Kücke T-21
Kücke T-21 is a studio-quality stereo FM tuner from the late 1970s.
The FM front end uses five BB204 varicap diodes and the TCA240 IC as an FM mixer. Further signal processing is handled by two large linear-phase 10.7MHz filters and the TCA420A FM/IF amplifier and discriminator, while stereo decoding is handled by the TDA1005 PLL stereo decoder.
The device features solid build quality and a sandwich PCB construction, which makes adjustments more challenging. A big advantage is the use of connectors, which allow each board to be easily detached. This particular unit has been fully restored and aligned. The device service manual was not available at the time, so we relied on our experience and IC datasheets when needed. The RF front end PCB design differs from the other boards, suggesting that it was sourced from a different manufacturer.
Manufacturer: Kücke & Schmitz (KS electronic)
Status: Active company
Official website: kuecke.de
General Specifications
Antenna Input: 75ΩFM Tuning Range: 87.5MHz-108.0MHz
Input Sensitivity (40dB): 18uV
Signal-to-Noise Ratio (mono): ≥63dB
Total Harmonic Distortion: ≤0.25%
Frequency Response (-1dB): 15Hz-15KHz
Stereo Threshold: 8µV
Muting Threshold: 2µV
Dimensions (WHD): 451×100×365mm
Factory Specification Sheet
Factory specification images are sourced directly from the device's original service manual or user manual. These documents are produced by the manufacturer and provide authoritative information on the product's specifications.
FM Tuner
Measurements of the tuner section were performed using an FM signal generator, with its output fed directly into the antenna input. AM measurements were not conducted.
