Concero 25 Monoblock Tube Amplifiers


concero 25 main

Our first Prestige Series amplifier is the Concero Direct Heated Tube Monoblock amplifier.

Using top of the line design, material and building techniques, we have managed to get pretty close to our Reference line amplifier performance, but in a more manageable design,as regards funds and size.

We endeavoured to produce a design that has all the sonic virtues of only the best of the best Single Ended amplifiers, but with absolutely none of their shortcomings. We strongly believe we have succeeded .

Driving the output tube, is a major task, which almost all SET amplifiers fell short, using tubes not adequate to the task. Tubes with high Rp and small current swing capabilities. What we choose to use is a small amp ,consisting of the special quality Siemens E280F super-tube, with it’s own power and bias supply.

This ultra wide-bandwidth/ very high trans-conductance tube is transformer coupled to the grid of the output tube using a very wide-bandwidth inter-stage transformer. No RC coupling is used in any of our amplifiers.

Output is rated @ 30W, via a massive output transformer, with 4 and 8 ohm taps.

The output transformer weighs more than many SET amplifier's total weight. The highest quality massive core of the output transformer used in the design, is mandatory for delivering true undistorted higher and lower bass, and driving any speaker through complex musical content. Many SET amplifiers get distortion when driving speakers with complex music,because of core saturation.Our output transformer can easily take 60W at 20Hz ,so at 25W intermodulation aftifacts are next to zero.

Separate power supplies are used throughout our design, using 4 toroidal transformers rated at over 1100VA total.Separate toroidals are used for driver stage,output stage,filaments and bias circuits.

Driver and output is ground-choke regulated and energy banks are over 4000 joule per channel.

• Full Power sensitivity: 1Vrms
• Noise floor: <-100db A-weighted
• THD: < -70db @ 60% Full power
• Power Bandwidth: 15Hz ~ 80Khz -3db @ 25W
• Tube list: 1x RCA 813, 1x Siemens E280F
• Power Consumption @ idle: 250W

Dimensions: 560 mm W x 420 mm D x 390 mm H
Weight is 70Kg each, unpacked.



    We guarantee that the driving capabilities of the Concero amp are not matched by any other SET in this power range. Absolutely no sagging is present during dynamic peaks, whatever the speaker’s power demands are and whatever the speaker impedance.

    Micro and macro-dynamics will be redefined in your system when you hear the Concero Monos.



    As an output tube, we use the RCA 813 DHP, also used on our top Reference model, the Exsequor. This transmitter tube, maybe is, the most linear power tube ever built. Triode curves quality are unmatched even by the most linear 300B tubes, of course bigger triodes like the 833 are far behind in linearity and sound. This 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.

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