[Fredly]

Hello everyone, I hope someone can help me here.

I am currently doing a few tweaks to my linear 5V Power Supply for my modded Squeezebox 3.

Nothing fancy, just dropping the PS in a Project Box and, where possible, upgrading both Power Cords with something a little nicer.
 
So far, I’ve installed a Cryo’d IEC on the Project Box for easy PC swapping and replaced the standard AC hookup wire with Chris VH’s cryo’d AC wire.

Theses small changes, in conjunction with a nice cryo’d DIY PC, REALLY helped the overall sound coming out of the SB3 top-to-bottom. No doubt about it!

Next up, was upgrading the 5V DC umbilical cord coming out of the Project Box.

This is where I would very much like some advice.

I was originally thinking of replacing the DC cord with some braided cryo’d Belden CAT 5 I have lying around. Four wires (2 for +, 2 for Grd), in a Litz configuration.

However, I also have at hand some real nice cryo’d 21 AWG Mag wire I bought from Take Five (http://www.takefiveaudio.com/mall/Cables/vampire_cable_21_mag.html), and thought perhaps this would be better for my application.

Anyone have any opinion which is best OR if this upgrade is really necessary?

Again, I’m very impressed with the payback on the initial tweaks, so am kinda second guessing whether I’ll hear any benefits with updating the DC cord.

(the finished DC cord will ultimately be covered with a nice nylon sleeve and kept as short as possible – approx 3’).

Thanx in advance for all who pipe in, and I have to say, I LOVE MY SB3!!!!

Cheers, Fred in Canada.

[TomS]

I know a couple of people have had good results making umbilicals for the Modwright external power supply to Sony/Denon CDP's using Jena Labs hookup wire braided in layers.  The Jena hookup wire is available from SAS Audio Labs (Steve).  This replaced the Revelation cryo'd ones Dan ships with the Platinum unit and these guys claimed it was a significant improvement.

[Wayne1]

Try a shielded twisted pair. It will have far greater noise rejection that a braided cable.

[alana106]

 
  Try a shielded twisted pair. It will have far greater noise rejection that a braided cable.


  Would you suggest connecting the shield at the power supply end to the
-5v, or just leaving it open at both ends

[Wayne1]

I suggest grounding the case to AC earth ground. Float the 5 volt ground and hot. Use a three conductor output connector. Use one of the pins for case (earth) ground and connect the shield to it. Float the shield at the SB end.

[alana106]

Thanks Wayne

[Fredly]

Wayne, I think I understand, but would appreciate a bit more clarification since your opinion is very important to me.

So…… let me put it to you another way to ensure I understand.

Are you saying leave the 5 volt ground and hot AS IS (they’re currently connected to the PS PCB) and put a shield around this grounded to the AC earth?

And equally important; cryo’d CAT5 or cryo’d 21 AWG Mag wire. Which do you think would do a better job for this application?

Thanx much for everyones input, Cheers Fred in Canada.

[Wayne1]

DO NOT ground the 5 volt negative to the case or earth,

Connect your case to the ground or earth connection of the IEC. Use a three wire AC cable into the IEC. Use a three conductor connector for DC out of the power supply case. Wire the postive and negative of the 5 volt DC PS to two of the output connectors. Run a wire from AC ground to the third connector. That way the whole case acts as a "shield" . Build up a shielded twisted pair. Connect the shield to the ground connector at the power supply. Leave it unconnected at the SB end.

I would not use any wire under 20 AWG. I have been using solid core, teflon insulated 20 and 18 awg wire for the umbilicals I build.

[Fredly]

Thanx Wayne.

I guess I did a bad job in my description, since that is what I effectively tried to describe, but obviously failed miserably.  

Cheers and thanx again for your input.

Fred in Canada.