SUN 833-X


Number of amp blocks 3 (1 Driver block + 2 Power blocks)
Inputs 2 XLR ; 2 RCA
Speakers 2, 4, 6, 8, 16 Ohms
Vacuum tube complement
– Output tubes: 833 x 2
– Pre & driver tubes: 1 x 12AU7 ; 2 x 6SN7 ; 2 x 6H13C (6AS7)
Output Power (per channel) 155W RMS
Frequency response 10 Hz – 32 kHz (-3dB)
Input Sensitivity 700mV
Input Impedance 100 kOhms
Power Requirements 230V (possible to set 100 /110/117/240v/50-60Hz by different markets)
Power Consumption 1400W
Dimensions (W x D x H) 45 x 50 x 35 (cm) x 2 block
45 x 50 x 25 (cm) x 1 block
Weight (kg) 165 kg {70kgs(2 blocks) + 25kgs(1 block)}
Phono MM/MC No
Remote control Yes



SUN-833X – Convergence of elites

The SUN 833-X is one of the pinnacle products of ThivanLabs officially launched in March 2022. It is an amplifier that converges many of our quintessential electronic and electrical engineering developments achieved in the past many years of product research and development. After the first version introduced in 2018, the SUN-833X is a remarkable improvement in both sound quality and product design with a completely different and creative technical R & D thinking.

During the development, ThivanLabs has always affirmed our position as a true “LABS” brand. According to this definition, our R & D people are always pioneers in research and development of electrical and electronic technology, always looking for new methods, optimized and efficient in sound reproduction. What’s more, we’ve also built a product quality standard and a sound philosophy for ThivanLabs audio equipment based on a diversity of research and extensive live music, acoustic, live recording experience to reproduce music and sound in a standard and emotional way. These are already the top two criteria and goals that define our new generation of audio equipment.

An overview of SUN-833X

Sun-833X is an integrated amplifier designed into three separate blocks including one driver block and two power blocks. This design represents a different creative mindset compared to the conventional design of Pre-Power amplifiers. The “POWER Stages – DRIVER Stage” separation is an extremely superior technical solution of ThivanLabs SUN-833X. This contributed to the cleanness of the sound. Accordingly, the naturalness of the sound is expressed intact without any interference and alteration.

– The electrical circuit with Point-to-Point direct connection method for the most stable and durable signal transmission quality.

– All power transformers, Interstage transformers, choke are designed and manufactured by Thivan Labs.

The outstanding innovations in the SUN-833X

The Sun 833-X has achieved an excellent low noise among the tube amps using output transformers, well below the human perceptual threshold thanks to the effective solutions applied as follows:

+ The 833 power blocks operate at a voltage of over 1000V. The filament current of 833 tube is very high up to 10A so the tube spreads an extremely high heat which can easily make noise for the amps. A separation of the large power transformers from the driver block is the most optimal solution applied to avoid noise for the Driver stage.

+ The Driver stage uses the tubes 12AU7, 6SN7, 6H13C operating at voltages below 350V. All of the pre-driver tubes are gathered on a separate block to reduce noise efficiently from the Power stage.


+ The Driver stage is a completely new innovative design compared to the previous version SUN 833 (2018). The amplifier circuits from input to output use the entire triode tubes with high linearity (12AU7, 6SN7, 6H13C, 833) giving the amplifier near-zero distortion.

Advantages of engineering solution for the 833 tubes

– The 833 tubes operating in Class A – Single Ended 155W bring outstanding power to all speakers driven by the SUN-833X. The generous power output capability of the Sun-833X gives it an ability to amplify signals with extreme resolution and control. This is the gorgeous result in enhancing the enjoyment of music to an unprecedented level that our new amplifier generation has achieved. In the field of amplifiers, the Class A is the most excellent amplifier circuit for the best sound and 155W Class A is the most powerful output power for tube amps. For Audiophiles, Class A circuitry is the pinnacle of perfection! Sine signal without radial distortion at maximum output power provides an ultimate sound for listeners.

– Using Interstage transformers in the connection between 6H13C and the 833 tubes provides the best detail and delicateness to the high frequency while the bass gets lower, fuller and warmer compared to using cascading capacitors.

– Do not use feedback to keep the details of the sound and the emotions in music expressed in the most complete, natural and elegant way. Zero feedback is a key technical solution of ThivanLabs tube amplifiers to get the high fidelity sound.

– Using a completely toroidal power transformer for both power stage and driver stage is also an effective solution to reduce the noise. Power supply for high voltage 833 tubes, 833 filament and driver stage are separated and provided by separate toroidal transformers for excellent noise reduction.

– The power source filter for the 833 tubes uses 22 Oil capacitors and extremely large Chokes to provide abundant energy for the tubes to get a clean and detailed sound. Whereby, the sound power will show up very well in the climax of the music.

– Bias for the 833 can be adjusted (200-270mA) by two variable resistors on the driver block.

SUN-833 X has amazingly done our most special and difficult test in the Spring Classical Concert at Renaissance Riverside concert hall before its official release in March 2022.

Spring Classical Concert was performed by the young Imagine Philharmonic Orchestra gathering the young musicians of Ho Chi Minh City Conservatory. To be able to fill up the sound for a very large concert hall with a very complicated acoustical space at Renaissance Riverside, the orchestra was supported by a ThivanLabs Hifi system with EROS-12 loudspeaker driven by the SUN-833X.

The system used the fantastic ThivanLabs MICROPHONE TUBE PREAMPS – M1 / M2 / M4 for recording live and amplifying musical instruments in the orchestra and vocal.

ThivanLabs may be the first pioneer in the world to have tried this difficult idea which uses tube amps and Hifi loudspeakers to amplify the sound for an orchestra at a classical music concert. It was a challenge for a Hifi system to amplify the sound in such a big hall and with such a difficult music genre like classical music but lastly ThivanLabs Hifi system amazingly successed. The following videos used the live records at the concert.