Jaycar in oz sell a regulated power supply providing +15/-15 /+5 in kit form
from Aud $17.95 each for board and components cat. no.kc5418
and a suitable toroidal transformer cat. no. MT2086 from Aud $21.95 with a better price on multiples
as far as i can tell they will ship outside australia if ordering online
and considering the state of the aussie dollar at the moment
it could be worth checking out.
Not too bad at all! Thanks diablo. I wonder how hard it would be to mod to +/-12V…hmmmm
Based purely on the picture given, I’d say you would need a 7812 and a 7912.
But that’s just a guess. 
LyleHaze
Yeh that’s what I was thinkin. Not bad!
I don’t think you would need to do even that the regs used for the +15 / -15 are adjustable
you only need to change 2 resistors on each side i haven’t checked it out fully yet but i think i may
be able to add a couple of trimmers to adjust the outputs so exact voltages can be obtained
they specify at the moment the standard cct to be within ±5% I want to see if i can improve on that
I will look into the data sheets of the regs and see what i can come up with they are
LM317 and LM337. any input would be very much appreciated
Great find, thanks for sharing this.
So good to see that they use the LM3x7 regulators, with trimpots added they can be adjusted up to 30V if I remember correctly.
This could be a nice substitute for the C64 power supply.
yes modify with 2k trimpots in place of the 1.1k resistors
then adjust to your requirements roughly 3 volts up to about 25 volts usefully
I guess. current supply will drop off at higher volts and heat becomes an issue
at lower volts however between 10 and 18 volts should be good for about 1 amp
you do need to recheck and adjust once you have connected up whatever you are powering
as the voltage will drop roughly by 1 volt once a load is connected .
cheers
Image taken from www.elektronika.lt
Those parts starting KP… are 7812 and 7912. Diodes can be replaced with common ones.
According to this schematic, you can get +/-15V easily.
Err, that’s +/- 12V
Err, that’s +/- 12V
There are no 7815 and 7915?
In that image? no.
have built this as a bench supply and improved it +/-15 within .01 volt adjustable by +/- 1volt from front panel
+/- 12 volt is easily acheived also with correct resistor changes
will post mods for both voltages when i can
I have built +15/-15 from +12 using two MC34063A. Inductors are a little bit noisy and I can hear sound, when they have load, but this DC-DC changer works perfectly. Online calculator that also draws schematic can be found here: http://www.nomad.ee/micros/mc34063a/index.shtml
Used these values:
Vin:12V
Vout:-15V
Iout:200mA
Vripple:5mV
Fmin:30kHz
Sorry for mistakes
Hmmm, switchmode… how’s the noisefloor? 
Don’t you wish *all* PSU chips had their own java schematic generator though? 
Inductors are quiet noisy
Quiet Noisy?? Sounds a bit confusing.
Switchers are great for efficiency, but they can create electrical noise that might be heard in an audio signal.
Since most of the bipolar supplies needed around here are for audio, I prefer to use linear regulators.
But that’s just my opinion. I’m really glad it works for you.
One thing I really like about 7815/7915 or 7812/7912 is that they are not adjustable, so there’s a few less things that need to be adjusted. I just like to keep it simple when I can.
Have Fun,
LyleHaze
Sorry, removed mistake Well yes, I made DC-DC changer because it was interesting to test and do it first time.
