Check the listing for details. Electro-Harmonix SLAP-BACK ECHO Analog Delay Effects Pedal Silver and Blue. Condition: New. Listed at 81.00 USD. The Electro-Harmonix Slap-Back Echo pedal is based on the late 1970s rarity, but modified to add modern updates and a Pico footprint. The 1950s gave birth to an iconic sound in which a single, short delay was utilized to add depth and rhythmic effect on countless recordings. The newly reissued all-analog design of the EHX Slap-Back Echo delivers this beloved classic sound and more in a Pico-sized pedalboard-friendly package. The Slap-Back Echo features gain and blend knobs as well as a time switch. The gain knob controls the input signal before the echo circuit and also adjusts the overall volume at the output with a boost of up to 20dB. The blend knob mixes the dry signal and the echo signal from 100% dry to 100% echo.