Advice needed -> Power Transformer

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Dyonight

Well-known member
Joined
Feb 18, 2014
Messages
90
Hi!

I need to power two preamps that need 18vac each.

I have one power transformer that deliver 18v-0-18v

Can I use one phase to feed on preamp and the second phase to drive the other?

If yes should I use the "tap" wire as the "+" on the second unit to send it a positive wave like what the first will recieve?

Thanks!
 
Wich preamps? how much current the preamps needs? how much current the transformer could give?

How is the input of the preamps supply, I mean, is some of the power supply input pins tied to ground or something else? maybe open it up and look, if the input is going to a rectifier bridge, which is more likely, you'll have to take care about all this, since both preamps will be shearing a ground at some point, and all this may not be a good idea, if it has one or  two half wave rectifier then one of the pins will be connected directly to ground, and you should use this as your center tap. In any case, you will be probably creating a ground loop at some point, and if you try to brake it somewhere, this isn't a good point to share or to be splitter and the current running from somewhere else. I don't think this is a good idea but I need more details to decide.

JS
 
Thanks for the reply!

The pres are two Presonus Bluetube (1st gen) which draw 1 amp of current each.

The power transformer gives 2.2A @ +18/0/-18v

Honestly I will need to re-read your post cause I'm not sure I got everything since I'm ot an electronic engineer...
 
Better and safer to use two individual transformers. They're not that expansive or hard to find.

Only way to tell if it is possible to use the 18-0-18 is to see the actual schematic for the unit.

Jakob E.
 
Maybe call up or email blue and ask what the current draw is. Then ask what voltage/s you need. I can try to help you from there.. the info may also be available in the manual or on the back of the unit. Where did you learn you need 18vac?

Post a schematic. I would guess a unit like that would take a DC supply? Is this one of those low cost "starved plate designs" that I've heard about?
 

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