Great point - I didn't realise they used the 6C45s too! i'd love to see that comparison too. Woo products and bottlehead products are probably my favourite looking amps - obviously each for very different reasons. I have a Crack kit to build at some point so i'm interested to hear how their products compare to something as polished as the WA7. I've been a bit intimidated to begin the build but one day they will sit side by side on my desk, looking totally incongruous but each providing a slightly different experience, I hope. With the added bonus of both using 12AU7s. My understanding was that the bottlehead kits, since they are DIY enabled the user to obtain an amp of a sonic quality far in excess of the price-tag so If the WA7+tp did go toe-to-toe with the Mainline at a similar price-point, I guess I would see the WA7/TP as great value because of the premium finish, the fact that it has already been professionally built (with a parts & labour warranty) and has the onboard DAC. I can't find many specs for the Mainline but it looks like it might be 0.6watts@32Ohm vs the WA7's 1watt? The Mainline would have the advantage of balanced output and 2 different RCA inputs (nice), and the glory of knowing you built it yourself... of course!