Предусилители — Riviera Audio Labs APL1

The APL1 is a valve line stage made in Italy by Riviera Audio Labs. The maker positions it as the mid-priced model in its preamplifier range, placed below the reference APL01 Special Edition, and several features of that costlier unit were carried over, including the output balance control and custom output transformers. Its valve circuit operates in Class A and uses no feedback.

Key specs that matter

Riviera lists two balanced inputs, both coupled through transformers, and three unbalanced inputs, along with a tape input and output. Outputs comprise one balanced XLR connection and two pairs of unbalanced RCA connections, all transformer coupled, and the maker states they work simultaneously at identical gain. Gain is 8 dB and input impedance is 47 kilohms. Valve complement is two ECC82, also known as 12AU7. The chassis is 44 cm wide, 50.5 cm deep and 16.4 cm high. It weighs 21 kg.

Engineering and use context

Much of the design effort went into the supply. Riviera uses a double pi filter, which it calls pigreco, followed by stabilised anode supplies, and in total the APL1 contains five separate stabilised supplies. Valves come from the Slovakian maker JJ Electronic, chosen for durability and stable characteristics over time. Output transformers isolate the valve stage from the cables and the power amplifier that follow, and they allow a true balanced output rather than one derived by a phase splitter. Transformer coupling on the balanced inputs also gives galvanic isolation from the source, which can help break ground loops when several digital components share the system. With its low gain the preamplifier works mostly as a selector and buffer with volume control, since most modern sources already deliver enough level. Simultaneous use of the balanced and unbalanced outputs lets a pair of power amplifiers and a subwoofer be fed in parallel, or supports a bi-amped setup.

Pairing

The balanced output feeding the true balanced XLR inputs of Riviera monoblocks keeps a fully balanced path from preamplifier to power stage. For sources, the two transformer-coupled balanced inputs suit a DAC and a phono stage with XLR outputs, leaving the unbalanced inputs for other line-level equipment.

Alternatives

The Riviera APL01 Special Edition is the reference preamplifier above the APL1 in the same range and served as the base for several of its features.