Description
Holo Audio Azure Fully Discrete Pre/Headphone Amplifier
In each channel in the Holo Audio Azure Fully Discrete Pre/Headphone Amplifier, one amplification module is responsible for signal buffering and volume control, and the other is responsible for signal amplification.
Amplification
Design of Amplification ModuleÂ
Its commonly known that the solid state equipment and the tube equipment ​​have their own characteristics. The advantages of the solid state machines are relatively balanced and full of details, and the advantages of the tube amplifier are more relaxed and rich timbre. There are many speculations why there is such a difference, but there is no proven results. A lot of time was invested in the research, to link design with the reasons for the formation of a sense of hearing. In the end, some key points have been found, and the amplification module is a new design based on these findings.
Generally speaking, most of the discrete amplifiers on the market are simple in structure, and their tested performance is not superior.
There are two reasons:
- First of all, to achieve high performance, you must have a complicated structure. Then the problem comes, the complicated structure is very difficult to control. For the amplifier, an ignorance of certain details will destroy the rest of the effort, and even a slightly longer route will lead to self-induced shock. Therefore, it is a considerable challenge to be able to master all the details of a complex amplifier without introducing problems and mistakes. In the process of developing this amplifier, there were more than ten versions of design, and slowly modify the structure and fine-tune the details to form the final design.
- In addition, the complicated structure of the amplifier means higher cost, and the material cost is only one aspect. Since the transistors in the amplifier need to be precisely matched, the labor cost is also very high if the pairing is performed manually. The Azure’s amplification module uses a considerable number of “twin transistors”, which solves the labor cost of pairing. Of course, due to the relatively expensive “Twin transistors”, the material cost is further increased. But considering that the twins are innately matched, it is much better than the pairing afterwards.
Features
Volume ControlÂ
The volume control of “Azure” is the step potentiometer controlled by the relay, 64 steps, each step is 1db. The advantage is that high-precision fixed resistors can be used, which is much better than the carbon film resistance of ALPS. It will not be biased to one channel at small volume. This step potentiometer has four channels and forms a fully balanced structure. Another advantage is that it can be remotely controlled.
Headphone Amplifier OutputÂ
The headphone amplifier output can be set to high-impedance output and low-impedance output, so that when driving high-impedance headphones and low-impedance headphones, they can be optimizaed accordingly, which achieves very good compatibility and can be used almost with any headphones on the market.
Pre AmplifierÂ
The preamplifier part of the Azure inherits the fine tradition of its predecessors, the “Mammoths”. This is not headphone amplfier with a pre amplifier, nor is it a pre amplifier with a headphone amplifier. It has the quality to be used as a stand alone pre amplifier.
Specifications
Analogue Inputs:
* Single Ended Input x 1
– Maximum Input 12Vpp
– Input Impedance 3.9k Ohms
* Balanced Input x 1
– Maximum Input 24Vpp
– Input Impedance 7.8k Ohms
Analogue Outputs:
* Single Ended Line Output x 1
– Maximum Output 16Vpp
– Output Impedance 33 Ohms
* Balanced Line Output x 1
– Maximum Output 32Vpp
– Output Impedance 66 Ohms
* Single Ended Headphone Output x 1
– Low Impedance Mode 400mW@32 Ohm Load
– High Impedance Mode 180mW@300 Ohm Load
* Balanced Headphone Output x 1
– Low Impedance Mode 1600mW@32 Ohm Load
– High Impedance Mode 720mW@300 Ohm Load
