Synths that use the "Kettle lead" (3 Pin) all have internal Power supplies,(Or 2 pin Like the Virus)anything that is not of that standard is usually a Transformer type PSU,with the Current being Converted by the Wallwart supply(Black box) before it reaches the Synth,the Adaptors for the synths are all the same for that particular model of synth you buy and the same with the 3 Pin synths,its the Plug which connects to your mains which differs,so a UK sold SH201 Adaptor will be the same as a Danish one,the conversion of Power will be done inside the Adaptor box,they usually differ from the conversion dependant on the Countries mains supply,but the synth itself will run on 12 Volts irrespective if its bought in a different country
Not every synth has the capacity to house an Internal PSU,as not every synth needs the same Voltage to run its circuits,some only need 9 or 12 volts so it needs to be converted somewhere along the Lines either before it reaches the Synth or internally via a transformer,the majorit of Lower Voltage units are externally converted so fitting a transformer inside isn't always practical or needed,dependant on the circuit layout,plus a lot of its is down to Heat Dissapation,usually many synths that are smaller units tend to have less Area for the Heat to circulate so need to have external Power supply otherwise they would suffer Heat Problems,and Circuit damage.those that do have internal PSU in smaller casing tend to have vents to help air flow....
Just look at the heat sink on the Back of the MemoryMoog....and you see what type of heat some circuits are capable of creating
I can never understand why some of these synths have external Power supplies,they can fit a 1U synth rack with an internal PSU,so why not all small synthesizers,they can do the voltage conversion inside for sure so theres No need for external Transformers,even wiht smaller synths theres room for air flow and and Internal transformer
I hate those external Power Supplies...
