L.R. BAGGS PPEAMPS
MIXPRO
USER'S GUIDE
483 N. FRONTAGE RD.
NIPOMO, CA 93444
WWW.LRBAGGS.COM
1 . Q U I C K S T A R T
1. Install the battery
2. Locate the "Internal Controls" diagram in section three to use as a reference.
3. If either of your sources require phantom power, turn it on now.
4. Plug a three-foot stereo cable into the guitar and into the Mixpro's input.
5. Plug a mono cable from the Mixpro into the PA or amp.
6. Pan the mix control completely to the first channel and set the gain and EQ.
7. Pan the mix control fully to the second channel and carefully set the gain so
that it is about as loud as the first channel.
8. Adjust the low cut to work with your second source's EQ settings.
9. Fine-tune the gain again to match the second source's volume with the first
source.
10. Turn the mix control to 12:00 and try both positions of the relative phase
switch to find the best phase for your combination. If you can't decide, choose
the relative phase that provides the smoothest pan.
2 . E X T E R N A L C O N T R O L S
A. Treble cont rol: Use to add or subtract the highest frequenci es, also known as
"presence."
B. Ba ss control: Use to add or s ub trac t l ower freque nc ies, add warmth or cu t
feedback.
C. Tr im c ontro l: The trim contro l is a mova ble 12dB /oc tave fi lte r tha t is
ad jus table from 27hz to 20 0hz. Th is filter cust omize s the effe ct of the Bass
control an d make s it pos sible to boost the low end in the wa rmth region without
adding excessive low bass. I t i s also useful to tame excess ive low end from mini mics and w oo fers.
D. Volume control: Unlike gain, whose adju st ment will affec t the cha ra cter and
personal it y of the so und, the volume simply con tr ol s the amo unt of the si gnal
that gets o ut of the box. The Mixpro wil l lik ely be the quiet es t thin g in you r
signal chain. So for the be st s ystem signal to noi se rat io, we reco mm en d that you
run the volu me as hi gh as you can w ithout caus in g th e PA to distort.
E. 1/4 ” outp ut: This is a regu la r un balanced output for a stan da rd mon o cabl e.
You can plug th is into ju st abo ut any thing.
F. Invert : This control chan ges the p olarity of the sign al. When the button is out,
the out put will be in phase w ith the inp ut sig na l. Phase aff ec ts t he way the
guitar top is pres su rized by the spea kers. When the guitar to p and s peaker are in
phase wi th each ot her, low-end feedbac k can oc cur.
G. Battery status LED : The batter y status LED rema in s on at all ti me s when the
unit is plugged in. As the battery weake ns t he lig ht wil l gradua ll y di m. When it
becomes di ff icul t to see, re place th e battery.
H. Bat ter y com par tme nt: To cha nge yo ur bat ter y, rem ove th e two s crews
adjacent to the belt clip using a scre wdriver or a di me. Sl id e th e preamp out of
the hous in g and re place the bat te ry.
A
B
C
D
H
JFE G I
I. Mix control: This cont ro l allows you to blend the two inputs to suit your ta ste
or a pplic ation . As you face t he con trol , full coun te r-clock wise (lef t) will g iv e
100% of w hate ver pick up you hav e placed on the tip. Ful l clock wi se will give you
100% of th e ri ng.
J. Input: Th is inp ut w il l acce pt a 1/4 " stereo cab le. You can also use a sta nd ard
mono cab le if you ju st wan t on e pi ck up o r do not have a stereo ca ble (t here will
not be an y signal on the ring channel). When instal li ng the pickups in th e g uita r,
choose t he primar y pickup -- this is usually t he one that i s mo st sta bl e -- to be on
the tip channel. A standard appli ca ti on would be a pic ku p such as th e Ribbon
Transducer or mag ne ti c pi ck up o n the tip and a mini- mi cropho ne on th e ring.
3 . I N T E R N A L C O N T R O L S
The Mix pro con ta ins all of the e ss ential con tr ol s to c on figure t wo p ic kups to
successful ly blend or complement each o ther. These controls m ay b e acce ssed by
removing the two large screws on the back of the unit , then sliding the pre amp
out.
3.1 Tip Chann el Controls:
A. Gai n c ontro l: Turn the mix co ntrol co mpl etely count er-cl ock wise bef ore
setting th is. Pl ease s ee sect io n 4.4 (sett in g the gain) f or m ore in form ation.
B. N ine volt pha ntom power: T he Mixpro provides ph antom po wer fo r mini -m ics
and devices that may be powered extern al ly, elimin at ing the need for batteries
on the g ui tar.
Caut ion: D o not use phanto m power w ith a ny thing oth er than d evi ce s that
specific al ly require it, such as mini-mic s or the L.R. Baggs Buffer Jack . Application
of phantom power reduces th e input imp ed ance to less than 20K ohms and will
render mo st pass iv e picku ps usel ess. I f your passive pi ck up so unds thin or weak,
check to m ak e su re phantom power is t urned off.
3.2 Ri ng C hann el Controls:
The most common use of the ri ng channel is fo r min i-mi cr op hones. The Mixpro will work wit h and powe r m ost min i- mics that can be conf ig ured
for a two-wire con nection. Many of these mic s have a th ird wire that must be atta ch ed to the ground con nection, through a re si stor, to achieve
two-wire status. We have provide d a char t fo r so me of the more popul ar mic s, which shows the wir ing and resistor value required for optimum
performance -- se e secti on 4.1.
G
A
B
F
D
E
C
C. Gain cont ro l: Tur n th e mix control com pl etely cloc kwise before setting this. It is reco mmende d that the ring cha nnel gai n be set so that the
device at ta ched to this chan ne l has a simila r volum e to that of the tip channel. This will provide a 50/50 mix when th e m ixer is no rmal iz ed at th e
12:00 po si tion . See s ec tion 4.4 ( setting the g ain) for addi ti on al i nfor mation.
D. Nine volt phantom power: The Mix pr o pr ov id es phantom power for min i-mi cs and dev ices that may be pow er ed externally, eliminating the
need for bat te ries on the g uitar.
Caution: Do not use phantom power wi th anyt hi ng other than devices that speci fi cally requ ir e it, such as mini -mics or the L. R. B ag gs Bu ffer Ja ck.
Applicatio n of ph antom power redu ces the input impe da nce to less than 20K ohms and will render mos t passive picku ps useless. If your passive
pickup s ounds thin or weak, ch eck to m ake sure ph an to m power is turn ed off.
E. Low-cut trim: This cont ro l is usef ul for controlling exc es s boominess from mini- mi cs and body -t ype pickups. As a general rule, adju st the low
end of t he mic o r body p icku p, u sing t his control, to
have a sim ilar low end respons e to your primary pickup on the tip chan nel. Adjust the low end respons e of th e ring pick up befo re finalizing the
gain set ti ng, as t he l ow e nd response w il l af fect the loud ne ss o f th e pi ck up.
F. Low- cut ran ge s witch : A wi de ran ge of low- cut adj ustme nt h as bee n provide d. The l ow ran ge sho uld provi de ade quate low fre quenc y
attenuation for m ini- mi cs used in th e standard near-soun dh ole mounting, or body pick ups, wh ich, bein g d eepe r in the body, r eq ui re a deeper low
cut.
Mics p laced deeper in the b ody or boomy bo dy pic kups may require mo re low f re qu ency at te nu ation. For t hese, use the h ig h range.
G. Relati ve phas e swi tch: T hi s control allows you to optimize the blend between your tw o sources. With the mix control at 12 :00 (equal pa rts tip
and ring chann el s), there will oft en be on e rel at ive p ha se settin g tha t sou nd s super io r. The optim um ph as e will usual ly be obvi ou s. If it isn't,
choose t he relative ph ase that prod uc es the s mo othe st blend as you p an from tip c ha nnel t o ring chan ne l.
4 . U S E R ' S G U I D E
4.1 Two Sources: The Mixp ro wi ll mix just about any t wo pickup s together. S ome pickups require a p reamp/ bu ffer on the guitar when mi xed with
cert ai n t yp es of pickups; othe rs can be run passively do wn one cord. The most co mmon us e of the Mixpro is to bl end a piezo undersadd le pickup
with a m ic .
Using a pass ive piezo pi ckup with a m ini- mi c down a stereo c or d will cause cr os stalk (se e section 4.2 for mor e inform at ion about this). The sol ut ion
to this problem is to use an active preamp /b uffe r on t he guitar or to replace the battery -powered pre amp with our pha nt om -powerable Buf fer
Jack.
Many under sa ddle p ic kups h ave some s or t of batter y-powered pr ea mp/buf fe r, which h as an output th at is co mp atible w ith a mi ni-m ic signal.
Many have solder pads to attach a mi c t o the ring channel. Some provid e power for the mic from the bat te ry and ot hers requ ir e pha nt om po we r
for the mic. The M ix pro wi ll wor k wi th eit he r type an d can pr ov id e power for the m ic ( and pi ckup) if ne ce ssary.
The following ch art s ho ws some common co mb inatio ns and r eq uirements:
Pickup
Mic + Ribbon
Transducer
Mic + LB6
Mic + Hex Pickups
Mic + Matrix
Mic + B-Band
Mic + Magnetic Pickup
Contact Pickups +
Ribbon Transducer
* when u se d with 3 ft s tereo cord
** requires St ra pjac k Pl us 4-pin stereo j ack. See en cl osed R TS sup pl ement
*** you may fi nd that an accep ta ble level of cros st alk is achievable wit h a high-outp ut ceramic p iezo pickup
4.2 C rossta lk: Crossta lk is inter ference or "bleed" between two si gn als withi n a common s hield, s uc h as a stereo g uita r cab le. Thi s commo n
problem is of ten encountered whe n a high- im pedance piezo pickup is mixed with a lo w- impe da nc e ac tive source, such as a mini-mic. The bleed
signal from the mic mixes in the cord with the pickup signal and appea rs i n th e pi ck up chann el . Th e hi gh er the amount of ampli fi cation (gain)
required for th e pickup (and long er the cabl e), t he more o f the m ic signal will be p re se nt in t he pi ck up channel. It is comm on to enc ou nt er 25% to
50% mic bl eed in to a cle an p icku p chan ne l.
Of te n the b es t relative ph as e for a p ar ticular pic kup and a mic will require that t he a ctual m ic cha nn el b e out of phase with t he p ha se o f the blee d.
This causes frequenc y resp on se pro bl ems with the mic and leads to a confusi on of the phase relationship between picku p and mic. This cause s
unpredic table fr equency c ancell at io n.
Onboard Buffer Required?*
Yes -- use Buffer Jack or RTS
preamp**
No -- but best with Buffer
Jack***
No
Yes -- use Matrix preamp or
Buffer Jack
Yes -- use B-Band preamp
only
No
No
Worse, it is often im poss ib le to get th e mic ble ed in the pic kup cha nnel low eno ugh to allo w it to be turned up witho ut the mi c starti ng to fe ed
back! Th e only adequately clean way to send a high- im peda nc e piezo pi ck up an d a mic signal side by side down one cord is to have some so rt of
acti ve b uf fer for th e pi ezo on t he guitar i ts elf.
4.3 Buffer Jack : The Buffer Jack prea mp is phantom-powerable by the Mixpro and provid es an input for the mic on the ring and an all -d iscrete
class A preamp/buffer for t he piezo on t he t ip. The Buffer J ac k el im inates crosstal k, pres er ves the inte grit y of both signa ls and g ets th e batt er ies of f
of the g ui tar. It is availab le from L. R. Ba gg s.
4.4 Setti ng the Gai n: G ain is not volu me. Gain is the am ount of am pl ific at io n
that is appl ie d to an input signal to boost it to a u seful level. To accomm od ate a
wide range of pickups, active devices and such, the Mixpro has adj us tabl e gain.
The idea i s to adj us t the gain to f ind a wi ndow b et ween h is s and distortion.
For in st ance, if you are u si ng a low output pa ssive pickup such as th e R ibbo n
Transducer, and you fail to tu rn th e g ai n way up, you wi ll need to tu rn th e PA u p
so high to he ar the picku p that there wi ll be a lot of hi ss. Conve rsel y, if you plug
in a high outpu t active pick up and do not turn the gain way down, ther e wil l be
massive dist or tion. The Mixpro is so quiet that th e gain window is pret ty wide.
But there is a s ma ller sweet sp ot withi n that w in dow.
With ever ythi ng plugged in and tur ned on, play your instr um ent ver y hard. Turn
the gain tri m up (cl oc kwis e) slowl y wh ile pl ayin g un til you be gi n to h ear so me
distor tion , then bac k th e gain off (coun te r- cloc kwise) unt il t he distortion just
disappea rs . This setting will be the richest soun di ng and the most quiet. On ce
you hav e de te rm ined your preferred se tt in g, we re co mm end that you leave the
gain control alone. Do not u se t he gain control as a vol um e co nt ro l. Using it in
this man ne r will v ar y the charact er of yo ur sound as you a dj ust it up and down.
Ground
Hot
Hot
3rd wire
Ground
Pickup
Mic
Loading...