Whilst in Hawaii recently I sat in with a local band and used the rig of the guitarist. He had an original 1968 Fender Super reverb amp, a great amp for surf music, and a Pod pedal board.
Now, to keep things simple, I asked him to bypass the the pedal board which he did by pressing the bypass switch on the board. So in theory I was going straight into the amp, no effects except for the amp reverb.
I noticed that the overall sound was ‘small’.
What I worked out was that by going through the pedalboard I was also going through the Pod’s analog to digital and then digital to analog converters. When not going through the pedal board the sound had more tone and was fuller sounding even when the pedal board was in bypass mode.
When you think about it, high quality digital converters are very expensive, more than the cost of the Pod, therefore you would assume that the converters in the Pod are of a lesser quality.
Try it some time and see if you notice the difference.