Cayin U-120D KT170*4 Vacuum tube Power Amplifier HIFI Class A Push-pull Amplifier & MONO/STEREO Channel Mode

Features:
TUNG-SOL KT170·Pure Class A
TUNG-SOL KT170, the representative of the four-beam tetrode family, is used as pure Class A push-pull power amplifier. It is the crystallization of Cayin's more than 30 years of experience in vacuum tube circuit design, a stable and efficient classic amplifier circuit, and a high-power pure Class A reserve. It can be matched with various speakers to enter a new realm of personal listening experience at any time.
Mono: 120W
STEREO: 60W+60W
RCA 17AX4GT rectifier tube provides a stable DC power supply for the preamplifier stage. Its excellent high voltage resistance and low internal resistance ensure that the charm of tube rectification is maintained when the sound is restored. The music detail restoration is significantly improved, and the emotional expression is better.

The voltage amplifier stage uses the side-heated dual triode JJ12AU7/ECC82, which has the characteristics of medium gain, low distortion, low noise, good linearity and stability, ensuring the low distortion output and high stability of the voltage amplifier stage, balanced sound, warm, natural and delicate tone.

The driver stage uses the side-heated dual triode JJ6SN7, which has the characteristics of medium gain, low distortion, low internal resistance, high voltage resistance and high current driving capability, ensuring the low distortion output and excellent linearity of the driver stage. The sound is loose and full, the tone is neutral and slightly warm, and it has both resolution and musicality.

Dual mode: triode (TR); ultra-linear (UL)
Triode mode (TR): KT170 screen grid is directly connected to the anode
Ultra-linear mode (UL): Add an ultra-linear tap to the primary winding of the output transformer and connect it to the KT170 screen grid, thereby changing the working state of the power tube.
Triode mode (TR)
Delicate, pure and smooth, suitable for enjoying vocals, string music and other types of music
Ultra-linear mode (UL)
Open, unrestrained, and powerful, suitable for enjoying large-scale, dynamic and other types of music

Dual tone: dynamic (DYNAMIC) | soft (SOFT)
By synchronously adjusting the working current of two KT170s, dual tone output is achieved.

Dynamic (DYNAMIC)
The sound performance is high in density, the dynamic contrast is more obvious, and the driving force is surging
Soft (SOFT)
The sound performance is loose, more delicate and soft details are unfolded, and it is more appealing to listen to

NFB. Negative feedback selection function
NFB.LOW working mode
The loop negative feedback is low, the sound is open and unrestrained, the momentum is good, and the details are rich
NFB.HIGH working mode
The loop negative feedback is high, the sound is soft, pure and smooth, and the lines are delicate

Four-speed input gain selection
Adapt to different pre-stage and sound source characteristics, from the analog warmth of vinyl to the sharp analysis of digital sound sources, all can be accurately matched.

Free evolution of mono and stereo
Through the back panel mode switch, two working modes can be freely selected: mono/stereo, adapting to multiple application scenarios, supporting free and flexible combination, and meeting the needs of audiophile players

Dynamic Auto Bias adaptive bias servo circuit
U-120D innovatively adopts integrated adaptive bias servo circuit design to replace power tubes, without manual adjustment. The automatic bias servo circuit can accurately control the bias of the power tube, so that the vacuum tube can better match the machine, improve safety and extend the life of the power tube

U-120D uses microcomputer MCU program to manage the entire machine, with built-in multiple protection circuits and power-on timing, from power-on, playback to power-off, providing appropriate protection in all aspects,
Protect the vacuum tube while keeping the whole machine working in an ideal state. 60 seconds soft start BMI power tube protection function delay protection to ensure abnormal operation. The light is on and BMI protection starts

Cayin has been selecting vacuum tubes for more than 30 years, U-120D The vacuum tubes used for the preferred imported vacuum tubes are all manually inspected and paired, and strictly tested for performance. The machines must pass 48 hours of aging before leaving the factory, and pass the actual human ear audition. The process is cumbersome and complicated to ensure the high standard of unified channel channels.

As one of the key components of vacuum tube amplifiers, Cayin always insists on self-developed high-quality toroidal power transformers. It adopts a high-purity copper enameled wire winding design, which produces lower magnetic noise than standard transformers. In addition, the shielding packaging technology and circuit protection measures are further developed to protect the machine circuit from noise interference and effectively improve the product life. The specially designed wide-band response El-type output transformer uses imported Z11 silicon steel sheets, which has low audio signal loss and higher restoration.

The welding of each electronic component in the host adopts the classic scaffolding process to ensure low signal transmission loss; the wiring in the machine is rigorous and the process is complex, which truly makes the audio transmission, power distribution ground wire, etc. completely independent and non-interfering. From the design considerations of each detail, the process implementation guarantees the electrical performance indicators and product reliability of U-120D.

The American AudioCapX PPFXS high-end coupling capacitor effectively isolates DC, improves the accuracy and stability of audio transmission, and enhances the overall sound quality.

Thick silver-plated signal leads and silver-plated electronic wires have good conductivity, ensuring the stability and reliability of signal transmission and reducing signal attenuation and noise interference.

Input terminals: one set of XLR, one set of RCA
Left and right channel speaker terminals: Output impedance 4Ω~8Ω, easy to match with speaker system
The sound quality is better when used with the preamplifier U-9LS

Specifications:
Rated output power:
Dual channel (STEREO)
32W+32W (RMS triode working state)
60W+60W (RMS super linear working state)
Dual channel (STEREO)
32W+32W (RMS triode working state)
60W+60W (RMS super linear working state)
Overall frequency response: 8Hz~70kHz (-3dB, RCA/XLR)
Total harmonic distortion: 0.2% (1W/1KHz; rated output power less than 2%)
Signal-to-noise ratio: 105dB (RCA, A-weighted) / 102dB (XLR, A-weighted)
Input sensitivity: 820mV (NFB.LOW) / 960mV (NFB.HIGH)
Input impedance: 18kΩ
Output impedance: 4Ω ,8Ω
Input terminals: one set of RCA; one set of XLR
Vacuum tubes used: J12AU7/ECC82x2, J6SN7x2, TUNG-SOL KT170x4, RCA 17AX4GTx1
Dimensions: 430mmx420mmx238mm
Net weight: 37.5kg
Power consumption of the whole machine: 420W (maximum)
Working conditions: Temperature: 0℃~40℃ Humidity: 20%~80%
Storage conditions: Temperature: -20℃~70℃ Humidity: 20%~90%