Question Power supply DIN4 plug

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Question Power supply DIN4 plug

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Does anyone know why some NAS have a DIN4 plug ? like my DS415+
Why a DIN4, thus with 2 12V inputs ?

is it : 12V to the board & 12V to the disks ? if it is so, which pins go to board & to disks ?

Does anyone know why some NAS have a DIN4 plug ? like my DS415+
Why a DIN4, thus with 2 12V inputs ?
DIN 4 plug:
1. avoid additional heat from electric transformation process
2. save a space in the NAS box
3. because Syno engineers decision

is it : 12V to the board & 12V to the disks ? if it is so, which pins go to board & to disks ?
a purpose of such question?
Hi Jeyare,
Thanks for your reply but I don't quite understand it.
I posted this thread in the "Mods" part of this forum because my question was technical, as simple as that.
1. avoid additional heat from electric transformation process
2. save a space in the NAS box
there is no "additional heat from electric transformation process" or "space to save" there.
I think you're talking about the 110-230VAC to 12VDC conversion that generate heat.
This step takes place outside of the box, this is not the point.
You can power such a device with a basic 5.5*2.5mm plug it would work perfectly with a wire in "Y" just after.. Simply because the PS delivers only 1 voltage, 12VDC.
3. because Syno engineers decision
Yes, of course.
But as an engineer myself & like any fans of Mods, I like to know "how it works?" "why this/that?" :)
a purpose of such question?
My inquiry is quite weird, I'm ok with that.
I like listening to music & I'm part of these weird people named "audiophiles" :)
They power their NAS with a linear power supply because the hifi gear sounds better than with the SMPS power supply. They modify their switches adding capacitors & other stuff etc.

I just want to know, if someone has the answer, why this double 12VDC power supply, in order to power the NAS with an home-made PS & get rid of the noisy SMPS.
By "noisy", I mean that :
- SMPS are dead efficient PS but they generate electrcal noise at high frequency, this noise pollutes the PCB, and you can here it on speaker : it sound harsh, not natural
- you can hear that noise because streaming (NAS to hifi gear / cloud to hifi) is not a strict TCP/IP process but UDP
- this "issue" is absolutly a no-issue when we talk about file transfer and other 100% data processsing & TCP/IP data transfer, of course.

I apologize for my post above, not clear enough.
I had assumed it was something to do with load being drawn from the PSU. Though I have used 12v 2A wall bricks with barrel connectors (for want of a precise term) for small Netscreen/Juniper firewalls, but they didn't have disks. The LaCie external Firewire enclosures (HD, CD-RW, DVD-RW) all used to have DIN power connections.

It could be the current is considered too high for a single line so it's split between two. I've wondered about this too but not so much as to ask :)

I hadn't considered there would be an electrical interference if the NAS was streaming.

Direct from my DS218+ (wall brick PSU) I have used a USB DAC (cheapo) to RCA phono into an old Rotel amp and could hear whining. Using the same USB DAC, and shielded cables, from Mac Mini/iMac to the amp and there's no whining. Any streaming from the NAS (Audio Station [DLNA, Airplay], Media Server, Plex) to wireless connected amps and I've not noticed whining.

Why would the PSU affect UDP transmission/reception? I could see that signals can be transmitted via physical cabling but how can the data be corrupted except somehow knocking out some UDP packets.

Does the whine happen on both wired and wireless LAN?
So clear glass of wine:

Just for an understanding of my consideration from my previous post.

1. as Synology HW engineer you can put electric transformer into NAS box or not.
a) few reasons for YES:
- enough space for such equipment in the NAS box (first problem of the 415+)
- enough space for AC C14 connector in the NAS box (second problem of the 415+)

- enough airflow for additional thermal energy ventilation from the transformer (third problem of the 415+)

b) few reasons for NO:
- when you can't do it in above YES
Then you have solution to use external adapter only. Then it's up to technical spec of used motherboard how to provide sufficient power supply. Also what kind of power input connector you will use at NAS side. I would like find no rocket science here. Look for the picture below for the one and only possible tiny space for the power supply adapter placement (red line with "here"). No way.

Then you have answer, why is there such tiny DIN4 connector.


2. Usage of basic DC 5.5*2.5mm plug (as you mentioned above), then split of the electric current to two lines sounds reasonable (e.g. Kirchhoff law). But as we can see, there must be a reason for two independent power source in single DIN4 connector:
- split of two current directly from the external adapter (demand balance, specific filtration for one of them, ...)
- or just simple reason - current demand for used wires between the adapter and NAS
- or just simple decision from Syno engineers w/o important reasons

3. If you are an engineer and fan of Mods you can use:
- measure of standard values for your target (linear power supply replacement) evaluation (current, demand, ...) for each of the pair independently
- or use an oscilloscope for harmonic measurements, what can help you to achieve more detailed audiophile evaluation scope.

When you replace the power supply from existing SMPS to Linear you will get no RF interference power supply. No doubt. But:
- not sure how interference from the PS flowed cross PCB to NIC and then has an impact to your last mile in your speakers connected to your amplifier. Is the amplifier connected to your data stream by wires/wireless?
- not sure, how the power supply provide an impact to packet protocols interference (TCP/UDP). Because it's just protocol layer. This is not the low level electric impact.

Question is what is a route from your data to your speakers?
Did you mean, that your NAS makes a direct interference impact to your speakers? What about a change of the place for the NAS? Did you tested all possible scenarios:
- NAS interference and WiFi operated frequencies?
- another near devices?
- UTP vs FTP vs STP wires? .... and is there E2E grounding (connectors, switches, ...)?

As @fredbert wrote, needs to more tests. More details, because no one can see into your "architecture" better than you.
Too many variables there

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