# Ensoniq ESQ-1 sustain pedal or expression?

**URL:** <https://forums.syntaur.com/t/ensoniq-esq-1-sustain-pedal-or-expression/9152>\
**Category:** Synth Repair\
**Tags:** ensoniq, esq-1-metal-case\
**Created:** [September 23, 2025, 3:26am UTC](https://forums.syntaur.com/t/ensoniq-esq-1-sustain-pedal-or-expression/9152 "2025-09-23T03:26:00Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Pik0](https://forums.syntaur.com/letter_avatar_proxy/v4/letter/p/3ab097/32.png) [@Pik0](https://forums.syntaur.com/u/Pik0)\
**Post date:** [September 23, 2025, 3:26am UTC](https://forums.syntaur.com/t/ensoniq-esq-1-sustain-pedal-or-expression/9152/1 "2025-09-23T03:26:00Z")

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So I’m trying to get a sustain working on this old ESQ-1 keyboard. So far i’ve tried a standard TS style pedal which yielded zero results in any voice. In reading the schematic, it looks like it’s expecting a TRS style pedal. If that’s the case, how does that work and what does it do? Variable sustain?

TIA!!

Andrew

• Model & revision/OS: 2.0  
• Symptoms (what changed, when): no sustain  
• Tests already done (voltages, parts replaced): tested TS pedal okay  
• Photos / audio clips:

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<div class="post-metadata">

**Author:** ![Pik0](https://forums.syntaur.com/letter_avatar_proxy/v4/letter/p/3ab097/32.png) [@Pik0](https://forums.syntaur.com/u/Pik0)\
**Post date:** [September 23, 2025, 3:27am UTC](https://forums.syntaur.com/t/ensoniq-esq-1-sustain-pedal-or-expression/9152/2 "2025-09-23T03:27:07Z")

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![Photo for reference](https://forums.syntaur.com/uploads/default/original/2X/d/d2b9790b7bd5a433d1e681d0cf98ea574ba661b9.jpeg)

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<div class="post-metadata">

**Author:** ![Travis](https://forums.syntaur.com/user_avatar/forums.syntaur.com/travis/32/1382_2.png) [@Travis](https://forums.syntaur.com/u/Travis)\
**Post date:** [September 23, 2025, 4:36pm UTC](https://forums.syntaur.com/t/ensoniq-esq-1-sustain-pedal-or-expression/9152/3 "2025-09-23T16:36:26Z")

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Any **normally open** foot switch should work. Make sure you plug it into the Sustain Ft. Sw. input and not the CV/Pedal input, that’s for an expression pedal.