From +15V to -15V ?

[Phattline]

Hi I need -15V, and I have +15V and Ground.

What parts I need to chance that?

(I am on the way to built in my tr606 a tr909 bd pcb - and this thing need +15 ground and -15V)

[illogik]

hi

maybe it is possible to do but i would suggest building(if you know how; high voltages!)/buying a small, bipolar (so with + and - supply) power supply.

if you wanna build one;

/www.cgs.synth.net/

good luck

btw; your going to build a 909kick pcb IN a 606 ???

[Phattline]

hi illogic

To built a power supply is not possible becouse- this little thing must be batttery driven- (to program beats in e.g. the train)

And yes a tr909 kick drum pcb in a tr606-

thats what I want-not want I have it- but only the -15 V are left

thanx for the link, when i have time - i will seek some shematic out-

[Phattline]

no that link dont solf the problem

[moebius]

Hmm..

I think best bet here is to use a charge pump voltage converter - at least Linear Technology LTC1144 and Microchip TC7662A are compatible with voltage ranges needed.

Bye, Moebius

[bosone]

i look at the matter, and decide to use a 79L15, to produce a -15V, coupled with a 78L15 which drives +15.

both are connected to the same power supply

i think i will use this for building an korg ms20 filter clone

[moebius]

Hi bosone,

That's a standard method if you have center tapped transformer and don't have to power "too many" (no such thing ;)) analog synth modules.

Bye, Moebius

[smashtv]

Dug this up from usenet:

One trick you can use with op-amps (and other things with low
current draws) is to put two resistors in series between the
terminals of a single voltage supply. If the resistors have
the same value, then the mid-point will be at half of the voltage
of the supply. So, you can take a single 9 volt battery, put
two resistors (say, 1 K) in series between them, and call the
middle point "ground" (a technically incorrect term, but that's
what most people call the zero reference). As far as the op-amp
is concerned, you just gave it a +/- 4.5 volt dual voltage supply.

In practical circuits, you should add some capacitors between each
battery terminal and the new "zero" point to keep it stable during
fluctuations in current load. This method doesn't work well for
higher currents, but does fine for a 741 op amp.

- Mark Sokos (msokos1@gl.umbc.edu) Electrical engineer, computer geek (er, 
  programmer), no-talent bum musician, and perpetual student
  http://www.gl.umbc.edu/~msokos1: alt.comp.hardware.homebuilt FAQ, ISA and 
  other bus info, and schematics (mostly audio).

Describes a method I have seen used in consumer stuff to power opamps.  Your gear may be designed so that powering it this way will kill it, like if the draw from either pole was way higher than the other.....

Best

Smash