Despite fairly thorough sanding, there were small patches of varnish left on the metal and the varnish reacted with the etch primer to create a crinkled look that would have really messed with the final paint finish. I was using an etch primer to ensure a good finish on the metal parts, but my first priming attempts didn’t go well. The plate choke brackets had a lot more varnish than the transformer bell, but both were tricky to sand and took multiple attempts to get right. The top of the main power transformer and the brackets on the plate chokes (the things on either side of the transformer) needed thorough sanding to remove the varnish that they are coated with during production. Painting the metal elements of the S.E.X.

To achieve the vintage look I decided to paint some of the visible metal parts and my fiancée convinced me to anodise (rather than paint) the aluminium chassis plate – thanks Lisa! Painting I love the Art Deco period and I thought that style would match the vintage tubeyness of the S.E.X. Having built the Crack completely stock in all ways except for staining the wooden base, I decided I would express myself a little more in this amp. was going to take only a tiny bit longer than the Crack… oops! Customisation What arrived at my door was a moderately sized box containing a couple of plastic bags of components and wires, 4 pieces of wood which make the base, 5 cardboard-wrapped power components (transformers, etc.), an aluminium chassis plate, a list of parts, and a CD containing the manual in PDF form.Īt first glance I actually thought the S.E.X. has a lot more wires than the Crack (partly due to having two output transformers) so it’s a slightly more complex build, but it’s still fairly simple point-to-point wiring with no circuit boards or finicky micro components. (The Crack is an output transformerless (OTL) design which will only work effectively with high impedance headphones.) uses output transformers to work with a wide range of headphones. It’s a different design to the Crack as the S.E.X. The next step in the Bottlehead range is called the Single Ended eXperimenter kit (or S.E.X. After thoroughly enjoying the Crack for over a year, I decided it was time to enjoy the next step up in the Bottlehead range for both a challenge and a new step towards audio nirvana. Some time ago I built the Bottlehead Crack amplifier and reviewed both the build process and the resulting sound.

Bottlehead power cable