I,ve never used many pedals in my rig but I bought a couple to try out for a total of 5 (including my tuner). I also bought a power supply, the only one available at my local shop, called a SignalFlex P 9. Trouble is when I use the power supply I get a terrible 60 cycle hum which makes the gain channel almost useless (yep it,s that loud). with wall warts I seem to be OK. The concensus on the HC reviews of this device seem to bear out the same problem. A couple of folks have got around it by using a 3 prong to 2 prong adapter to plug it in (someting to do with the amp and power supply using the same ground). I am going to try this but if it does not work it,s going back and I will be looking for an inexpensive power supply for my peadals. I,ve heard good things about the One Spot. Any opinions or other tales of hum hell from power supplies?