I've read about how the transformer is key to amp tone and how an upgrade to an expensive one can make a difference. What is inherent in the materials and design and build of the expensive boutique transformers that makes them so much better? Here's why I ask. I was installing a second chime for my doorbells, and so I needed a more powerful transformer. Hardware store only had the 12v cheapies, when I realized I had a 24v behemoth in my garage that I'd bought when I tried to fix an old boiler. This is a $130 transformer, which the supply store wouldn't take back, even though it had been wired in for five minutes and metered out at a healthy 25.8v. Now it's powering my doorbells, and they sound great! (LOL). I haven't listened closely (how hi-fi is a door chime anyway), but they sure do ring. Maybe it's the extra 1.8v -- maybe my whole house is about to burn up, who knows? But it made me wonder -- what's in that $130 transformer that isn't in the $15 special from Ace? Clearly the expensive one is heftier than the Ace one would be, despite their similar voltage ratings...