The Kasleder FX Toxic Twins is a dual overdrive pedal from Hungary, built by Kasleder FX, the maker also known for the Dirty Little Thing overdrive. It packs two overdrive circuits in one box: the left channel is based on a Blues Breaker circuit and the right channel on a Tube Screamer circuit1. The two channels are organized in parallel, so they stack on top of each other when both are on1.
Pedal of the Day called it "a 2-channel classic rock mammoth" and found its range runs wide for an overdrive: it "goes from clean boost to low gain to crunchy grit to balls-out, borderline distortion, all with ease"2.
The two channels
Each channel has three knobs: Level, Drive, and Tone1. Pedal of the Day lists the left side's controls as Level, Tone and Gain, and the right side's as Level, Tone and Drive, controlling the saturation and punch2.
The channels have distinct voices. Delicious Audio describes the left channel as "a light low gain organic overdrive with a balanced equalisation, like it is a part of your amp," and the right as "a boutique overdrive that gives you the dynamic crunch sound with the classic mid hump"1. At default settings the left is more tube-like and transparent, the right more mid-rangey1. Pedal of the Day heard the same split: the left side produces a modified Bluesbreaker circuit "with tube-like saturation and warm, tube amp-like breakup," while the right is "a more boutique-style overdrive, with dynamic crunch and a classic mid hump"2.
| Channel | Circuit basis | Controls | Character |
|---|---|---|---|
| Left | Blues Breaker1 | Level, Tone, Gain2 | Tube-like, transparent, low gain1 |
| Right | Tube Screamer1 | Level, Tone, Drive2 | Dynamic crunch, classic mid hump1 |
The controls and internal DIP switches
Both channels hide extra voicing inside the box. The left side has an internal DIP switch set with various clipping options, and the right side has one that extends the voicing capabilities for boosting the bass2. On each side, two switches create four different options2.
The clipping switches on the left channel change which diodes shape the signal. With both switches off, no clipping diodes are engaged and the pedal works as a clean boost with the most headroom, a setting the maker describes as suited to pushing an amp1. The bass switches on the right channel set how much low end comes through; with both off, the channel has the least amount of bass, which the maker suggests works well with humbucker pickups1.
The clipping comes from an original circuit using a combination of uncommon NOS diodes, including the 1N456 and the 1N41511. The maker says the 1N4151 was discovered during the creation of the Dirty Little Thing circuit1.
What reviewers said
Pedal of the Day reviewed the Toxic Twins on 30 December 2020 and came away surprised by it2:
"produces some intriguing and unusual sounds, making what you think will be yet another overdrive pedal something special and exiting right from the get-go."2
Pedal of the Day, 30 December 20202
Delicious Audio's write-up, published 9 September 2021, highlighted the pedal's two sets of internal DIP switches for fine-tuning clipping and bass response, and noted the maker's claim that the Toxic Twins "is faithfully recreating the same sound, wherever and in whatever it is plugged in," meaning the same sound at bedroom level as on a big stage1.
Videos
Kasleder Fx
Kasleder Fx
Kasleder Fx
Questions
Can you stack both channels on the Toxic Twins?
Yes. The two channels are organized in parallel, so they stack on top of each other when both are on. That lets you run the Blues Breaker-style left channel into the Tube Screamer-style right channel, or use either one on its own.
What diodes does the Kasleder Toxic Twins use?
The circuit uses a combination of uncommon NOS (new-old-stock) diodes, including the 1N456 and the 1N4151. The maker says the 1N4151 was discovered while designing the Dirty Little Thing circuit. Internal DIP switches select which clipping diodes are engaged.
Does the Toxic Twins work as a clean boost?
Yes. With both clipping DIP switches set to OFF, no clipping diodes are engaged and the pedal acts as a clean boost with the most headroom, which the maker describes as a setting for pushing an amp.
Where is Kasleder FX based?
Kasleder FX is based in Hungary. The Toxic Twins, like the maker's other pedals such as the Dirty Little Thing, is built there.
Is the Kasleder FX Toxic Twins based on a Bluesbreaker?
Partly. The left channel is based on a Blues Breaker circuit, which Pedal of the Day describes as a modified Bluesbreaker. The right channel is based on a Tube Screamer circuit instead.
Can the Toxic Twins go from clean boost to distortion?
Yes. Pedal of the Day found it goes from clean boost to low gain to crunchy grit to borderline distortion, all with ease. The range comes from the Drive and Gain controls plus the internal clipping DIP switches.
Sources (2)
- Kasleder FX Toxic Twins Dual Tweakable Overdrive, Delicious Audio, 2021-09-09
- Kasleder FX Toxic Twins Dual Overdrive, Pedal of the Day, 2020-12-30
