Selling my Bottlehead Crack. This does not have the speed ball upgrade. I wasn't interested because I had read the speed can subtract some of that lush tube sound. I didn't build this one - it was used from these classifieds. Physical condition is pretty good minus a couple small dings in the painted metal and divots in the wood. I really liked the cream and light stain colors the builder chose. Power tube is the Tung Sol. Including two 12AU7 / ECC882 and an extra RCA power tube to roll. The cracks output impedance is 120ohm.