a buck converter for non-audio applications is absolutely fine. Input caps aren't a problem as long as they're not diyAudio spec - which means below about 470uF. No buck converter I know has larger.
  Reply With Quote
Old 30th August 2020, 11:01 AM   #24
profdc9 is offline profdc9
diyAudio Member
 
Join Date: Aug 2020
Default CMC power supply filter board

I am working on an audio amp and I designed a PCB for it because I originally planned on using two LRS-350-48 Meanwell supplies for it.



PowerAmpAudio/PowerCond at master * profdc9/PowerAmpAudio * GitHub


However, to use it, a metal chassis should be use so that the RF from the switching noise and other noise sources is separated from the supply rails.
Attached Images
File Type: png PowerCond.png (58.4 KB, 391 views)
Attached Files
File Type: pdf PowerCond-schematic.pdf (66.7 KB, 53 views)
  Reply With Quote
Old 5th September 2020, 04:45 PM   #25
kasey197 is offline kasey197
The Dastardly Dad of Three
diyAudio Member
 
Join Date: Sep 2009
Mean well vs generic power adapter vs  audio oriented smps
I did some measurements today for a Meanwell LRS350-48... loaded at 1A
- with L only - 8uH common mode inductor, and
- then L+C with 33kuF of capacitance (just to be absurd).

22hz-80khz bandwidth (and then in brackets Hi freq noise 20k-80k)
SMPS w/o filtering: 1.2mV (1.08mV)
L only filter : 457uV (62uV) ; wow that cm inductor really works !!
LC filter: 226 uV (11uV)
as above but with mains switch off: 184uV (4.5uV)

So not bad - adding some simple passive filtering makes these large & economical PSUs quite useful indeed.

ps the large cap triggers hiccup mode so beware ...
Attached Images
File Type: jpg lr350-48-unflitered-hirez.jpg (322.5 KB, 353 views)
File Type: jpg lr350-48-Lfiltered-hirez.jpg (333.1 KB, 346 views)
File Type: jpg lr350-48-LCfiltered-hirez.jpg (331.4 KB, 339 views)
File Type: jpg lr350-48-LCF-unpowered.jpg (325.8 KB, 335 views)

Last edited by kasey197; 5th September 2020 at 04:48 PM.
  Reply With Quote
Old 5th September 2020, 05:30 PM   #26
Kyrk is offline Kyrk  Greece
diyAudio Member
 
Join Date: Jul 2019
Location: Athens
At how much dbV does it get audible? Or thre isent a general rule? There is a large spike at 80khz how so? Do the transistors switch at such high speeds? You brought that curve down nicely, but should we even care about what happens after 20k? most speakers cant even reproduce those frequencies let alone the fact that class d output filters should turn them down, moreover who can hear after 20khz
  Reply With Quote
Old 5th September 2020, 05:45 PM   #27
Sangram is offline Sangram  India
diyAudio Moderator
 
Sangram's Avatar
 
Join Date: Sep 2002
Location: India
Mean well vs generic power adapter vs  audio oriented smps
The switching frequency is 160kHz, looks like. The spike at 80 would be the half-cycle switching spike.

I'm concerned about the load being too low to properly test ripple. I could expect the ripple to hit about 30mV at 50-60% load, which while high would still be acceptable and that is when you see the greatest contribution of LC filtering post the supply.

While the 50Hz spike looks bad, even the worst designs will have about 40dB of ripple rejection at low frequencies and this is not a problem. Would be very happy to see some results at higher load, as Meanwell's own datasheets show much higher ripple measurements when fully loaded.
  Reply With Quote
Old 6th September 2020, 09:47 AM   #28
kasey197 is offline kasey197
The Dastardly Dad of Three
diyAudio Member
 
Join Date: Sep 2009
Mean well vs generic power adapter vs  audio oriented smps
Quote:
Originally Posted by Kyrk View Post
At how much dbV does it get audible? Or thre isent a general rule? There is a large spike at 80khz how so? Do the transistors switch at such high speeds? You brought that curve down nicely, but should we even care about what happens after 20k? most speakers can't even reproduce those frequencies let alone the fact that class d output filters should turn them down, moreover who can hear after 20khz
True - nothing much beyond 20khz will eventually get amplified (or even reproduced !) Much of the ripple and noise is actually at lower frequencies tho so it makes the effort worthwhile...
  Reply With Quote
Old 6th September 2020, 01:52 PM   #29
kasey197 is offline kasey197
The Dastardly Dad of Three
diyAudio Member
 
Join Date: Sep 2009
Mean well vs generic power adapter vs  audio oriented smps
Quote:
Originally Posted by Sangram View Post
The switching frequency is 160kHz, looks like. The spike at 80 would be the half-cycle switching spike.

I'm concerned about the load being too low to properly test ripple. I could expect the ripple to hit about 30mV at 50-60% load, which while high would still be acceptable and that is when you see the greatest contribution of LC filtering post the supply.

While the 50Hz spike looks bad, even the worst designs will have about 40dB of ripple rejection at low frequencies and this is not a problem. Would be very happy to see some results at higher load, as Meanwell's own datasheets show much higher ripple measurements when fully loaded.
Here is the spectrum with a 4.5A load and as you pointed out - seeing more ripple. A second stage LC or a cap multiplier would clean this up nicely if required
  Reply With Quote
Old 6th September 2020, 02:41 PM   #30
kasey197 is offline kasey197
The Dastardly Dad of Three
diyAudio Member
 
Join Date: Sep 2009
Mean well vs generic power adapter vs  audio oriented smps
With no filter and 4.5A load ... and then with same filter as post#25 and 4.5A load
Attached Images
File Type: jpg lr350-48-unflitered-hirez-4.5Aload.jpg (331.9 KB, 91 views)
File Type: jpg lr350-48-LC-filtered-hirez-4.5Aload.jpg (331.7 KB, 81 views)
  Reply With Quote

Reply


Mean well vs generic power adapter vs  audio oriented smpsHide this!Advertise here!
Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Generic Power Entry PCB baseonmars Power Supplies 18 26th August 2020 08:46 PM
Google Chrome Audio power adapter is better than iFi Audio iPower? Solve Power Supplies 2 9th September 2019 12:57 PM
Generic Prototyping Board For Audio jkuetemann Parts 20 6th February 2015 06:44 AM
Power-oriented cap-meter Elvee Equipment & Tools 10 28th December 2014 08:39 PM
ORIENTED or Not ORIENTED cores for OPT ja2dhc Tubes / Valves 14 5th July 2008 01:31 PM


New To Site? Need Help?

All times are GMT. The time now is 10:36 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2021 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2021 DragonByte Technologies Ltd.
Copyright ©1999-2021 diyAudio
Wiki