Klangfilm (Siemens) 6SEla 2156

Описание: The Klangfilm (Siemens) 6 S Ela 2156 is a vintage mixer/preamplifier unit, part of the extensive 6SELA series produced by Siemens for cinema and professional public address (ELA) applications during the 1950s and 60s.
While specific datasheet snippets for the 2156 are rarer than the power amplifier counterparts, it follows the design architecture of the high-end Siemens 6SELA preamp line. Below is the technical profile based on its series specifications and historical documentation:
Technical Profile
• Device Type: Professional Audio Mixer / Preamplifier.
• Era: Approximately mid-to-late 1950s.
• Tube Complement: Typically utilizes EF804 or EF86 low-noise pentodes for the input stages and ECC81/ECC83 for the mixing/output stages. (Note: Earlier models like the 2117 used the rimlock EF40, but the 2150+ series transitioned to the noval EF86 family).
• Inputs: Multiple balanced microphone inputs and high-level line inputs (Radio/Phono). These often featured high-quality input transformers (e.g., T41 or T42 models) for impedance matching and isolation.
• Output Stage: Often features a cathode follower design with a 600-ohm output transformer. This allows it to drive long cable runs to power amplifiers (like the 6SELA 2733 or 2525) without high-frequency loss.
• Build Quality: Modular construction with point-to-point wiring or early high-quality circuit boards, housed in a heavy-duty steel chassis designed for 24/7 continuous operation.
Key Characteristics
1. Impedance: Designed to interface with the standard German studio and cinema equipment of the time, often expecting 200Ω–600Ω at the input and providing a 600Ω or high-impedance output.
2. Transformer-Coupled: One of the most sought-after features today is the use of high-nickel content (mu-metal) input and output transformers, which provide the "vintage" warmth and saturation highly valued in modern recording studios.
3. Power Supply: Most 6SELA preamps did not have an internal power supply; they were designed to be powered via a multi-pin connector (e.g., Tuchel) by the master power amplifier or a separate dedicated PSU (like the 6 S Ela 2805).
Common Use Today
In the modern market, these units are often "racked" and converted into standalone boutique microphone preamplifiers or summing mixers. Audiophiles and recording engineers prize them for their:
• High Headroom: Capable of handling significant signal levels before distortion.
• Sonic Color: The combination of vintage Siemens transformers and EF86 tubes provides a rich, "thick" midrange that is difficult to replicate with modern solid-state gear.
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