Предусилители — Concert Fidelity CLS-050 Mk2

The CLS-050 Mk2 is a valve line stage preamplifier designed by Masataka Tsuda of the Japanese firm Concert Fidelity, and it belongs to the brand's Resolution Series. Every stage uses valves, with two 6V6 tubes driving a custom line output transformer made in Japan. Signal paths are kept short in a deliberately simple topology, and a solid-state headphone amplifier is built in alongside the valve line stage. Concert Fidelity sells it without tubes fitted, as it does its other valve products. No price is published, and buyers are referred to distributors.

Key specs that matter

Connectivity starts with four line-level inputs. Inputs 1 to 3 use RCA sockets, and input 4 toggles from RCA to XLR. Loading measures 100 kohm single-ended and 50 kohm balanced. Outputs comprise one balanced XLR pre out and two single-ended RCA pre outs, and the owner selects which type is active. Gain is 6 dB. Headphones plug into a 6.35 mm TRS jack or a four-pin balanced XLR. The chassis is 450 mm wide, 140 mm high and 310 mm deep, with a weight of 14 kg.

Engineering and use context

In standard form the gain stage accepts the 6V6 in its MT8B form, the 6V6GT in T9 form or the CV511, two of them in each unit, and a 5AR4 or GZ34 handles rectification. As a custom order option Concert Fidelity can build the preamplifier around other valves, listing the 6V6G in ST14 form, 6SN7, 5692, WE310A, WE337A, 5U4 or 5R4 and 274B. Volume runs through a high-resolution custom ELMA attenuator. Concert Fidelity also invites buyers who already own a good set of valves to raise them when ordering. Within the same series, the CLA-050 handles MC and MM phono duties as a companion valve stage. Mains transformers are fitted per destination, with options for 100 V, 110 to 120 V, 220 to 230 V and 240 V, and failures outside the destination country are excluded from the warranty, while mains voltages outside those listed carry no guarantee of proper function.

Pairing

The two RCA pre outs make it possible to drive two power amplifiers without a splitter, while the XLR output suits amplifiers with balanced inputs. The brand's Resolution Series offers the DHS-300B single-ended and DHP-300B push-pull valve power amplifiers, and the Reference Series adds the ZL-200FX2 and ZL-120FX2 MOSFET monoblocks.

Alternatives

The Concert Fidelity CF-080LSX3 is the preamplifier offered one tier higher in the Reference Series, above the Resolution range that contains the CLS-050 Mk2.