FERROGRAPH ST 77 STEREO.
7.5 & 3.75 IPS
Monaural Recording & Stereo Replay.
This model is similar in style to the earlier Series 66, but does have the correct Series 3 deck.
This model was discontinued in 1958 and replaced by the Series 3S, which required the addition of the Stere-Ad unit for stereo replay.
A little short of controls, they had no amplifier stages so needed connection to external amp and speaker/s.
These models are derivatives of the YD range designed for scientific and industrial use, although they now employ inline or stacked heads to give true stereo record/replay rather than dual channel which had separate staggered heads.
FERROGRAPH ST 88 STEREO.
7.5 & 15 IPS.
Stereo Recording / Replay.
This machine was fitted with inline stacked record/play heads for proper stereo recording.
IMPORTANT:
Due to crosstalk problems with newly developed stacked stereo heads, this model was not suitable for normal half track mono recording.
Ferrograph recommend feeding the same signal into the left and right channels simultaneously and recording what would be effectively full track recording.