The Concero 65 Reference is the first model to our 3 level Concero 65 series

“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 Series

The Concero 65 monoblock power amplifier series come in 3 versions, the Reference, the Signature and the highest level – the Limited Edition.

The Concero 65 Limited Edition descends from our Legend Series Achilleas amplifier, based on our 813 driving 813 circuit topology.

The Concero 65 Reference and Concero 65 Signature are both smaller versions of the Exsequor monoblock power amplifier, which is our top level 814 driving 813 circuit topology.

The 813 Tube

The Concero 65 Ref 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.

Driver stage

The driver stage uses it’s own PSUs and special biasing circuits. The driver stage is built like as a small SET amplifier driving the output stage using a unique interstage transformer. A sample of the driver’s capabilities it the fact that it can deliver 14W of power if needed. The output stage is driven in absolute fidelity of the input signal.

The output transformers massive core used in the design is mandatory for delivering true undistorted upper and lower bass, and driving any speaker through complex musical content.


All three DH tubes,output and driver are using triple PI filters with a total of 700,000uF of capacitance,giving a completely ripple and noise free filament current.

Driving the output tube is a major task, and where many SET amplifiers fall short… our driver stage can deliver more power if asked than the majority of other Single Ended power amplifiers.

Driver and Output PSU

All PSU are independent using their own transformers,chokes and our proprietary Super Capacitors. This unique type of film capacitors present a set of specifications unprecedented in capacitors used in audio, such as ESR and ESL values 100 times lower than electrolytics, as well as a maximum current surge measured in Kiloamperes.

Biasing circuits

Both driver and output stage as biased with our custom biasing circuits, with all tubes monitored and biased on the fly. There is no need for external instruments. Using the biasing monitor system, a user can fine tune the amplifier sonic wise, to suit the system – on the fly, and while music is playing.

Technical Specifications


Output Power:



x2.7 (8.5db)

Noise floor:

<90db (Ref) un-weighted

Tube list:

1 x 814, 2 x 813 (per channel)


-70db H2 @ 1W -50db H2 @10W

Signal bandwidth:

8Hz-110KHz @80% max power

Energy storage:


Power supply:

1,800VA power transformer


RCA, AC link proprietary input

Output impedance:

User selectable (impedance matching system)
1.6ohm (8ohm setting), 0.8ohm (4ohm), 0.4ohm (2ohm setting)

Tube Bias:

Adjustable bias on the fly

User readouts:

Output and driver online monitors


No capacitors in the signal path.
SuperCapacitors used for output and driver power supply
(1mohm ESR capacitors)

Power Consumption:

400W per channel


510mm W x 590mm D x 350mm H


95kg per channel