With the Cornell Voyager 20 Head we set out to create a new 20 watt head the aim was to maintain the feel and clarity of a vintage classic amplifier but deliver the gain that a modern guitar player expects. 
To achieve this we needed to streamline the circuit design, this is because every component in the signal path dilutes the clarity of the tone of the amplifier.   (Note that out of all the old classic amps the simplest ones sound the best).
In selecting components, particularly the use of carbon composite resistors, we discovered that these resistors produced a sweeter tone more than their successors and are a crucial part in maintaining the harmonic tone quality in all our amplifiers.
When I worked for the MOD It was part of their procedure to coat these resistors with a conformal coating. This seals the resistors and prevents any moisture absorbing into the carbon, It also reduces any damage caused by vibration.  
Valves characteristics are important too,  potentials like voltage, current and impedance have been nurtured to obtain the best performance. The secret is not just in the components, but the way the Valve characteristics contribute to the whole.
The Voyager has taken over three years of design and development, component tweaking has taken a major part and we called on many Pro players to help with the tweaking, so thanks must be given to all the professional musicians that have played a part in producing this hyper amp.