Lehle Little Dual II Operating Instructions Manual

OPERATING INSTRUCTIONS
LEHLE LITTLE DUAL II

Dear Musician!
Thank you for purchasing your LEHLE
LITTLE DUAL II!
I have been building units that switch,
split and route signals with no technical
compromises and with maximum musical
fidelity since 1999. Your new LEHLE
LITTLE DUAL II comprises only the very
best components.
Every assembly of your LEHLE LITTLE
DUAL II has been made and tested in
Germany.
Your LEHLE LITTLE DUAL II is of extremely
robust design and construction, to make
sure that you get absolutely years and
years of enjoyment from it. If you should
nonetheless have a problem, or simply a
question, just mail me or a member of the
Lehle team at: [e-mail]
I wish you the very greatest pleasure and
success using your LEHLE LITTLE DUAL II!

LEHLE GmbH · Germany · w ww.le hle.com · suppor t@le hle.com

CONTENT

Introduction

4

Technical data

6

General description

7

Selecting the operating mode

12

Selecting the foot switch mode

13

Restoring factory setting

14

Typical uses of the LEHLE LITTLE DUAL II as
amp-switcher

15

amp-switcher for stereo eects and 2 amplifiers

16

amp-switcher in a wet/dry system

18

amp-switcher for one instrument with piezo and magnetic pickup to two amps

20

amp-switcher for one instrument with piezo and magnetic pickup to one amp

21

and a mixer
tuner mute box

23

LEHLE LITTLE DUAL II signal flow diagram

24

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INTRODUCTION

The LEHLE LITTLE DUAL II is the successor
to the Lehle Little Dual and is a maximum
signal-fidelity amp switcher for two amps.
By using the soft-touch switches you can
switch between two connected amplifiers
hum-free and without sound loss.
Two dierent operating modes are ready
for you. You decide if you want to activate
or deactivate every output individually or
if you want to switch between the amps
and activate the remaining one.
The LEHLE-Switches work with a micro­controller and an intelligent True-Bypass­Relay-Circuit with active pop noise sup­pression circuit. Thereby they switch the
LEHLE LITTLE DUAL II even faster than
mechanical switches and in addition to
that wear- and noise-free.
The easy-action mushroom-shaped but­tons characteristic of LEHLE products are
mounted in the cover, so that your foot
pressure is transmitted indirectly only, via
a spring. Thus the electronics board is not
exposed to mechanical loads, making the
LEHLE LITTLE DUAL II virtually indestruct­ible and guaranteeing years of trouble­free switching.
High-intensity LEDs make it easy to read
o switching state A or B, or both, even
under high-power spots.

The centrepiece of the LEHLE LITTLE
DUAL II is its high-end LEHLE TRANS­FORMER HZ, which galvanically isolates
output A from output B, making history
of hum loops - permanently! The LEHLE
LITTLE DUAL II features a gold-plated
contact phase inverter and a gold-plated
contact ground switch. The two inputs
can also be routed in stereo to outputs
A and B, if you use the stereo signal of
an eects unit as the input, for example.
This also makes it possible to route in­struments equipped with two pickups, in­cluding many acoustic and hybrid guitars,
and also double basses, via two amplifier
systems - with no complications.
Additionally the LEHLE LITTLE DUAL II is
equipped with a TRS switch. Therewith it
is possible to send in above-mentioned
stereo- or dual-mono signals via a TRS
jack or “stereo-jack”.
These signals can be operated either in
alternation or in parallel - without hum,
and without sound losses, needless to
say.
The LEHLE LITTLE DUAL II - small, but so
utterly eective!
We take care of your signal so that you
can take care of the music.

LEHLE GmbH · Germany · w ww.le hle.com · suppor t@le hle.com

4

TECHNICAL DATA

Weight 540 g

Length

Width

Overall height

Supply voltage

Current consumption

Max Level

Total harmonic distortion

Frequency range

Input impedance

(transformer load impedance)

3.9“

4.8“

1.85“

9-15 V DC

63 mA

+20 dBu (THD < 1%, 50 Hz - 20 kHz)

0.003 % (0 dBu, 1 kHz)

20 Hz – 100 kHz -0.1/ +0.4 dB

(source 600 , load 1 M)

min. 2 M at 2 kHz

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5

GENERAL DESCRIPTION

2

345678

1

9

A

10

LITTLE DUAL

MADE IN GERMANY

11

1. TRS SWITCH

TRS

Press this switch to distribute a stereo- or
dual-mono-signal, provided by a TRS
jack, to both outputs A and B.

If you have a mono-signal (TS jack), or
a stereo-signal via two TS jacks, use the
A/B input or input A/B and A respectively.
However some instruments oer a TRS
output, where e.g. the separated signals
of a magnetic pickup and piezo pickup
are supplied or e.g. separated signals of

B

B

TRS

ABAA

the neck- and bridge-pickup.
Now you can insert these signals via a
TRS-TRS cable into the LEHLE LITTLE
DUAL II, by pressing the TRS switch, so
the signal is distributed to both outputs
A and B.

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6

2. A/B-INPUT SOCKET

AB

Connect your instrument or the output
from an eects unit or DAW here.

5. PHASE SWITCH
Here you can invert the phase of output
A if necessary.

The mono input signal is fed into this
socket; should the input socket A (3) be
used as well this signal will be routed to
output B only.
If the TRS switch (1) is pressed, a stereo­or dual-mono-signal can be distributed
to both outputs.

3. A-INPUT SOCKET

A

Connect the second pickup of your instru­ment or the second stereo output from an
eects unit or DAW here.

The signal from this input socket is routed
to output A only. Stereo signals such as
the signals from stereo eects pedals or
dual-mono signal from dierent pickups
can be switched individually to the out­puts A and B, which could be 2 separate
amplifiers or PA channels.

4. B-OUTPUT

B

Connect your amplifier or the input of a
mixing desk here.

The signal is routed to output B directly
via a microcontrolled relay-switching-cir­cuit with no semiconductors. The LEHLE
LITTLE DUAL II, and therefore the instru­ment connected, is grounded via this
socket. This output should therefore al­ways be occupied.

This switch can be used to invert the phase
of the input signal from the A output sock­et by 180°. Splitting signals to two amps
may sometimes cause phase cancella­tions, resulting, for most musicians, in a
“thin” sound. Inverting the phase elimi­nates this problem. Experiment to find
out which position you prefer - as always,
your individual taste is what counts.

6. A-OUTPUT

A

Connect your amplifier or the input of a
mixing desk here.

Output A is galvanically isolated from
output B by the LEHLE TRANSFORMER
HZ - so hum loops are impossible, even if
A and B are switched on simultaneously.
A balanced or an unbalanced signal is
possible, irrespective of the type of signal
fed from the input, this way you can con­nect any guitar or bass amp as well as
balanced inputs on a mixing console.
If both input jacks A/B (2) and A (3) are
occupied, but not output jack A (6), a
passively summed signal will be sent out
of output B (4). This way you can easily
sum down a stereo signal to mono, in
case you don‘t have enough space for
your second amp or it‘s simply too loud.
Please keep in mind that the stereo signal
has to be sent out of one device. If the

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