Sony CF-950S

Manufactured by Sony Corp., Tokyo.

In 1976 Sony released a close relative of the ICF-5900, the CF-950S has a built-in cassette recorder.

Sony CF-950S

Technical data

Power supply


  • 430 x 300 x 150 mm, weight 5.6 kg


Sony CF-950S


The Sony CF-950S is a relatively large portable world band receiver with a built-in cassette recorder. Technically, the receiver circuitry is based on that of the ICF-5900W, a double conversion set with a crystal calibrator, and a built-in cassette recorder with a microphone and the possibility to insert a voice commentary into a running recording.

The bulky set is equipped with protective handles on both sides of the front panel; the set can be laid on its front for transport without being damaged. The set with its dimensions of 43 x 30 x 15 cm has a weight of 5.6 kg, the controls are arranged on the large front panel, partly in a somewhat confusing manner.

The telescopic antenna is in a vertical position on the right face of the set.

The set can be operated with 110/120 or 220/240 volts mains voltage, which is advisable in view of the power consumption, otherwise the set can also be powered with four UM-1 batteries.

The upper front panel contains the front loudspeaker on the left, the S-meter on the right, the large switch for the integrated crystal calibrator below, and the vertical film dials for shortwaves, mediumwaves and the FM broadcast band on the right. The active band is indicated by a small visual marker, the band switch buttons are located just below it. The dial divisions are quite coarse on VHF and MW, the calibration marks on the shortwave dials are easy to tune in the low frequency bands, on higher frequencies they are extremely close to each other, which makes it very difficult to tune a specific frequency on the high frequency end of the shortwave range.

Just below the band selector buttons, next to the built-in microphone, is the tuning knob for coarse tuning. In the short-wave bands, this is used to tune the set directly or, with the crystal calibrator activated, to the signal maximum of the calibrator signal at the corresponding 250 kHz mark; on medium and in the FM band, only this tuning knob is used.

The fine tuning button right next to it is used for fine tuning in the shortwave ranges: Coarse tuning is used to tune to the calibrator signal of the nearest 250 kHz marker, fine tuning is used to tune to a frequency +/- 125 kHz above or below the calibration mark with a high accuracy of less than 5 kHz.

The RADIO/LINE IN switch serves as the main switch, in the ON position the receiver is switched on. The lower right row of controls contains, from the left, the separate bass and treble controls and the volume control, to the right the switches for BFO and AFC (on VHF) or the attenuator, which is active in the shortwave ranges in the LOCAL position.

The mono cassette recorder is located at the left of the front panel. Below the cassette compartment are the usual buttons for PLAY, fast forward and rewind, etc. The headphone jack is located in the lower left corner, the CREDIT IN switch allows to insert a commentary (spoken into the microphone) into a running recording, the cassette is equipped with a mechanical tape counter, as usual at that time, which allows to find a certain position on the cassette.

The reception performance corresponds to that of the ICF-5900W, which is based on the same circuit, but the frequency marks for the crystal calibrator transmitter are even closer together in the high frequency ranges. The operation of the receiver with its combination of a crystal calibrator and a calibrated fine tuning dial requires some experience and understanding of the receiver concept in order to achieve good reception results - whereby the search for a station on a known frequency is still quite simple when proceeding as described above. Determining the exact frequency of an unknown station is considerably more complex, especially when searching only with the coarse tuning knob. If the fine tuning dial is not set to zero, the difference has to be added to the frequency read from the frequency dial.

Sony CF-950S Since most of the sets were probably not sold to radio amateurs familiar with the extraordinary operating concept, many CF-950S probably met the fate of similar sets that were somewhat complex to operate, they ended up as VHF / medium wave „kitchen radios“ and the enthusiasm for shortwave reception declined.

Later Sony receivers with digital frequency display made tuning child's play.

Today, the CF-950S is an interesting, technically somewhat unusual collector's item, although apart from the Sony ICF-SW1000T and Sangean's ATS-818CS, there are hardly any other shortwave receivers with integrated cassette recorder.

Technical principle

Double conversion superhet with crystal calibrator.


The set is equipped with semiconductors.

Technical documentation


Further information

en/cf-950s.txt · Zuletzt geändert: 2021/04/28 20:52 von mb