Split +/-12V Phono preamp Power Supply

[partialresponse]

My Audio Alchemy VITB power supply (+/-12V) has died and I'm having a very difficult time finding a replacement for it. Currently, I'm tempted to use the +/-12V rails from a spare computer power supply - but I think it may sound too noisy. I suppose I could also use two single-ended 12V supplies (tying the (-) rails together and calling that ground.)

Any better ideas?

thanks
Kofi

[mjf]

hello.
two 12v batteries/akkumulators in series...............
or building a psu with volt regs............like lm317/lm337 or so..........there are some threads in the forums that can help.
greetings...........

[russo]

A computer power supply is single ended, that means that there are no -12V, only +12V and ground, in fact, each molex connector has +12V(yellow), +5V(red wire) and 2 grounds in the middle.
And you cant connect two grounds, or else, you can, but doing that doesn't give you a symmetrical power supply, to have one symmetrical, you must connect the +12V to the ground line of other equal power supply and then the 12v will be +12v, the ground will be -12v and the 12v connected to the ground is your new ground.
But, isn't easier to repair the original power supply?

[Glowbug]

Not sure if you wanted a pre-made PCB or not, but...

New bipolar low-voltage power supply for solid-state projects

[Steerpike]

Originally Posted by russo

A computer power supply is single ended, that means that there are no -12V, only +12V and ground, in fact, each molex connector has +12V(yellow), +5V(red wire) and 2 grounds in the middle.

Thats only the disc drive connector. The main supply to the processor board caries -12 and +12.
But as pointed out, it will be noisy, it being a switched mode power supply with only the bare necessities of filtering.

Buying two identical +12v supplies & commoning one (+) and one (-) will work perfectly well; or make your own as mentioned with the LM317/337 chips. Or if you are less fussy, simpler versions can be had using the LM7812 and LM7912 regulators - it's very simple.

[picowallspeaker]

Go hollow state .
use two 5Y3 GT , feed them with 5V each , add an LCLC made from 10 H and 100 uF ,Polyester .

A 50 W trasformer would be good for the duty

Note :It is not scientifically demonstrated , but the heavier the better ..

[partialresponse]

Originally Posted by picowallspeaker

Go hollow state .
use two 5Y3 GT , feed them with 5V each , add an LCLC made from 10 H and 100 uF ,Polyester .

A 50 W trasformer would be good for the duty

Note :It is not scientifically demonstrated , but the heavier the better ..

What is "hollow state"? This is a little cryptic; could you elaborate a little?

Thanks
Kofi

[partialresponse]

Originally Posted by russo

...to have one symmetrical, you must connect the +12V to the ground line of other equal power supply and then the 12v will be +12v, the ground will be -12v and the 12v connected to the ground is your new ground.

Of course, you're right. What I described would be a parallel connection.

Originally Posted by russo

But, isn't easier to repair the original power supply?

The original was sealed - no civilized way to get in.

Thanks
Kofi

[Coreyk78]

I would recommend trying the power supply designed by RJM for the vsps, it's simple and it works very well, I'm listening to it right now.

RJM Audio - Construction Guide

[partialresponse]

Originally Posted by Coreyk78

I would recommend trying the power supply designed by RJM for the vsps, it's simple and it works very well, I'm listening to it right now.

RJM Audio - Construction Guide

I don't see anything there that is just a power supply. I need just an unregulated power supply because the VITB has all the regulation inside it.
I'm not averse to building a simple power supply if he has a kit for just that. Does he?

Thanks
Kofi