Text preview for : pioneer_sa-9500ii_[ET].pdf part of Pioneer pioneer sa-9500ii [ET] Pioneer Audio SA-9500-2 pioneer_sa-9500ii_[ET].pdf
Back to : pioneer_sa-9500ii_[ET].pd | Home
(a-[' (:r^
t-
O
' r /
tf
l I
h
(DrqoNeErl
sA-9E'ootr
M O D E L S A - 9 5 O O I I O M E SI N F O U R V E R S I O N SD I S T I N G U I S H E D S F O L L O W S :
C A
U L ( U . S . A . )a p p r o v e d
C S A ( C a n a d a )a p p r o v e d
S E M K O ( S w e d e n ) , E M K O ( N o r w a y ) ,D E M K O ( D e n m a r k )
N
22OV and 24OV (Switchable)
a n d E l ( F i n l a n d )a p p r o v e d
12 O V . 2 2 O v a n d 2 4 O V ( S w i t c h a b l e ) G e n e r a le x p o r t m o d e l
This servicemanual is applicableto the KU-type. When repairing the KC-type, HG-type, S-type,
please the additionalservice
see manual.
f CONTENTS
1. S P E C T F T C A T I O. N. S
. . 5
2. CONNECTION IAGRAM
D 6
3. F R O N TP A N E L F A C I L I T I E S . . 7
4. BLOCK DIAGRAM 9
5. CIRCUITDESCRIPTIONS
5.1 E q u a l i z e A m p l i fi e r
r 11
5.2 Tone Controls 11
5.3 PowerAmplifier 12
5.4 ProtectionCircuit 13
5.5 PowerSupply Circuit 14
,}
6. LEVEL DIAGRAM 15
'}tt 16
7. D I S A S S E M B L Y.
8. PARTS LOCATION
8.1 Front PanelView 18
8.2 Front View with PanelRemoved . . 19
8.3 Top View 20
8.4 Bottom View . 21
8.5 RearView 22
9. ADJUSTMENT 23
10. E X P L O D E DV I E W S 24
1 1 . S C H E M A T I CD I A G R A M S ,P . C .B O A R D P A T T E R N SA N D
PARTS LIST
11.1 Miscellanea 32
11.2 SchematicDiagram 33
3
1 1 . 3 Switch Assembly (AWS-1
09) 35
'tI.4 Phono (AWX-107)
Jack Assembly 41
11.5 Amplifier Assembly(AWF-024)
Equalizer 42
11.6 (AWS-1
SwitchAssembly 02) 45
11.7 Control Amplifier Assembly(AWG-045) 46
11.8 PowerAmplifier Assembly(AWH-052) 50
12. PACKING 53
sA-s|500II
1.SPECIFICATIONS
Semiconductor T o t a lH a r m o n i D i s t o r t i o n
c
Transistors 55 (20H2 o 20,000H2)
t . 0.01%
Diodes 33 Frcqucncy csponsc
R
Power Amplifier Section P H O N O R I A AL q u a l i z . r t i o n )
( .2OHt to 20,000H2
10.2d B
Circuitry . . . 2 - s t a gd i f f e r e n t i aa m p l i l ' i eP a r a l l c l
e l r
T U N E R A U X , T A P EP L A Y
, . . 5 H zt o 5 0 , 0 0 0 H 2
P Pd i r e c t - c o u o l Od L .
eC _,1d8
Continuous P o w e r u t p u t f o r m 2 0 H e r t zt o 2 0 , 0 0 0H e r t z
O
l o n c C o n t r r r ( 2 d Bs t c p )
l
( B o t hc h a n n e ld r i v e n ) . 8 0 w a t t sp e r c h a n n e( 8 o h m s )
s . l
BASS M A I Nt 8 d B ( 1 0 0 H 2 )
I 0 0 w a t t sp e r c h a n n e( 4 o h m s )
l
s u B 1 6 d B( S O H z )
T o t a l H a r m o n i c i s t o r t i o n t 2 j H e r t z .t o 2 0 , 0 0 0 H e r t z
D a
f R EBL f M A I N1 8 d B( 1 0 k H z )
C o n t i n u o u sa t e dp o w e ro u t p u t
r . . 0.05%
S U B1 6 d B( z O r H z )
4Owatts p c r c h a n n ep o w e r u t p u t ,8 o h m s . . . . 0 . 0 1 %
l o
Filtcr
l w a t t p e r c h a n n p o w e r o u t p u 8,o h m s. . . . . . 0 . 0 1 %
el t
LOW I5Hz(6dB/oct.)
c
Intcrmodulationstortion Di
HIC,H. 8 k H z( 6 d B / o c t . )
C o n t i n u o u sa t e dp o w c ro u t p u t
r . 0.05%
Loudncss ontour
C
4 O w a t t s e r c h a n n ep o w e ro u t p u t ,8 o h m s . . . . 0 . 0 ' l %
p l
( V o l u m c c o n t r o l s c 1a 1- 4 0 d B p o s i t i o n ) + 6 d B( 1 0 0 H 2 )
l w a t t p e rc h a n n ep o w e ro u t p u t ,8 o h m s
l . 0.01%
+ 3 d B( 1 0 k H z )
Frequency esponscR 5 H e r t zt o I 0 0 , 0 0 0 H e r t zt d B
l Hum and Noisc
In p u t( S e n s i t i v i t y / p e d a n c e )
ml ( l H F , s h o r l - c i r c u i l c dA n e t w o r k )
,
P O W E R l \ 4 PN
A l ]V/5Okohms
PHONO 75dB
Output ... Speaker A,B,A+B T U N I R ,A U X ,T A P EP L A Y. . . .95d8
Headphone: Lowimpedance
Muting ..0,-20d8
D a m p i n g a c t o r 2 } H e r t tt o 2 0 , 0 0 0 H e r t z , 8 o h m.s.) . 3 0
F (
H u m a n dN o i s c l H F , s h o r t - c i r c u i r e d n e t w o r k ) . l l 0 d B
( A , . Miscellaneous
Preamplifier Section P o w c rR c q u i r c m c n t s . . . l 2 0 V 6 0 H zo n l y .
Powcr onsumption
C 2 3 0 w a t t sUL )
(
C i r c ut r y
i
E q u a l i z e rm p l i f i e r : s t s t a g ed i f f e r e n t i aa m p l i f i e r3 - 490VA (CSA), 60watts Max.)
5 (
a 1 l
Dimcnsions . . . . 4 2 0 ( W )x 1 5 0 ( H ) 3 7 6 ( D ) m
x m
s t a g ed i r e c t - c o u p l eA c l a s sS E P P .
d
.l 1 6 - 9 1 1x 5 1 1 8x 1 4 1 3 1 1 6n
6 i
C o n t r o la m p l i f i e r : s t s t a g c d i f f e r e n t i a l a m p l i t e r 2 -
f
Weight . W i t h o u tP a c k a g e : l 6 k g ( 3 5 1 b o z )
4
s t a g e i r e c t - c o u p l e N,F B t y p e .
d d
In p u t ( S e n s i t i v i t y / p e d a n c e )
ml W i t h P a c k a g c : 1 1. 9 k g( 3 9 1 b o t )
7
F P H O N O l. . . . 2 . 5 m Y 1 1 0 , 2 5 , 5 0 , 1 0 O k o h mFurnished arts
s P
tr F'
9., P H O N O 2. . . . 2.5mYl10,25,50,lOOkohms peratinglnslructions O ......1
B 'l t
E C A R T R I D GL O A D E . . . B o t h P H O N Oa n d 2 , I C o n n e c t i o nC o r d w i t h P i n P l u g s l
1 0 0 ,2 0 0 , 3 0 0 , 4 0 0 p F H c x . W r c n c h ( U s e df o r l ' a s t e n i n V o l u m c K n o b ) . . . . . . 1
g
TUNER 150mV/50kohms
AUX 150mV/50kohms
TAPEPLAYI.... 1 5 0 m V / 5 0 k o h m s NOTE:
TAPEPLAY2.... l 5 0 m V / 5 0 k o h m s Specifications and the design subject to possible modifica-
P H O N O v c r l o a d e v e ( f . H . D .: 0 . 0 5 % )
O L l lion utithout noticedue to improuements.
P H O N |O . . . . 3 0 0 m V( l k H z )
PHONO 2 3 0 0 m V( l k H z )
O ut p u t ( L e v e l /m p c d a n c e )
l
T A P ER E C1 . . l50mV
T A P ER E C2
P R EO U T . . . . . . . . tu)io,,n.r,,oupoon,'.rt,t';Il
5
2. CONNECTION IAGRAM
D
CARTRIDGE
TAPE PLAYER TAPE DECK 1
TURNTABLE 1 TUNER
f,...:--.Tl-l o o
aJ
f-- -- jr)-
r ppr';l (-) rr tf
OUTPUT
LINE
UT-
PUT
TURNTABLE2
D E C K2
f-l f--l l.-l
t o t t . t L r - r \ -
lle{"r:,4ll E
o--.t-i g -J lr :
LINE INPUT INE OUTPUT
sA-95001I
?" l
a
FI F F
C o n n e c tt o
groundterminals
of turntables,
t u n e r ,t a p e d e c k ,
-
:
C-D
(-D
[E lEl
I t t I
lEl 16l
f N V E N , a , :E OUTLE
etc.
GROUND
LEAD
AC CORD
GROUNDING
TO EARTH
A S P E A K E RS Y S T E M B S P E A K E RS Y S T E M
3. FRONT PANEL FACILITIES
P O W E RS W I T C H
TREBLE WIN CONTROLS
T
vol
S e t t o O N p o s i t i o n o e n e r g i zS A 9 5 0 0 1 1 . f t e r s e t t i n g o
t e A t Ad
C o n t r o l s f o r a d j u s t i n gh i g h f r e q u e n c yt o n e s .
O N , t h e r e i s a b r i e f d e l a yb e f o r es o u n di s o b t a i n e d T h i s
. att
I 0 k H z : A d j u s t sf r e q u c n c i ea b o v e . 5 k H z .W i t h r e s p e c t
s 2
i s d u e t o t h e o p e r a t i o no f t h e m u t i n g c i r c u i t w h i c h arb
t o 1 0 k H z a d j u s t m e n a n g es t 8 d B .
, rt i
p r e v e n t s o i s ew h e n t h e P O W E Ri s s w i t c h e dT h i s f u n c -
n . bin
2OkHz: P r o v i d e a d d i t i o n aa d i u s t m e ntto t h c l 0 k H z
s l
t i o n d o e s n o t i n d i c a t ed i f f i c u l t y a n d n o r m a l o p c r a t i n g wic
c o n t r o l f o r t h e b a n d a b o v e5 k H z . A d i u s t m e n t
c o n d i t i o n s a t t a i n c d n a f c w s e c o n d s .h e P O W E R w i t c h
i i T s
r a n g e i t h r e s p e ctto 2 0 k H z i s t 6 d B .
w
a l s o c o n t r o l s t h e r e a r p a n c l S W I T C H E Dc o n v e n i c n c e
outlets.
TONESWITCH
I n t h e O N p o s i t i o n ,t o n e a d j u s t m e n t c a n b c p e r f o r m c d
s
w i t h t h e B A S Sa n d T R E B L Et w i n c o n t r o l sW h e ns e t t o
.
t h e u p p e r ( O F F ) p o s i t i o n ,t h e t o n e c o n t r o l c i r c u i t sa r e
d i s e n g a g e d d f r e q u e n c yc s p o n s ie f l a t . T h i sf u n c t i o ni s
an r s
c o n v e n i e nfto r c h e c k i n g h o n oc a r t r i d g e n d s p e a k etro n e
p a
q u a l i t y n dl i s t e n i nr o o ma c o u s t i c 5 .
a g
B A S ST W I N C O N T R O L S
C o n t r o l s o r a d j u s t i n go w f r e q u e n c yo n e s .
f l t
l 0 0 H z : A d j u s t sf r c q u e n c i eb e l o w4 0 0 H 2 .W i t h r e s p e c t
s
t o 1 0 0 H 2 , dj u s t m e n t a n g e s : t 8 d B .
a r i
5 0 H z : P r o v i d e s d d i t i o n a la d j u s t m e n t o t h e . l0 0 H z
a r' '' '"1
c o n t r o lf o r t h e b a n db e l o w2 0 0 H 2 . d j u s t m e n t
A
r a n g e i t h r e s p e ctt< t5 0 H z i s i 6 d B .
w
P H O N E SA C K
J
W h e n l i s t e n i n gw t h s t e r e o h e a d p h o n e s c o n n c c t t h e m t o
,
thisjack.
r
NOTE:
Set SPEAKE,RS switch to OFF when listening only u..tith LOW FILTER SWITCH
headphones. S e t t o 1 5 H z p o s i t i o ni n t h e e v e n tt h a t t u r n t a b l er u m b l e ,
r e c o r d i n gc u t t i n g n o i s e o r o t h e r l o w f r e q u e n c yn o i s e
S P E A K E RS W I T C H
S
b e c o m e so b j e c t i o n a b l eA t t e n u a t i o n i n t h e f r e q u e n c y
.
b a n db e l o w1 5 H z i s 6 d B / o c t a v e .
I MUr
I
I *:
S e l e c ts p e a k es y s t e m p e r a t i o n .
r o
OFF: S o u n dn o t o b t a i n e d r o m s p e a k e r(s h e nu s i n g
f w HIGH FILTER SWITCH
headphones). S e t t o 8 k H z p o s i t i o ni f r e c o r ds c r a t c h o i s e r o t h e rh i g h
n o
A:
tJ:
S o u n d o b t a i n c d f r o m s p c a k e r sc o n n e c t e d t o A
s p e a k c rt e r m i n a l s .
S o u n d o b t a i n e d f r o m s p e a k c r sc o n n e c t e d t o B
f r e q u e n c yn o i s e b e c o m e s b j e c t i o n a b l eA t t e n u a t i o ni n
b 8
t h c f r c q u c n c y a n da b o v c k H z i s 6 d B / o c t a v c .
o .
| :*
I
s p e a k e r se r m i n a l s .
t B A L A N C EC O N T R O L
A + B: Sound obtained trom spcakcrsconnectcd to
b o t h A a n d B s p e a k c rt c r m i n a l s .
C o n t r o l f o r a d j u s t i n gs t c r e o b a l a n c cb e t w c c n l c f t a n d r i g h t Lrouo
speaker systems or hcadphoncs.Turn clockwisc from When
NOTE:
c c n t c r t o i n c r c a s e i g h t ( R ) c h a n n c lv o l u m c a n d c o u n t c r -
r
When listening with headphones or to lemporarily inter_ enha
rupt the speaker sound, set su,titch to OFF or to an c l o c k w i s cl r o m c c n t c r t o i n c r e a s ee f t ( L ) c h a n n c lv o l u m c
l
huma
u nused speaker p ositio n. i n o r d er t o o b t a i n a b a l a r r c .
e
switc
siA-9sc,Otr
V O L U M EC O N T R O L F U N C T I O NS W I T C H
A d l u s t ss p e a k e r n d h e a d p h o n e o l u m e .S c a l ei n d i c a t c s
a v Selectsdesired playback programsource.
res.
a t t e n u a t i o ni n d B w i t h m a x i m u m v o l u m e a s s i g n e d n a PHONO To playrecords a turntable
2: on connected
to
. Withrespect
a r b i t r a r yv a l u eo f 0 d B . C o n t r o lc a n a l s ob e u s e di n c o m - the PHONO2 jacks.
B.
.l b i n a t i o nw i t h t h e M U T I N G s w i t c ht o o r o v i d ea f i n e ra n d PHONO :
1 T o p l a y r e c o r d s n a t u r n t a b l c o n n e c t et o
o c d
o thc 0kHz
wider range f adjustment.
o t h e P H O N O1 i a c k s .
:.Adiustment
T U NE R : T o l i s t e n t o b r o a d c a s tw i t h a t u n e r c o n -
s
tB. I
n e c t e do t h e T U N E Rj a c k s .
t
AUX: T o p l a y a c o m p o n e nc o n n e c t e t o t h e A U X
t d
C A R T R I D G E O A DS W I T C H E S
L jacks.
Select phono input circuit resistancend capacitance a
a c c o r d i n g o t h e s p e c i f i c a t i o n s r t h e e m p l o y e dp h o n o
t fo
cartridge.
TAPE MONITOR SWITCH
E m p l o y f o r t a p e p l a y b a c k r t o m o n i t o r a r e c o r d i n gn
o i
progress.
.l
: P l a y b a c ko r m o n i t o r i n g o f a t a p e d e c k
.l
c o n n e c t e do t h e T A P E i a c k s .
t
S O U R C E : B e s u r c t o s e t t o t h i s o o s i t i o nw h e n n o t
u s i n g h e t a p ed e c kf o r p l a y b a c k .
t
2'. P l a y b a c ko r m o n i t o r i n g o f a t a p e d e c k
\"
connected the TAPE 2 iacks.
to
) NOTE:
When listening to records or broadcasts, sure to set be
this stDitch to SOURCE. Sound will not be obtained
from speahers set to 1 or 2.
if
T A P ED U P L I C A T E W I T C H
S
E m p l o y w h e n u s i n gt w o t a p e d e c k s f o r d u p l i c a t i o n r o
(0 ProNCCn ,,sA-s500[ e d i t i n g .B e s u r et o s e tt o t h e O F F p o s i t i o n t o t h e rt i m e s .
a
1 - 2: D u p l i c a t i o no f t a p e f r o m T A P E 1 ( p l a y b a c k
m o d e )t o f A P E2 ( r e c o r d g m o d e .
in )
OFF: S e t t o t h i s p o s i t i o n h e nn o t u s i n g h ed u p l i c a -
w t
tion featurc (this includes simultaneous
r e c o r d i n g i t h t w o t a p e d e c k sa n d t a p e p l a y -
w
table umble,
r back).
truencynoise 2'1: Duplication f tapefrom TAPE 2 (playback
o
1e frequencY m o d e )t o T A P E I ( r c c o r d i n g o d e ) .
m
M U T I N GS W I T C H
S w i t c hf o r r e d u c i n g o l u m eb y 2 0 d B f r o m t h e V O L U M E
v
c o n t r o l s e t t i n g . o n v e n i e nfto r t e m p o r a r i l y e d u c i n g h c
C r t
MODE SWITCH
o r o t h e rh i g h v o l u m ew h e nc h a n g i n ge c o r d s r t a p e s s i n c e t c l i m i n a t c s
r o , i
i
t t e n u a t i o nn t h e n e e d f o r c o n t i n u a l l yr e a d j u s t i n gh e V O L U M E
t REV: e l s
R e v e r s el s f t a n d r i g h tc h a n n es t e r e o i g n a l s
te. c o nt r o l . a n d r e p r o d u c ets e ms t e r e o p h o n i c a l l y .
h
S T E R E O : S e t t o t h i s p o s i t i o nf o r n o r m a ls t e r e o e p r o -
r
duction.
L + R: M i x c s l e f t a n d r i g h t c h a n n e ls i g n a l s n d
a
lcft andright LOUDNESS SWITCH r e p r o d u c e h e mm o n o p h o n i c a l l y .
ts
rckwise from W h e nl i s t e n i n g t l o w v o l u m cs c t t i n g ss e ts w i t c ht o O N t o
a , L: Left channelsignal is reproduced ono- m
and countcr-
e n h a n c el o w a n d h i g h f r c q u e n c i e s .h e r e s p o n s o f t h c
T c p h o n i c a l l yr o m b o t h s p e a k e r s .
f
ranncvolume
l
h u m a n e a r t o s o u n dd i f f c r s a c c o r d i n g o l o u d n c s sT h i s
t . R: R i g h t c h a n n e ls i g n a li s r e p r o d u c e d o n o -
m
s w i t c hc o m o e n s a t co r t h i se f f e c ta t l o w v o l u m c s .
fs p h o n i c a l l yr o m b o t h s p e a k e r s .
f
a
4 . B L OC K DI A G RA M
I iffi- ; k l
AUX
VRza, , BALANC
b F
TUNER
l-un, B A S S5 0 H z lro*rn
ir S+o S+. VRo B A S S1 0 0 H 2
+= i,0
1C
VRs
PF.t t.to1
0
I VRza
o vnla
I Sro
PHONO
2
T Lffi E Q U A L I Z E R M P L ITER
A F
VR+ VRs
I
Sr + o 'it-
tt" I V R t' T R E B L lEk H z
'
t tt '.*rJF
'^'TpLA)
rApE
o Ssu
u,
V R r a ,V o L u M ,
I
L.-
v n o , T R E B L Eo k 1 z
z
c o N T R O LA M P L T F I E R
.--J
_.o*
ittl'tfG- - c
'REcY
L E F TC H A N N E L
R I G H TC H A N N E L
AUX
C
.r 5c
TUNFR
s+o Sqa
EQUALIZER
PH0N01(q--o ANPLIFIER riRru C O N T R OA I l P L I F I E
L
S1b^.
Pfl0N0
2
- PLAY
T A P E1 Ssu
LREC
st+r Szr PRE
- PLAY
I TI TAPE2
LREC
Ssa POW
S\lIfCHES, S + a - d ' T A P EM O N I r 0 R Sioa,b ' TON F -
OFF ON
Sta-d ' FUNCTI0N 1 - I A P E 12 O F F Srta-d : SPEAKER
1 . P H 0 N20 2 P H O NIO 3.TAPE 2 1. OFF 2 . A 3 . B
3 . T UN E R 4 . A U X S s o - c' 1 1 0 D E 4. A+B
Sza,b' C SELEC]-OR IREV 2.STEREO S , n
v t L
L
RE AY
1 . 1 0 0 p F 2 2 0 0p F 3 . L + 3 .+ . t 5 R o
v t J POWIR OFF-ON
3 3 0 0 p F ' 1 . 4 0 0p F S s a , uY I U T I N G
' O F F - - 2 0 dB Sr+a
,u C
R SFLE TOR
S 3 o - a , D U Ll C A T E
P S r o , u ' L O U D N E S S O F F- O N 1. r0kQ ? 25k4
1
J .
1,->n
I L 2 OFF S e o , b' H I G HF I T T E R O f F - B k H z 3. soko -+ 100k4
3 7- 1 S s o , u' [ O w F I L T I R E - 15 zH
P O W EA I l P L I F I E R
R
r--
-l**rn
BASS 0Hz
5 t*
z
BASS 00H
1 :
VRs VRe
lrnrour
I Sroa
ss
oc SPE ER
AK
vR+ VRs I \
TREBLE0kHz
1 TL L
TREBT20kHz
E -J
NTROL }lPLIFIER
A LF F T
CHANNEL
RIGHT
1,'oNEs L
CHANNE
SPEAKTR
P R O T E C T T OC I R C U I T
N
AMPLIIIIR
P0WER
ONTROL I l P L I F I E
A
Q ^
.Lrgr, Q t.s o
T op n o t e c t i o n
crrcurT
T *
+
I
L a[P
T o L c h pow en
T
PRE O U T
T o c o n tno amp
I
POW IN
ER T o p o w e ra m P
T o e g u a l i z ea m P
n
-
OFF 0 N To pr-otection clrcuit
Stoa,b : TONE
Srto-d SPEAKER T o p o w e ra m P
1. OFF z . A3 B TocontrolamP
f s e Q ulaz e na m p
i
4. A+B
S," RE AY
L
-ON
Srs PO\NEROFF
S t + a , b R S E LC T O R
E
'l-o -
1. l0k0 7 25k0 R ch power,tP
3. s0kQ, -+ l00ka,
siA-s|5clcltr
5 . C I R C U I TD E S C R I P T I O N S
7=l20(a
FUNCTION + C= 100pF
S|{IICH
PHONO
2
'I
PHONO
OUT
CARTRIDGE
LOAD
F i g . 1 . S c h e m a t id i a g r a mo r e q u a l i z ea m p l i f i e r
c f r
5 . 1 E O U A L I Z E RA M P L I F I E R 5.2 TONE CONTROLS
The circuit diagram for the equalizer amplifier is The SA-9500 II features two sets of tone controls
shown in Fig. 1. The two separatephono inputs are (Tkin Tone Controls) with different turnover fre-
selectedby the FUNCTION selector on the front quencies for bass and treble. And each of these
panel. The input resistance and input capacitance controls may be used independently.
can both be adjusted to 4 different levels(R=l0kCl, Incoming signals are amplified to the required level
25kO, 50kA and 100kO, C=1-00pF, 200pF, 300pF by the 2 stage amplifier which uses a differential
and 400pF) by means of the CARTRIDGE LOAD amplifier at first stage. T\vo tone control circuits
control knobs (R and C) which switches in and out, (C-B feedback NFB type) are connected together
additional resistors and capacitors in parallel with in series. The second stage is the normal tone
the input terminal. Hence, optimum load condi- control (MAIN), while the other is a seeondary
tions for different phono carbridges can be ad- tone control at a different turnover frequency
justed, as well as modifying the cartridge's fre- (SUB). On the TREBLE side, this (SUB) tumover
quency response in the high frequency range and frequency is higher than the MAIN, while on the
thus producing variations in its characteristics. BASS side, it is lower.
The first stageof the equalizer amplifier (Q, & Qr) The basic principles of the NFB type tone control
is a differential amplifier using PNP transistors. The circuit are outlined in Fig. 2.
next stage (Q.) is a bootstrap circuit employing C1,
R1 to provide high voltage gain. The output stage
(Q+ & Qr) is a complementary-symmetrical SEPP
circuit, whose high voltage utility factor results in
a high output voltage. This gives the equalizer
amplifier a very wide dynamic range, and a con-
siderable overload input level of 300mV (RMS at
lkHz) with no more than 0.05V"distortion.
The equalizer elements (Cr, Cr, Rz and R3) consist
of polypropylene film capacitors (tolerance !2Vo) R" YR" R,
and metal film resistors (tolerance xIVo). Phono TREBLE
equalizer RIAA deviation has been reduced to less Fig. 2. Basiccircuitry of NFB type tone control circuit
than t0.2dB (20H2 - 2OkHz\.
Midrange Operation
The Cr and C2 reactancesare considerably smaller
than VRr at frequencies above midrange, effec-
tively shor