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Cable Quality: 

Within reasonable limits, it has been our experience that you get 

what you pay for in cables.  A good set of shielded input connection 
cables coupled with large gauge, high quality low-loss speaker wire 

is well worth the investment.  Do not degrade the remarkable 

performance of your amplifier with inferior connecting cables. 

 

The Marvelous Vacuum Tube:

 

Triode Vacuum Tubes were the first method of practical audio 
amplification patented in 1907 by Lee De Forest.  At first, he used 

an open flame to produce thermionic emissions, but later found an 

electrically heated filament was much more practical.  

 

The first triodes were inefficient and often very mismatched in 

performance.  Thankfully we now have reliable sources of precision 
manufactured triode tubes, which are very consistent in quality and 

performance. 

 

Over the years, BK Butler has experimented with virtually every 

type of audio vacuum tube.  In 1992 he obtained a large Vacuum 

Tube Analyzer formerly used by the FAA to test and analyze radar 
tubes for aviation control towers.  This old but very high-quality 

apparatus enabled him almost unlimited control to adjust and 

experiment with virtually every conceivable parameter of any tube.  

For example, input and output pins could be reassigned.  B+ 

voltages and bias currents switched to any desired value or 

configuration.  During these test, it was noted that a Phantom 
voltage was being generated. 

 

It turned out to be nothing less than the original thermionic effect 

that one of Edison's assistant technicians (a Mr. Hammer) 

discovered in the late 1800's while testing early light bulbs.  He 
noted a blue glow around the positive pole in a vacuum bulb and a 

blackening of the wire and the bulb at the negative pole.   At first, 

this was referred to as "Hammers Phantom Shadow", but later 

Edison took credit for the discovery himself (as was his practice) 

and re dubbed it as "Thermionic Emission".  More tests followed and 

soon the first vacuum tube diode was invented.   Limited at first to 
rectifying AC into DC, Edison failed to make the one essential step 

needed for tubes to achieve useful amplification. 

 

However, around 1906, Lee De Forest vastly improved the  

2-electrode vacuum tube diode by adding the crucial element: a 

third electrode, or control grid.  The rest is history.  The successful 
invention of the amplifying vacuum tube triode, which could regulate 

the thermionic emissions of electrons from heated cathode, 

became the foundation for our modern electronics industry.  

Without De Forest's great insight and marvelous discovery, you 

would probably not be enjoying your new Butler Audio amplifier! 

Содержание 2250

Страница 1: ...UUM TUBE DRIVEN TWO CHANNEL POWER AMPLIFIER UTILIZING b T H E R M I O N I C VACUUM TUBE TECHNOLOGY Concept Design B K Butler Patented in the USA Worldwide patents pending Tube Driver Tube Driver Blue Thermionic and Blue Tube illumination appearance method are trademarks of or patented by BK Butler ...

Страница 2: ...put Protection 2 Use and Operation Front Panel Power Switch Rear Panel Remote Jack 3 Inputs Speaker Output Binding Posts Speaker Phasing Remote Operation 4 Specifications 5 Cable Quality The Marvelous Vacuum Tube 6 Tube Reliability 7 Warranty Repair Policy 8 ...

Страница 3: ... ended ZERO global negative feedback circuit topology Previous hybrid designs employing vacuum tubes generally utilized tubes only in impedance isolated preamp or driver stages However Butler 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 speaker load This also c...

Страница 4: ...ms An appropriate source of 120VAC nominal input line voltage with a minimum current supply of 12A is required 230 240 VAC models require approx 50 of the current rating of 120V models Protection Listed below are the various types of internal protection provided for unexpected conditions 1 AC input fuse for protection against any major system power fault Do not replace with a fuse of higher curren...

Страница 5: ... LET YOUR AMP BREATHE Use and Operation Important Do not apply power until you have read and understand this section Connect or disconnect cables only with amplifier OFF Note Your new Butler Audio amp is designed to operate in stereo with ONE separate speaker system connected per channel Connect Speaker Outputs to speakers only DO NOT SHORT ANY SPEAKER OUTPUT POST TERMINAL TO ANY OTHER SPEAKER OUT...

Страница 6: ...e should be kept as short as possible and away from input cables Shielded cables must NEVER be used as this may cause high frequency loss and introduces a needless capacitive load to the amplifier DO NOT SHORT ANY POST TO ANY OTHER POST Speaker Phasing Upper post RED ring is POSITIVE Lower post BLACK ring is NEGATIVE Correct speaker phasing is essential for optimum operation Note Never short ANY s...

Страница 7: ...ts into 8 Ohms S N ratio Better than 120dB A Weighted Slew Rate 15V uSec Vacuum Tube Complement One 6SL7GC twin triode per channel Idling Consumption Approx 40Watts Approx 0 3A 120VAC or 0 15A 230VAC Full Power AC Consumption Model Power Nominal Current 120VAC 230VAC 2250 8 Ohms 4 Ohms 720 Watts 1200 Watts 6A 10A 3A 5A Dimensions 17 W x 16 D x 8 5 H with Feet 7 H without Feet Weight 43 Lbs 19 2 Kg...

Страница 8: ...tube For example input and output pins could be reassigned B voltages and bias currents switched to any desired value or configuration During these test it was noted that a Phantom voltage was being generated It turned out to be nothing less than the original thermionic effect that one of Edison s assistant technicians a Mr Hammer discovered in the late 1800 s while testing early light bulbs He no...

Страница 9: ...Floyd s David Gilmour if BK Butler s low voltage tube guitar pedals aren t the most reliable and best sounding ever made What this means to you is that the tubes installed in your new Butler amplifier should last as long as the other high quality electronic components in the design No special tube care replacement matching biasing or maintenance is usually necessary In the unlikely event a tube be...

Страница 10: ... purchased from anauthorized Butler Audio retailer h Any amplifier purchased outside the USA Amplifiers purchased in another country are covered only by that country s distributor and not by Butler Audio Any removal alteration or tampering of the serial numbers or tampering with the inside of the amplifier will result in voiding the warranty Butler Audio reserves the right to determine and make fi...

Страница 11: ...A U D I O I N C WWW BUTLERAUDIO COM ...

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