The Best Power Supply for PCDP

serge1996

It is not a big secret that nowadays most PCDPs are used as stationary, not portable players. We have iPhones/iPods/Questyle/Pono/A&K/iBasso/etc.etc when going outside. So... what is the best way to "feed" PCDP: batteries, off-the-shelf (RadioShack) wall-warts, original Sony/Denon PS, use of power conditioners? Or getting PS Audio Power Plant in the chain won't make much of a difference because in the end DC will be messed up inside the player by DC-DC converters? Any thoughts?

kaosun

All models I have ever seen powered by batteries have DC-DC supplier built-in. The portable players don't like desktop players, they need consider battery life. For an example, if you have a battery with 12V voltage while your player needs only 5V, in the desktop you can make the difference which is 12-5=7 to be dissipated by heating. Say if your PCDP is using 5V at 1A, the difference will be 7*1=7W, you only use 42% battery power but 58% is wasted.

In PCDP, the common sense will be decrease the 12V to be 5V by DC-DC switching power supplier. At that time, DC-DC's efficiency can reach 80% which means total consumption is 6.25W with little heating. Therefore, the battery can last longer.

At that time, if the PCDP needs different power voltage like negative 5V, 3.8V, 3.5V... The PCDPs might have several DC-DC power supplier unlike desktop player, all different voltages are all handled by one power transformer. A few hi-end desktop are using two power transformers to separate digital and analog power supplier like SONY CDP-707ESD.

A small part of hi-end audiophiles can distinguish the tiny noise of PCDPs and they can tell the difference between portable and desktop. The extremely example is: my friend's friend who is a super audiophile. One day he asked my friend whether the level of the Yangzi River rises because he found the horses' clop from his CD was more fierce and his family electricity comes from a water power station on the river.

The best I can do is distinguishing the difference between D15 and D25.
I also tested my ears, the best I can hear is 15,000Hz.
How about you?

serge1996

as of last year I could hear up to 16kHz, which is a borderline miracle for my age. However, reproducing or hearing sinewaves has absolutely nothing to do with music or hi-end audio: two best (well at least the most accomplished) reviewers at Stereophile, Art Dudley and Mike Fremer, are older and much older than me and they have no problems with critical listening. Your friend is right, hi-end systems are sensitive enough to reveal slight changes in power supply. Since I am one of those crazies whose CD player is more expensive than his car, I know the pains of spending thousands on such stupid things as interconnects and power cords. But if you can hear the difference, and if the difference is for the better, what else can you do?...
Back to my question: since PCDPs are not in the same league as hi-end toys, I was wondering if anyone ever noted the benefits of cleaning their 9V DC power source. The question came to me when I noticed that D-50MkII sounds noticeably better when fed by your Li-Ion battery than by Sony's 9V power adapter.
Latest Stereophile recommends iFi power supplies, so last week I bought 9V/2.0A iPower, also bought regulated 1.7A ac/dc power supply off eBay, and one 9V/2.0A power brick normally used for laptops. Going to test them against Sony's 9V/600mA adapter, and against your Li-Ion battery ;-)

kaosun

The one I know comes without switching power supply is Panasonic XP7!
It uses positive and negative 6V to power itself. I might be same with XP5.
Try them!

kaosun

One more thing, most of the SONY 9V power adapter comes without 9V regulator like LM7809. So I made some compatible power adapters with 7809. At mean time I made some identical power adapters with LM317 which is an adjustable regulator I set at 9V output.  A few audiophiles told me they liked the LM317 version because it sounds cleaner! It's amazing! I couldn't tell any difference though!

serge1996

Yes, thanks to your tip I bought Technics SL-XP5 and it sounds real nice!! Once I am done recapping and playing with it I will send it to you for a new battery, along with other stuff that only you know how to fix (my apologies about the delay are at the end of BP100/200 thread).
I put U3V12F9 in the battery pack for my D-50 to make it work with rechargeable batteries but cannot comment on its sound. Without regulator my D-50 does not work with rechargeables. During startup it draws 700mA, then settles at 500!!