Ferrograph 634 Service Manual

Page 2

FERROGRAPH

MODELS 632. 634 81 632H

SUPPLEMENTARY
NOTES
with
Revised Circuit Details
Serial No. 6/50.000 onwards

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6.. Stem needing (microphone)

Thin requirea two teparate miaophonea or a apecial two unit ateteo microphone.
With the former, muita will vary with the ieparation and angle of the individual
microphone head- (if ribbon type). and utually tome experimenting will be neceuary.
With the tteteo mimphone. the only variable in the potitiooin; of it relative to
the tound to be recorded. the out: factor: being tare-determined.

To malte a Reading. the procedure it iimilar to that dumbed for single channel
working. except that both tracks will be working together.

if headphone monitoring is «winged. each earphone should be connected
teparately to eaeh output jack on the teat panel.

The panel mntrols ahould be net initially an follows:
Knobs I. 2 at zero (alto 9, and 10, if no monitoring).
Knob 3 to weed desired.

Switch 4 to "TAPE".

Knob 1 to STEREO".

Prat the record lock button (C) at the tune time turning the main function
twitch to "RECORD" and tet peak level meter to zero (check with twitch B on
Ui'iBil and LOWER).

With the microphone working. and witch 8 on "UPPER", advance knob 5
until the meter it twinning to a on in aeale.

Set twitch to LOWER and advance knob 6 for the tame mult. Note counter
(F) radio; and itart tape running.

0A2. Stereo recording front dine

Once again, moat oi' the noun concerning dlae recoding on single channel apply.
tincture external amplifien and speaker: for monitoring. and SWITCH 4 will compare
ORIGINAL" and "RECORDING" on both ehanneh. if no external amplifier:
and loudipeakeni are used. both tignalo will be heard morally" on the internal
ioudtpeaiter.

0.5. Special Application

it b recommended that the preceding pagea are ttudled before any of the following
application: are attempted. u in were], they are eomln'nations or simple variants of
tundard recording techniquea.

Ga. Recording two alpala aimiaitaneottaly on one tench (mixing)

The lirtt important thing it to note that one iicnal munl be )5 ml! (or more)
and the other between 2 and I90 th.

is

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Once tuluble signals are availeble it it oitnply e matter of injecting the luger
into INPUT 2 and the mullet into iNIUT l.

Oomiderinz the upper tneh. net the recording levels of each tignll Independently
by mean» at knob: 5 and I. turning one gain control to zero while determining the
letting of the other. Finally tum both to their lore-determined netting and proceed
with the recording in the untal way.

0.8.2. Playing beet on one met and recording ou the other

This in done by combining the institutions for tingle channel playback and
reeording on dill'erent oaths. end it in portihle to copy a recording from one truck
to the other by linking in output with the input 2 lack of the other tract by I double-
ended lad: plug lead. (cut be ordinery flex).

Thin can be applied to pen. 6.5.I. thing one previously recorded melt II one
rignnl end toy I microphone to the other.

0.. Echo «fleet

An eeho effect maybe obtained by connecting. uy, the upper trod: OUTPUT to
the upper end: INPUT 2. The tignel touree u. a microphone. would then be
plugged in INPUT I. It is of grcat enhance in netting the controln if e pair of
headphones be also connected heron the OUTPUT. in. in pmllei with the lead to
INPUT 2. Now proceed at for a normal tingle ehennel recording with headphone
monitoring (Pen. M.) but elowly ndvanee knob l. which will bring in the echo.
It will be found that I careful ediuetment it required to avoid multiple echoes or even
feedback instability whieh occur with too greet a setting of knob l.

Chonging to the tlower Ipeedt will give 3 greater delay in the echo.

6... WWW,

A: ttated above, for monitoring nfi' the tape while recording on the Model 634. the
pleyboet heed thould be in the up petition (head lever Q back). 11» operation and
the control netting: will be the nine as outlined for the Model 632 Ibove.

"J. Mono

Controlt end operation are at outlined for tnonturtl recording above, but
attention thould be pold to the tequeoee of the four met: on the tape. They are
numbered from the top - I, 2, 3 end 4 - and the univmally accepted recording
ueqtteneeir 1 «4-3-2.

Thin i! obtained by recording on UPPER on Side A of the reel (Track 1). At
the end of the reel reverie the tape and record on UPPER on Side B [Treeit 4).
AgnlnatthecndtevenetheupewthltitilnowbaehtoSideAandreeordon
LOWER (reach 3). Finally reverte the upe and recordon LOWER on Side II (Tuck 2).
This errlngetnent it ehown in Fig. 4.

l9

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m: I tOAowa 0 \OO' CAHIHI

in memory an be 3'10"ch to I matter of I few seconds. Monitoring for fault conditions it
In obvious nmtliatltm of the I'Ictlity, u immediltely I fault 0mm it can he Irmnged that
either manually or Iutornltt'ully the deck 1 that down to thu Illerwnrdu on pluyhttelt. the
eondniom lending up to the eituhlinhment or the fault cum readily be traced.

When muting the eom-mion to endleu loop tiperiition. the tIke-up Ind tmguine moron
must he dnennnected 0 thrt they do not revolve. 11th can he done by breathing the link
between the text muted 0 6t 5 on the tar tuba-rd of the deck behind the take-up mntur.

liefore tilting to the deck II will be neeemry to loud the eanette with the required Irnount
nl upe. it in not wite to eueed the maximum running time no, hearing in mind that It 7|
in Jane. the tape velocity it 37; tl.;mtn. Ind It 3] in Me. ll!) ft.,v'min.. the Ipprtmriate length
should he cut from I reel of well used ACETATE BASED tIpe. 0n no account should Inpetn
with either PVC or POLYESTER (MYIAR) hacking he med. otherwiwc melting Ind binding
between the turm in the ensure will occur.

The three screwtt tmd their npneeru Irnund the periphery of the ensure ihntild he removed
Ind the mull peg inwtted in the way thown In Fig. 5. The Hill" of the tape should he mused
from the outside through to the inside of the uncut: over the fourth roller counted in I counter-
clnekwine direction {mm the pee. Ind the winding should pmceed in I ennwntionnl "coating
inuide" mInner over the peg. the purpose of which is to ensure thIt when it it removed. the
tune ll left very lootely wound. It mutt of enune be retrieved before my Itternpt h made to
ope-me the equipment Ind the periphenl tween nhould Ilw be replaced. The tllmtratlon

22

Page 55

APPENDIX I!

COMPONENTS LIST FOR MODELS .3211 AND MU (WV, 80 c,-a)

cmcmr
m vuva unuo TOL. uncannou mn- nos.

R1 2201: 1) w 521;, Carbon 1291913
R2 MK 11 27w Vitreous Enamel RF 1281918
R3 IM 1! w 209., Carbon 81'12863 ,R
R4 I-SK 11 w 5",. High Stability 31'128231R
R5 IODK u [w 57. High Stabdlity DP 1285011!
R6 1M u [w 209;. Carbon BP12863 18
R7 1K u w 5",; Carbon 11112908 (R
R8 270K 11 w 5" Carbon RP1285518
R9 220K u {w 5",. Carbon BP129191R

R10 250K u Dual Carbon PM.
(with R31) 1111243611
R11 ISOK 1.1 [w 5'31, Carbon 11912853112
R12 82K 1: 1w 5'32. Carbon 1281811!

R13 500K 11 Dual Carbon Pm.
(whh R39) 311243811
R14 Iron u w 5% Carbon RP 12853111
R1 5 100K 1) w 30% Carbon 191235211!
R16 47K u w 20% Orbon BP123491R
R18 1-8K :1 [II '31:, Carbon BP129171'R
R19 1M 1: [w 20% Carbon BP128631R
320 8-2K 11 [w 5% Carbon BP128381R
R21 lKu w 5! Carbon 1!? 290811!
R22 22K 11 :w 109:: Carbon BP:29131R
823 417K 11 [w 1021. Carbon 1912331 1R
R24 100K 11 III 20%;, Carbon BP128M1R
R25 1M 11 [w 20% Carbon BP128631R

R26 'IM 11 sum a Work-
R27 471: 1: w 20% Carbon BP12M91R
R28 10M 11 M 20%;, Carbon 3112866111
R29 1K1! Carbon lor. 311243911
R30 1M 11 {w 20% Carbon BP128631R
R31 R n {W 93;, High Srabil1ry BP128231R
R32 100K n {w 911, High Stability BP128501R
:33 11.»: u M 20";, Cnbon BP128631R
34 1 u w 5"; Carbon 1!? '2908 'R
R 270K 11 :10 511: Carbon BP128551R
R36 220K u [a1 93;, Carbon 31129191R