Note
90505 - 120 VAC, 60 Hz
90507 - 220 VAC 50/60 Hz
QST, Aug 1940, p. 13. (QST article)
QST, Dec 1940, p. 84. (first actual ad)
QST, Feb 1945, p. 94.
Millen catalog 1940-1941
Millen catalog 1947
QST, Jul 1941, p. 68.
Radio's Master 1942, p. H-128.
Millen catalog #15. (1951)
Based on a construction article in the August, 1940 issue of QST, page 13.
A precision frequency standard for both laboratory and production use. Adjustable output at intervals of 10, 25, 100, or 1000 kHz, and useful to 50 MHz. Harmonic amplifier with tuned plate circuit and panel range switch, and a switchable 800 Hz modulator. Also has a built-in detector with a headphone jack and gain control. Built-in power supply.
The 1000 kHz crystal, supplied by General Electric, is sealed in a helium filled metal tube envelope. It has a frequency-temperature coefficient of less than 1 Hz / MHz / Cº. Unit may be zero-set to WWV or any primary frequency standard.
The unit includes a mixer, so that signals connected to the input terminals will be mixed with the output, permitting determination of the frequency of the input signal.
Initially offered in models 90501, 90502, 90503 and 90505, 90506, 90507 with various line voltages and frequencies, and with or without tubes and crystal, subsequent catalogs listed only the 90505 and 90507, which were complete and ready for use.
Power: 105–125 VAC, 60 Hz, 44 watts
Tubes: (1) VR-150, (1) 6K8, (2) 6SC7, (1) 6V6, (1) 6L7, (1) 5W4
