Radio set Passed Examination by The Ministry of Posts and Telecommunications
No.61 Toshiba Model ZS-1007 2 Band All Wave Super Heterodyne Tokyo Shibaura Electric Co., Ltd. (1948)
Early Model (Wooden Cabinet)
(right) Pamphlet (License card size, List of short wave stations on the back side)
TUBES: 12G-C5 12G-R6 12G-DH3 30G-P9 30G-K5, 2 Band All wabe, Permanent
Dynamic Speaker
In 1947, Toshiba introduced new series of GT tubes for transformer-less super heterodyne.
The new series was similar to American tubes: 12SA7-12SK7-12SQ7-35L6-35Z5
However, specifications of new series were different from American tubes.
Original name was given to new tubes. Difference was as follows.
Heater current was 175mA .
Rectifier tube 30G-P5 did not have tap for pilot lamp.
12G-DH3 (like 12SQ7) had only one diode unit.
12G-R6 was ordinary pentode not variable Mu tube.
Power tube 30G-P9 was not beam type.
Pin connection was equal to American tubes.
Model ZS-1007 was small 2 band all wave set using new GT tubes.
New tubes did not have enough to realize transformer-less set at the line voltage 100V.
This set equipped small auto-transformer to increase B voltage.
The price was low but design was poor. It seemed that this model was promotion model for new tubes.
New transformer-less GT tubes did not prevailed.
This model changed cabinet to modernized design and continued production until 1949.
New GT tubes discontinued production and changed into American standard tubes.
The tubes of this example were replaced into ordinary ST tubes.
Appeared on The Denpa Kagaku (Radio Technic & Science) 08/1948 published
by Nippon Housou Shuppan Kyokai(tubes and prototype)
Appeard on the magazine Musen to Jikken (The Radio Experimenter's Magagine)
059/1948 published by Seibundo-Shinkosha
Appeared on The Denpa Nippon Vol.45 No.3 published by Nippon Denpa Kyokai
(Collection No.11615)
Later Model (Metal Cabinet)
TUBES: 12G-C5、12G-R6、12G-DH3、30G-P9、30G-K5
Permanent Dynamic Speaker, BC: 550-1500kc, SW: 6-18Mc
Midel ZS-1007 was changed cabinet to modernized design and continued production
until 1949.
Knobs were not original. Tubes were changed into AMerican standard tubes.
(Collection No.11980)