CANEVER AUDIO LASCALA POWERAMP


More in depth info and photos about the new CanEVER unique amplifier... "The CanEVER Audio LaScala PowerAmp is one of the rare audio amplifier designs, consequently following the main results in research about audio amplifiers in engineering history."

First of all: The CanEVER Audio LaScala PowerAmp is a current source amp! Why is this important?

To design the “correct” type of amplifier, it is important to understand, how the load connected tothe amp is working. The load of an audio amplifier is a loudspeaker. Each driver inside a loudspeaker follows the laws of physics – not the “ideas” of more or less talented people designing amplifiers. These laws of physics “command” any kind of speaker driver to move as a function based on theCURRENT of the input signal. This means, that the movement of the cone is direct proportional to the applied CURRENT.

Unfortunately, most of the audio amplifiers on the market are designed as VOLTAGE amplifiers. How does this affect the sound of my loudspeaker?

It is known very well, that a loudspeaker does NOT represent a pure resistive load to the connected amplifier. In fact, the loudspeaker represents a complex load called impedance. This impedance is dramatically irregular with maxima and minima along the band of frequencies, the loudspeaker is radiating.

Once an audio amplifier is producing an output VOLTAGE, which is proportional to its input signalcoming from the various audio sources in an audio system, this VOLTAGE has to be “converted” into CURRENT to drive the speaker. The IMPEDANCE CURVE of the loudspeaker influences this“conversion” strongly. This is not a linear function as described above. Even for a non-engineer, it is easy to understand, that under those conditions the movement of the loudspeaker cone is“modulated” by the impedance curve of the loudspeaker. The result is ALWAYS a colored soundradiated from the speaker. There is no way out!

This situation is changing completely, if the audio amplifier is working as a CURRENT SOURCE!

In this case, the output CURRENT of the amp is directly proportional to that of its input signal and makes the cones of the speakers move directly proportional to that applied CURRENT. The speaker is moving proportional to the original audio input signal, not matter what crazy “roller coaster”function its impedance curve is riding.

The result is a clean sound representing the original audio signal and not that “created” by theimpedance of the loudspeaker.

There is only ONE correct implementation of an audio amplifier and this is a CURRENT SOURCE amplifier represented for example by the CanEVER Audio LaScala PowerAmp!

How is the CanEVER Audio LaScala PowerAmp working in principle?

In a nutshell: This amp is a push-pull amplifier based on two “branches” of single ended pure class A
amps for each audio channel simply combining the best of both “worlds”.
Directly connected behind the XLR input connectors for each channel one can find a first transformer working as a phase splitter to create the two “branches” of the signal feeding the voltage stage of theamp. This more or less consists of one double triode 6N6P per channel. As this first stage is working as a voltage amplifier, the following stage is doing the current amplification. An interstage transformer connects both stages - again working as a phase splitter. The special winding scheme of this interstage transformer creates on its secondary side two signals being 180 degrees out of phase– in easy words: The interstage transformer creates two signals as “mirror image” of each other.

Why is this type of interstage transformer important?

Usually push-pull configurations make use of two “complementary” types of transistors – “N” type and “P” type. Unfortunately, the specifications of those devices are NEVER exactly complementary!This creates some very “nasty” types of distortions in a push-pull amplifier.

As the interstage transformer inside the CanEVER LaScala PowerAmp creates two “mirror images”, it is possible to use two power transistors of exactly the same type. CanEVER Audio uses two lateral N- channel MOSFETs of the latest generation. This type of MOSFET does not need any kind of feedback for the thermal stabilization!

As all stages inside the power amp are running in pure class A mode, no distortions are created in the crossover section. Specially designed BIAS control circuits manage the symmetry of the signals of the tubes and the MOSFETs. The result is a perfect symmetry in the processing of the audio signal, even if some SPECs of the active element are different. The bias for all stages is fix without feedback. The individual bias is independent from the power generated, the impedance of the connected loudspeakers and the processed audio signal!

As a special feature, the microprocessors running the BIAS modules offer the functionality to switch the output power of the CanEVER LaScala PowerAmp between 50W and 90W per channel. As thewhole design is “floating”, it is possible to switch the amp from 2-channel STEREO mode into one channel MONO mode. Of course, one can DOUBLE the output power of the amp using this mode.
The final result is a perfectly symmetric design, which minimizes odd order harmonics usually“hurting” our ears during listening.
The CanEVER Audio LaScala PowerAmp is made of two amplification stages only – one for voltage and one for current. Please note, that there is NO CAPACITOR and NO FEEDBACK implemented in the complete signal path!

Also important: The output transformers!

The CanEVER Audio LaScala PowerAmp is using an output transformer for each channel!
Why this is important in the design of the amp, we will cover in another article to be published at a later point in time.

Interesting as well: The cooling system!

As the CanEVER Audio LaScala PowerAmp is working in pure class A mode, the whole circuit gets VERY hot. To dissipate this heat, there is a very special cooling system implemented – totally different from usual heatsinks. We will describe this system in an additional article at a later point in time.

For those of You, who are curious, here two pictures of one heatpipe, that is implemented for EACH of the four power MOSFETs:


Last but not least: The separate power supply

The CanEVER Audio LaScala PowerAmp comes with a very special DUAL MONO (one per audio channel) power supply in a separate cabinet. The transformers in this power supply offer a total 1800VA of reservoir power.

The weight of that power supply alone is about 32 kg !!

The description of that power supply we will cover in another article to be published at a later point in time as well.

Here you can see the basic circuit of the power supply:

For all You, which by reading the above article became curious to learn more about the interesting design of the CanEVER Audio LaScala PowerAmp as well as the other products from CanEVER Audioas the ZeroUno DAC or the ZeroUno PLUS, we kindly invite You to visit us during the coming High End Show in Munich. You might find us in Hall 3 / Booth P08.

For further information, please visit our website www.canever.eu or send us an e-mail, addressed to:sales@canever.eu.

Following you can find a gallery of photos showing more details of the CanEVER Audio LaScala PowerAmp: