SAEQ - ASTRAEUS headphone amplifier
Astreus represents a structural leap towards tubes with the intention of taking advantage of the physiological pleasantness of tube sound but also to bypass the negative structural limits imposed by output transformers on tube amplifiers and a number of other shortcomings of tubes related to adaptability to a wide range of different headphone impedances.
This carefully designed hybrid overcomes with ease.
The result is a very sophisticated presentation full of details with microdynamics that confuse you, bringing to the stage finesse that we did not notice on well-known tracks.
As the first step in the construction, the input buffer is made with an ECC 88 /6922 tube that gives the basic character of the sound. The input of the tube buffer is directly exposed to the source without volume control. It must be taken into account that the maximum input voltage to the tube buffer is approximately 5V (peak to peak). Definitely avoid DACs without output regulation and with a voltage greater than 6V (peak to peak). High output voltages of the source are unnecessary and undesirable in this case because the tube input is sensitive.
The next step in this hybrid topology is the 99-step volume control that allows for flawless regulation regardless of the sensitivity of the headphones, thus avoiding input and output attenuation with the aim of good volume control.
Advanced two-level volume memory functions facilitate comparisons with headphones with a significant difference in sensitivity.
The tube sound is transmitted via germanium transistors at the input stage of the power amplifier. The simple and effective application of germanium has preserved the general character of the tube sound.
The output stage operates in class A up to 5W of power. For higher output levels, it switches to class AB, avoiding unnecessary dissipation.
The powerful output stage is insensitive to headphone impedance and the number of headphones connected, so it can easily drive 4 headphones at the same time without any loss of playback quality.
Specification
Please carefully read the data on the input sensitivity of the amplifier to avoid damage to the input and volume control.
Astraeus is a hybrid with a direct tube buffer. This means that the volume control is behind the tube buffer!
Be careful not to load the input beyond the allowed parameters.
* Load Impedance headphones out - direct: direct output: 4- 600 ohms
* Load Impedance speakers out: 4-16 ohms
* Output Power : 30/4 ohms, 20W/8 ohms, 8W/16 ohm, 4W/32ohm, 2W/64ohms, 1/120 ohms, 0.5W/300 ohms, 0.25W/600 ohms at 1khz/sine
* Frequency Response: Out 10V sin. 10hz – 100kHz (-0.5dB/ +/-1dB)
* Power Bandwidth: Better than 10-80kHz (-0.5db) at 5W/16ohm )
* Distortion:
- Better than 0,15% at 1khz
- Signal to Noise Ratio: Better than 93dB
* Input Impedance: 47kΩ
* Input Sensitivity for full OUT / Max input signal (input overload)
- 2,4V (peak to peak) direct to RCA - 0,8VRMS / 24V peak to peak max / 8VRMS - atenuator (on back side) must be -10dB ON for higher output DAC
* Input Connections:
- INPUT 1- 2 RCA Single-Ended
- INPUT 3 - 2 XLR 3-pin Balanced (female)
* Output Connections:
- 1 x XLR 4-pin female +6,3mm stereo jack-direct,
- 1 x XLR 4-pin female + 6,3mm stereo jack direct/attenuation 5-10db (balanced Planar & Dynamic headphones)
Misc
* Max Power Consumption: 150W, without signal 40W
*Working voltage: 115V/230VAC (selector switch)
* Dimensions: Height 130mm, Width 385mm, D 250mm
* Weight: NET- 9,5kg, PACK 10 kg
* Remote control: YES –type RC-1