6 | JL Audio - 300/4v3 Owner ’ s Manual
7
on ea ch “I nput V olt a ge” switc h se lects an
input s ens it iv it y r an ge be t ween 8 0 0m V a nd 8V .
Th i s is u sef u l for c er t a in h ig h- out put prea mp
leve l sig na l s as we l l as s pea ker-le vel out put
f rom sou rce u n its a nd s ma l l a mpl if iers . T o u se
spe a ke r-level s ourc es , spl ic e t he spe a ke r outpu t
w ire s of t he s ourc e u nit or sm a l l a mpl if ier
onto a pa i r of RCA plugs for e ach i nput pa i r
or us e t he J LAud io EC S Sp ea k er Wi re to RCA
adaptor (X D - CLR AIC2- SW).
IMPORT ANT
The out put of t he amp li f ier w i l l dec rea se
for a gi ven input volt age w hen t he “Input
Ra nge ” sw itc h is pla ce d in t he “H ig h”
posit ion . Conver se ly , t he output w i l l be h ig her
w ith t he s w itch i n t he “L ow ” posit ion . Wh i le
t his m ay sou nd cou nter-i ntu it ive, it i s cor rec t
as descri bed.
3) I nput Se nsit iv it y Adju stm ent: Loc ated n ex t
to t he “Input V o lta ge” s w itc h i n ea ch i nput
se ct ion i s a ro ta r y c ont rol la bele d “I nput
Sens.”. Once t he appropr iate “Input V olt age”
ra nge h as b een s ele ct ed , t h is cont rol c a n be
us ed to m atch t he s ou rce u n it’s output volt age
to t he i nput st age of e ach p a ir of a mpl i f ier
cha n nel s for ma x i mu m cle a n out put. Rot at i ng
t he cont rol cl ock w i se w i l l re su lt i n h ig her
sen sit iv it y ( loude r for a gi ven i nput volta ge) .
Rota ti ng t he c ont rol cou nter- cloc k w is e w i l l
resu l t in lower s ens it iv it y ( qu iete r for a g iven
input vo lta ge ). T o prop erly s et e ach p a ir
of a mpli f ie r cha n nel s for ma x i mu m cle a n
out put, ple as e refer t o Append i x A (pa ge 14 )
in t h i s ma nua l . A f ter u si ng t h is pro ce du re,
you ca n t he n adju st t he rel at ive le vel of ea ch
cha n nel p ai r by adju st i ng t he i nput s ensit i v it y
dow nwa rd on eit her or b ot h ch a nne l pa ir s, i f
t hey re qu ire a tt enuat ion t o ach ie ve t he des ire d
sy ste m ba l a nce . Do not inc rea s e t he “I nput
Sens.” s et t in g for a ny a mpl i f ier i n t he sy ste m
be yond t he ma x i mu m le vel es ta bl ishe d du ri ng
t he proc edu re out l i ned i n App end i x A (page
1 4). Doi ng so w i l l res u lt i n aud ible d i stor t ion
a nd pos sible s pe a ker d a ma ge. B e awa re t hat
bot h “Input S ens . ” adjust m ents w i l l have to
be ma de, r ega rd le ss of how ma ny i nput c able s
a re feed i ng t he a mpl i f ier. Th es e cont rols w i l l
a l low you to se t t he appropr iat e rela ti ve leve ls
for f ront and r ea r ch a nne ls a nd a ny ot her
a mpli f ie r cha n nel s i n t he sy ste m.
CROSSO VER CONTROLS
Cros sover s a re g roups of i nd iv idu a l ele ct ron ic
f i lter s wh ich a l low on ly c er t a in f re quenc y
ra nge s to pa s s t hrou g h t hem by at te nuat i ng
f reque ncie s outs ide t he se lec te d ra nge . T hes e
f i lter s a l low t he us er to s pec i f y wh at f requ enc y
ra nge w i l l b e sent out of e ach c ha n nel s ec t ion
of t he a mpli f i er. Th is , in t u r n, a l lows e ac h
spe a ke r sy ste m to on ly repro duce a r a nge of
f reque ncie s it is wel l- su ited for, resu lt i ng i n
reduc ed d is tor t ion a nd i mproved f id el it y .
Fron t And R ear Filter Section:
Bridged
Left Right
+12VDC Ground Remote
Front F ilter Controls
Front Input Section Front Speaker Outputs
Bridged
Left Right
Rear Speaker Outputs
Left Ch. Right Ch.
Filter Fr eq. (Hz)
Filter Slope
Freq. Range
Input Voltage Input Sens. Input Mode
12dB
|
24dB
Filter Mode
Off
|
LP
|
HP
x1
|
x10
Low
|
High
Rear Input Section
Left Ch. Right Ch.
Input Voltage Input Sens.
Low
|
High 2ch
|
4ch
50
60
75
95
1 30
200
500
30 0 / 4v3
Four-Channel Full-Range Amplifier
Rear Filter Contr ols
Filter Fr eq. (Hz)
Filter Slope Freq. Range
12dB
|
24dB
Filter Mode
Off
|
LP
|
HP
x1
|
x10
50
60
75
95
1 30
200
500
Bridged
Left Right
+12VDC Ground Remote Front F ilter Controls Front Input Section Front Speaker Outputs
Bridged
Left Right
Rear Speaker Outputs
Left Ch. Right Ch. Filter Fr eq. (Hz)
Filter Slope
Freq. Range
Input Voltage Input Sens. Input Mode
12dB
|
24dB
Filter Mode
Off
|
LP
|
HP
x1
|
x10 Low
|
High
Rear Input Section
Left Ch. Right Ch.
Input Voltage Input Sens.
Low
|
High 2ch
|
4ch
50
60
75
95
1 30
200
500
30 0 / 4v3
Four-Channel Full-Range Amplifier
Rear Filter Contr ols
Filter Fr eq. (Hz)
Filter Slope Freq. Range
12dB
|
24dB
Filter Mode
Off
|
LP
|
HP
x1
|
x10
50
60
75
95
1 30
200
500
Th e 30 0/4v3 employs t wo se pa ra te, but
ident ic a l f i lter s ec t ions for it s f ront a nd rea r
cha n nel p ai r s. T hes e se c ti ons con sis t of t he
fol low in g cont rols
1) “ Fi lter Mo de ” Cont rol : T hi s s w itch a l lows you
to con f ig u re t he f i lter i nto one of t wo f i lte r
t y pe s or to de feat it c omplete ly :
“Off ” : De fe ats the filter for that channe l
se ct ion c omplete ly , a l low in g t he f u l l ra n ge of
f reque ncie s pres ent at t he i nputs to fe ed t h at
pa i r of cha n nel s. T h is i s us ef u l for s ys tems
ut i li zi ng outbo a rd cro ss overs or requ i r in g f u l l-
ra nge re produc t ion f rom t h at pa i r of cha n nel s.
“LP ” (L ow-Pass): Con f ig u re s t he f i lt er to
at tenu ate f requ encie s ab ove t he se lec te d
f i lter f re quenc y. Usef u l for con nec t ion of
subwo ofer(s ) to t hat c ha n nel s ec t ion.
“HP ” (Hi g h-Pas s ): C onf ig u res t h e f i lter to
att enuate f reque ncies b elow the s elec te d
f i lter f re quenc y. Usef u l for con nec t ion
of compon ent spe a ker s to t hat c ha n nel
se ct ion i n a bi-a mpl i f ied s ys tem .
Ground Connection
Th e cha ss is g rou nd con ne ct ion mu st be m ade
usi ng 4 A WG pure c opper w ire a nd s hou ld be
kep t as sh or t as p oss ible , wh i le acc es si ng a s olid
piec e of she et me ta l i n t he veh ic le. T he su r fa ce of
t he she et me ta l s hou ld be s a nded at t h e conta ct
poi nt to cre ate a c lea n, me t a l-to-me ta l c onne c ti on
bet ween t he c ha ssi s a nd t he ter m i nat ion of
t he g rou nd w ire w it h a bra ss or c opper p ower
ri ng. For opti ma l g rou nd i ng , we rec omme nd
t he us e of a J LAud io EC S ma st er g rou nd
lug (XB -M GLU) . A lter nat ive ly , a she et me ta l
sc rew or b olt ca n b e us ed w it h a s ta r wa sh er.
IMPORT ANT
Ma ny veh icle s employ sma l l (10 A WG - 6
A W G) wi re to g rou nd t he bat ter y to t he veh ic le
cha ss is a nd to con nec t t he a lter nator ’ s posit ive
con nec t ion to t he bat ter y. T o pre vent volta ge
dr ops, t he se w i re s shou ld b e upgr ade d to 4
A W G pur e coppe r wi re w hen i nst a l li ng a mpl if ier
sy stems w it h ma i n f use r at in gs above 6 0A .
TU R N O N L EA D
Th e 30 0/4v3 use s a convent iona l + 12V remote
tu r n-on l ead , t y pic a l ly c ontr ol led by t he s ourc e
un it ’ s remote t u r n-on out put . T he a mpli f ie r w i l l
tu r n on w hen + 12V i s pres ent at it s “Remote ”
input a nd t u r n of f when + 12V is sw itc hed of f . If
a sou rce u n it doe s not have a d ed ic ated re mote
tu r n-on out put , t he a mpl i f ier’s tu rn- on lea d ca n
be con ne ct ed to + 12V via a s w itc h t hat de ri ves
power f rom a n ig n it ion-s w itche d ci rcu it .
Th e 30 0/4v3’ s “Remote ” tu r n-on con nec tor i s
des ig ned to a cc ept 18 A WG – 8 A WG wi re.
12 A WG is more t h an a deq uate for t h i s pur p os e.
T o con nec t t he remo te t ur n- on w ire t o t he
a mpli f ie r , f i rst b ack out t h e set s cre w on t he top
of t he a mpli f i er, usin g t he suppl ied h ex w renc h.
St rip 1/2 i nch (12mm) of wi re a nd i ns er t t he
ba re w i re into t h e rec ept acle on t he f ront pa nel
of t he a mpli f i er, seat in g it f i rm ly s o t hat no b a re
w ire i s ex p ose d. W hen u sin g sma l le r w ire , it may
be ne ce ss ar y to st r ip 1 i nch of i nsu lat ion f rom
t he w i re a nd fold t he ba re w i re i n ha l f pr ior to
in ser tion . W h i le hold in g t he w i re in t he t er mi na l,
t ig hten t he s et sc rew f ir m ly, ta k i ng c ar e not to
st r ip t he hea d of t he sc rew a nd ma k i ng su re t hat
t he w i re is f i r m ly g rip ped by t h e set s cre w.
FR ON T AN D R EA R I NP UT S EC TI O NS
Th e 30 0/4v3 has t wo s epa r ate i nput se ct ion s,
one for its f ront c ha n nels a nd a not he r for its re a r
cha n nel s. E ac h se ct ion c onta i ns a pa i r of RCA-
t y pe input jac ks , a n “Input V o lta ge” s w itc h a nd
a n “Input S en s. ” rota r y cont rol .
Bridged
Left Right
+12VDC Ground Remote Front F ilter Controls
Front Input Section
Front Speaker Outputs
Bridged
Left Right
Rear Speaker Outputs
Left Ch. Right Ch.
Filter Fr eq. (Hz)
Filter Slope
Freq. Range
Input Voltage Input Sens. Input Mode
12dB
|
24dB
Filter Mode
Off
|
LP
|
HP
x1
|
x10
Low
|
High
Rear Input Section
Left Ch. Right Ch.
Input Voltage Input Sens.
Low
|
High
2ch
|
4ch
50
60
75
95
1 30
200
500
30 0 / 4v3
Four-Channel Full-Range Amplifier
Rear Filter Contr ols
Filter Fr eq. (Hz)
Filter Slope Freq. Range
12dB
|
24dB
Filter Mode
Off
|
LP
|
HP
x1
|
x10
50
60
75
95
1 30
200
500
Bridged
Left Right
+12VDC Ground Remote Front F ilter Controls Front Input Section Front Speaker Outputs
Bridged
Left Right
Rear Speaker Outputs
Left Ch. Right Ch. Filter Fr eq. (Hz)
Filter Slope
Freq. Range
Input Voltage Input Sens. Input Mode
12dB
|
24dB
Filter Mode
Off
|
LP
|
HP
x1
|
x10 Low
|
High
Rear Input Section
Left Ch. Right Ch.
Input Voltage Input Sens.
Low
|
High
2ch
|
4ch
50
60
75
95
1 30
200
500
30 0 / 4v3
Four-Channel Full-Range Amplifier
Rear Filter Contr ols
Filter Fr eq. (Hz)
Filter Slope Freq. Range
12dB
|
24dB
Filter Mode
Off
|
LP
|
HP
x1
|
x10
50
60
75
95
1 30
200
500
Th e “Front Input S ec t ion ” a ls o cont a in s a n
“Input Mod e ” sw it ch to a l low oper at ion of a l l
four a mpl i f ier c ha n nel s w it h one or t wo pa i rs of
input s ig na l s.
1 ) Input Mo de Sw itch : If you w i sh to op er ate
a l l four c ha n nel s of t he 30 0/4v3 wit h a s in gl e
pair o f st er eo in pu ts, sele ct the “2ch ” posit ion
on t he “I nput Mod e ” s w itc h a nd con ne ct a
si ng le pa i r of input c ab les to t he i nput ja ck s
in t he “Front I nput Sec t ion ” . In this mod e,
t he a mpli f i er w i l l route t he si g na ls c on nec te d
to t he f ront i nputs to t he r ea r i nputs a s wel l .
If you w i sh to u se s ep ar ate i nput s for t he f ront
a nd rea r ch a nne l se ct ion s ( t o a l low fr ont- to-
rea r fa d in g, for e xa mple) and t he s ou rce u nit
is e quip ped w it h f r ont and re a r out puts , se lec t
“4 ch” on t he “ Input Mo de” sw itc h. I n t h is
mode , you mus t con nec t s epa r ate pa i rs of i nput
ca bles t o eac h input s ec t ion.
2) I nput V olta ge Ra n ge: A w ide r a nge of sig n a l
input vo lta ges c a n be a ccom mo dat ed by e ach
of t he 30 0/4v3’ s i nput se ct ion s (20 0m V – 8V).
Th i s w ide ra n ge is sp lit up i nto t wo su b-
ra nge s, a cc es sible v i a sw itc hes l oc ated i n e ach
input s ec t ion of t he a mpl i f ier. Be awa re t h at
eac h i nput se c tion’s “Input V olt age” s w itch
w i l l have to be c on f ig u red , reg a rd les s of how
ma ny i nput ca bles a re ac t u a l ly fee di ng t he
a mpli f ie r. The “L ow ” pos ition on ea ch “I nput
Vo l t a g e” s w itch sele c ts a n i nput s en sit iv it y
ra nge b et we en 20 0 m V a nd 2V . T hi s mea n s t hat
t he “I nput Se ns . ” rot a r y cont rol w i l l oper ate
w it hi n t h at volta ge w i ndow. If you a re usi ng
a n af ter ma rk et sou rc e un it , w it h convent iona l
prea mp -level ou tput s , t hi s is mo st l i kel y t he
pos iti on t hat you w i l l us e. The “High ” pos ition