So just finished my first build (5e3) - some of you will have undoubtedly seen my thread in the shock brothers forum. Throughout the build I was consuming as much info as I could on amp building, mods, troubleshooting, etc. I've watched a ton of youtube videos (D-Lab and Uncle Doug) and ended up picking a scope and audio generator for good prices off my local Craigslist. I totally get that a signal trace / audio probe and DMM can be plenty to analyze amps. I will be making a viable BillM-style audio probe (there is no way I'd put my pedal audio probe anywhere near an amp). But, I really have a desire to check them out through an oscilloscope as well. With that being said, there is some conflicting info on safe methods to do so - obviously many of the same rules apply as checking voltages and working on amps: -One hand in pocket -Never short B+ to ground (and/or never short anything to anything) -Always drain filter caps if working on amp and confirm they are drained -In my case: keep chassis on 100% rubber mat and stand on 100% rubber mat -Turn amp off when moving probes to new and/or tight locations In addition to the above I'm curious what other safety precautions should be considered when hooking an amp to an oscilloscope. I've come across various info and can't seem to keep it straight: 1. Do you guys hook up your amps to isolation transformers when scoping them? I never plan to work on a "widowmaker" but it sounds like some people will hook up non-widowmakers to isolate ground from neutral so that you and your scope don't become a ground path for mains voltage. However, there is still obviously high voltage present via DC and if you happen to short hot to neutral anyways. 2. If you don't do number 1, do you use isolated probes on your scopes? I have been familiarizing myself with just the Oscilloscope and Audio Generator - and having a blast with it. I will be using a high-wattage dummy load and plan to start by just hooking the scope up to the output jack dummy load. Eventually, I'd like to have the flexibility to trace through the amp with the scope. Any considerations, precautions or answers to my questions are appreciated. Thanks!