My project is powered by switching 1A DC-DC down-coverter that can convert any input voltage between 6 to 48 Volts into 5 Volts needed to power ATMega and LED matrix. Now to power this internal PSU I need a AC to DC wall wart type supply.
I'm trying to decide with power supplies best suited for this. 6 Volts? 12V? I'd imagine converting 110 AC to 12 DC should be easier than 110 to 6 V and thus supply will be less bulky and generate less heat/live longer? 
Is it a good idea to have switching supply or regular one will be just as fine (since I'm using switching internally)? Quality and efficiency are my top priorities...
I am using 6V 1Amp switching supplies right now, but 12 Volt supplies are easier to source and non-switching kind cost less, thus the question
I'm trying to decide with power supplies best suited for this. 6 Volts? 12V? I'd imagine converting 110 AC to 12 DC should be easier than 110 to 6 V and thus supply will be less bulky and generate less heat/live longer?
A 6V transformer (used in linear supplies) can be just as efficient as a 12V transformer. It's the linear regulator where most of the efficiency is lost. And switching supplies (or your DC-DC converter) can be very efficient.
A 12V 1 Amp, supply is capable of 12W, and a 6V 1 Amp supply is capable of 6 Watts. So the 12V supply might be bulkier (assuming the same current rating). Since your DC-DC converter is efficient at any voltage, the actual power consumed (and heat) will be the same in either case. (Less current will be drawn from the higher-voltage supply.)
The 6V supply is at the bottom of your DC-DC converter's specs, so it might be better to go with something higher.
Is it a good idea to have switching supply or regular one will be just as fine (since I'm using switching internally)? Quality and efficiency are my top priorities...
You actually have 3 choices -
- A regulated switching supply (most efficient)
- A regulated linear supply (least efficient)
- An unregulated linear supply (almost as efficient as the switching supply)
An unregulated supply will deliver (approximately) the rated voltage at it's rated current. With no load, it's typical to see 50% more voltage, so maybe 18V from a 12V supply with no load. In your application, this is fine.
The unregulated linear supply is the simplest, with the least parts, so it might be the most reliable. But, since these are normally used to save cost, it could also be cheaply made... who knows? (Most modern electronics are generally very reliable, so I wouldn't worry about it too much.)
Switching power supplies can be had pretty cheaply these days. I've used these without trouble.
Thank you! That's a lot of useful info!
BTW, I think I put some wrong info. My DC-DC converter is actually 4-38 volts but since I need to get 5 at the output it seems 6 V in is the lowest I can get away with
I do see a lot more choice when it comes to 12 V supplies on eBay, and they pretty cheap to.