The Bottlehead S.E.X. 2.1 is an integrated amplifier designed to drive any headphone, and high-efficiency speakers. This unit is NEW, purpose-built for Audiogon, professionally assembled. It contains two upgrades: the Bottlehead 2.1 CS4 (constant current source) and the Output Impedance Switch 2.1 kit which permits the user to adjust the impedance to 4, 8, 16, or 32 Ohms. The S.E.X. is a 'busy' build, requiring the basic build, then removing components and installing the upgrades, and a time-consuming venture. Kit price with upgrades was $670 as shipped from Bottlehead. Then, I have roughly 15 hours of labor into it.
Sound: This unit has been burned in for 100 hours, so what you hear upon powering up is how it will sound. What you can expect is a very even-handed treatment of the audible spectrum with no pronounced humps/dips. Whereas the Crack is more a 'front-row' experience, the S.E.X. is more 1/3rd hall, and a more neutral amplifier. It has greater soundstage depth and width, is even quieter than the very quiet Crack, and more detailed; it's simply a more refined amp. I've auditioned at length during burn-in with Bach to ZZ Top and it's an excellent amplifier of sound, modern tube design. Don't be put off by "kit"; these are seriously good amplifiers that would have to retail for twice the price.
Great care has been taken soldering the unit with Cardas Quad Eutectic throughout. What you won't get is burned wires, solder blobs, cold joints, nicked wires leading to eventual failure, and solder splatters. I use a temperature controlled soldering station and three different tips to tailor the heat to the components being worked. I've completed a third and final voltage check as well as a third visual inspection of all joints, wiring and components under magnification. I proof the amp with Sennheiser HD-600s.
The alder wood base has been hand-sanded and all edges broken to soften the aesthetic It it ready for you to take to a local finisher with a sample of your decor to suit your preference. I have taped the Bottlehead badge to the front in a couple photos for viewing, but will leave it unattached in case you wish to finish the wood.
Transformer metal surfaces and the top plate have 3-5 coats of antique gold and flake, with the top plate getting a 'distressed' treatment; it's very handsome and should accommodate a variety of finishes to the base. There is a small foxing in the finish on the very rear of the power transformer bell, and a pinhead size blemish on the left output transformer. Brass screws have been used throughout to accent the gold finish.
This S.E.X. will arrive with a document CD containing the manual and information on both upgrades, a pair of RCA 6DN7s, a Bottlehead brass badge, and power cord; I'll also include a pair of GE 6DN7 which I slightly prefer to the RCA. The S.E.X. has a venerable track record and this one is ready to plug and play. It will be securely double-packed for transit.
Thanks for looking!
Tubes by Tom
Bottlehead S.E.X. specifications: <i>The amplifier’s power output is approximately 2 watts RMS per channel at 10% THD at 500Hz, similar to a single ended 45 tube amplifier. Frequency response at 1V output is -3dB at 27Hz and 22kHz. The amplifier has an input sensitivity of .62V RMS and a gain of approximately 15 dB at 1 kHz and can be wired for 4,8,or 16 ohm speakers or 32 ohms for use with virtually any headphone. Input impedance is 100Kohms.
Most any dynamic headphones with a standard TRS plug will work with the S.E.X. amp – Sennheiser, Grado, Beyer Dynamic, Sony, AKG, etc. The S.E.X. is particularly adept at driving picky headphones like AKG K1000s, Audeze LCD-2s and the Hi-Fiman headphones.</i>