Here is a custom-built pair of Open Baffle hifi loudspeakers, designed to be used with low-powered tube amplifiers. The design is centered around a matched pair of vintage Altec fullrange drivers, the 403A. This driver is run fullrange (NO crossover elements whatsoever), with support provided at both frequency extremes. More info on this driver can be found here:
http://www.altecpro.com/pdfs/vintage/SpeakerAndMics/ceiling/403A%20Ceiling%20Speaker.pdfFor the highest octave (>10k), a newly manufactured Aurum Cantus G2Si ribbon tweeter picks up where the Altec driver rolls off naturally. By using a single high-quality film capacitor to roll off the LFs, it blends seamlessly with minimal phase shift.
At the lowest two octaves (<250hz), the widely popular Eminence Alpha 15 (15") woofer fills in the lower bass frequencies. It's used in many current hi-end speakers, particularly in open baffle designs where very few woofers can reach extend below 80hz. The Eminence Alpha 15 can reach 40-45hz with minimal baffle support, and at very high sensitivity (96db). The single coil crossover maintains system efficiency and blends the woofer more harmoniously with the sweet mids of the Altec.
All elements of these speakers have been well-thought out. Hookup wire is Kimber, and the binding posts are Edison Price Musicposts (tragically no longer available). The wood is Baltic Birch ply, and the rear surface is covered with cork in order to damp rear wave reflections. The neat baffle shape is designed to produce a flat driver response, and to be as diminutive as possible for best soundstaging. The width was calculated to roll off the Altec wideranger right at the point where the Alpha 15 kicks in, due to OB wave cancellation.
These speakers sound absolutely fantastic, and are at their very best with single-ended tube amplifiers like 300B or 2A3. From personal experience, anything less than a 2A3 (2.5 watts) will not be enough. The 300B is ideal, but I've mostly used them with 2A3s (as seen in photos). Please be aware - due to the minimal protection provided by this crossover, high-power amps can be a problem for either the ribbon tweeter or Altec driver. I'd personally stay away from amps that are more powerful than a Dyna 70.
Measurements: 36"H (measured at center) x 18"W, while the "wings" extend about 9 inches back. Not sure about weight, but I doubt it's more than 30lbs or so. Also included are (2) replacement ribbons for the Aurum Cantus tweeter. I've never had to replace them, but apparently the ribbons can be easily damaged.
Local pick-up only, unless other arrangements are made. I'm located in the Washington, DC area (USA) but am flexible about driving to make a hand-off. Please contact me privately.
Gauranteed to be in good working condition. I'm open to ANY questions. Thanks for looking!
Asking $750, but open to trades and other offers.
