Linear PS with no ground pin

McQuaide · 17th August 2011, 02:46 PM

Hi all,

I just finished building a Pass DIY Phono preamp (actually two, one for each channel), and I'm looking at ways to power it. It requires +28-34v, ground, and -28-34v connections. I tested the boards with 6 9v batteries in series, with ground connected at the midpoint, and they work well.

So I purchased this PS: Power Supplies, Power Supply, Bench Supplies, Transformers

Unfortunately there's no ground connection on the supply, and I can't locate a schematic for it. Any ideas for using this particular supply with my project? Or is it a writeoff?

Thanks

DF96 · 17th August 2011, 03:17 PM

That appears to be a 28V supply, which will give you 0 and +28V. Not what you need.

McQuaide · 17th August 2011, 03:22 PM

Quote:

Originally Posted by DF96

That appears to be a 28V supply, which will give you 0 and +28V. Not what you need.

OK, that's what I thought. Live and learn

The instructions for the preamp say wall warts can be used. I assume I could connect two 30v wall warts together in the same way I connected the batteries?

DF96 · 17th August 2011, 03:36 PM

If their outputs are isolated from the mains, then yes. This will probably be the case.

Why not buy or build a proper power supply?

McQuaide · 17th August 2011, 03:40 PM

Quote:

Originally Posted by DF96

If their outputs are isolated from the mains, then yes. This will probably be the case.

Why not buy or build a proper power supply?

I was hoping to buy rather than get into another project at this time. Anything you can recommend? The Pearl 2 already has voltage regulation and filtering (doc here) http://www.passdiy.com/pdf/PEARL%202.pdf

Thanks for your advice.

McQuaide · 17th August 2011, 07:13 PM

Here's another thought. Since I already invested in the PS, I could just buy another of the same model, and connect them in series with the midpoint going to the ground.

DF96 · 17th August 2011, 07:31 PM

If the output is isolated.

McQuaide · 17th August 2011, 07:43 PM

Quote:

Originally Posted by DF96

If the output is isolated.

I can't tell if it is or not. Can you tell from the photo and data sheet linked below? Thanks again.

http://dl.dropbox.com/u/370002/PS%20data%20sheet.pdf

Frank Berry · 17th August 2011, 08:43 PM

The power supply has an isolated output.
You can safely use two of them to create a bipolar supply.
Connect the - of one supply to the + of the other supply.

McQuaide · 17th August 2011, 08:45 PM

Quote:

Originally Posted by Frank Berry

The power supply has an isolated output.
You can safely use two of them to create a bipolar supply.
Connect the - of one supply to the + of the other supply.

Thanks.

17th August 2011, 02:46 PM	#1
McQuaide diyAudio Member Join Date: Jan 2011 Location: Southeastern Pennsylvania	Linear PS with no ground pin Hi all, I just finished building a Pass DIY Phono preamp (actually two, one for each channel), and I'm looking at ways to power it. It requires +28-34v, ground, and -28-34v connections. I tested the boards with 6 9v batteries in series, with ground connected at the midpoint, and they work well. So I purchased this PS: Power Supplies, Power Supply, Bench Supplies, Transformers Unfortunately there's no ground connection on the supply, and I can't locate a schematic for it. Any ideas for using this particular supply with my project? Or is it a writeoff? Thanks

17th August 2011, 08:43 PM	#9
Frank Berry diyAudio Member Join Date: Sep 2003 Location: Midland, Michigan	The power supply has an isolated output. You can safely use two of them to create a bipolar supply. Connect the - of one supply to the + of the other supply. __________________ Frank

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17th August 2011, 03:17 PM	#2
DF96 diyAudio Member Join Date: May 2007	That appears to be a 28V supply, which will give you 0 and +28V. Not what you need.

17th August 2011, 03:36 PM	#4
DF96 diyAudio Member Join Date: May 2007	If their outputs are isolated from the mains, then yes. This will probably be the case. Why not buy or build a proper power supply?

17th August 2011, 07:13 PM	#6
McQuaide diyAudio Member Join Date: Jan 2011 Location: Southeastern Pennsylvania	Here's another thought. Since I already invested in the PS, I could just buy another of the same model, and connect them in series with the midpoint going to the ground.

17th August 2011, 07:31 PM	#7
DF96 diyAudio Member Join Date: May 2007	If the output is isolated.