voltage regulator precision

aletropot · Joined: Jun 10, 2012 Posts: 33 Location: Amsterdam

Hi all?

How precise needs to be a synth psu?
A 15V bipolar with 14.75V and -15.05V its acceptable?
If not, what kind of problems this can make?

cheers

blue hell · Posted: Tue Mar 18, 2014 10:55 am Post subject:

Yes, those voltages will be fine.

aletropot · Joined: Jun 10, 2012 Posts: 33 Location: Amsterdam

Thanks.

Even if the diference its bigger, like 13v and -15v?

blue hell · Posted: Tue Mar 18, 2014 11:58 am Post subject:

13 Volt would be a bit low, and could be due too overloading the supply a bit or indicate a wiring problem ... I'd look into that ...

When a 15 Volt regulator really outputs 13 Volt (measured on the device itself) I would replace it.

When however the voltage at the regulator is about 15 Volt but the voltage on the synth parts is only 13 Volt I'd have a look at thee wiring and the current consumption.

xpmtl · Joined: Aug 10, 2007 Posts: 162 Location: Brussels, Belgium

Also, and Blue Hell correct me if i'm wrong, you need to measure your voltages under load cause it can make quite a difference in the readings.

blue hell · Posted: Tue Mar 18, 2014 12:45 pm Post subject:

Yes, measure under load.

PHOBoS · Posted: Tue Mar 18, 2014 3:24 pm Post subject:

The voltage levels themselves aren't that important as long as they are stable and of course within a certain range (feeding something with +/- 9V
which requires +/- 15V is not really a recipe for success). Sometimes there are reference voltages derived from the powerrails (not really a good method
btw) but a good circuit should have an option to adjust it if it's a level that needs to be very accurate (V/Oct VCO's come to mind). So as long as your
supply gives out a stable voltage you should be good to go.

aletropot · Joined: Jun 10, 2012 Posts: 33 Location: Amsterdam

I was getting the first values, I was just wondering what kind of fails a lower voltage gives.
For sure the p-p waveform voltage its lower, right?

PHOBoS · Posted: Tue Mar 18, 2014 6:33 pm Post subject:

That depends very much on the circuit itself. For a circuit with digital chips for example the output is very close to the supply voltage so if that's lower the
output will be too. However circuits that process a signal often have an output voltage independent of the supply voltage but related to the input
voltage. Of course the supply voltage has to be high enough else the signal would clip and then it does effect the output level.

new voodoo · Joined: May 06, 2013 Posts: 94 Location: RVA USA