Transformers: --------------- www.victoriamagnetics.com - custom made toroidal transformers www.plitron.com - toroidal output transformers www.partsexpress.com - lots of toroidal power transformers Check Ebay as well. Have to do some homework on what voltages/amps/etc. are actually needed. This isn't going to be as easy as building a kit unfortunately. Also, looking at Piltron, some of their weights for their output transformers at higher wattages are no better than EI ones. Weber MT200 as a viable option, may have to ask about it. Hybrid design might be best. Also look at Sun 100S, 2xKT88's producing 100 Watts. Might be able to pull the weight out of that. Consider Hypex amps, ColdAmp Class D power amplifiers with Tube amp emulation. Maybe consider an 12AT7 power section feeding the poweramp to give a little bit of sag but with lots of power. Truepath is also an option. 41Hz.com has kits.