The current rating is not so important when it is above the 150 mA which are required. You can use a PS with 70 A rating although this is of course completely overdone.ultravista wrote:I have many power supplies that are labeled as 12-15V and 100-150ma but when measured, are nowhere near the printed output. All are over voltage and current.
The bigger problems are:
a) Noise free transformer power supplies are rare to find. In some countries they are kind of forbidden because of energy wasting. You only can buy switched PS which cause RF noise.
b) If you are still lucky to find one on ebay or similar it is often not clear whether the 12 V are stabilised or not. In many cases they have no stabilisation and the voltage drops maybe from 16 V to 10 V when a load is connected. Additionally they have a big 100/120 Hz hum on the output.
I cannot give an advice where to find a suitable readymade PS because this depends on where you live and which sources are available in your area. But generally small stabilised wallplugs with a transformer are rare. Sometimes you can still find some on ebay. But make sure they are stabilised. And be careful: Some sellers do not understand the difference between a switched PS and a transformer PS and label their offers wrong!
I am afraid this is all a difficult matter nowadays.