---

QUALITON A75 INTEGRATED AMP

---

Overview

The Qualiton A75 is a remarkable integrated amplifier, building on the success of the A50i. It offers 2 x 75 watts of power, providing ample headroom to drive most speakers with ease. The A75 features a wide complement of tubes, delivering the warmth and richness expected from tube amplifiers while minimizing distortion. With a wide and flat frequency response and total harmonic distortion of less than 0.1%, the A75 ensures a clean and detailed sound.

The amplifier includes both balanced and unbalanced stereo inputs, an Automatic Bias System for the power tubes, an updated input selector system, and a sleek new remote control. The A75 combines precision design, craftsmanship, and high performance in a compact footprint. It’s a versatile and powerful choice for audiophiles seeking high-end sound characters.

KT-Series Power Tubes

The amplifier's power block is specifically designed for KT-series power tubes, known for their high power, low distortion and magical sound character. This creates the perfect foundation for our amplifier, further enhanced by our custom output transformers for excellent low and high frequency performance. Moreover, our proprietary Automatic Bias System ensures seamless operation with KT90, KT120, KT150, and KT170 power tubes, so you’re free to choose your favorite without needing any modifications.

Custom Output Transformers

Our amplifiers' transformers are custom-designed and built in our in-house transformer workshop. Our output transformers are constructed using high-permeability, large cross-section toroidal magnetic cores, which undergo initial impregnation during the production process. Following this, the winding process begins, utilizing a multi-layered, sectioned, and specially arranged winding configuration. This meticulous design ensures optimal performance across both low and high frequencies. Once the winding is complete, the transformers are encased in metal shielding cans to minimize electromagnetic interference.

Custom Power Transformer

Just like our output transformers, our power transformers are also custom-designed and built in our in-house transformer workshop. We manufacture them with the same precision and attention to details: the high-permeability, large cross-section toroidal cores are also impregnated, and then the winding process follows. The parameters of the windings are designed to avoid saturation of the magnetic core and to ensure efficient operation even under heavy load conditions. It is important to note that we use double electromagnetic shielding for our power transformers. Finally, we employ the same epoxy compound used to pot the output transformers to eliminate mechanical vibrations and associated noises.

Automatic Bias System

This circuit continuously monitors the behavior of each tube and regulates the bias voltages accordingly, ensuring the smallest possible output voltage noise while guaranteeing the highest degree of linearity of the output stage. Additionally, it prevents the sensitive, high-permeability output transformer cores from saturating by precisely equalizing the quiescent currents of the power tubes. Furthermore, the bias system incorporates a built-in soft-start function, which prevents the tubes from drawing excessive current during start-up and eliminates pops and noises. The result is that no further adjustment is required once the electron tubes supplied with the unit have been installed; the Automatic Bias System takes care of everything.

Aesthetics

Our approach to the visual design centers around maintaining visual neutrality. We intentionally avoid overdesigning the appearance, aiming for aesthetic simplicity and cleanliness. Our products are not meant to be theatrical or ostentatious; rather, they seamlessly integrate into the audio system's interior without disrupting the user experience. However, we add unique touches that make our devices instantly recognizable.

Relay-Controlled Input Selection

The amplifier features a total of four analog inputs: three unbalanced Line IN and one balanced Line IN. Selection between these inputs is accomplished using precision, low-power, ultra-miniature Japanese relays with ultra-low contact resistance gold overlay silver contacts. The front panel Status LEDs indicate the currently active or inactive inputs.

ALPS Motorized Volume Control

The japanese made ALPS passive volume control potentiometers are a top choice among audiophiles due to their high quality, low noise, and smooth operation. Precision engineering and premium materials ensure superior sound performance, while minimal electrical noise keeps the audio signal clean and accurate. Their design allows for consistent volume adjustments, crucial for maintaining fidelity. Known for durability, these potentiometers offer reliable performance over time.

4-Function Remote Control

The remote control features a black matte finish. Alongside the basic VOLUME UP and VOLUME DOWN functions, it also includes a convenient MUTE function and an INPUT SELECTION button.

Special Components

• Tested and Selected Vacuum Tubes

  
  

  The power tubes in all our amplifiers come in matched quads. The preamp tubes are selected for low noise, symmetry and minimum distortion.




• Gold-Plated Ceramic Tube Sockets

  
  Ensuring reliable connections.



• Gold-Plated Audio Terminals

  
  Enhancing signal transmission quality.



• Film Capacitors



• We exclusively use film capacitors in our audio circuits for optimal performance.



• Ceramic Composition Resistors

  
  These resistors are placed in critical positions to enhance reliability.



• Long-Life, High-Temperature-Tolerant Capacitors

  
  Employed in our power supplies to withstand demanding conditions.

SPECIFICATIONS

Rated output power	2 x 75 W, stereo
Total harmonic distortion	< 0.1% (f = 1 kHz, rated output)
Frequency response	25 Hz to 70 kHz (-3 dB, rated output)
Input sensitivity, Balanced Stereo IN	920 mV, to rated output
Input sensitivity, Unbalanced Stereo IN	920 mV, to rated output
Number of input ports / channel	3 unbalanced Stereo IN, 1 balanced Stereo IN
Number of output ports / channel	2 unbalanced Power OUT
Gain	+28.5 dB (RL = 8 Ohm)
Input impedance, Balanced Stereo IN	40 kOhm
Input impedance, Unbalanced Stereo IN	10 kOhm
Load impedance	4 Ohm and 8 Ohm
Signal-to-noise ratio	> 100 dB (RL = 8 Ohm, rated output)
Power requirements	620 W
Tubes required	4 x KT120 (KT150 or KT170 optionally); 4 x 12AT7; 2 x 12AX7
Weight	21 kg
Dimensions	35 x 42 x 22 cm