need 18V and 24V from 24V. PS?

Hi,

I'mplanning out my next project - a 312 pre, eqp-1 and compressor in one box. I'm using Fabio's Neve style output board for makeup gain on the eqp-1 and it needs +/-24V. I goofed though thinking that the 312 also needed 24V. but it needs +-15-18 V. instead. I'd really like to power both of these from Fabio's PS board but it only has one adjustable +/- output.

So... should I:

Power the Neve style makup gainstage with 18V. Will it work ok?

Use a discrete op-amp that will use 24V. in the api instead of a melchor or 2520? Will that work?

Do something to drop the voltage from 24V to 18V after powering the makeup gain board? I've never done that on abipolar PS before so I'm not sure how

I'd use a +/- 24V. pre if I had to rather than put a second PS in this box coz I want itto be small and portable.

thanks,

Kiira

just take the +24V rail, feed it into the input pin of a 7818. Take the Common pin of the 7818 to 0V. Take +18 of the most sweet, juicy Volt's you've ever tasted from the output pin of the 7818. For continued freshness, use a couple of 100nF ceramics close to the 7818. (Input-to-ground and output-to-ground.)

DO the same for the -24V but with a 7918 and you'll have -18V also.

Be aware that the input and 0V on the 78 and 79 series are reversed. 78xx (Positive reg) are: In-Common-Out, 79xx (negative reg) are Common-in-out.

That'll do for up to about half an amp. -plenty for pre gainstages, I'm sure. Six components, under five of your Earth Dollars.

Keef

Our Powerstation 5 rail power supply kit/pcb will do it: 4 sepperately adjustable +/- rails and a +48 phantom rail.




M

[quote author="SSLtech"]just take the +24V rail, feed it into the input pin of a 7818. Take the Common pin of the 7818 to 0V. Take +18 of the most sweet, juicy Volt's you've ever tasted from the output pin of the 7818. For continued freshness, use a couple of 100nF ceramics close to the 7818. (Input-to-ground and output-to-ground.)
[/quote]

Yay. :grin: thanks thanks.

Kiira

[quote author="mattmoogus"]Our Powerstation 5 rail power supply kit/pcb will do it: 4 sepperately adjustable +/- rails and a +48 phantom rail.
[/quote]

Yeah that's one thing I was considering too but Iwanna keep my extrcosts down now. It's really the berries,what I'd use for amore ambitious project, like if I were building a jlm99 pre which I'd love to do.

thanks,

Kiira

.
Do you have Fabio's Rel312 PS? If you build as-is, you can use the +-18v rails for 24v... just dial in +-24v with the LM317/337/var R section as easily as +-18. It has the 5v/48v rails, then all you need is a small daughterboard with SSLTech's add-on for the 18v rail, drawn from the old-18v-now-24v PS312 pinouts alongside the Neve card.

A toroid =>25va should power the pre and Neve card fine. Worth checking reg heat / heatsinks.
Hope it helps, Paul

[quote author="mattmoogus"]Our Powerstation 5 rail power supply kit/pcb will do it: 4 sepperately adjustable +/- rails and a +48 phantom rail.




M[/quote]
Thats what I am doing
+24, +18, +18, -18, -18
http://www.groupdiy.com/index.php?topic=9609