A 12AU7 configured just like the “front half” of the Foreplay III is direct coupled to a 6080 tube configured as a cathode follower. To keep the kit price manageable (the kit is about 1/4 of the price of some past OTL amps) we use surprisingly nice sounding electrolytic capacitors as the output coupling capacitors, but of course our kits often induce tweaking – in fact we imagine Crack may become the biggest cause of tweaking yet. You could spend more on different large 100uF film capacitors than you than you did on the kit and spend hours putting in different caps and comparing them. And of course you can tweak to your hearts content tube rolling different 12AU7 and 6080/6AS7 variants.
A single pair of gold RCA jacks, a stereo potentiometer volume control and a Neutrik 1/4″ TRS headphone jack complete the signal path, and the kit comes with an IEC power entry socket so you can use one of those fancy $2500 power cords on your $299 kit if you so desire. Or you can order a really great sounding cord from us for a whole lot less.
It comes in a standard Bottlehead “gravity mount” cabinet configuration where all components mount on a 10″ x 6″ laser cut aluminum chassis plate that sits on a lovely Northwest alder wood base that you assemble and finish yourself. The manual is in PDF format and you can blow up the high res photos to see each assembly step in detail.
I got this kit for my birthday (in 2015!!) and so far I’ve had one attempt at building the wooden cabinet, and that’s it.
The other thing I plan to do with this kit, once I’ve got the basics working, it to add a Raspberry Pi and sound card (like the https://www.hifiberry.com/) and make it into a wifi streaming speaker (at least DNLA and Airplay™).