The Triode 25 was born out of the huge success of the long-standing Triode 20 amplifier, and released as part of the 25th anniversary celebrations of Unison Research's formation. It's been developed over an extended period to ensure it is a worthy successor to the Triode 20's name.
Like its predecessor, the Triode 25 is a push-pull amplifier that utilizes EL34 tubes in the output stage. The push-pull circuit includes a final stage with two power tubes intended for the amplification of the audio signal, and is then followed by a symmetrical output transformer stage that reconstructs the signal into a high-quality linear wave.
Using a push-pull structure in this amplifier design allows for numerous benefits, including higher-output power compared to single-ended designs, improved efficiency and no static polarization of the output transformer for greater performance in the output section. However, for this to work well it is essential that all the individual amplification stages are carefully designed and constructed to prevent the formation of dangerous and compromising odd-order harmonic distortion.
The addition of a USB input modernises the Triode 25 and increases its appeal to the growing world of computer audiophiles, who use their laptop or computer as a high-quality audio source for their hi-fi. The USB input is 32-bit/384kHz and DSD 128 compliant to support the latest standards in studio quality audio.
• Push-pull integrated valve amplifier
• Switchable Triode and Pentode modes
• Locally sourced materials
• Based on the long-standing Triode 20 design
• EL34 tubes in the output stage
4 x Line (RCA)
N / A
1 x Tape (RCA), 1 x Subwoofer (RCA)
N / A
45W in Pentode mode, 25W in Triode mode (approx.)
Single Wire / BiWire:
2 x ECC83 (12AX7), 1 x ECC82 (12AU7), 4 x EL34 (6CA7)
Dimensions (W x H x D):
300 x 200 x 450mm