Combining the warmth of tubes with the grip of transistors is the promise of hybrid amplifiers. The HTA-2500B is the most powerful model in the hybrid range from Polish manufacturer Taga Harmony. Two tubes in the preamplification stage and six pairs of output transistors, supported by a generous power supply, make it a stereo integrated amplifier capable of driving demanding systems without complicating everyday use.
The design is based on a clear division of tasks. At the input, two 12AX7-T PSVANE Treasure Mark II tubes process the signal at preamplifier level, giving the sound a smoother, rounder character. Power is then handled by six pairs of Sanken transistors (2SC4468/2SA1695), with the whole unit operating in Class AB. The tubes shape the sound, while the transistors provide energy and speaker control: this combination avoids the main drawback of all-tube designs, which are often limited in power and more difficult to match with certain speakers.
In dual mono, each channel has its own amplification chain and transformer. Interference between the left and right channels is therefore reduced, helping to maintain a stable, well-separated soundstage.
Two toroidal transformers share the power supply, delivering a total output of 1200 W, or 600 W per channel. This energy reserve explains the output figures: 200 W per channel into 8 ohms, and double that, 400 W, into 4 ohms. An amplifier that doubles its power when impedance drops demonstrates a strong ability to deliver current, useful with power-hungry or large speakers.
Audiophile-grade ELNA capacitors (2 × 80 V/10000 µF per channel) store energy and release it during dynamic peaks, when the music suddenly demands substantial power.
The HTA-2500B incorporates its own digital-to-analog converter, built around Wolfson WM8805 and Cirrus Logic CS4344 chips. It accepts high-resolution files up to 24-bit/192 kHz via an optical input or a coaxial input. Enough to connect a television, a network player or a CD player with a digital output, without an external converter.
Bluetooth 4.0 supports audio streaming from a smartphone, tablet or computer, for quick, cable-free listening.
On the analog side, two line-level inputs (labelled CD and Line) accommodate sources such as a CD player or a phono preamplifier. The RCA sockets are made of machined brass, a choice intended to ensure high-quality electrical contact, while speakers connect to gold-plated terminals.
An RCA preamplifier output (pre-out) can be used to add an external power amplifier or a powered subwoofer as the system evolves. For headphone listening, the HTA-2500B features a dedicated stage supporting impedances from 32 to 300 ohms.
At 21 kg, the HTA-2500B is among the heavier integrated amplifiers, largely due to its transformers and heatsinks. Each channel benefits from its own oversized aluminum heatsink, designed to dissipate the heat generated by the tubes and transistors during extended listening at high levels. This heat is part of the normal operation of a tube amplifier and requires leaving some space around it for airflow.
Volume is controlled by a Japanese-made ALPS potentiometer, renowned for its quiet operation. The tubes remain visible behind an illuminated window whose brightness can be adjusted with a dimmer. Two tone controls (bass at 100 Hz, treble at 10 kHz, ± 12 dB) adjust the balance according to the room or recording, and an aluminum remote control completes the package. The IEC-standard power cable can be replaced as desired.
No. Both analog inputs are line-level (CD and Line). A turntable therefore requires a phono preamplifier, either built into the turntable or in the form of a separate box placed between the turntable and the amplifier.
Tubes need to warm up to perform at their best. Allow 5 to 15 minutes after switching on, depending on the room temperature.
Yes. The two 12AX7 tubes are mounted on ceramic sockets and are easy to replace. They can be swapped for other compatible tubes to slightly alter the sonic character, a common practice among tube enthusiasts.
No, the digital section is limited to an optical input and a coaxial input; this model does not have a USB input.
Direct mode bypasses the tone controls to shorten the signal path and stay as close as possible to the source. Loudness mode boosts bass and treble at low volume, when the ear perceives the ends of the frequency range less well.
It delivers 350 mW into 300 ohms, enough to drive most hi-fi headphones, including more power-hungry high-impedance models.
Yes, the HTA-2500B uses a detachable IEC-standard power cable. You can replace it with another cable of your choice.
Francois
Very satisfied with my purchase, this is a very good amplifier that perfectly matches the Focal speakers.
Comment from February 12, 2024 — Experience from February 01, 2024
