Photo courtesy of Gino Mancini
This in my opinion was the best Ferrograph, since the 632.
This was the first model to address some of the omissions of earlier models, although under the skin it still preserved some of the mechanical features of the Super 75 and original Series 7's.
The model name reflects the addition of the soft-touch logic control buttons.
Gone the rotary control knob of machines from 1948. In with soft touch buttons, and easy operation.
Compared to other manufacturers these changes appeared a bit late, but better late than never.
For the first time a clean, clear tape path. No pressure pads and back tension control Easy access for editing (always a strong point with Ferrograph) greatly improved.
Unfortunately, the pinch roller and drive idlers were manufactured with the same neoprene that caused problems in later life.
Nice clear controls. Ganged recording level controls on the left. Ganged playback on the right of the bottom panel.
Note: the separate tape source switching, and bass / treble controls.
The microphone input was a standard quarter inch jack.
On the left of the amplifier panel the ganged master recording level control and playback volume control.
This allowed a balance to be obtained between the Mic / line inputs, with the master record level allowing overall control of the maximum recording level.
Again separate tape /source switching and bass / treble controls.
Note: the mu-metal shield on the replay head, to guard against inducing any hum.
One welcome feature is the clean head path, devoid of any messy pressure pads, and helping to reduce the wow & flutter performance, less friction on the rear of the tape, important if trying to use matte backed tapes. Like Maxell 35-90B or TDK Audua.
The difference in tape tension generated at the start of a new supply reel and when it is nearly empty can be substantial.
Older machines had friction pads to generate a degree of back tension, then it was done by energizing the rewind motor to generate a slight opposite force.
The mechanism on the Logic 7, reduced the amount of back tension when the tape reel was getting near to empty, reducing the risk of Wow & Flutter.
1/4 track 0.043 in (1.1mm)
Record Head. 250 microns (6.3 microns
Replay head. 80 micro inches (2microns)
3,600 ft (1080 m)of tape
1 hr 36 min @ 7.5 i.p.s.
3 hr 12 min @ 3.75 i.p.s.
Fast Wind Time
Continuously variable in either direction.
2 min for 1800 ft of tape.
3 min for 3600 ft of tape.
0.08% @ 15 i.p.s (38 cm/s)
0.10% @ 7.5 i.p.s (19 cm/s)
0.17% @ 3.75 i.p.s (9.5 cm/s)
Frequency Response
Record/Play
30Hz - 20kHz @ 15 i.p.s.
30Hz - 17kHz @ 7.5 i.p.s.
40Hz - 14kHz @ 3.75 i.p.s.
15 i.p.s. 35 microsecs
7.5 i.p.s. 50/3180 microsecs
3.75 i.p.s. 90/3180 microsecs.
Bass Control.
Continuously Variable
+/- 15 dB @ 50Hz
+/- 20 dB @ 20Hz
Treble Control.
Continuously Variable
+/- 10 dB @ 10kHz
+/- 15 dB @ 20kHz.
Internal Speakers
Input Level
For full depth recording
Microphone 200microvolts - 50mV imp 200-1000 ohm.
Line 50mV - 7V @ 2 Megohm.
Outputs from full depth recording
600 ohm: 2V @ 600 ohm
Low level: 300 mV into 10kohm or greater.
Loudspeaker: up to 10 Watts R.M.S into 8-16 ohms
Phones: Suitable for phones of 8 - 600 ohms impedance.
Power Supply
200-250V. 50 Hz: Suffix A 117V - 60 Hz.
Stereo - Approx 50db:
Mono - better than 65dB @ 1kHz