Ferrograph 5 Owners Manual

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SERIES 5 FERROGRAPH

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programme will not be recorded sufficiently loudly. This must be resisted, as it
will be found that subsequently, when a loud passage comes along, overloading will
result. Once the recording is overloaded, turning down the gain control during
playback will not remove any distortion which has been introduced.

Having thus ascertained that the receiver is properly tuned in and that the
signal level is correct, the tape may be started and the recording proper commenced.
The turns counter reading should be noted at its commencement, so that it may be
wound back to without difficulty for playback.

6.1.2. Direct from Detector System

The method described above is perfectly satisfactory from well designed receivers.
Cases may arise however where poorly filtered I-I.T. supply systems may cause
hum to be generated in the receivers ouput stage, and although this may not be
unduly noticeable on the sets own speaker, the superior low frequency response
of the Ferrograph may make it a source of annoyance.

A better method exists for those who are able to employ it, which involves
taking the output from immediately after the receivers detector stage. This avoids
using the receivers output stages, which are unnecessary so far as the Ferrograph
is concerned, and avoids the distortion and hum normally associated with such stages.
Here the signal will normally be of a lower level, and may be taken into Input 1
of the recorder if adequate gain is not provided at Input 2. If the latter socket
is used, and the lead from the detector stage is coming ofl" at high impedance, it will
be necessary to insert a shorting plug in the left hand socket (see technical notes on
circuitry, Section 18.3.).

In the same category of radio recording may be included the use of specially
designed high quality tuner units, which can be powered from the octal socket at
the rear of the instrument provided that their supply requirements do not exceed
the figures given in Para. 11 (Auxiliary Socket). In general, this will apply to most
AM tuner units, but not to the FM variety (these usually have their ovm power
supply).

A popular tuner unit uses a straight aerial and H.F. section followed by an
infinite impedance detector. As it has no output stage, monitoring during recording
is usually carried out either through the 15 ohm extension speaker socket or through
the internal speaker, when the speaker switch should be set to ON.

6.1.3. Microphone Method

Although hardly worthy of mention as a serious means of recording, this is
included for the sake of completeness. It is a method which should be used only
in the last resort when the others are completely out of the question, or when special
effects are required. It involves the use of a microphone placed near the loudspeaker
of the receiver while it is operating normally. This brings it almost into the category
of a live recording and substantially the same remarks apply. It is dierefore largely
dealt with under this heading.

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By suitable use of the Erase Link and Superimposition Link facilities, a variety of
recording eflects can be obtained. The 1,000 ohm potentiometer is now included in the
list of accessories available for use with the Ferrogtaph.

HT 5MOOTH ED
OUTPUT.

OUTPUT VALVE
ANODE .
EARTH .

6-5 HEATER. SUPPLY
C.T. EARTHED.

AUXSOCKET WIRING
(VIEWED FROM REAR.)

FIG. 7. AUXILIARY SOCKET WIRING

ll. AUXILIARY SOCKET

To increase its scope, the Ferrograph is provided with an international octal (valve base)
auxiliary socket which is located on the rear panel. From it may be taken both HT. and LT.
supplies for powering ancillary equipment such as tuner units, mixers, etc. The appropriate
connections are shown in Fig. 7., and it should be noted that the LT. winding has its centre
tap connected to chassis.

During recording, 1 Amp of L.T. (6.3 V., A.C.) and l5mA of HT. (+250 V., D.C.)
may be taken from this socket, with an increase of 40mA HT. current on playback only. Also
on this socket is a connection from the anode of the output valve.

A suitable octal plug to fit the socket is given in the list of accessories in Appendix C.

12. TO CHANGE TRACKS

The manner in which the tracks are disposed upon the tape is shown in Fig. 8. The ad-
vantage of this system is that two tracks can be accommodated side by side, thereby doubling
the length of playing time per reel. In practice the system is operated in this way. After a full
half hours recording has been made upon the top track in the normal way, the magazine reel
will be empty and all the tape will be on the take-up reel. The reels are then removed and the

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