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ggking7 27th October 2011 12:36 AM

Soldering a molex connector
I have one of these on the way:


I'd like to power it via a 12V SLA battery. The power input is via molex so I need to figure out how to solder the red and black leads from my battery to a male molex plug. Should I only connect the red and black and ignore the other two pins on the plug?

adurand 27th October 2011 12:47 AM

Just make sure you have the pinout correct. The two pins in the center (if I remember correctly) are ground. One outside pin is 5v, one is 12v. If it's going inside your PC why don't you just power it with the PC's power supply? (just curious)

JoelS 27th October 2011 01:42 AM

the link explains that it's a sound card that provides an independant power connector for connection to a linear power supply or battery, presumably for low noise power as compared to a typical PC supply. I would ask the manufacturer to verify the pinout. from the website it looks like you only have to connect 12V so 2 pins in the molex connector should be enough


ggking7 27th October 2011 01:52 AM

I'd like to compare powering it from the computer's PSU and powering it from an SLA battery to see if there is a sonic difference. Obviously there is a lot more noise coming from the switching power supply than the battery.

I just realized I should have a much easier time if I take a male molex connector that is already wired, cut the wire, and solder that wire to the other connector going to the battery which is a male "Deans" connector.

The SLA battery is 12V and the SOtM tx-USB unit accepts 12V input via molex. I would solder the yellow wire to positive on the connector going to the battery, the adjacent black wire to negative, and seal the ends of the other two wires with electrical tape?

Here is a simple diagram of how the SOtM tx-USB works:

Tubehunter 21st February 2012 07:13 PM

Hi GGking
What was the result of your experiment? i plan also to power by a separate rail this USB card from a paul hynes PSU.
Can the wires be soldered directly to the USBcard board without the Molex connector?

marce 22nd February 2012 11:47 AM

Most digital noise comes from the digital circuitry itself, not the SMPS. Even with a battery, the noise will be present from the PC because of the PCI connector to the PC motherboard. Its digital anyway, though it would be interesting to see some scope shots and eye diagrams of the resultant USB output to see if there is any difference.

qusp 22nd February 2012 02:38 PM

normally you would be right marce, but i understand for this board they have actually developed an isolated PCI connection card. i considered just getting that board, i'm covered for usb, but this actually looked quite interesting if you can sort through the usual nonsense
edit: i remembered incorrectly, it was an inline 'ripple eater' noise filter for the sata interface, but i dont know if it will cope with todays sata speeds. at $65 its almost worth trying out just to see.

you would think they would provide an i2s/lvds output on their convertors

phofman 22nd February 2012 02:52 PM

That PCI USB controller is a regular add-on USB controller with properly filtered power lines for the USB connectors and option for using external power supply for USB.

qusp 22nd February 2012 03:25 PM

I know, but i was also talking about the convertor further up the page, as well as the separate SATA ripple eater

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