“Single Ended Triode (SET) amplifiers in our opinion present music in a sonically pure form, with an enormous amount of emotion and timbral accuracy quite unmatched by any other type of amplifier. The presentation is truly special, and for some – once heard, there is no going back. We have invested thousands of hours in the lab developing a comprehensive range of SET amplifiers. The Concero 65 series, with it’s sheer power and size, takes SET performance to the highest level possible. These amplifiers are big, bold and very dynamic, with treble details and purity, and a liquid midrange as we would expect from the very best SET designs. In our case, the Concero 65 also has rock solid bass control and bass detail unmatched by any other SET design available today.”

The Concero 65 Signature uses a parallel pair of RCA 813 tubes in the output stage. As an output tube, we believe this tube is one of the most linear tubes ever built. Triode curves quality are unmatched even by the most linear 300B tubes for example. And of course most bigger triodes like the 833 are far behind in both linearity and sonic performance.

This 813 big bottle tube never seizes to impress us whenever we compare it in our labs with ANY power tube used today, and is our weapon of choice when designing SOTA SET amplifiers.

All three directly heated triode tubes – output and driver are using triple PI filters with a total of 700,000uF of capacitance, providing a completely ripple and noise free filament current. In the Concero 65 Signature all filaments are inductively isolated from their PSUs.

As in all circuits using directly heated triodes, the filament power supply units are part of the signal circuit. This in turn means filament current supply is critical to the end sonic result. Having a very low noise PSU is mandatory. In the Concero 65 Signature we took the extra step and isolated the PSU from signal, using specially designed inductors which isolate the PSU from the signal.