Like new tube/solid state hybrid amp, unique circuit. Extremely black background, completely inaudible noise floor. Perfect for inefficent speakers like Maggies, e'stats, etc. Tube warmth with SS muscle.
Previous designs generally employed vacuum tubes in impedance-isolated preamp or pre-driver stages. BK Butler's Tube Driver BLUE technology places the triodes exactly where they should be: DC coupled through the output power devices to the speakers. Therefore, the tubes are positioned to naturally and actively respond to the dynamic speaker load. This also completely eliminates one of the most inefficient and non-musical components in a typical tube power amplifier: the Output Transformer. Without the phase shift and induction generation caused by hundreds of turns of wire and massive core iron to overcome, BK Butler's newly patented current multiplying DC coupled circuitry allows the 6SL7GT output driver tubes to directly operate into the constant ratio-reduced speaker load. This novel design allows the tubes to safely produce authentic power vacuum tube dynamic characteristics hundreds of times greater than their original design capabilities.
ZERO negative feedback. No global degenerative negative feedback loop
• Open Ended Audiophile Circuitry
• Musical, warm and dynamic
• Load Independent; Will drive any speaker
• Hand selected/matched 6SL7GT Twin Triode tubes
(One per channel)
• Fully regulated Tube Heaters with Delayed Soft Start
(10-15 second turn-on delay)
• Load Adaptive Vacuum Tube Driven output circuitry
• Modular power channels with a seperate massive, oversized heatsink for each channel
• Independent AC Secondaries and Rectifiers
with 60,000µF per channel filtering
• DC fault / Short Circuit Protection Circuitry
• Diagnostic LEDs: Red=Fault
• Custom-made Hard Gold Plated Eutetic Brass RCA connectors
• Custom-made Hard Gold Plated Eutetic Brass 5-way Binding Posts
• Frosted Platinum finish
• Tube Illumination: Internal BLUE LEDs
• Patented Design
• Concept & Design: BK Butler / USA
Specifications:
• Rated Power (all channels driven):
2 x 250 Watts RMS per channel @ 8 ohms
2 x 400 Watts RMS per channel @ 4 ohms
1 x 800 Watts RMS Bridged (Mono) @ 8 ohms
• Freq response: 20Hz to 20kHz (+/- 0.5dB)
Power Bandwidth: -3dB, 50kHz
• THD: <0.10% @ 8 Ohms, <0.15% @ 4 Ohms
• S/N Ratio: Better than 120dB (A-Wtd)
• Slew Rate: 15v/µsec
• Input Sensitivity: 2V for 250 Watts into 8 Ohms
• Input Impedance: 47k Ohms
• Idling Consumption: Approx. 40 Watts
(Approx. 0.3A @ 120VAC or 0.15A @ 230VAC)
• Dimensions: 17"W x 16"D x 8.5"H w/feet (7"H w/o feet)
• Weight: 43 Lbs. (19.2Kgs.)
More than enough power for Magneplanars (400 watts at 4 ohms). The tubes are run at such a low voltage they will last for decades with no degradation. Amp is set up in a system with Maggies on Vashon Isalnd, WA if you're nearby for audition. Magnificent sound!!
Cash with local pickup or Paypal, will split PP cost. 206 463-2671 from 0800-to 8 PM Pacific time. Buyer to Pay shipping . Cellfone: 206 852-4372
link to review:
http://www.6moons.com/audioreviews/butler/2250_3.html for pics, email terryroth2@comcast.net
