The Stone Deaf EP-1 Expression is a proprietary expression pedal from Stone Deaf FX, designed specifically for Stone Deaf products such as their parametric overdrives and distortions1. Instead of controlling volume, it sweeps the frequency control on a compatible Stone Deaf pedal, letting you use it as a tonal sweeper, a wah pedal and a phaser1. It is an active pedal, designed and built in the UK, and it is now discontinued12.
The EP-1 Expression is listed by Stone Deaf FX as sold out and discontinued1. Its last listed price was £128.00, down from £160.001.
Sweeping the frequency of Stone Deaf pedals
Stone Deaf's overdrives and distortions, such as the PDF-2 and the Trashy Blonde, are built around a parametric EQ, sometimes called their Paracentric EQ, whose frequency control sets which band is boosted or cut13. The EP-1 plugs into that: it is an expression pedal whose treadle moves the frequency knob for you, so a static tone-shaping control becomes something you can play with your foot. Delicious Audio describes it simply: "Frequency sweep can be controlled with the Stone Deaf EP-1 Expression Pedal"3.
Stone Deaf lists the pedals it works with:
- PDF-2, PDF-1X, Fig Fumb, Warp Drive, Trashy Blonde and Kliptonite, where it works as a tonal sweeper, wah pedal and phaser1
- Rise & Shine, where it controls the tremolo rate, allowing heel/toe variation1
The sweep itself comes from a custom reverse log taper potentiometer, which Stone Deaf says gives a wider frequency sweep than most wahs and expression pedals1. Used with their standard overdrives, it will go past two different resonance points1.
Controls and feel
The EP-1 has a control knob on its side that sets the position of the frequency knob on the main unit, for example a PDF-2. It is active when the pedal is in bypass and the treadle is disengaged, and it does not affect the Q of the filter1. There is also a bypass footswitch at the top of the treadle's travel2, and adjustable bolts for treadle resistance, so you can set how stiff the pedal feels underfoot2.
Guitar.com's Richard Purvis reviewed the EP-1 alongside the PDF-2 and described what the pairing sounds like2:
"At minimum the mids are hollowed out for something like a manual phaser effect, while nearer the top of the dial the boosted frequencies leap out to create some classic (and some weirdly synth-like) wah tones"2
He also offered a usage tip:
"the EP-1 is arguably at its best when you don't use it too much. Rhythmic rocking is fine, but subtly creeping through the range is even more effective for creating fresh and dynamic sonic textures"2
A player listed on Stone Deaf's page, M from Finland, uses it with a PDF-2 as a wah and with the Fig Fumb, noting: "I use the PDF-2's switch for on/off, which also allows to start to sweep from any given point"1.
Build and power
The EP-1 is an active pedal, so it needs power: 9V at 35mA, center negative1. It can also run on a 9V battery or a DC adapter, neither supplied2.
Stone Deaf warns that anything other than 9V center negative may harm the product and will cause it not to work, and that this is classed as user error, not covered under warranty. They recommend an isolated power supply and advise against low-cost non-isolated daisy chains or single wall-wart supplies1.
Physically, it is compact: 12.5cm long, 6.5cm wide, 6cm high, and 400 grams1. Guitar.com called it and the PDF-2 "metal-clad slabs of old-fashioned British engineering"2, and a Premier Guitar reviewer who tried it with the Trashy Blonde in 2023 called it "one of the most rugged ex[pression pedals]" they had seen, recommending anybody considering the Trashy Blonde try it with the EP-14.
Warranty
Stone Deaf FX gave the EP-1 a 1-year product warranty covering defects for one year from purchase. Wear and tear and misuse are not covered, the warranty is not transferable, and refunds are not offered under it1.
Questions
Is the Stone Deaf EP-1 true bypass?
Yes. Stone Deaf FX lists the EP-1 Expression as true bypass. It also has a bypass footswitch at the top of the treadle's travel, so you can disengage the sweep with your foot without touching the pedal it is controlling.
What power polarity does the Stone Deaf EP-1 need?
It needs 9V center negative. Stone Deaf warns that anything other than 9V center negative may harm the product and will stop it working, and that this counts as user error not covered by the warranty. An isolated power supply is recommended over cheap daisy chains or single wall-wart supplies.
Which Stone Deaf pedals work with the EP-1 Expression?
Stone Deaf lists the PDF-2, PDF-1X, Fig Fumb, Warp Drive, Trashy Blonde and Kliptonite as compatible overdrives and distortions, where it works as a tonal sweeper, wah and phaser. It also controls the tremolo rate of the Rise & Shine.
Can the Stone Deaf EP-1 work as a wah?
Yes. With a compatible Stone Deaf pedal such as the PDF-2, it sweeps the frequency control like a wah. Guitar.com's reviewer found it produced classic and even synth-like wah tones, and that subtle slow sweeps through the range were more effective than fast rhythmic rocking.
Is the Stone Deaf EP-1 still made?
No. Stone Deaf FX's product page lists the EP-1 Expression as sold out and discontinued. It was designed and built in the UK, and second-hand units are the main way to find one now.
What warranty does the Stone Deaf EP-1 have?
Stone Deaf FX gave it a 1-year warranty covering defects from purchase. Wear and tear and misuse are not covered, the warranty is not transferable, and refunds are not offered under it. Damage from using the wrong power polarity is classed as user error.
Sources (4)
- EP-1 Expression, Stone Deaf FX
- Stone Deaf PDF-2 & EP-1 Expression Pedal Review, Guitar.com, 2018-10-15
- Stone Deaf FX Warp Drive, Delicious Audio, 2021-09-10
- Trashy Blonde Distortion Filter Review by Stone Deaf, Premier Guitar, 2015-01-29
