I have had the kit for six months but only started building it yesterday.
It sounds amazingly good with sennheiser hd530
How is this solder iron for the crack?
80W is more than ample, it might be to hot! Something with variable temperature can be found at a similar price
I have been using one of these solder stations and have been pleased with it (Maplins also sells different sized spare tips).
One small thing I discovered. When the tube is making squeal, then when I unplug the headphones and then plug them in again it goes quiet. Have tested it 5 times, and it works everytime.