Ferrograph 4 A Owners Manual

Page 1

THE MANUAL

OF THE

FERRO GRAPH

Page 2

THE FERROGRAPH SERIES 4

Page 3

ERRATA AND ADDENDA

Fig. 18~Page 33
Tape guide MP [1827 should read MP/3281.
Felt pad BP /1 102 /F is now BP /1 109 IF.
Capstan flywheel assembly MP [1833 should read MP [2196.

Section 21 and Ferrograph Model 4S-Pages 42, 45, 46

The FP.l4 head has been superseded by the latest stereo head type FP.16 which wll
fit in the same way as the FP.14 head except that its height should be adjusted so that the head
laminations overlap equally the top and bottom edges of the tape running through on playback.

The playback transformer 979 is superseded by the type 973A which is of identical
construction but has a stepvup ratio of 15 : 1 and a better high frequency response.

When feeding into amplifiers of 100k ohm impedance and lower, the 969 head matching
transformer is available with a step-up ratio of 8 : 1.

Replacement Components

At the beginning of 1960 the value of the 3k ohms potentiometers (R4, R25, R38 and
R44) was changed to 5k ohm. R4, R38, and R44 became BP,2428/P and this component is
a replacement for all earlier models. The meter zero (R25) became a carbon potentiometer
BP /2433 [P and again this is a replacement for earlier models.

In 1961, SW6 (Mains ON /OFF) became BP/4074 IS (square body) and is also a replace-
ment for all models.

Later equipments have the automatic stop switch MC/1216A replaced by switch block
MC /3345 with contact clip MC/3303 on the insulated pressure arm pin.

Serial Nos. 4/6100 onwards

These instruments have output transformer T1663 fitted instead of T1428. They are
electrically identical but use different methods of mounting and, therefore, are not inter-
changeable.

Serial Nos. 4/14,000 onwards

On these recorders the amplifier panel is fitted with metal capped knobs MC/3867 and
dummy plug MC /3947, and the meter is mounted behind the panel and becomes BP /1933 ,/M.
It is illuminated from the side by 2 sub-miniature lamps (6.5V, 0.15A) BP/1813 [L in holders
LES 14, BP/lSl4/H. These are connected in parallel and are across the heater supply in
series with a 4.7 ohm resistor BP/2795 /R which reduces the lamp voltage to 5V. Neon
BP /1810/L and R24 (4.7k ohm) are omitted. The meter zero potentiometer is 2k ohm and
replacements are BP/244l /P mounted on panel MP /389Q and fitted with knob MP [3994.

Appendix D . . . Steread Unit
The Steread Unit has ceased production and is no longer available.

Page 20

Any.» me new... types u. murmur/w... ,....,.. ....__, we u... mt un. acuvaiuy .

ranging from the cheap diaphragm crystal types, through the medium priced dynamics
and multi-crystals, to the very expensive moving coil or ribbon dynamics. There is little
point in purchasing microphones having a frequency response greatly in excess of the
instrument itself and which may cost almost as much. At the same time it is equally
without point unnecessarily to restrict the overall fidelity by the use of the very cheapest.
Generally speaking, having regard to all the factors involved, the most suitable for general
purposes is undoubtedly the medium priced low impedance moving coil or ribbon micro-
phone. A type of the latter exceptionally well suited to the Ferrograph is included in
its list of accessories. The matching transformer necessary is also listed.

The great advantage of the low impedance version is that long leads (up to 40 ft.)
may be used without picking up unwanted hum, providing the matching transformer is
used close to the recorder. High impedance moving coil and crystal microphones may be
used, but some care will be necessary with the screening of the cable and connections
and it is not normally practicable to operate these with very long leads because of hum
troubles. Because of the relatively low output voltage delivered by microphones they
will always require to be plugged into the left hand socket (see Fig. 3).

It is during live recording that the necessity arises for silencing the internal speaker
to prC\'Cnt acoustic feedback, particularly where the machine and microphone are in the
same room. This takes the form ofa bowl as the noisefrom the speaker feeds back into
the microphone, is itself amplified and transmitted again through the speaker in a vicious
circle, gradually building up in volume. It will happen if the external 15 ohm speaker
is left in circuit while the microphone is plugged in. It should accordingly always be
removed when any sound from it is likely to reach the microphone. The demuting plug
however can usually be employed to provide a greatly reduced signal for monitoring on
the Ferrographs own speaker, and trouble should not be experienced if reasonable
spacing precautions are taken. It is always desirable during recording to keep the instru-
ment as far away from the microphone as possible as a certain amount ofmechanical noise
or vibration from the machine is inevitable and where the highest quality recordings
are sought, it is undesirable that even the faintest unnecessary noise should be present.

The chief point of difference in the operation of the recorder itself, between live
recording and recording from a radio signal, is that the studio control of dynamic range
usual in the latter is not present. This means that somewhat more attention will need
to be paid to the signal level meter and the gain control. Because the dynamic range of
certain programme material may exceed that of the tape, a certain amount of volume
compression may be necessary. This means reducing the level of the loudest passages
and increasing that of the weakest so that the former shall not overload the tape or the
latter be lost in the background noise.

With regard to the detailed use of the microphones themselves, individual manu-
facturers will issue appropriate instructions depending upon type and whether or not they
are directional. Here detailed consideration will be given only to the models listed amorg
the accessories.

15

For Service Manuals Contact
MAURITRON TECHNICAL SERVKIES
8 Cherry Tree Rd, Chinnor
Oxon OX9 40V
Telz- 018444551694 Faxt- 01844-3525
Email:- enquiries®mautitronwut

Page 55

APPENDLX A

OPERATIONAL FAULT ANALYSIS

FAULT POSSIBLE OPERATIONAL CAUSE
1. Machine will not start; Fuse blown (see Fig. 1).
indicator lamp does not Mains lead or plug faulty.
light up. Selector knob loose or missing.

2. Motor starts, but starting
switch will not lock in,
amplifier having had time
to warm up.

Tape not properly positioned in head box.
(See Page 6).

3. Start switch only just holds
in, or releases during playing.

Low mains voltage.
Check position of selector knob and actual

mains voltage.

4. Tape slips in drive or wows

For Service Manuals Contact
MAURITRON IECHNICAL SERVICES
5 Cherry Tree Rd. Chinnor
Oxon OX9 40V
Tole dim-351694 Fax:- 01844-352554
Email:- enmifies®mauri1mnmm

Dirty capstan or accumulation of tape deposit
on pressure roller. Bad splice in tape sticking
in guides or heads.

Buckled reels scraping on deck.

Dirt in gate mechanism preventing proper closure.
Oversize tape.

Oil or Grease on idler wheel rim.

5. Known, well recorded tape
will not play baCk but tape
drives.

Input plug left in.

Unconnected output speaker plug left in.

Tape incorrectly positioned in head box.

Piece ofsplidng tape sticking over head working
face.

Gain Control at zero.

6. Tape plays back with poor
frequency response.

Accumulation of foreign matter or tape coating
over head gap.

7. In recording position tape
erases but will not record.

Microphone or input plug not properly inserted,
or in wrong socket.

Microphone cable faulty.

No input signal.

52

Page 63

\ppendix D: continued

Low Impedance Microphones

Type REL/TM, high fidelity, low impedance (30 ohms) fitted with 3 pin plug [socket
nount for attaching to a floor, table or desk stand with 18 feet screened lead and plug, and

ncorportiting matching unit in lead.

Type RBL /T, high fidelity, low impedance (30 ohms) microphone with 3 pin plug /socket
m0unt and fitted with 18 ft. screened lead and plug.

Microphone Stands
Heavy bases finished grey with chromium pillars. Desk model height 8 inches. Table
model adjustable 16/24 inches. Floor model adjustable 3ft. /5ft. 9 ins.

Motor Pulley for 60 cycles/sec. Mains Supply

Converts the standard Ferrograph (50 cycles /sec) to 60 cycles {sec working. If the mains
supply is 110/130 volts, the motor capacitor should be replaced by one of2-5 mfds. capacitance.

The following spares can also be supplied
8v 0-3 amp. M.E.S. Cap.
Belling Lee Type LlOSS/l.

Indicator Lamp

Fuse ..
Unscreened input plug [granic P.50 or equivalent.
Screened input plug .. Ferrograph S.P.7.
External output plug Igranic P50 or equivalent.
Octal plug Bulgin Q575 or equivalent.
Hublok Reels (empty) 200 ft. Ferrogtaph R.E.3.

600 ft. Fer-rograph R.E.5.
1,200 ft. Ferrograph R.E.7.
1,750 ft. Ferrograph R118.

Hublok Reels full Tape to WW372/49 200 ft. Ferrograph F.T.3A
600 ft. Ferrograph F.T5A

1,200 ft. Ferrograph F.T.7A
{,750 ft. Ferrograph F.T.BA

NOTE 2-Tape deck parts which may require replacement after long use or accidental damage
are indicated in the illustrations. When ordering these, please specify the part number.

60