Amplifiers

Structurally, the Audio Research I/50 is a classic push-pull amplifier with 6550 tubes installed at the output – one pair per channel. The functions of the input and driver tubes are taken over by three 6922 dual triodes.

Doubled the power supply capacity (vs. M.1.1) High End amp offers bandwidth up to 500kHz and delivers 2 x 550 Wt (4 Ohms load)!

Fully discrete, balanced Dual Monaural line-stage (preamplifier) with heavily regulated and filtered power supplies and extreme wide-bandwidth frequency responses.

Boulder 1152 is capable of driving almost any speaker system on the market. The amplifier is capable of delivering 350 W per channel at 8 Ohm, 600 Ohm at 4 Ohm and 750 Ohm at 2 Ohm load.

The integrated amplifier Audio Analogue AACento is built according to a zero-feedback scheme - both in the preamplification section and in the output stages. The signal circuits use ceramic resistors of increased size - this reduces the total heat. Switching of sources is carried out using electromagnetic relays, and the precision digital volume control (but the signal in chain always remains analog) does not use operational amplifiers. The linear power supply contains a toroidal transformer with a power of 480 watts. Cooling radiators for the output stage transistors are located inside the case.

The Fjord Audio P150 mono tube power amplifier from the South Korean company Fjord Audio features an original DFD (Direct Full Difference) circuit and does not use any negative feedback, which provides impressive sound.

Vincent Audio has updated the popular hybrid integrated amplifier Vincent Audio SV-500, which was named Vincent Audio SV-500 MK. The new product is equipped with a new DAC chip that supports 32-bit / 384 kHz resolution, a Bluetooth module and an HDMI ARC input. Like its predecessor, the Vincent Audio SV-500 MK input stages are implemented on tubes, and the output stages are transistor ones, which allows it to develop a power of 50 watts when working on a load with a nominal resistance of 8 ohms and 80 watts for 4 ohms in each of the channels.

The Audiolab 9000Q preamplifier is equipped with a DAC unit based on the ES9038PRO chip from ESS Technology. The DAC module is capable of decoding PCM audio up to 32-bit/768 kHz and DSD up to 22.5 MHz (DSD512), as well as MQA. There is also Bluetooth version 5.0 with support for aptX HD and LDAC codecs. Analog connectivity includes three unbalanced line inputs on RCA connectors and one balanced XLR, as well as a phono input for working with moving magnet (MM) cartridges, which has been further improved compared to that installed in the 9000A integrated amplifier.

Technics SU-R1000 is a fully digital device. Signals from analog inputs are digitized, all their processing occurs in digital form. The output stages operate in class D, and all power supplies are pulsed. As we know, audiophiles do not respect such solutions too much, preferring time-tested class A/AB amplifiers. Well, the company set an ambitious task - to create a fully digital amplifier (without introducing hybrid circuits for current and voltage into the circuit design, like, say, Devialet Expert 220 Pro, which we recently reviewed), breaking all traditional canons on the topic of how such a device should sound.

The amplification stages in the Riviera Audio Labs APL1 operate in pure class A. Riviera Audio Labs APL1 uses a more powerful power transformer and a capacitor block of the power supply filter. The preamplifier also uses an input transformer circuit for both types of inputs.

The Croatian company Limestone has introduced the Limestone PP1 mono power amplifier, which uses KT88 tubes. The model is housed in an “armor-piercing” case made of 1.5 mm stainless steel. Kerrock decorative panels add exquisite touches and allow the devices to fit into any interior.

The manufacturer states that this model was developed as a linear preamplifier that combines the rich and mature sound of the G-70 with the power of the flagship G-1000.

The output stage of the NAT Transmitter Evo amplifier can operate in two modes – high power up to 80 W or low power up to a moderate 40 W. Both modes use a directly heated triode in a single-ended connection. With a power of 80 W in a single-ended configuration, it is possible to choose almost any speaker system as a partner - NAT Transmitter EVO is capable of working with speaker systems with an impedance of 2 to 16 Ohms.

The PIVETTA Silente Nanofluid power amplifier is based on a cylinder made of the famous Murano glass from Venice. Each component of the amplifier is immersed in a stabilizing liquid Nanofluid, the composition of which the manufacturer keeps secret. This solution protects against electrical interference and thermal fluctuations, which minimizes the effects of thermal drift and dampens microvibrations. A massive waterproof aluminum frame provides additional stability, reducing even the slightest vibrations.

The TEAC HA-507 model is made as a fully balanced scheme with a “dual mono” configuration and is capable of providing an output power of up to 6.7 Wt per channel when driving headphones with a nominal impedance of 32 ohms with a balanced connection, which makes it suitable for working with a wide range of headphones.

Devialet has developed an ADH-class amplification circuit (low-power class A supported by a voltage follower and containing deep negative feedback) specifically for the amplifier line.

Devialet Astra rethinks the concept of High Fidelity, offering 2 x 300 W (4Ω speakers) of output power with zero distortion, zero saturation.

The QUAD 303 stereo Class A/B power amplifier also uses proprietary “triples” output stages.

QUAD has announced the revival of its legendary QUAD 33 preamplifier.

According to the manufacturer, the Unison Research Triode 25 Black Edition has an optimized amplifier circuit - both in the signal path and in the power supply.