The Pathos Adrenalin amplifier represents the point of arrival of the INPOL (“Inseguitore a Pompa Lineare” – Linear Pump Tracker) concept.
The essence of such apparatus is that of a tube amplifier featuring a very sensitive and refined timbre, combined with a surprisingly and amazing output capacity.
It really seems that Pathos designers and technicians achieved their goal: an iron fist concealed in a velvet glove.
InPol (Inseguitore Pompa Lineare – Linear Pump Follower) is a system patented by Pathos Acoustics which has enjoyed great success and won many awards.
Inpol devices have a special sonic personality obtainable only by means of this particular circuit design – fully balanced in Class A using a single solid state component in follower configuration, with high current gain and with voltage gain together. The valve amplifier amplifies the input signal voltage and InPol supplies the current to drive the loudspeakers without any further amplification. In this way the signal is entrusted to the valves and becomes a true copy of the original, with all the quality, purity and harmonic content of the original.
This technology allows an increase in the theoretical output in pure Class A of between 25% and 50% together with a low output impedance which is fundamental for the damping factor, and further improved by the double InPol.
Symposium of power and fidelity
The monoblock delivers 200W of power on a load of 8 Ohm and uses a layout tested many times by Pathos. In fact, this is a balanced stage, which means that each amplifier is made of two power stages connected with INPOL configuration, intrinsically functioning in class A.
We would like to underscore that an INPOL stage can work only in class A. It is neither a push-pull circuit (where it is possible to choose how deep to polarize the final stage during the phase of design), nor a single-ended stage; considering the presence of a reactive element that works in symbiosis with an active device (in this case a group of mosfets connected at common drain). INPOL represents an alternative between the two configurations; hence, this topology created and patented by Pathos has properly gained by now its place in the Gotha of Hi-End.
This power buffer with unitary gain, is controlled by a tube amplification stage using three double triodes, two ECC83/12AX7 and one 6H30. The first stage generates voltage amplification based on differential totem pole with two12AX7. The second is a buffer with a common anode with the 6H30 that has the function of driving two groups of power mosfets. The signal on the two outputs amplified and out of phase between them, is delivered to two buffers with INPOL technology.
We have created a very powerful, extremely linear amplifier without using global feedback. It’s difficult to describe the sizing of this apparatus power part; you should see it to fully understand the creativity of Pathos technicians and designers (as if we try to describe the Missouri battleship!).
The polarization of the two power stages is at a very high level: it allows a delivery of constant electrical current to avoid interface problems with diffusers. In this machine, technicians will find a series of outstanding details in the sophistication of the design. Starting from a power supply (completely stabilized for the signal stages on anodic voltage) that has a built-in C-multiplier in order to obtain the maximum filtering, on the voltage current generators and on the ignition voltage of filaments, usually considered less noble (but not by Pathos). The main important feature that distinguishes this project is the sensitive power supply that has to deliver a continuous electrical current of more than 12 A. Because the amplifier is at zero feedback, is necessary to use power supplies, filtered, in order to avoid hum noise in the output. Pathos, as usual, did not care about the cost of components and has used an optimum inductive/capacitive switching power supply able to perfectly filter the electrical current of the two power stages (for instance – the weight of filter reactance is 12 Kg).
|Type||entirely balanced, Double INPOL® power amplifier in pure class A|
|Inputs||1 balanced XLR|
|1 unbanced RCA|
|Input inpedance||100 Ohm|
|Outputs power||200 W @ 8 Ohm|
|Frequency response||5Hz ÷ 60kHz ± 0.3 dB|
|Signal/noise ratio||98 dB|
|THD||0,01% @ 1W|
|0,2% @ 50W|
|Absorption at rest||475 W|
|Tubes||1 x 6H30|
|2 x 12AX7 ECC83|
|Size||68cm (D) x 30cm (W) x 44cm (H)|