Lehle D.Loop
The Lehle D.Loop is a fully programmable Effect-Loop/Switcher with two independent, realTRUE BYPASSloops routed via gold-plated relays. Apart from that, it features a facility to switch via an in-built High End Buffer Amp. Loops and Buffer Amp are fully stereo. If required, the Lehle D.Loop is also remote-controllable via MIDI.
Lehle1 - Input signal This jack receives the incoming signal. If the Lehle D.Loop is inactive (not connected to an electric supply), the signal remains unchanged. As all Lehle D.Loop jacks are fully stereo, stereo signals can be processed. However, mono signals can also be easily processed.
2 - Loop A This is the SEND jack of Loop A. Use this jack to connect to the Input of an effect-unit to be activated by Loop A, or to connect to an amplifier. Connect the RETURN jack to the Output of the effect-unit to be used with Loop A. When Loop A is active, the incoming signal is routed via Loop A, which is shown by the indicator light (located below) being ON.
3 - Loop B The same procedure (see 2) applies to Loop B. Loop B is serially connected after Loop A. The Lehle D.Loop allows for very flexible usability: The SEND jacks are outputs that connect to the signal when the respective Loop is active. So, together with the regular output (see 4), the Lehle D.Loop provides THREE stereo outputs.This allows the Lehle D.Loop to be used for things like selective switching of three different amp inputs (e.g. active monitors, different power amps etc.) The RETURN jacks of the Loops provide inputs, which process the signal when the respective Loop is active. With the input jack (see 1), the Lehle D.Loop provides THREE stereo inputs. These can also be used to route three different signal sources to the output (e.g. 3 guitars, 3 keyboards).Of course, the Loop functions can also be mixed.
4 - Output The Output provides an unaltered signal, as long as Loop A and Loop B are inactive. Are both loops in active mode, the signal first runs through Loop A, then through Loop B. To suppress natural relay switching noises, during switching, software controlled very high impedance Audio Opto-couplers are sent to the outputs via the built-in Micro-controller. During normal usage, when the switches aren’t being used, the sound is not affected in ANY way, as the Opto-couplers aren’t in the signal path.
5 - Buffer amp The additional feature to route the signal via the Buffer Amp allows a reduction of signal impedance if so required. Real True Bypass Effects don’t alter the high impedance of magnetic pick-ups commonly used in electric guitars and basses, because this can often affect sound and amp interaction. In certain situations this could actually be a desired effect, to ‘refresh’ the sound with low impedance - for example when extra long leads are required. The Lehle D.Loop allows you to route the signal to Loop A via the Buffer Amp, which is equipped with a high impedance JFET-input. When the buffer amp is active, the indicator is ON.
6 - How to program the D. Loop The SET and RESET buttons are used to program the Lehle D.Loop. The Lehle D.Loop can be used in three different modes. The first mode allows both Loops and Buffer Amp to be switched on/off independently. The second mode allows freely programmable allocation between switch-buttons and their functions. MIDI program-change signals are processed in the MIDI mode (mode 3).
7 - Power supply The Lehle D.Loop requires a power supply of between 9 and 20 V. Polarity is of no importance. The supply voltage is internally rectified and stabilized in order to guarantee trouble-free operation. A thermal cut-out automatically trips and switches the unit off if a short-circuit occurs. A correctly fitting plug connector for the power-supply jack of the Lehle D.Loop is supplied. This can be soldered to the required power unit if necessary.
