Me WM8 User manual

Marchand Electronics Inc.
PO Box 18099, Rochester NY 14618
Tel:[phone] F x:[phone]
info@m rch ndelec.com www.m rch ndelec.com
(c)1997....2005 M rch nd Electronics Inc.
WM8 Installation Instructions
CONTENTS
Specific tions
Introduction
Inst ll tion
Sep r te Components
Bi mping
Oper tion
Setting Qs
Setting Fs
Setting BOOST
Setting Qb
Vented Spe kers
Fin l Adjustments
Technic l Description
Circuit
Options
Assembly (kit version)
Gener l Wiring Pr ctice
PC Bo rd Assembly
Ch ssis Wiring
Appendix A - Schem tic Di gr m
Appendix B - PC Bo rd L yout
Appendix C - Ch ssis L yout
Appendix D - PC Bo rd P rts List
Appendix E - Over ll P rts List
Appendix F - Troubleshooting
SPECIFICATIONS*
Frequency Response
(Boost=0, Qs=Qb) 2 Hz-100kHz
H rmonic Distortion <.01% (1 kHz)
Sign l/Noise R tio >110 dB (Ref. 10 V)
Input Imped nce 80 kΩ
Output Imped nce 10 Ω
M ximum Output Volt ge 25 V (P-P)
Output Lo d C p bility 100 Ω (min.)
B ss Boost R nge 0-24 dB
Net Q R nge .25 - 1.0
Dimensions 17"W x 8.5"D x 3.5"H
*Specific tions subject to ch nge without notice.
INTROD CTION
The BASSIS is speci lized electronic
equ lizer which en bles coustic-suspension
(closed-box) loudspe kers to t ke on wide
r nge of ltern tive b ss responses improving
some vented (b ss-reflex) designs.
By djusting the front p nel controls, the line-
level udio sign l is equ lized s the ex ct
inverse of given loudspe ker's b ss response,
nd the new b ss cutoff frequency nd d mping
re defined. The filtered sign l is then p ssed to
the power mp nd on to the spe kers, where the
existing b ss response is c ncelled nd repl ced
by the desired b ss response. Figure 1 illustr tes
the frequency response t v rious points in the
sign l p th.
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INSTALLATION
There re sever l w ys of connecting the
BASSIS to you system, depending upon your
present setup. In ny c se, make sure all
components are turned off while making
connections, and read the rear panel labelling
carefully. Do not pply power to the unit when
inst ll tion is complete. You must m ke the
djustments described in "Oper tion" first.
SEPARATE COMPONENTS
If you own sep r te pre mp/power mp
combin tion, you c n use the rr ngement shown
in Figure 1, where the O TP T from the pre mp
is connected to the BASSIS' INP T j cks, nd
the BASSIS' O TP T j cks re connected to
your power mp's INP Ts. The BYPASS switch
removes the BASSIS circuitry from the sign l p th
by connecting the INPUT directly to the O TP T.
This llows e sy ev lu tion of the equ lizer's
effectiveness.
If you own n integr ted mplifier or receiver
with PREAMP O T nd POWER AMP IN j cks,
the s me connection s for sep r tes c n be
used.
MULTIPLE TAPE LOOPS
If your integr ted mp or receiver h s n
unused t pe loop (or dedic ted sign l-
processing loop), you m y connect the BASSIS
s shown in Figure 2, below.
Be sure to press the TAPE 2 MON button on your
receiver. You c n remove the BASSIS from the
sign l p th in two w ys now: (1) turn off the
TAPE 2 MON button on your receiver, or (2) use
the BYPASS switch on the BASSIS.
BIAMPING
If you wish to equ lize the response of
independently mplified woofers or subwoofer(s),
you m y use the BASSIS solely in the low-
frequency sign l p th, using the rr ngement in
Figure 4.
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OPERATION
The v rious controls on the BASSIS must be
djusted to m tch your system's requirements
before power is pplied to the unit. If the 24 dB
(f ctor of 16) m ximum BOOST setting is pplied
incorrectly, d m ge to your spe kers nd/or
mplifier m y result.
SETTING Qs
Figure 5 shows the b ss response of v rious
coustic-suspension loudspe kers. If the
spe ker's Q is gre ter th n 0.7, the response m y
re ch pe k t the "reson nt frequency", then f ll
off t r te of 12 dB/oct ve t lower frequencies.
If your spe ker h s "boomy" or "he vy" sound,
then it is likely th t it Q is in the "underd mped"
r nge from 1.0 to 1.6. On the other h nd,
spe kers whose Q is .5 or .6 will be "well-
d mped", with "tight" or even "lightweight"
sound (due to the prem turely-f lling b ss
response).
You must djust the Left nd Right ch nnel
controls l belled Qs (Spe ker Q) ccording to
your own spe kers' ch r cteristics. (You will
ordin rily use the s me settings for Left nd Right
ch nnels.) Choose v lue which pproxim tes
the d mping for your spe kers, s suggested
bove. If in doubt, use setting round .7,
corresponding to the v lue most spe ker
designers im for. You c n l ter fine-tune the
setting if necess ry.
Setting Fs
You must now set the Left nd Right ch nnel
Fs (Spe ker Corner Frequency or -- less
ccur tely -- Reson nt Frequency) controls. If
you h ve frequency response specific tions for
your loudspe kers of the form:"55 Hz to 18 kHz +
3dB" or ".3 dB point t 75 Hz", you c n
pproxim te Fs by m king use of Figure 5 nd
your estim te for Qs. For ex mple, if your
spe ker's v lue for Qs is .5, then Figure 5 shows
th t its -3 dB point is ne r 1.6 x Fs. Thus, if your
specs indic te -3dB poi9nt of 75 Hz, then
setting of Fs = 75/1.6=45Hz should be used. On
the other h nd if your spe ker h s Qs= 1.4
(boomy-sounding), then Figure 5 indic tes its -3
dB point is ne r .65 x Fs. Hence if its
specific tions indic te frequency response like:
"52 Hz to 22 kHz + 3dB", then you should use
setting of Fs + 52/.65 = 80Hz. Fin lly, if you
ssume Qs = .7 for your spe kers, then Fs
equ ls the specified -3 dB point.
If you h ve no frequency response specs for
your loudspe kers, or if the specs re of the form
"50 Hz to 20 kHz" (without + x dB limits) then you
will h ve to estim te Fs. Most medium-size
"bookshelf" spe kers h ve Fs round 65 Hz;
comp ct spe kers (enclosure less th n 14" high)
m y h ve Fs closer to 80 Hz; l rge spe kers
(gre ter th n 30" high) m y h ve Fs round 40-
50 Hz. For those tiny die-c st spe kers like
R dio Sh ck's Minimus 7, try v lue of 100 Hz or
higher for Fs, with Qs round .8 or .9.
While these settings re not too critic l, it is
import nt to get in the b llp rk of the correct
setting before using the BASSIS. The settings
m y be fine-tuned l ter if necess ry. As n
ex mple of the effect of severe mism tch,
suppose your spe ker h s Fs = 50 Hz, nd Qs =
1, nd suppose th t you incorrectly set the
BASSIS ccording to Fs =100 Hz, Qs = .5. If you
m ke the rem ining djustments (Boost nd Qb,
s described below) to try to extend the b ss
response, the BASSIS will give 6 dB boost
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In the net response t 100 Hz nd more th n 12
dB too much b ss t 50 Hz. (This spe ker would
be ne rly fl t to 50 Hz. without equ liz tion.) The
unnecess ry b ss boost will give very "he vy"
sound to most recordings, nd m y d m ge the
spe kers or c use distortion when listening t
high levels.
SETTING BOOST
Once the correct settings of Fs nd Qs h ve
been m de to m tch your loudspe kers, you m y
never need to re djust these controls. However,
the rem ining controls -- BOOST nd Qb -- m y
be djusted to give the best results with your
choice of listening levels nd source m teri l.
BOOST indic tes the mount by which low
frequency sign ls re mplified. If the Fs nd Qs
setting re correct, only those frequencies where
your spe ker is deficient will be mplified, so th t
the effect is to extend b ss response. (In
contr st, the BASS control on your receiver or
pre mp indiscrimin tely boosts the entire low-
frequency portion on the sign l, often le ding to
"boomy" or "he vy" qu lity.) A setting of BOOST
= 0 dB will not extend the b ss, but will llow you
to effectively djust your woofer's d mping by
ch nging Qb s described below. A setting of
BOOST = 12 dB will extend b ss response one
oct ve lower, nd setting of BOOST = 24 dB
will extend b ss by two oct ves.
SETTING Qb
The best setting for Qb is l rgely dependent
upon your t ste nd on the listening-room
coustics. This control djusts the Q (see Figure
5) of the new b ss response dict ted by the
BASSIS. If you w nt very "tight" sound, choose
Qb = .5 or sm ller. If you w nt "looser", more
"full" b ss, use Qb = 1. Qb = .7 gives the
"m xim lly-fl t" response. Figures 6 nd 7 show
the results when the BASSIS is used to correct
somewh t boomy-sounding spe ker whose
response drops below 60 Hz (Qs = 1.4, Fs = 60).
In both c ses BOOST = 24 dB is used, but in
Figure 6 setting of Qb = .7 is used, while in
Figure 7 Qb = .25 is used.
It is interesting to note th t settings of Qb< .5 give
tr nsient response with bsolutely no "ringing",
so th t the BASSIS llows you to chieve "non-
reson nt" b ss response without need for
refridger tor-sized "tr nsmission-line"
loudspe ker enclosure.
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VENTED SPEAKERS
The BASSIS c n be used to reduce the
boominess of poorly tuned vented ("ported",
"b ss-reflex", or "p ssive r di tor") spe kers. In
this c se, use setting of BOOST = 0 dB (never
boost the b ss below the reson nt frequency of
vented spe ker!), Qs = 1.4, nd djust Qb to your
t ste. Or, you c n plug the vent nd forego the
efficiency dv nt ge of the vented design,
llowing you to use the entire r nge of
equ liz tion options s you would for n coustic-
suspension loudspe ker.
FINAL ADJUSTMENTS
You re now re dy to pply power to your
system including the BASSIS. Adv nce your
VOL ME control slowly to m ke sure the unit is
working properly. If you h ve difficulties, see the
"Troubleshooting" section of this m nu l
(Appendix F). There re few ddition l points to
keep in mind to obt in optimum perform nce.
If your source m teri lis LP records, you should
test your system's sensitivity to record w rps.
Remove the grilles from your spe kers. With the
VOL ME control set low nd the BASSIS set with
BOOST = 24 dB, pl y the silent le d-in observing
your woofer cones. If signific nt "pumping"
motion is visible t your norm l VOL ME setting,
eng ge the 20 HZ C T filter on the BASSIS.
Even when properly djusted, the b ss
extension offered by the BASSIS must be used
with discretion. While the BASSIS c n give 6-
1/2" woofer the s me b ss response s th t of
12" woofer, it c nnot incre se the power handling
of sm ll spe kers. Do not eng ge your pre mp
or receiver's LO DNESS button or m ke
excellive use of the BASS tone control while
using the BASSIS. When listening t high
VOL ME levels to m teri l with signific nt low-
b ss content, it is wise to reduce the BOOST
setting, reduce Qb, or BYPASS the unit entirely.
Fortun tely, the low-b ss content of most
recordings is much sm ller th n the content of
the rem ining frequency r nge. In these c ses
the low-frequecy boost pplied by the BASSIS will
not imp ir the spe ker or mplifier power
c p bilities.
When using the BASSIS, don't expect to he r
the sort of elev ted b ss produced by turning up
your pre mp or receiver's BASS tone control or
pressing the LO DNESS button. Inste d, the
mid-b ss will be reproduced with impoved
neutr lity nd "openness", nd the response will
extend smoothly into the lower b ss, p rticul rly
when using high-qu lity source m teri l.
On the other h nd, extending the b ss
response will m ke your system more sensitive to
"st nding w ves" in the listening room. You m y
h ve to experiment with new loc tions for your
loudspe kers or listening se t to obt in the
smoothese over ll b ss response.
TECHNICAL DESCRIPTION
The equ liz tion offered by the BASSIS c n be
described in terms of the biqu dr tic transfer
function:
where ws nd ds re the corner frequency
nd d mping r tio of the woofer nd wb nd db
re the new corner frequency nd d mping r tion
chosen by the user (w =2piF nd d =0.5/Q). The
numer tor c ncels the 2nd-order high-p ss effect
of the coustic-suspension woofer nd the
denomin tor defines the new 2nd-order cutoff.
CIRCUIT
The circuitry for e ch ch nnel of the BASSIS is
cont ined on n individu l printed circuit bo rd
(PC bo rd), using high-speed op- mps nd close-
toler nce p ssive components. A power supply is
cont ined on third bo rd. The schem tic
di gr m of single ch nnel is shown in Appendix
A.
The he rt of the circuit is 4- mplifier
biqu dr tic filter, supplemented with ddition l op-
mps to llow the independent djustment of the
d mping nd cutoff frequency p r rmeters. Op-
mps IC1, IC2 nd IC3 provide the equ liz tion,
while IIC4A is p rt of the 20 Hz C T filer. Op-
mp IC4B provide low output imped nce nd high
current c p bility, to llow long c ble runs with
minim l lo ding effects.
Du l potentiometer VR3 djusts the frequency
m tching the spe ker's corner frequency over the
r nge: Fs = 30 Hz to 130 Hz. Potentioometer
VR2 djusts the d mping which ex ctly c ncels
the spe ker's response, for spe kers with Qs
from .4 to 1.6. Potentiometers VR1 nd VR4 set
the corner frequency nd d mping of the new
b ss response over the r nge: Fb = Fs to Fs/4
nd Qb = .25 to 1. Since e ch oct ve of b ss
extension requires 12 dB of mplific tion t low
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ws2 + 2 dswss + s2
G(s)= --------------------------------------
wb2 + 2 dbwbs + s2

frequencies, pot VR1 is ctu lly l belled BOOST,
with r nge of 0 to 24 dB.
Switch S1 ctiv tes the 20 HZ C T (high-p ss,
infr sonic, or "subsonic") filter with n 18
dB/oct ve slope below 20 Hz, to void the
mplific tion of in udible but potenti lly
destructive low-frequency sign ls. Switch S2
combines the Left nd Right ch nnels t
frequencies below the spe ker's origin l corner
frequency (provided the settings for Fs, Qs,
BOOST, nd Qb re identic l for both ch nnels)
to c ncel out-of-ph se R MBLE sign ls. Switch
S4 provides BYPASS function to elimin te the
equ lizer from the sign l p ther, nd Swith S3
llows the user to reg in t pe monitoring
c p bility, in the event th t the BASSIS is used in
the sole t pe loop of receiver or pre mp.
OPTION 1
If you re constructing your own enclosure for
the BASSIS, you m y choose to c lcul te the
v lues of fixed resistors which reflect your
p rticul r spe ker's Fs nd Qs, nd which provide
fixed mount of boost. This llows you to
elimin te ll but
Single potentiometer -- which controls the
d mping (Qb). Since the setting of the Qb control
influences the level of b ss bout the new corner
frequency (comp re Figures 6 nd 7), you ret in
control of the net b ss extension. To implement
this option, follow the ssembly procedure
det iled in the next section of this m nu l, except:
( ) le ve out the Molex connectors which tt ch
the BOOST nd Fs pots to the PC bo rd; (b) wire
only th t p rt of Molex connector P2 which
tt ches the Qb pot to the PC bo rd; (c)
rec lcul te the v lues of resistors R7, R8, R16,
R4, nd R26 ccording to your spe kers'
ch r cteristics nd the desired mount of boost:
R7 = R8 = 1/(6.28 x Fs x C1)
R16 = R19 x Qs
R4 = R26 = R28 x 10 boost/40.
Where BOOST is given in dB. Now you c n use
du l 10k line r pot to djust the d mping (Qb)
of the Left nd Right ch nnels simult neously.
Or, if you w nt to elimin te the rem ining control
s well, remove VR4 nd rec lcul te R11 for the
desired (fixed) v lue of Qb:
R11 = R2 x Qb.
OPTION 2
There is sp ce in the st nd rd BASSIS
enclosure for n ddition l power supply for
constructors interested in true du l-mono
oper tion. Simply follow the steps in the
"Assembly" section of this m nu l, but wire the
inputs of second + 15 V power supply to the
power cord s well, nd power the Right-ch nnel
PC bo rd from this power supply.
OPTION 3
On the other h nd, if the BASSIS is to be
used with single-ch nnel, independently-
mplified subwoofer, then only single PC bo rd
need be ssembled, nd sm ller enclosure m y
be employed. Assembly is the s me s
described in this m nu l, except th t the switches
m y be SPDT r ther th n DPDT.
ASSEMBLY (KIT VERSION)
The p rts for stereo implement tion include:
two BASSIS printed circuit bo rds nd
components, one + 15 V power supply ssembly
(such s M rch nd Electronics' Model PS10), nd
one enclosure with h rdw re. The Appendices of
this m nu l cont in det iled Over ll P rts List
s well s PC Bo rd P rts List. You will first
ssemble the circuit bo rds, then mount them in
the enclosure nd tt ch the front p nel controls.
GENERAL WIRING PRACTICE
The tools necess ry to ssemble the BASSIS
include: 15 - 30W soldering pencil, rosin-core
solder, wire cutters, nd Phillips-he d
screwdriver. Other useful tools re:
desoldering tool or solder wick (to remove excess
solder), project holder, long-nose pliers, nd
wire stripper. A cle n, well-lit working re will
minimize frustr tions.
When soldering component to the circuit
bo rd, first mount the component so th t it fits
snugly g inst the silkscreened side of the bo rd.
Next, he t the component le d nd the circuit
bo rd tr ce (on the foil side) simult neously with
the soldering pencil nd pply solder until it melts
nd flows round the component le d. With
pr ctice the entire process should t ke only 5
seconds or so. Remove the pencil nd llow the
connection to cool for few seconds before
moving. Cut off the excess le d close to the
solder joint. If solder bridge w s in dvertently
m de to nother tr ce, remove the solder
c refully with desoldering bulb or br id. Keep
the tip of the soldering pencil cle n by wiping on
d mp sponge every few minutes.
Components c n be identified s follows.
Resistors use the 4-b nd color code in the ch rt
shown below. The fifth b nd is lw ys brown,
indic ting 1% toler nce. For ex mple, resistor
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m rked Brown-Bl ck-Bl ck-Gold-Brown is 10
Ω resistor with 1% toler nce.
1st, 2nd, & 3rd B nds 4th B nd
Bl ck 0 Bl ck x 1
Brown 1 Brown x 10
Red 2 Red x 100
Or nge 3 Or nge x 1000
Yellow 4 Yellow x 10,000
Green 5 Green x 100,100
Blue 6 Blue x 1,000,000
Violet 7 Silver / 100
Gr y 8 Gold / 10
White 9
Figure 8. Resistor Color Code
C p citors nd diodes re individu lly
m rked, though somewh t cryptic lly. C1 nd C4
m y be l belled "393", while C5, C7, nd C15 re
m rked "104K".
Before beginning ssembly, it is suggested
th t you comp re the components to the P rts
List nd sort them ccordingly. (Look inside the
he t-shrink tubing if nything is missing!)
PC BOARD ASSEMBLY
Assembly of the BASSIS is simplified by
guide which h s been silkscreened on to the
printed circuit bo rds. Appendix B repe ts this
l yout di gr m. To mount components onto the
bo rds, observe the pl cement shown on the
l yout di gr m nd on the silkscreen p ttern, nd
m tch with the v lues shown on the PC Bo rd
P rts List in Appendix D. The following checklist
should be completed, for both the Left nd Right
ch nnels.
L R
[ ] [ ] 1. Bend the le ds of resistors R1-R35
nd solder them in pl ce s shown on the l yout
di gr m. Cut off the excess le ds s you go.
[ ] [ ] 2. eleted.
[ ] [ ] 3. Mount diodes D1-D4 nd solder them
in pl ce. Be sure to observe the correct polarity
by positioning the side with the band as shown in
the diagram.
[ ] [ ] 4. Mount nd solder the four (4) IC
sockets in pl ce on the circuit bo rd. Be sure the
side with the notch is oriented as shown. Do not
insert the op- mps into these sockets yet.
[ ] [ ] 5. Inst ll the luminum electrolytic
c p citors C8 nd C14, being careful to orient the
+ and - leads as shown. Inst ll the nonpolar
electrolytic c p citor C9 with either orient tion.
[ ] [ ] 6. Inst ll the rem ining polypropylene,
polyester nd cer mic c p citors C1-C7, C10-C-
13, nd C15-C16. (These c n be oriented either
w y.)
[ ] [ ] 7. Inst ll Q1, 2N5087.
[ ] [ ] 8. Inst ll Q2, 2N2222.
[ ] [ ] 9. Mount the 3-pin m le Molex connector
nd the five (5) 5-pin m le Molex connectors
ccording to the di gr m. The edge with the
plastic protrusion corresponds to the band on the
layout diagram.
[ ] [ ] 10. Press op- mps 1C1-1C4 into the four
IC sockets, being sure to orient them so that the
notch matches the notch on the sockets, as
shown on the diagram. You m y need to (gently)
bend the le ds inw rd slightly to m tch the holes
in the sockets. If you resolder ny of the socket
le ds l ter, remove the corresponding op- mp
first to protect it from excessive he ting.
Now inspect the foil side of the bo rd for solder
spl shes or bridges nd remove them with the
desoldering tool. Check for ny empty holes,
possibly indic ting missing component. (Some
unused holes m y rem in, to llow substitution of
c p citors with differing physic l dimensions.)
Double-check the orient tion of the luminum
electrolytic c p citors, diodes, tr nsistors,
connectors, nd ICs.
CHASSIS WIRING
At this point you should h ve ssembled the
Left nd Right ch nnel PC bo rds, nd + 15 V
power supply. The Over ll P rts List in Appendix
E det ils the p rts needed for ssembling the
BASSIS ch ssis. Appendix C sketches the
interior of the unit fter completion of single
ch nnel.
o not apply power to the unit until all the
assembly is complete and you've read the
"Operation" section of this manual.
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[ ] 11. Mount the BASSIS PC bo rds nd power
supply inside your enclosure with st ndoffs nd
#6 screws. The PS 10-power supply should be
oriented with the tr nsformer closer to the re r
p nel.
[ ] 12. Mount potentiometers VR1-VR4 for e ch
ch nnel (tot l of eight (8) pots on the inside of the
front p nel. The du l pots (VR1 nd VR3)
correspond to the BOOST nd Fs l bels on the
front p nel. The pots should h ve their solder
lugs f cing up.
[ ] 13. Mount the fuseholder on the re r p nel but
do not insert the fuse yet.
[ ] 14. Mount the power entry connector onto the
re r p nel.
[ ] 15. Mount the DPDT volt ge selector switch
on the re r p nel.
[ ] 16. Mount the RCA bukhe d connectors on
the re r p nel. Two h ve bl ck insul tors nd
two h ve red insul tors. Mount the red
connectors in the right ch nnel nd the bl ck
ones in the left ch nnel.
Front P nel
DPST rocker switch
Re r P nel
Fuse Holder
Re r P nel
Power entry
Re r P nel
Volt ge selector
GREEN/
YELLOW
N
L
PS10 tr nsformer
termin l block
WHITE
BLACK
WHITE
BLACK
BLACK
BLACK
BROWN
RED
RED
Wire to
c se
WHITE
Power entry with volt ge selector switch on re r
p nel nd rocker switch on front p nel.
Power entry with voltage selector switch.
The PS10 power supply of the crossover should
be grounded to the c binet through power
resistor.
Solder one le d of the 2400 Ohm power resistor
to the solder lug.
Solder 3” length of wire to the other end of the
power resistor.
Inst ll the shrink tubing over the resistor nd p rt
of the solder lug.
Att ch the solder lug to the c binet using one of
the 6-32 screws on the front p nel.
Insert the free end of the wire in the center
termin l of the three position termin l block of the
PS10 output. This is the neutr l DC output.
Solder lug
Resistor
Wire to PS10 output
ground
Now the AC power wiring will be hooked up to
the power supply.
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Use high volt ge (thick insul tion) #22 hookup
wire to m ke the connections between the power
entry connector, the power switch on the front
p nel nd the power selector switch on the re r
p nel nd the fuse holder. Inst ll he t shrink
tubing over ll junctions. Use wire colors s
shown.
M ke sure to securely inst ll the grounding wire
between the ground termin l on the power entry
connector nd the ch ssis. Solder 3” piece of
green/yellow hookup wire to one of the solder lugs
provided. Solder the free end of the wire to the
ground termin l nd secure the solder lug to the
ch ssis with one of the 6/32 screws holding the
re r p nel.
Set the volt ge selector switch to the proper
volt ge before proceeding.
teflon shoulder w sher
RCA connector
teflon fl t w sher
gold pl ted solder lug
gold pl ted nut
re r p nel
RCA connector mounting cross section
Inst ll 1A fuse in the fuse holder.
We will now test the power supply. Plug the
cord in nd turn on the power switch. The two
LED indic tors on the power supply nd the front
p nel LED indic tor should light up.
UNPLUG the power cord before proceeding.
[ ] 17. Cut 4" piece of brown wire nd 4" of red
wire, strip 1/4" from e ch end, nd tt ch sp de
lug to one end of e ch wire. Slide 1-1/2" piece
of he t-shrink tubing onto the other end of e ch
wire. Solder the brown wire to the c thode le d of
the front p nel LED (the c thode is the le d closer
to the fl ttened edge of the LED). Solder the red
wire to 10k resistor. Solder the other end of this
resistor to the rem ining LED le d. Slide the
he t-shrink over the exposed le ds nd he t with
m tch. Mount the LED in the ppropri te
socket on the front p nel. Le ve the other ends
of these wires loose for now.
For the rem ining steps, the codes shown in
Figure 9 will be used to refer to the lugs on the
potentiometers, switches nd Molex connectors.
[ ] [ ] 18. For the Left nd Right ch nnel
circuit bo rds, cut pieces of red, brown, nd
or nge wire long enough to re ch from m le
Molex connector P4 on the circuit bo rd to the
output termin ls on the power supply (with few
inches to sp re). Strip 1/4" from e ch end.
Att ch sp de lugs to one end of e ch of the three
wires nd twist the wires together for ne tness (--
unless you're color-blind, in which c se you
should tt ch the wires one t time to keep
tr ck!). Att ch Molex termin l pins to the other
end of e ch wire. Using the coding in Figure 9,
press the pin tt ched to the brown wire into j ck
A in 30pin fem le Molex connector, nd press
the pins on the red nd or nge wires into j cks B
nd C, respectively. Sn p the fem le connector
onto P4.
[ ] [ ] 19. Screw the sp de lugs tt ched to the
brown wires for e ch ch nnel to the -15 V
termin l of the power supply, long with the sp de
lug tt ched to the c thode of the front p nel
LED. Screw the sp de lugs tt ched to the red
wires to the Ground termin l on the power supply.
Screw the sp de lugs tt ched to the or nge
wires to the + 15 V termin l of the power supply,
long with the sp de lug tt ched to the node of
the front p nel LED. These connections are
critical. Double check th t you've linked j ck A of
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the Molex connector to the - 15 V termin l, j ck B
to Ground, nd j ck C to + 15 V.
[ ] [ ] 20. Using short piece of b red wire link
lugs C nd F together on the BOOST pots, nd
link lugs A nd D together on the Fs pots.
[ ] [ ] 21. Cut 5 wires of different colors, long
enough to re ch from m le Molex connector P1
on the circuit bo rd to the corresponding BOOST
pot. Strip 1/4" from e ch end nd twist the wires
together for ne tness. Att ch Molex termin l pins
to one end of e ch wire, nd slide 3/4" piece of
he t-shrink tubing onto the other end. Press the
termin l pins into 5-pin fem le Molex connector
s shown in Figure 9. Solder the other end of
e ch wire to the lugs of the BOOST pot,
observing the colors so th t (see Figure 9): j ck
A on the Molex connector connects to solder lug
D on the pot, j ck B connects to lug E, j ck C
connects to lug F, j ck D connects to lug B, nd
j ck E connects to lug A. Slide the he t-shrink
over the solder joint nd he t with m tch. Sn p
the fem le Molex connector onto m le connector
P1.
[ ] [ ] 22. Using the s me procedure s in Step
21 (don't forget the he tshrink tubing), connect
j ck A of the fem le Molex connector you will use
with P3, to lug F on the Fs pot. Connect j ck B to
lug E, j ck C to lug D, j ck D to lug B nd j ck E
to lug C. Sn p the Molex connector onto P3 on
the circuit bo rd.
[ ] [ ] 23. Using the s me procedure s in Step
21, connect j ck A of the fem le Molex connector
corresponding with P2, to lug A on the Qb pot.
Connect j ck B to lug B on the s me pot.
Connect j ck C to lug C on the s me pot, nd use
short piece of wire to tt ch lug C of the Qb pot
to lug C of the Qs pot. Now connect j ck D to lug
B of the Qs pot nd j ck E to lug A of the Qs pot.
Sn p the Molex connector onto P2 on the circuit
bo rd.
[ ] [ ] 24. Using the s me procedure, connect
j ck A of the fem le Molex connector
corresponding to P5, to lug D (Left ch nnel) or lug
A (Right ch nnel) of DPDT switch (see Figure
9). Be sure you re holding the switch so th t the
keyhole t b is on the underside of the sh ft.
Connect j ck B to lug E (Left ch nnel) or lug B
(Right ch nnel). Connect j ck C to lug F (Left
ch nnel) or lug C (Right ch nnel) of the s me
switch. Skip jack on the Molex connector. Sn p
the Molex connector onto P5 on the circuit bo rd.
When both ch nnels re completed, mount the
DPDT switch in the 20 HZ C T hole.
[ ] [ ] 25. Connect j ck A of the Molex
connector P6 to lug F (Left ch nnel) or lug C
(Right ch nnel) of the rem ining DPDT switch.
Connect j ck D of the Molex connector to lug E (L
ch nnel) or lug B (R ch nnel) of the switch.
Connect j ck E to lug D (L ch nnel) or lug A (R
ch nnel) of the switch. Mount this switch in the
BYPASS hole on the front p nel.
[ ] [ ] 26. Inst ll jumper wire between j ck B
of connector P6 nd j ck C of s me. Sn p the
Molex connector onto P6 on the circuit bo rd.
[ ] [ ] 27. Inst ll jumper wire between the
t pe-in nd t pe-out termin ls of the 8-position
blue termin l block on the WM8 circuit bo rds.
[ ] [ ] 28. Mount ll the knobs onto the pots,
nd insert the fuse into the fuseholder.
Note th t the knobs re mounted so th t they will
turn the s me ngle fully clockwise s fully
counterclockwise.
You h ve now completed the ssembly of your
BASSIS. Double check th t you've completed ll
the steps. At this point you m y plug the unit into
w ll outlet nd turn on the POWER switch to
observe whether the power light comes on.
However, do NOT tt ch it to your system until
you've m de the djustments discussed in
"Oper tion".
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