Unlike other active loudspeaker systems, the Integris Active 300B places
its amplifiers in a completely separate chassis apart from the loudspeaker enclosures, more like a conventional
amplifier. This maximizes the system’s resistance to vibration – a point made more critical with the use of
vacuum tubes.
The Integris amplifier chassis is solidly built and conservatively fashioned. The Integris owner can take
pride in displaying it as part of a fine music system.
The single chassis design ensures that the system is easy to set up and operate and perform to its maximum
potential. Only one power cord and one set of interconnects are needed. Having more separation would mean more
potential signal loss, complexity and risk of picking up noise and hum.
The unit uses completely separate power supplies for the solid-state and tube sections. Each is fed by
massive potted Plitron toroidal power transformers and uses substantial power supply filtering. AC power is
kept entirely in the rear third of the amplifier chassis and well away from the low-level signal circuits at
the front. The vacuum tube power supplies, including all filaments, use choke-equipped pi-filters with
high-value capacitance to reduce noise to completely insignificant levels and maximize low-level signal
resolution.
Vacuum tubes have been selected specifically for their performance into the mid and high frequency bands.
The best performers found to date are the mesh-plate 300B power tubes from Sophia Electric and the
ElectroHarmonix 6SN7.
The latter in particular rival the very best expensive NOS samples we have had the opportunity to try.
The amplifier will easily accept any 300B and 6SN7 substitutes and allow the user to discern their audible
performance.