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Musings on Switching Power Supplies (LPS for Oppo / DirecTV/ Radiance)

So, this whole story begins about a couple months ago when I was watching a satellite television show on my HT system.  While I was watching, I noticed that my Oppo bluray player was still on (I often turn everything on in the beginning to warm stuff up and/or listen to music).  Well, I hit the remote button to turn off the Oppo and a weird thing happened.  The sound got a little bit better.  It lost a small bit of that digital “solid-state” harshness / brightness.  I then thought, “wait a minute, something is going on here”.  The next thing I did was, even though my Oppo was powered off in “stand-by” mode, I went and just unplugged it completely.  The sound actually got a tiny bit better after that.  Now I have read postings that say switching power supplies can cause noise in other devices when they share the same circuit/outlet.  I never really gave it much thought, but apparently this is definitely a thing.  My Oppo is plugged into the same outlet as me left surround amp, which is a completely different circuit than my HT processor and other amps.  However, the switching power supply in my Oppo BDP-103 was still causing havoc in the system!

I have four dedicated 20 amp circuits for my HT equipment.  I also had two other devices that still contain switching power supplies:  DirecTV Genie satellite receiver and a Lumagen Radiance video processor.  My DirecTV was plugged into the right surround outlet and the Radiance was plugged into the same outlet as my Krell S1200 HT processor.  So the next step was to pull those out and connect them to regular house outlets (which are different circuits and not even in the same subpanel).  I could see immediately that I lost some of the video quality through HDMI.  The picture was not as sharp and it introduce a little bit of noise into the image.  However, it did improve the sound even more (got rid of more of that digital harshness).

So what to do next?  Well, of course get rid of all these switching power supplies and, somehow, implement linear power supplies!

auxinput
nonoise's avatar
nonoise
10,547 posts
 
@auxinput, I'm beginning to think you can read my mind lately. 🤔

I wanted to go the same route as you with a replacement LPM power unit for my OPPO 103 but Funjoe over at Clones Audio only makes them for the 205 series. The SE unit from that eBay site is supposed to run cooler than their standard version but I went with the Furutech IEC inlet with the Mundorf wiring and that made an appreciable difference so I left it at that. Here is the site if anyone is interested. I'm sure someone with better skills than me can build it for less. 👍

Since I'm only using the OPPO for movie watching, I contacted OPPO and asked their opinion on whether or not the newer line of 4K blu-ray players will out perform my old 103 if I forgo 4K and stick to standard blu-ray and they told me no, keep your 103. So, maybe someday I'll look into that SE LPM unit in the future.

Thanks for your pioneering spirit and all the best,
Nonoise
auxinput OP
2,920 posts
 

Yep, and the 203 no longer support Netflix streaming, which I use a lot!

I have seen that Clones Audio power supply as well and it looks like a very nice one indeed!  Unfortunately, like you said, they don't make one for the older 103 models.

There are a bunch of Oppo LPS on ebay from China that are all less than $130 each. These all have smaller amounts of capacitance and I'm not sure how well these actually operate, but I have no regrets with my OPPOMOD LPS.

I have also seen that Furutech + Mundorf wire update.  Yes you could make your own, but you would have to find the proper plug/connector for the main board, or just chop the stock one.  I was considering this after I did the LPS, but after my experience with silver fuse, I'm not going to introduce any silver elements into the mix.  I might upgrade the IEC inlet sometime in the future.  I have an AC-1001 rhodium filtered IEC inlet sitting here that was used in a previous project.

imhififan's avatar
imhififan
2,108 posts
 
So what to do next? Well, of course get rid of all these switching power supplies and, somehow, implement linear power supplies!

How about your TV/Monitor? Are you considering install LPS as well?
kijanki's avatar
kijanki
4,394 posts
 
It all depends on how SMPS is designed.  They got bad rap from crude computer applications, but can be extremely quiet and are line and load regulated.   Many manufacturers use SMPS for the reason of lower noise.  Benchmark got 10dB S/N improvement in DAC3 by switching from linear power supply to SMPS.  Jeff Rowland used SMPS in Capri preamp for the same reason.   Linear power supplies are also sort of SMPS switching at 120Hz at max voltage creating a lot of high frequency noise.
nonoise's avatar
nonoise
10,547 posts
 
The only thing that's keeping me from splurging on a LPM for my OPPO is the results that Dan got over at Modwright. He tried to come up with one himself and it wasn't worth the hassle. He claimed it ran way too hot so he got one of Mr. Lee's unit (like the one that auxinput has) and found it to be good, but still too hot for his tastes.

He says he got very little in the way of measurable differences between the SMPS and the LPM units but that could be written off as sour grapes since auxinout says the LPM unit has started to cool off as it broke in.

The one work around that I"ve done before is to take the upper lid to a shop and have them drill some holes in it to aid in ventilation. You can also go further and carefully have some vent holes drilled in the bottom of the unit for better air flow but just doing the lid top should be good enough.

All the best,
Nonoise
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