The modification simply consists of buying a pair of adapters and some tubes. It takes all of 2 minutes. The 5687s have a different pinout from the stock tubes. You need 1x Little Dot Mk III, 2x Mullard EF95 (or equivalent), 2x 5687s (Sylvanias are good), and a pair of these adapters: http://m.ebay.com/itm/5687-to-6N6-Vacuum-tube-adapter-socket-converter-tube-socket-Music-buffs-DIY-/262451561666?nav=SEARCH. I buy my tubes at Langrex in the UK.