Limited Edition Bottlehead Crack + Speedball
Will Ship To: Canada, USA
Bottlehead crack + speedball - Built by Bottlehead. Limited edition (only 8). Second owner - original owner purchased in July 2012, but didn't receive it until August 2012. I received in July 2013. Less than 100 hours total. Pics from original classified; condition has not changed. Selling to fund a desktop setup that is friendly to sensitive iems as well as the HD600. Price includes PP fees, shipping and insurance. Will include an extra tube and adapter. PM with questions.
Link to original owners ad: http://www.head-fi.org/t/670457/sold-limited-edition-bottlehead-crack-speedball-mint-condition-price-drop
Original post from Doc:
PB has cooked up a cool special deal in the form of a limited run of custom, assembled Crack amps. Here's what he plans to build -
"Just now, we have found ourselves with a shortage of PT-3 power transformers for the Crack OTL, but plenty of all the other bits for construction, and some extra PT-7's that would normally go in the SEX amp. Consequently, we've been able to cook up a little special on some custom built Crack amps integrating the new PT-7 and an alternate high current driver tube to boot!
Available from Doc B's stash of tubes - six custom crafted Crack OTL tube amplifiers built from the ground up with the Speedball upgrade to use the ECC99 tube from JJ. These beefy double triodes were designed to drive demanding directly-heated triodes like the 300B and 2A3. The ECC99 is very similar to the 5687, but it retains the 9A pinout of tubes like the 12AU7. Sonically, this tube has just a hair more gain than the 12AU7, and has won out over old stock 6CG7's and 12AU7's in plenty of DIY projects since its introduction, with many measurements of ultra low distortion and extended frequency response. Frankly, these tubes could drive 20 6080 cathode followers without breaking a sweat, and they should provide a long service life in the Crack circuit.
This modification involves roughly tripling the current through the driver tube, and raising the bias voltage at the cathode by means of an alternate LED. With all the extra current running through the driver stage C4S, some additional parts will have to be substituted to handle the extra heat, and LED's need a little extra current to operate at this level. With the additional current being drawn by the driver, the power supply has been tweaked slightly to retain proper voltages. These modifications are significant enough (especially the different power transformer), that it is only reasonable to offer these as built items. "