Princeton Thermionic Effects


Sex Pedals,
The Best for Your Axe
Since 2018


Add some sizzle to your sound

Effects pedals have a long rich history.
Some are unforgettable:
fuzztone in “Satisfaction,”
univibe in “Bridge of Sighs,”
flanger in “Unchained,”
echoplex in “The Song Remains the Same,”
wah in “Voodoo Child,”
talkbox in “Sweet Emotion,”
…The list goes on & on.
An effect pedal can truly enhance your sound.

Every Princeton Thermionic effects pedal is built by hand in our barn shop.
Let us know what you’re listening for; we can build your dream pedal.


Your Unique Sound,
Your Custom Pedal


Premium Components

We build your stompbox using the highest-quality components available, sourced from around the globe. Handmade circuitboards, soldered the old fashioned way. Hand assembled one at a time in our barn workshop.
No assembly line.


Previous Sex Pedals

Stereo Pi

Stereo Fuzzbox
ABY switching
Blend of ’60s & 70s circuits:
Violet Muff and Russian Muff
plus Tubescreamer mid
Volume control
Tone control
Fuzz control
Sustain control
True Bypass
fx.transposed PCB
All analog signal path

Harmoni-Trem

Tremolo: Traditional & Harmonic
Dynamic swirling modulation
Wave shape control
Rate control
Depth control
Spacing control
Harmonic Mix control
Tap Tempo footswitch
True Bypass
Zeppelin Design Labs PCB
All analog signal path

Mono Pi

Mono Fuzzbox
Blend of ’60s & 70s circuits:
Violet Muff and Russian Muff
Volume control
Fuzz control
Sustain control
True Bypass
GGG PCB
All analog signal path


Now Accepting Production Requests


To reserve your stompbox on our production list,
email us: info@princetonthermionic.com.

Princeton Thermionic

We don’t ‘have’ a custom shop; we ARE a custom shop.

Princeton Thermionic
Heavenly Tone, Louder than Hell.

New Hope, Pennsylvania USA
info@princetonthermionic.com