Butler Audio MONAD A100 User Manual

It has been our experience that you generally 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 this 

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 quite 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.  Our proprietary Butler 300B directly heated power 

triode produces unmatched audio performance and reliability.  It is 

a classic favorite among audiophiles the world-over.  Thanks to the 

recent break-through of BK Butler’s thermionic patent, this 

wonderful tube can now be appreciated at elevated power levels 
unavailable with former conventional designs. 

 

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 a heated cathode, 

became the foundation for our modern electronics industry.