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Maestral ONE headphone amp

Posted in: Products / Head amps

Technical details:

Operation on low impedance (<80 ohm):    OTL (single end class A)
Operation on high impedance (>80 ohm):    OTL (single end class A)
Driver tube (& equivalent):    6DJ8, ECC88, 6n23P
Power tube (& equivalent):    6AS7, 6N13S,6080
Power output (32-600ohm, THD <1%):    160mW
THD on declared power:    0,55%
Input impedance:    50K
Out. impedance on low switch /feedback:    33 ohm / 6dB
Out. impedance on high switch/feedback:    130 ohm / 0 dB
Freq. Response (+-3dB):    7- 65kHz
Sensitivity for declared power:    0,775Veff /0dB
Max. Input voltage:     1,55Veff /6dB
Max. Out voltage/impedance:    10V/600 ohm
Signal/Noise db:    82dB
Stereo Crosstalk dB:    62 dB
Input conn:    RCA
Out conn:    6,3mm conn
Pass trough conn:    RCA
Supply voltage:    110-120/220-240V
Power consumption:    75VA
Dimension mm(W x D x H):    200x320x90(200 tube)
Weight kg:  
Suitable for CAT SE box (2 x 2W on 6 ohm):    Yes


Model ONE amplifier

First in the series of three tube headphone amplifiers, this SE OTL (single ended output transformer-less) amplifier is the smallest in the Maestral family and yet, it provides enough current for driving 32 Ohm headphones at the lowest of frequencies with minimum of negative feedback used. It is equally capable of providing enough voltage for driving high impedance headphones. For the latter, it is possible to fully disable negative feedback via the simple switch on the back panel and thus achieve maximum dynamic range. Simple mathematics shows that for 250 mW of output power at 32 Ohm load, 2.85 V of voltage and 88 mA of current is required. If we exclude designs with multiple output tubes, the choice of readily available tubes capable of meeting these specifications is rather limited.

In the model ONE amplifier, the output signal from the triode is generated on a cathode resistors. At the same time, operational range of the output tube is set to allow for maximum linearity. Like the other members of the Maestral family, the model ONE amplifier offers three pairs of RCA connectors: line input, loop output and preamplifier output. In addition, there is a sensitivity adjustment potentiomater on the back panel which allows for greater flexibility of the volume potentiometer when used with high sensitvity headphones.


The CAT module (for use with model ONE and TWO amplifiers only)

This step-down CAT (cathode auto-transformer) module is the result of years of research and development that enables our headphone amplifiers to be used as low power output speaker amplifiers. This module significantly expands the flexibility of our headphone amplifiers and can deliver 2 W of power at 8 Ohm load.  Providing the use of high sensitivity speakers, this will be enough for a small room or an office.

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