
OPERATING INSTRUCTIONS
LEHLE SUNDAY DRIVER SW II
LEHLE SUNDAY DRIVER SW II#
Dear Musician!
Thank you for purchasing the LEHLE SUNDAY DRIVER SW 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 SUNDAY DRIVER SW II comprises only the very best components. Every assembly of your LEHLE SUNDAY DRIVER SW II has been made and tested in Germany.
Your LEHLE SUNDAY DRIVER SW 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:
support@lehle.com

I wish you the very greatest pleasure and success using your LEHLE SUNDAY DRIVER SW II!

General Description#
1. INPUT SOCKET
Connect your instrument to this socket.
The LEHLE SUNDAY DRIVER SW II processes signals from electric and acoustic stringed instruments, such as electric guitars and basses, western guitars, classical guitars and all kinds of stringed instruments. This compact preamp has no trouble balancing out low signal levels, and eliminating sound losses caused by long cables and treble pickups.
2. S/D-SELECTOR SWITCH
Use this switch to select the mode you want.
This gold-plated contact switch enables you to change between the two sound modes. Mode D for ”Driver” (switcher pressed) selects neutral amplification, and the incoming signal is amplified at the input impedance of a guitar amp, 1 MOhm, efficiently eliminating sound losses caused by long cables and/or multiple effects. The signal remains strong and clear, and retains its dynamics.
In mode S for ”Sunday” (switcher not pressed), the input impedance is multiplied by five, to 5 MOhm, making previously unheard details suddenly audible whilst imparting an unmistakable and characteristic warmth to the sound when the gain knob is turned up.
3. TS/TB-SELECTOR SWITCH
Use this switch to select the bypass mode you want.
In OFF status, the LEHLE SUNDAY DRIVER SW II provides two different modes of operation. In TB for “True-Bypass” mode, the input and output are linked with zero losses to one another via an intelligent True-Bypass-Relay-Circuit with active pop suppression circuit.
True-Bypass mode (switch pressed) is the best option for a small setup with short cable routings and for when a treble booster or a classic fuzz pedal is looped in after the LEHLE SUNDAY DRIVER SW II.
The line driver function, located at the start of the signal or in an effects chain, is the better solution for long cables and for complex effects board configurations. Switch the LEHLE SUNDAY DRIVER SW II to TS for “True Sound” mode, and it is active as a buffer, without amplifying the signal in any way. In this mode, the LEHLE SUNDAY DRIVER SW II operates as a neutral line driver and works with 5 MOhm or 1 Mohm input impedance – depending on the selected S or D mode.
4. OUTPUT SOCKET
Connect your target device here.
For instance, an amplifier, a mixer panel, a stage box or a sound card. The output can be tapped unbalanced (TS jack) or balanced (TRS jack). To tap the output balanced, the LEHLE SUNDAY DRIVER SW II has to be either activated (LED blue) or the TS/TB-selector switch (3) set to “True Sound”.
5. EXTERNAL POWER SUPPLY
Connect a power supply with a voltage of 9 – 15 V.
In order for the LEHLE SUNDAY DRIVER SW II to work flawlessly, it needs a current supply. This should supply a minimum of 9 V and a maximum of 15 V. Polarity is of no importance. The input voltage is rectified from the power supply socket, then filtered, stabilized and transformed to 30 V which guarantees maximum headroom.
In order to avoid noise it‘s recommendable to use a single power supply or an output of a multi power supply offering galvanically isolated outputs for the LEHLE SUNDAY DRIVER SW II.
6. LED
If the LED is showing blue, the gain controller and S/D-selector switch are active.
The high-intensity LEDs under the lenses clearly indicate the switching-state, even under stage lighting. If the LED is showing white, the LEHLE SUNDAY DRIVER SW II is in bypass and depending on the position of the TS/TBselector switch (3) in “True-Bypass” or “True Sound”.
7. GAIN CONTROLLER
Use the gain controller to adjust the intensity of the preamp from a slight level up to a powerful boost.
The gain control knob consists of black anodized aluminium and is recessed into the housing. It can be easily turned by placing your fingertip in the top depression, and thanks to the recessed design, your setting cannot be inadvertently disturbed on stage or during transportation. The LEHLE SUNDAY DRIVER SW II with its discrete Class A JFET circuitry performs two functions simultaneously – reducing signal impedance on the one hand, and boosting the signal on the other.
THE LEHLE SUNDAY DRIVER SW II AS AN IMPEDANCE CONVERTER:
When the gain controller is at the lefthand stop (in the ”0” or ”seven o’clock” position), it operates purely as an impedance converter. With the knob in this position, you can compensate for sound losses that can occur when long cables or multiple effects are used.
THE LEHLE SUNDAY DRIVER SW II AS A BOOSTER:
A buffer starts to amplify the signal when the gain controller is turned further in the clockwise direction. Tube amplifiers, preamps and distortion pedals can thus be driven slightly beyond the limit. Since the frequency response of tubes especially are not linear, the LEHLE SUNDAY DRIVER SW II ensures that the resultant overdrive distortion sounds harmonious and amplifies less treble in ”S” mode as the “Boost” rises. The result can range from a pleasant sound with no shrillness, up to a silky warm, harmonious overdrive distortion on tube amplifiers.
8. TRUE-BYPASS-SWITCH
Use this switch to select between the original and the boosted signal.
The LEHLE SUNDAY DRIVER SW II switches all audio signals controlled by a microcontroller and an intelligent True-Bypass-Relay-Circuit with an active pop suppression function.
Triggered by the easy-action mushroom shaped button characteristic of LEHLE products mounted in the cover so that your foot pressure is transmitted indirectly via a spring. Thus the circuit board is not exposed to mechanical loads, making the LEHLE SUNDAY DRIVER SW II virtually indestructible and guaranteeing years of trouble-free switching. In OFF status, the LEHLE SUNDAY DRIVER SW II provides two different modes of operation, TB for “True-Bypass” and TS for “True Sound” mode. In ON state, the LED (6) shows blue, the gain controller is active and you can choose between the sound modes D for “Driver” and S for “Sunday”.
9. BASE AND FIXING
If required, mount the LEHLE SUNDAY DRIVER SW II to a pedalboard using the mounting kit.
The LEHLE SUNDAY DRIVER SW II 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 Mounting 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!
For flexible solutions we recommend using 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 before you cover it, in case you have a support question for us later and don‘t fancy dismantling your board!
Typical Uses Live#
Long cable runs and complex effects cascades on stage or in the concert hall can cause unwanted signal loss. Where electric guitars are used with tube amplifiers, an additional boost is often necessary, to generate a harmonious distortion. The LEHLE SUNDAY DRIVER SW II is designed to perform both tasks perfectly.
Typical Uses in the Studio#
The LEHLE SUNDAY DRIVER SW II gives top performances not only on stage and in the concert hall, but also in the recording studio.
Its wide 20 to 100,000 Hz transmission range and extremely good signal-to-noise ratio makes it the ideal recording preamp.
Signal Flow Diagram#
