The LEHLE P-ISO TRS XLR STEREO brings you closer to the main mixing system.

It converts your stereo audio signal not only to balanced XLR but lifts the ground so there’s no chance of unwanted noise or humming loops. Perfect for your pedal board, modeler and amp simulation in studios, clubs, bars or stadiums – all fitted into a handy size.

The combination of passive isolation with highest possible signal fidelity is only realisable thanks to its core, existing of two LEHLE TRANSFORMER HZ, which galvanically isolate the signals.
While being designed especially for high impedance signals, they process low impedance signals with the same uncompromising sound quality as well. The high coupling and flat frequency response won’t let you miss any detail in the signal.

The classic application for the LEHLE P-ISO TRS XLR STEREO is the connecting link in between your stereo device and the professional world of mixers, FOH and DAW recording systems.
It lifts the ground in between those worlds, so the devices are galvanically isolated – any hum or noise caused by a ground loop becomes a thing of the past.

Offering balanced audio signals at the two male XLR sockets by Neutrik gets you protected even closer to the mixer while using simple standard XLR cables.

Not only for stereo effects, digital modeler and amp simulation devices – even keyboards, synths, playback systems or audio interfaces are in safe hands of the LEHLE P-ISO TRS XLR STEREO.
You won’t find a power connection as you get all the performance of that compact box passively, without the need for a power supply.

And due to its optimised size and low weight, it fits easily below your pedalboard or in any pocket – always installed or as flexible tool to share (if you really want).

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 signal ground.

UNBALANCED SIGNAL ROUTING

Balanced signal lines are used to cross larger distances without interference.

They are generally fitted with XLR connectors or TRS (Tip Ring Sleeve) jack plugs.

Here, three cores are required:
there are two signal conductors.

In a balanced signal line, the signal is present in phase at the tip, as in the case of an unbalanced signal line (XLR Pin 2). The second signal conductor carries the same signal, but with the opposite polarity 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

DEVICE CONNECTION

	Output effects pedal
	Input mixer

Background noise can often occur if you connect the stereo outputs of your effects pedal to a mixer.

Here again, ground loops occur when units grounded by a protective earth conductor (“PE conductor”) are connected to each other. If you place the LEHLE P-ISO TRS XLR STEREO in between the effects pedal and the mixer, this connection is isolated and the noise eliminated.

The signal connections can be either symmetrical or asymmetrical.

HOW TO DO THIS:

1. Connect the right output of the effects pedal to the right INPUT SOCKET of the LEHLE.
2. Take the left output of the effects pedal and connect it to the left INPUT SOCKET of the LEHLE.
3. Use the right R ISO output to connect to the right input of your mixer. Use balanced cables with XLR connectors.
4. Now take the left L ISO output and connect it to the the left input of your mixer. Again with XLR and balanced cables.
5. Use the ground lift switch to determine which position eliminates the most background noise.
6. There you go!

DEVICE CONNECTION

	Output preamp
	Input Audio interface

If connecting a preamp or amp modeler to the audio interface generates a ground loop, causing undesirable noise, again this problem can be effectively eliminated using the LEHLE P-ISO TRS XLR STEREO. The built-in LEHLE TRANSFORMER HZ galvanically isolates the ground connections and offers a balanced signal to record.

The signal connections can be either symmetrical or asymmetrical.

HOW TO DO THIS:

1. Connect the right output of the preamp to the right INPUT SOCKET of the LEHLE.
2. Take the left output of the preamp and connect it to the left INPUT SOCKET of the LEHLE.
3. Use the right R ISO output to connect to an input of your interface. Use balanced cables with XLR connectors.
4. Now take the left L ISO output and connect it to another input of your interface. Again with XLR and balanced cables.
5. Use the ground lift switch to determine which position eliminates the most background noise.
6. There you go!

DEVICE CONNECTION

	Stereo outputs pedal board
	Stereo inputs mixer

Background noise often occur when you connect the stereo outputs of your last device to the mixer or the stagebox / FOH.

It not only converts your stereo audio signal to balanced XLR, but also lifts the ground, so there is no possibility for unwanted background noise or humming loops. Place the LEHLE P-ISO TRS XLR STEREO in between the output of your pedal board, modeler or amp simulation and the mixer or stagebox / FOH and this connection is isolated.

The signal connections can be either symmetrical or asymmetrical. If your last device already offers balanced outputs, you can connect them balanced via TRS to the inputs of the LEHLE P-ISO TRS XLR STEREO.

HOW TO DO THIS:

1. Connect the right output of the last stereo pedal to the right INPUT SOCKET of the LEHLE.
2. Take the left output of the pedal and connect it to the left INPUT SOCKET of the LEHLE.
3. Use the right R ISO output to connect to the right input of your mixer. Use balanced cables with XLR connectors.
4. Now take the left L ISO output and connect it to the the left input of your mixer. Again with XLR and balanced cables.
5. Use the ground lift switch to determine which position eliminates the most background noise.
6. There you go!

DEVICE CONNECTION

	Output keyboard
	Input speaker

The LEHLE P-ISO TRS XLR STEREO can be used in any scenario to eliminate noise resulting from ground loops or hum. Ground loops occur when units grounded by a protective earth conductor (“PE conductor”) are connected to each other. E.g. here a keyboard which is connected to two active speaker. 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-ISO galvanically isolates the ground connection. The hum loop is thus broken at this point.

The signal connections can be either symmetrical or asymmetrical.

HOW TO DO THIS:

1. Connect the right output of your keyboard to the right input socket of the LEHLE.
2. Connect the left output socket of your keyboard to the left input socket of the LEHLE.
3. Use the right R ISO output to connect to the right speaker. Use balanced cables with XLR connectors.
4. Now take the left L ISO output and connect it to the the left speaker. Again with XLR and balanced cables.
5. Use the ground lift switch to determine which position eliminates the most background noise.
6. There you go!