Voodoo Lab Amp Selector User manual

DIGITAL MUSIC CORPORATION
AMP SELECTOR
User’s Manual

Please visit our web site at:
www.voodoolab.com
Copyright ©2003-2004 by Digital Music Corporation.
This publication is protected by copyright and all rights are reserved.
No part of it may be reproduced or transmitted by any means or in any form
without the express prior consent in writing from Digital Music Corporation.
Voodoo Lab is a trademark of Digital Music Corp.

VOODOO LAB AMP SELECTOR
User’s Manual
Introduction
The Voodoo Lab Amp Selector is the ultimate stand-alone tool for
switching your guitar into multiple amplifiers. It lets you use up to
four amps simultaneously without added hum or loss of tone. You
can switch between them or layer them in any combination. The
switching is absolutely silent with no clicks or pops. If you play
multiple amplifiers, this is what you’ve been waiting for!
The Amp Selector’s unique programmable switching lets you
tailor its operation to your own playing style. On/off mode allows
you to operate it as four independent on/off controls. Or exclusive
mode means that whichever button you select, only that amplifier is
active. This permits you to change amps with only a single button
press, no need to first turn one off and then another on. You can
even use both modes simultaneously to provide one touch control
yet still select an additional amp for layering!
Level controls for each output provide a convenient way to balance
the volume between amps. There is also second input which if used
will split the Amp Selector into two separate A/B/Both functions.
This is great for applications using two guitars (electric and acous-
tic, for example) or a stereo signal path. And we included a tuner
out‚ which gives you an additional output without loading down
your guitar’s tone. Of course you can use this output to run a tuner,
but it can also drive a direct signal to a console or even chain addi-
tional Amp Selectors if you need more than four amps.
Voodoo Lab provides tone tools for the serious artist and profession-
al player. Your Amp Selector is hand made using the finest possible
components and engineered to be rugged, reliable and provide the
best possible tone. Enjoy it!

Overview
1. Power: Use 9VDC regulated power supply, center negative.
2. Inputs: Connect from guitar or pedalboard out.
3. Tuner Out: Driven from Input-A for tuner or other slave.
4. Ground Lift Switches: Normally ON to ground amplifier.
5. Amp Outputs: Connect to amplifier inputs.
Note: Plugging into Input-A powers up the Amp Selector. Unplug
this cable when not in use to preserve the battery.
6. Level Controls: Control output volume to balance amps.
7. Amp Select Buttons: Turn individual amps on/off.
8. Status LEDs: Illuminates to show active amp.
The Voodoo Lab Amp Selector’s inputs drive a pair of ultra trans-
parent buffer amplifiers. These amplifiers input characteristics
have been carefully matched to that of a traditional vacuum tube
AMPSINPUTS
1 4
POWER
GROUND
LIFT
TUNER/THRU
9VDC 41
32
B
AHand made in U.S.A.
+
-
V
OODOO LAB AM P SELECTOR
234
1
VOLUME VOLUME VOLUME VOLUME
AA/B
23
145
7
6
8
AMPSINPUTS
1 4
POWER
GROUND
LIFT
TUNER/THRU
9VDC 41
32
B
AHand made in U.S.A.
+
-
V
OODOO LAB AM P SELECTOR
234
1
VOLUME VOLUME VOLUME VOLUME
AA/B
23
145
7
6
8

guitar amp. This insures that your guitar pickups will see the correct
load and therefore sound their best. Using a buffer amplifier is
what allows us to drive multiple amplifiers and a tuner without
excessively loading your guitar and destroying your tone.
Each amplifier output is coupled using a high quality shielded and
sealed transformer. Isolating each output with a transformer is what
breaks the ground paths between amplifiers. Without this, current
would flow through ground loops causing your amps to hum. In
addition, we have developed a proprietary matching technique to
drive the transformers. By carefully matching impedances and
component values we are able to greatly improve the performance
of the transformer. The result is a true, super accurate sound without
any loss of tight low-end response.
The Tuner output provides a copy of whatever goes into Input-A.
This is a non-isolated slave output for a variety of purposes. It is
always active regardless of amp switching status. Typical uses would
be to drive a tuner, direct out for recording, or to chain additional
Amp Selectors.
Individual level controls allow you to conveniently balance volumes
of each amp. Normal position is about 3 o’clock. At maximum they
will provide a very small amount of boost. Any significant volume
changes should be done with the level controls on your amp itself.
In normal operation, the amp select buttons simply toggle each amp
output on and off. Check out the Operation section of this manual
for programmable switching options.

Connections
Connect the output of your guitar into Input-A of the Amp
Selector. If you are using pedal effects in front of the amplifier,
then connect from the output of your last pedal into Input-A of the
Amp Selector.
Connect Amp Outs 1, 2, 3 and 4 to the inputs of each of your
amplifiers.
Initially, set each of the Amp Selector’s Ground Lift switches to the
ON‚ position.
If you are going to use two guitars (or the other channel of stereo
effects) simultaneously with different amps, you can connect the
2nd guitar into Amp Selector Input-B. If you do this, the Input-A
instrument will only access amps 1 and 2, and the Input-B instru-
ment will only access amps 3 and 4.
Power
The Amp Selector can be powered either by its internal 9V battery
or an external power source. The battery compartment is on the
bottom of the unit. Use a Phillips head screwdriver to remove the
single screw holding the battery cover in place.
The external power jack requires a regulated 9VDC power source.
The connector polarity must be center negative. The best choice to
power your Amp Selector would be with a Voodoo Lab Pedal
Power. It will also work fine with other 9VDC regulated adapters
such as the Boss PSA.
Powering the Amp Selector on and off is done via the input jack,
just like most pedal effects. Insert a cable into Input-A to power
on. Remove it to turn the power off. If you are powering the Amp
Selector with a battery, always remember to disconnect the Input-A
cable to preserve battery life.

Operation
On/off and Exclusive Mode
The default switching method of the Amp Selector is what we call
on/off mode. In on/off mode, each of the four buttons 1 through 4
simply toggle the corresponding amp output on and off.
Using on/off mode is a good choice if you want maximum flexibili-
ty to switch or layer amps. However, if you only need to select one
amp at a time, you can choose exclusive mode. In this mode, each
button exclusively selects the corresponding amp. This means that
when you select a new amp, you don’t need to turn the old one off.
Program
To enter the Amp Selector’s programming mode, do the following:
1. Power off the unit by unplugging the cable in Input-A.
2. Press and hold button 1 while powering on by inserting the
cable into Input-A.
3. All LEDs will flash to indicate you’re now in programming
mode.
Now you can select on/off or exclusive mode independently for each
output. Pressing each button will toggle the mode:
LED Off = On/off mode
LED On = Exclusive mode
To exit programming mode and return to normal operation, simply
power the Amp Selector off by removing the cable in Input-A.

Combining Modes
You may have already noticed that you can set on/off or exclusive
mode individually for each output. This allows you to group some
outputs together in exclusive mode and still have direct access to
layer those set for on/off mode.
Example: Let’s say you want to use amps 1, 2 and 3 one at a time
(exclusively). And you also have a 4th amp that you want to use for
layering. To do this, enter the Amp Selector’s programming mode.
Set 1, 2 and 3 into exclusive mode by pressing the buttons so that
their LEDs are on. Set 4 into on/off mode, its LED will be off.
Exit programming mode. That’s it!
Ground Problems
You should always start with all of the Amp Selector’s Grounds
Lift switches in the ON position. This means the output is grounded.
If the amp is humming, the first place to look is if there is a two or
three position ground switch on the amplifier itself. Try each posi-
tion of the amp’s ground switch to find the least hum. If the amp
continues to hum, then try switching the Amp Selector Ground Lift
to the OFF position. This now isolates that output. Then try each
position on the amp’s ground switch again to find the least hum.
If you are still having problems, make sure that all amplifiers are
powered from the same power source. Outlets in different parts of
a room can have significantly different ground potentials making it
more difficult to find settings that are hum free.
Since ground connections in a multi-amp setup can get complicated,
you may need to experiment a bit with different combinations of
settings to find one which keeps all the amps from humming.

Warranty
Digital Music Corporation warrants this product against any defects
that are due to faulty material or workmanship for a period of five
years from the date of original retail purchase. This warranty does
not include damage to the product resulting from accident or mis-
use. This warranty is given to the original purchaser only and it is
not assignable to any other person.
If the product should become defective within the warranty period,
Digital Music will repair it or replace it free of charge, provided it
is returned freight prepaid to Digital Music with a valid RMA
(return material authorization) number. Return shipping will be
paid by Digital Music within the U.S. only.
This warranty shall not apply to any goods that have been repaired
or altered by anyone other than the manufacturer. There are no
warranties which extend beyond the terms described herein.
Should you experience any difficulty with this Digital Music
product, contact us as described below. If it is determined that the
product must be returned to the factory for repair, you will be
issued an RMA and given shipping and packaging instructions.
How to Reach Us
All Voodoo Lab products are manufactured by Digital Music. You
can reach us by any of the following:
Tel: [phone]
Fax: [phone]
Mail: Digital Music/Voodoo Lab
1320A Industrial Avenue, Petaluma, CA 94952
Email: [e-mail]
Website: www.voodoolab.com