The Empress Effects Germ Drive is a compact analog overdrive pedal from Canadian maker Empress Effects, built around germanium diode clipping to imitate the breakup of a 1950s tweed tube amp. Empress describes it as delivering "warm, harmonically rich overdrive that cleans up with a twist of your volume knob"1, which puts it in the camp of amp-like drives rather than the mid-humped Tube Screamer school. It was released around October 2011 as one of Empress's three Singles pedals, and it is now effectively discontinued, with Empress selling off remaining stock2.
What it does to your sound
The Germ Drive's whole design idea is tweed amp breakup. Premier Guitar, covering a later Empress release, noted that the Germ Drive circuit "simulated the breakup characteristics of an old Tweed amp"4. The germanium diodes in the clipping stage are what give it that character; Guitar Pedal X's reviewer Stefan Karlsson wrote that "elegantly applied Germanium Diodes lend this style of overdrive a beautifully harmonically rich Tweed Tube Amp-like texture"2.
Two behaviors matter most to a player:
- Volume-knob cleanup. RockBoard's PedalPedia lists this as a headline feature: "Seamlessly clean up your sound by rolling back your volume knob"3. Back off the guitar's volume and the drive backs off with it, the way a tube amp responds.
- Natural breakup. Empress says the pedal "stays true to your original tone" as it breaks up1, meaning the core character of your guitar and pickups comes through rather than being replaced by the pedal's own voice.
Controls
The control set is deliberately small: gain, two bands of EQ, and output13.
| Control | What it does |
|---|---|
| Gain | Sets the amount of overdrive, from light breakup upward |
| EQ (hi shelf) | Cuts or boosts the treble shelf |
| EQ (low shelf) | Cuts or boosts the bass shelf |
| Output | Sets the overall level leaving the pedal |
The EQ is a pair of shelf filters rather than a single tone knob, with hi shelf and low shelf EQs that let you tweak your sound. That is a step up in flexibility from the one-knob tone control on most compact overdrives1.
How it compares to a Tube Screamer
The obvious reference point for any mid-focused overdrive is the Tube Screamer family (see Boss SD-1 vs Ibanez TS9 for that comparison in detail). Karlsson's verdict at Guitar Pedal X was direct:
"much more adaptable than your typical tube-screamer variety - delivering a far better balance of frequencies"2
Where a Tube Screamer cuts bass and pushes a strong midrange bump to sit in a mix, the Germ Drive's hi and low shelf EQs let you keep the low end and shape the top independently. For players who find Tube Screamer-style pedals too narrow, that two-band EQ and the germanium clipping character are the practical differences12.
Power, connections and specs
The Germ Drive runs on a standard 9V DC center-negative supply through a 2.1mm barrel connector, drawing about 35mA13. There is no battery option mentioned by the maker, so plan on a pedalboard power supply.
| Specification | Value |
|---|---|
| Signal path | All analog1 |
| Bypass | True bypass13 |
| Input impedance | 1M1 |
| Output impedance | 2.2k1 |
| Frequency response (-3dB) | 20Hz to 20kHz1 |
| Enclosure | Die cast aluminum1 |
| Dimensions | Approximately 4.5" by 2.5" by 1.5"13 |
| Weight | 0.5 lbs1 |
The 1M input impedance and 2.2k output impedance mean the pedal presents a normal load to passive pickups and drives most amp inputs without issue1.
Where it came from
The Germ Drive arrived around October 2011 as one of Empress's three Singles pedals, a small-format line the company released that autumn2. Karlsson recalled the launch price as "around $199 initially" and noted the Singles were down to $99 each at the time of his 2022 review2. By then, Empress was "simply selling off what they have left in stock," which he described as making the pedals discontinued "for all purposes and intents"2. The maker's own page still lists the Germ Drive at $109.00 USD as of October 20261, so leftover new stock can still surface.
The circuit line lived on in Empress's range: Premier Guitar reported in 2026 that the company's new Empress Drive "is based on Empress' earlier Germ Drive"4, so players who want that tweed-style breakup character in a current production pedal have a modern option from the same maker.
The Germ Drive is discontinued for practical purposes. Empress has been selling off remaining stock, so availability is limited to whatever new old stock retailers and the maker still hold2.
Videos
Empress Effects
Brett Kingman
Alberto Barrero
Questions
Is the Empress Germ Drive discontinued?
Yes, for practical purposes. Empress has been selling off remaining stock, and Guitar Pedal X described the Singles series, which includes the Germ Drive, as discontinued in all intents and purposes. The maker's product page still lists it at $109.00 USD, so new old stock may still be found.
Does the Germ Drive use germanium diodes?
Yes. Guitar Pedal X's review credits the pedal's character to elegantly applied germanium diodes, which give this style of overdrive a harmonically rich, tweed tube amp-like texture. The name Germ Drive refers to that germanium clipping.
Is the Empress Germ Drive true bypass?
Yes. Empress states that the Germ Drive employs true bypass, so the pedal does not affect your signal when it is disengaged. RockBoard's PedalPedia listing confirms the true bypass switching.
Does the Germ Drive clean up with the guitar volume knob?
Yes. Empress describes the Germ Drive as delivering warm, harmonically rich overdrive that cleans up with a twist of your volume knob, and the product page lists seamless volume-knob cleanup as one of its features.
How does the Germ Drive compare to a Tube Screamer?
Guitar Pedal X's reviewer found the Germ Drive much more adaptable than a typical Tube Screamer-style pedal, with a far better balance of frequencies. Where a Tube Screamer pushes a strong midrange hump, the Germ Drive's hi and low shelf EQs let you shape the tone more openly.
Sources (4)
- Germ Drive, Empress Effects Inc.
- Guitar Pedal X, Guitar Pedal X, 2022-12-14
- Germ Drive by Empress Effects, RockBoard PedalPedia, 2026
- Empress Effects Releases New Overdrive, Premier Guitar, 2026-05-05
