The Vertex Tone Secret OD is an overdrive pedal from Vertex Effects, designed in California. It answers what Vertex calls the love/hate relationship many guitarists have with "a particular screaming green overdrive pedal that originated in late 1970's Japan": the Tube Screamer. Instead of copying that circuit outright, the Tone Secret pairs a Screamer-style overdrive with a second circuit, a solid-state version of a Blackface Fender 12AX7 preamp, and uses only half the gain of a traditional green overdrive1.
The premise is simple: a Screamer-style pedal driving a cranked Blackface-style amp is a classic recorded sound, but most players do not play at the volume that sound requires. Vertex describes the Tone Secret as giving you "the sound of a screaming overdrive pedal running into a cranked 12AX7 amplifier at" low volumes, with the maker's own page calling it the "DNA of a classic 'Screamer' hitting a 'Blackface' 12AX7 preamp"21.
A Tube Screamer circuit voiced like a Blackface preamp
The Tube Screamer family has a long lineage. JHS Pedals recounts that a Maxon engineer took the Boss OD-1 circuit and altered it into the TS-808 by adding a tone control, a different symmetry of clipping and other small changes3. That midrange-forward, low-gain overdrive became one of the most copied circuits in pedals, and it is the starting point for the Tone Secret's drive side.
What makes the Tone Secret different is the second circuit. In the Sweetwater demo video, Mason Marangella of Vertex explained that "we've created a preamp that resembles that of most blackface fender style amplifiers in addition to including the tube screamer" circuit, and that the overdrive side is "based on what our version is of the best possible tube screamer to pair with your tube or solid-state amplifier"4. Premier Guitar's launch coverage described the two halves the same way: one is Vertex's take on the Screamer, "the other is a solid-state version of the legendary blackface 12AX7 preamp"2.
Because the preamp is built in, the pedal is designed to run into an amp that does not need to be cranked and mid-scooped to complete the sound. Pedal of the Day's review put it this way: the Tone Secret "aims to harness the DNA of iconic 'screamer' users, but without the need for a cranked, mid-scooped amp"5.
How much gain does it have compared to a Tube Screamer?
Vertex states that the Tone Secret "only utilizes 50% of the gain found in a traditional green OD pedal"1, and Pedal of the Day repeated the same figure, noting that "it only utilizes 50% of the tube screamer gain in the traditional sense"5. The missing gain is not a limitation so much as the design: the Blackface-style preamp supplies the amp-like half of the equation, and the Grit knob dials in the dirt amount on top5.
In the Sweetwater demo, Marangella contrasted the Tone Secret's flexibility with a stock Screamer: "when i think about tube screamers it's kind of like one core tone you know and it's and you can't really dial that back," whereas the Tone Secret offers varying shades of gain4. For context on what a modified Screamer circuit can do, the runoffgroove analysis of the UBE Screamer, a Tube Screamer clone project, found that its "gain control is very wide, ranging from almost clean, to light OD, to moderate OD to a nice and full distortion," and that at minimum gain there is less bass loss than in a real TS6. The Tone Secret takes a different route to the same goal: rather than widening the gain range of the Screamer circuit alone, it splits the job between a half-gain Screamer and a preamp.
The controls
The Tone Secret OD has five knobs, and the pre- and post-overdrive controls are the heart of the design. Delicious Audio's write-up noted that "the added pre-overdrive and post overdrive controls allow you to tweak the OD characteristics to match any amplifier and" simulate amp break-up7.
| Control | What it does |
|---|---|
| Pre-Vol | Pre-overdrive level; sets how hard the drive circuit is pushed, shaping the overdrive characteristics5 |
| Grit | Dials in the amount of dirt5 |
| Master | Post-overdrive output volume; controls the output volume of both circuits working together2 |
| Treble | Treble frequency tonal flavoring5 |
| Mid-Range | Mid-range frequency tonal flavoring; dials mids in and out54 |
The Pre-Vol and Master pair is what lets the pedal match different amps: Pre-Vol changes how the overdrive breaks up, Master sets the final volume of the combined Screamer and preamp circuits25. The Treble and Mid-Range controls give independent EQ shaping, where a stock Tube Screamer offers only a single tone control.
Power, bypass and buying notes
The Tone Secret OD is true bypass and runs on 9VDC center-negative power, with the adapter not included1. Vertex backs it with a lifetime warranty and a 30-day money back guarantee1. The maker's current page lists it as refurbished B-stock, so check the listing condition when comparing prices1.
A related pedal worth knowing about: Chase Tone's Secret T. Booster, a different maker's take on pairing a boost with Screamer-style circuitry, runs on standard 9VDC center-negative or a 9V battery. It is a separate product, not a version of the Tone Secret8.
What reviewers said
Vertex describes the Tone Secret as a screaming overdrive pedal that nails the classic and contemporary sounds heard on your favorite records, and positions it as the answer to the love/hate relationship countless guitarists have with a particular screaming green overdrive pedal that originated in late 1970s Japan1. The maker says the TS only utilizes 50% of the gain found in a traditional green OD pedal, and it is designed in California1.
The Sweetwater demo video walks through the concept and the controls, with Marangella and Ford Thurston showing the pedal delivering "the sound of a classic overdrive pedal into a cranked Blackface-style amplifier" and demonstrating how the Mid knob dials mids in and out4.
Videos
Vertex Effects
Shawn Tubbs
Questions
Is the Vertex Tone Secret OD true bypass?
Yes. Vertex lists the Tone Secret OD as true bypass, so when the pedal is off the guitar signal passes through without the circuit coloring it. It runs on 9VDC center-negative power, with the adapter sold separately.
How much gain does the Tone Secret OD have compared to a Tube Screamer?
Vertex says the Tone Secret uses only 50% of the gain found in a traditional green overdrive pedal. The idea is that the built-in Blackface-style preamp supplies the rest of the character, so you get Screamer-style drive without needing a cranked, mid-scooped amp to complete the sound.
What power supply does the Vertex Tone Secret OD need?
It needs a 9VDC center-negative power supply, and the adapter is not included with the pedal. There is no battery option listed, so plan on a standard pedalboard power supply with a center-negative barrel plug.
What does the Pre-Vol knob do on the Tone Secret OD?
Pre-Vol is a pre-overdrive level control. It sets how hard you push the overdrive circuit itself, before the drive stage, which changes the pedal's overdrive characteristics. The Master knob then sets the post-overdrive output volume of both circuits together.
Sources (8)
- Tone Secret OD, vertexeffects.com
- Vertex Effects Unveils the Tone Secret, Premier Guitar, 2019-03-11
- WHAT IS THE JHS 3 SERIES SCREAMER?, JHS Pedals, 2022
- Vertex Effects Tone Secret Demo, Sweetwater, 2020-10-14
- Vertex Tone Secret Overdrive, Pedal of the Day, 2021-09-06
- UBE Screamer, runoffgroove.com, 2006-08
- Vertex Effects Tone Secret Overdrive, Delicious Audio, 2019-02-28
- SECRET T. BOOSTER™ - Chase Tone®, Chase Tone
