This is a vintage CBS Technology Center Model 1690 Azimuth Meter.
This specialized analog test instrument was historically used by audio technicians and broadcast engineers to precisely align and adjust the azimuth angle of magnetic tape heads on high-end tape decks (such as reel-to-reel and top-tier cassette decks like the Nakamichi Dragon).
Key Functions & Details Azimuth Alignment: Ensures the playback/recording tape head is perfectly perpendicular to the direction of the tape travel. Misalignment results in severe loss of high-frequency response.
Scale Indicators:
The central needle measures deviation in minutes of an arc (left or right from zero).
The lower scales measure frequency loss (in kHz) caused by a 3 dB drop.
The lowest scale measure the attenuation at 10 kHz.
Controls: Features a Reset button, an Auto/Off/Manual toggle switch, and a fine-tuning knob on the lower right to calibrate the instrument.


















































