Lehle P-SPLIT III User manual

OPERATING INSTRUCTIONS
P-SPLIT III

LEHLE GmbH · Germany · www.lehle.com · [e-mail]
Dear Musician!
Thank you for purchasing your LEHLE P-
SPLIT III!
I have been building units that switch,
split and route signals with no technical
compromises and with maximum musi-
cal fidelity since 1999. Your new LEHLE
P-SPLIT III comprises only the very best
components.
Every assembly of your LEHLE P-SPLIT III
has been made and tested in Germany.
Your LEHLE P-SPLIT III is of extremely ro-
bust 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 P-SPLIT III!

LEHLE GmbH · Germany · www.lehle.com · [e-mail]
CONTENT
Introduction
Technical data
Unbalanced signal routing
Balanced signal routing
Preconditions for passive splitting
General description
Typical uses of the LEHLE P-SPLIT III as
splitter for two amps
compact passive DI box
line isolator – the universal cure for hum loops
recording splitter
reamplification box
balanced/unbalanced signal converter
passive summing box for stereo signals
LEHLE P-SPLIT III signal flow diagram
4
6
6
7
8
10
13
14
15
16
18
19
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LEHLE GmbH · Germany · www.lehle.com · [e-mail]
The LEHLE P-SPLIT III combines passive
splitting with the highest possible signal
fidelity.
Its applications range from splitting sig-
nals and eliminating hum, to balancing
and re-amping along with any signal
routing that requires a clean signal free
from noise.
At its core is the high-end LEHLE TRANS-
FORMER HZ, which galvanically isolates
the two outputs, eliminating any possibil-
ity of ground loops. The LEHLE TRANS-
FORMER HZ was specially designed for
use with high-impedance signals but also
splits low-impedance signals with un-
compromising sound quality. The signal
can be picked o either symmetrically or
asymmetrically from the ISO output.
By using the phase inverter switch with
gold-plated contacts you can flip the sig-
nal phase at the ISO output, preventing
phase cancellation from impairing signal
reproduction.
The classic application for the LEHLE P-
SPLIT III is splitting an input signal to two
outputs, enabling you to connect an in-
strument to two devices, which may, for
example, be two amplifiers, or an amp
and a mixer/recording unit (PC/DAW).
Thanks to its ability to pick o the bal-
anced signal on the ISO output, the LEH-
LE P-SPLIT III is also eminently suitable for
use as a high-quality compact DI box for
all types of signal.
Another useful application for the LEHLE
P-SPLIT III is as a hum suppressor. Fre-
quently background noise, caused by
ground loops occurs when two electronic
devices are connected to each other. The
LEHLE P-SPLIT III provides a simple, but
extremely eective remedy when installed
between the two units. Using the ISO out-
put, the devices are galvanically isolated
and background noise becomes a thing
of the past.
You can even use the versatile LEHLE P-
SPLIT III as a passive mono summing unit
for a stereo signal by using the DIR output
as second input.
And just in case you are looking for a
power connection: the LEHLE P-SPLIT
III performs all its functions without any
need for a power supply.
INTRODUCTION

5
LEHLE GmbH · Germany · www.lehle.com · [e-mail]
TECHNICAL DATA
Weight 375 g
3.55“
3.6“
1.45“
+20 dBu (THD < 1%, 50 Hz - 20 kHz)
0.003 % (0 dBu, 1 kHz)
min. 2 MΩ at 2 kHz
20 Hz – 100 kHz -0.1/ +0.4 dB
(source 600 Ω, load 1 MΩ)
Length
Width
Overall height
Max Level
Total harmonic distortion
Frequency range
Input impedance
(transformer load impedance)

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LEHLE GmbH · Germany · www.lehle.com · [e-mail]
UNBALANCED SIGNAL ROUTING
Unbalanced signal lines predominate
when instruments such as guitars, basses
and keyboards are used.
These signal lines have two conducting
cores.
The signal itself is present on the signal
conductor and is connected to the tip of
the jack plug.
The second core, which is connected to
the sleeve of the jack plug, screens the
signal conductor and constitutes the sig-
nal ground.
UNBALANCED SIGNAL ROUTING
Tip
Signal in phase
Sleeve
Ground
JACK JACK
Cable
Sleeve Sleeve
Ground
Tip Tip
Signal in phase

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LEHLE GmbH · Germany · www.lehle.com · [e-mail]
BALANCED SIGNAL ROUTING
Balanced signal lines are used to cross
larger distances without interference.
They are generally fitted with XLR connec-
tors or TRS (Tip Ring Sleeve) jack plugs.
Here, three cores are required:
there are two signal conductors. In a bal-
anced signal line, the signal is present in
phase at the tip, as in the case of an un-
balanced signal line (XLR Pin 2).
The second signal conductor carries the
same signal, but with the opposite polar-
ity or mirror-image phase (Ring, XLR Pin
3).
The third conductor is the screening,
and again constitutes the signal ground
(Sleeve, XLR Pin 1).
BALANCED SIGNAL ROUTING
JACK XLR
Cable
Sleeve Pin 1
Ground
Ring Pin 3
Signal in mirrored phase
Tip Pin 2
Signal in phase

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LEHLE GmbH · Germany · www.lehle.com · [e-mail]
PRECONDITIONS FOR PASSIVE SPLITTING:
The LEHLE P-SPLIT III is a passive splitter
which can be used to split high-imped-
ance signals to high-impedance inputs.
There are certain preconditions which
must be met to ensure that this is accom-
plished without problems and no loss of
sound.
HIGH-IMPEDANCE SIGNAL SOURCES
AND INPUTS
Passive magnetic pickups as generally
used - in the form of single-coil and hum-
bucker pickups, on electric guitars and
basses - supply high-impedance signals.
High-impedance signals have an output
impedance in a range of 10 kΩ (10,000
Ω); the higher this figure, the more sensi-
tive the signal is to interference.
High-impedance inputs are found on
guitar and bass amplifiers, and on sound
cards with a “Hi-Z” input; “Z” stands for
the impedance, which is the physical ex-
pression for the internal resistance of a
signal source or a signal input, and thus
defines its low/high-impedance perfor-
mance.
High-impedance signals are generally
transmitted unbalanced and are relative-
ly susceptible to interference. Long cable
routings audibly attenuate high frequen-
cies. Electromagnetic interference from
the environment then becomes more no-
ticeable than in the case of low-imped-
ance and balanced signals. There are,
nonetheless, very many musicians who
swear by the sound of an electric guitar
or bass with passive pickups connected
directly to a tube amplifier via a good
cable.
The input impedance of high-impedance
inputs is generally 1 MΩ (1,000,000 Ω)
or more. Here, too, the input becomes
more sensitive, the higher this figure is.
LOW-IMPEDANCE SIGNAL SOURCES
AND INPUTS
Keyboards, active pickups, preamp out-
puts, sound cards and mixers supply low-
impedance signals. The output imped-
ance of such signals is typically 100 Ω to
around 600 Ω.
Low-impedance inputs predominate in
the line input of mixing desks, power
amps and sound cards with no Hi-Z in-
puts, and also in microphone inputs and
in virtually all balanced inputs. Low-im-

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LEHLE GmbH · Germany · www.lehle.com · [e-mail]
pedance inputs have input impedances
of around 600 Ω to 10 kΩ.
WHAT IS POSSIBLE
The LEHLE P-SPLIT III can be used to split
the signal from an electric guitar or elec-
tric bass with passive magnetic pickups to
two amplifiers, each of which has high-
impedance inputs. Please use the short-
est, best-quality possible cables for this
purpose. You will hear the 100% original
signal on both amps.
Instead of an amplifier, you can also split
the signal to the Hi-Z input of a sound
card.
It’s important to remember: a high-im-
pedance signal can be passively split if
you connect only high-impedance inputs.
You can split a low-impedance signal,
such as the output from a preamp, e.g.
the LEHLE SUNDAY DRIVER II or the out-
put from a sound card, to a tube amp
with a high-impedance input and the low-
impedance input of a power amp. Since
the signal to be split is a low-impedance
one, you can connect low-impedance
and high-impedance inputs behind this if
you wish - there won’t be any problems!
WHAT IS NOT POSSIBLE
Audible sound losses will occur if you use
long cable routings from the passive gui-
tar to the splitter and from the splitter to
the amps. The sum of all cable lengths to
the splitter and to the amps should gener-
ally not be more than 10m.
Your individual taste will ultimately de-
cide, however.
Splitting your high-impedance instrument
signal to a low-impedance input, such as
the line input of a mixing desk, for exam-
ple, and to a high-impedance input on
a tube amplifier using the LEHLE P-SPLIT
III will result in the high-impedance input
being attenuated by the low-impedance
input of the mixing desk. The signal will
become significantly quieter and will lose
presence.
Solution: these problems can be eec-
tively eliminated by connecting a preamp
or a buer, which will convert the high-
impedance to a low-impedance signal, in
the signal path.
The LEHLE SUNDAY DRIVER II, for exam-
ple, can be used here.
INPUT
INPUT
DIR
DIR
Hi-Z
Hi-Z
Low-Z
Hi-Z
Low-Z
Hi-Z
Hi-Z
Hi-Z
Hi-Z
Hi-Z
Low-Z
Hi-Z
Low-Z
Hi-Z
Low-Z
Low-Z
Hi-Z
Hi-Z
Low-Z
Low-Z
Low-Z
Low-Z
Low-Z
Low-Z
ISO
ISO
!
!
!

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LEHLE GmbH · Germany · www.lehle.com · [e-mail]
GENERAL DESCRIPTION
DIR
ISO
MADE IN GERMANY
P-SPLIT
1. INPUT SOCKET
Connect your instrument or the output
from an eects unit or DAW here.
The input signal is fed into this socket.
The LEHLE P-SPLIT III operates entirely
passively.
The input signal remains connected to the
ISO and DIR outputs at all times, with no
semiconductors or any other active com-
ponents in the signal path.
Both balanced and unbalanced signals
can be split, since the LEHLE TRANS-
FORMER HZ is capable of handling both
types.
2. OUTPUT SOCKET
Connect the input of an amplifier or ef-
fects unit to be connected directly to the
LEHLE P-SPLIT III input here.
The input signal and its ground are pre-
sent directly on the DIR socket. The signal
1
2345
6
DIR

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LEHLE GmbH · Germany · www.lehle.com · [e-mail]
from the DIR output is always the same
which is fed into the input (1).
If the input signal is unbalanced you will
have an unbalanced direct signal at this
socket. The same will occur with bal-
anced signals.
3. PHASE INVERTER SWITCH
The phase of the input signal from the
ISO output can be inverted if necessary.
This switch can be used to invert the
phase of the input signal from the ISO
output socket by 180°.
Splitting signals to two amps may some-
times cause phase cancellations, result-
ing, for most musicians, in a “thin” sound.
Inverting the phase eliminates this prob-
lem.
Experiment to find out which position you
prefer - as always, your individual taste is
what counts!
4. GROUND LIFT SWITCH
Connect the grounds of the DIR and ISO
output if necessary.
Pressing this switch connects the ground
conductors of the ISO and DIR outputs.
Connecting the ground conductors of the
DIR and ISO outputs can help in some
situations, depending on the units con-
nected and on their power supplies.
Use the ground lift switch to find out for
yourself the position in which noise is
minimised.
5. ISO OUTPUT
Connect your amp or the audio input of a
DAW or a mixer here.
The ISO output has an input signal which
is isolated by means of the LEHLE TRANS-
FORMER HZ.
A balanced or an unbalanced signal is
possible, irrespective of the type of signal
fed from the input.
6. BASE AND FIXING
If required, mount the P-SPLIT III to a
pedalboard using the mounting kit.
The P-SPLIT III can be mounted to a plate
such as a pedalboard using the two holes
in the bottom of the pedal.
You can find the optional LEHLE Mount-
ing Kit V3 (order number 100981) online
at www.lehle-components.com.
To mount, undo the four housing screws
by using a 2.5 mm Allen Key and detach
the cover.
Then fix the device base to a base plate
using the two screws, the washers and the
spacers of the Mounting Kit.
Attach the cover and tighten the four
housing screws - done!
ISO

12
LEHLE GmbH · Germany · www.lehle.com · [e-mail]
For flexible solutions we recommend us-
ing 3M Dual Lock™ instead of Velcro for
stability, which you can also find in handy
sizes at www.lehle-components.com !
If you are using the Velcro / Dual Lock™
method, please make a note of the serial
number on the bottom of the pedal be-
fore you cover it, in case you have a sup-
port question for us later and don‘t fancy
dismantling your board!

13
LEHLE GmbH · Germany · www.lehle.com · [e-mail]
TYPICAL USES
LEHLE P-SPLIT III AS A SPLITTER FOR TWO AMPS
The LEHLE P-SPLIT III operates as a split-
ter for one instrument to two amps. Use
the shortest cables possible to connect
instruments with passive pickups to the
input of the LEHLE P-SPLIT III.
Most musicians find the sound of two am-
plifiers working in parallel extremely pow-
erful and simply big.
HOW TO DO THIS
1. Connect your instrument to the input
socket of the LEHLE P-SPLIT III.
2. Connect the first amplifier to the DIR
socket (2).
3. Connect the ISO socket (5) to the input
of the second amp.
4. Use the phase inverter switch (3) to de-
termine which setting you prefer.
5. Use the ground lift switch (4) to find the
position at which noise is minimised.
6. There you go!
DEVICE CONNECTION
DIR
ISO
MADE IN GERMANY
P-SPLIT
Input
Output
Instrument
Amplifier 1
Output Amplifier 2
ISO
DIR

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LEHLE GmbH · Germany · www.lehle.com · [e-mail]
LEHLE P-SPLIT III AS A COMPACT PASSIVE DI BOX
The LEHLE P-SPLIT III can be used as a
passive DI box.
Balanced or unbalanced signals from the
ISO output can be fed.
A TRS/XLR adapter will be needed if you
want a balanced signal for an XLR input
(please also see “Balanced signal rout-
ing” on page 7).
HOW TO DO THIS
1. Connect your active instrument or the
output from a preamp or buer to the in-
put (1) of the LEHLE P-SPLIT III.
2. Connect your amp to the DIR output
socket (2).
3. Connect the ISO socket (5) to the input
of your mixer or stage box.
4. Use the phase switch (3) to find out
which setting sounds better to you.
5. Use the ground lift switch (4) to deter-
mine which position eliminates the most
background noise.
6. There you go!
DEVICE CONNECTION
DIR
ISO
MADE IN GERMANY
P-SPLIT
Input
Output
Instrument (active)
Amplifier
Output Input mixer,
stage box
ISO
DIR
The signal from a passive pickup can-
not be split to an amp and mixer without
negative eects on your sound, since bal-
anced inputs are usually low impedance.
The LEHLE P-SPLIT III functions excellently
as a neutral splitter and as a high-quality
DI box with instruments which have ac-
tive pickups, and/or when another buer,
such as the LEHLE SUNDAY DRIVER II is
positioned between the instrument and
the input of the LEHLE P-SPLIT III.
!

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LEHLE GmbH · Germany · www.lehle.com · [e-mail]
LEHLE P-SPLIT III AS A LINE ISOLATOR – THE UNIVERSAL CURE FOR
HUM LOOPS
The LEHLE P-SPLIT III can be used in any
scenario to eliminate noise resulting from
ground loops or hum. Ground loops oc-
cur when units grounded by a protective
earth conductor (“PE conductor”) are
connected to each other.
The protective earth conductor and the
ground connection of the audio signal
create a loop which will pick up external
interference generated, for example, by
coils. Such interference will impair the
signal. The LEHLE TRANSFORMER HZ
included in the LEHLE P-SPLIT III galvani-
cally isolates the ground connection. The
hum loop is thus broken at this point.
Both high- and low-impedance signals
can be fed, the LEHLE P-SPLIT III has no
problems with balanced or unbalanced
signals.
HOW TO DO THIS
1. Connect the signal source to the input
(1) of the LEHLE P-SPLIT III.
2. Do not use the DIR socket (2).
3. Connect the ISO socket (5) to the sig-
nal input.
4. Use the ground lift switch (4) to deter-
mine which position eliminates the most
background noise.
5. There you go!
DEVICE CONNECTION
DIR
ISO
MADE IN GERMANY
P-SPLIT
Input Signal source
Output Signal input
ISO
In the above scenario, the LEHLE P-SPLIT
III is grounded via the signal source in-
put. In some cases, it may be a good idea
to connect the ground to the other side,
in order to eliminate even more interfer-
ence. To do this, simply swap the input (1)
and the ISO output (5).
!

16
LEHLE GmbH · Germany · www.lehle.com · [e-mail]
LEHLE P-SPLIT III AS A RECORDING SPLITTER
It can be very useful, when recording gui-
tar or bass, to record not only the ampli-
fied signal, but also the dry (unprocessed)
signal. This signal can then be routed in
the mix either to a real amplifier, or to a
digital emulator, for editing.
It’s also helpful to be able to hear your
accustomed sound from an amp while
recording the dry signal.
In this configuration, the LEHLE P-SPLIT III
again functions as a neutral splitter.
HOW TO DO THIS
1. Connect your instrument to the input
(1) of the LEHLE P-SPLIT III.
2. Connect your amp to the DIR output
socket (2).
3. Connect the ISO socket (5) to the Hi-Z
input of a sound card or DAW.
4. Use the ground lift switch (4) to deter-
mine which position eliminates the most
background noise.
5. There you go!
DEVICE CONNECTION
Input
Output
Instrument (active)
Amplifier
Output Sound card (Hi-Z)
ISO
DIR
DIR
ISO
MADE IN GERMANY
P-SPLIT

17
LEHLE GmbH · Germany · www.lehle.com · [e-mail]
We recommend the use of a buer be-
tween the instrument and the input of
the LEHLE P-SPLIT III to convert the high-
impedance instrument signal to a low-
impedance signal in cases in which your
sound card or DAW has no high-imped-
ance input (Hi-Z) and you wish to record
the dry signal from your passive pickups.
The LEHLE SUNDAY DRIVER II is the per-
fect solution for this task.
DIR
ISO
MADE IN GERMANY
P-SPLIT
MADE IN GERMANY
SUNDAY DRIVER
SD
/
DI
You can, of course, also use a balanced
input on your sound card or DAW to
record the dry signal. In this case, it’s a
good idea to take a balanced signal from
the ISO output of the LEHLE P-SPLIT III
(please also see “Balanced signal rout-
ing”, page 7).
DEVICE CONNECTION
LEHLE P-SPLIT III
DEVICE CONNECTION
LEHLE SUNDAY DRIVER II
Input
Output
Input
Output LEHLE
SUNDAY DRIVER II
Amplifier
Instrument (passive)
Output
Output
Sound card Low-Z
Input
LEHLE P-SPLIT III
ISO
DIR

18
LEHLE GmbH · Germany · www.lehle.com · [e-mail]
LEHLE P-SPLIT III AS A REAMPLIFICATION BOX
Once you’ve recorded the dry signal, it
can be fed through an amplifier during
mixing; connecting the amp to the sound
card or DAW will almost certainly gener-
ate a ground loop, causing undesirable
noise.
This problem can be eectively eliminat-
ed using the LEHLE P-SPLIT III. The built-
in LEHLE TRANSFORMER HZ galvanical-
ly isolates the ground connections, and
functions perfectly with both balanced
and unbalanced signals from a sound
card or a DAW.
HOW TO DO THIS
1. Connect your sound card or DAW to
the input socket (1) of the LEHLE P-SPLIT
III.
2. Do not use the DIR socket (2).
3. Connect the ISO socket (5) to the input
of your amp.
4. Use the ground lift switch (4) to deter-
mine which position eliminates the most
background noise.
5. There you go!
DEVICE CONNECTION
Input Signal source
(un)balanced
Output Signal input
(un)balanced
ISO
DIR
ISO
MADE IN GERMANY
P-SPLIT
In this case, the LEHLE P-SPLIT III is
grounded via the output of the sound
card or DAW. It may, in some cases, be
a good idea to connect the ground to
the other side, to eliminate interference
noise. To do this, simply swap the input
(1) and the ISO output (5).
!

19
LEHLE GmbH · Germany · www.lehle.com · [e-mail]
LEHLE P-SPLIT III AS A BALANCED/UNBALANCED SIGNAL CONVERTER
Some units feature only balanced inputs
and outputs, whereas others have only
unbalanced inputs and outputs. A LEHLE
P-SPLIT III can be used to connect these,
also enabling you to separate the ground
connection (see “Types of signal routing”,
pages 6 & 7).
HOW TO DO THIS
1. Connect the balanced or unbalanced
signal source to the input socket (1) of the
Lehle P-Split III.
2. Do not use the DIR socket (2).
3. Connect the balanced or unbalanced
signal input to the ISO socket (5).
4. Use the ground lift switch (4) to deter-
mine the position in which the most back-
ground noise is eliminated.
5. There you go!
DEVICE CONNECTION
Input Signal source
(un)balanced
Output Signal input
(un)balanced
ISO
DIR
ISO
MADE IN GERMANY
P-SPLIT

20
LEHLE GmbH · Germany · www.lehle.com · [e-mail]
Unbalanced setups often include long
cable runs from a pedalboard to an amp
which, on large stages, can be some dis-
tance away.
Recording in a mixing room via an amp
located in a separate soundproof booth
will also necessitate long cable runs.
Long distances like these should be
bridged using balanced lines, in order to
keep interference as low as possible.
The solution is simple: use the LEHLE
SUNDAY DRIVER II to convert the unbal-
anced instrument signal to a balanced
signal.
Up to 100m of cable can be connected
to the TRS output socket. The LEHLE P-
SPLIT III can be used at the end of the line
to convert the balanced signal back to an
unbalanced signal for input to your amp.
This system makes it possible to convey
the signal across great distances without
signal losses.
DIR
ISO
MADE IN GERMANY
P-SPLIT
MADE IN GERMANY
SUNDAY DRIVER
SD
/
DI
DEVICE CONNECTION
LEHLE P-SPLIT III
DEVICE CONNECTION
LEHLE SUNDAY DRIVER II
Input Input Output LEHLE
SUNDAY DRIVER II
Instrument (passive)
100 m balanced
Output
Output
Amplifier
Input
LEHLE P-SPLIT III
ISO