The Demon FX Microtubes A7K Bass Preamp is a Demon Fx preamp pedal, currently around $67.88. Close alternatives include the Demon FX Microtube D7K "Bass" Preamp and the Electro-Harmonix Nano Operation Overlord. It pairs well with the Fjord Fuzz Odin and the Fjord Fuzz Berserk.
Demon FX Microtubes A7K Bass Preamp
Demon Fx · pedal
The Demon FX MICROTUBES A7K is a budget bass preamp and overdrive pedal from the Chinese effects manufacturer Demon FX, inspired by the Darkglass Microtubes bass preamp circuit architecture. Delivers aggressive transistor-clipped bass overdrive with bass-specific EQ shaping including parametric midrange control. Suited for metal, djent, and modern aggressive bass tones.
What stands out
“Suited for metal, djent, and modern aggressive bass tones”
— from the listing
“Budget pricing makes aggressive bass overdrive preamp accessible”
— from the reviews
“Delivers aggressive transistor-clipped bass overdrive with bass-specific EQ shaping including parametric midrange control”
— from the listing
“The MICROTUBES A7K delivers aggressive transistor-clipped bass overdrive inspired by the Darkglass Microtubes circuit approach, providing modern aggressive bass tones with bass-specific EQ at a budget price point for players who want Microt…”
— from the community notes
“Use-case wise it suits metal, djent, and modern rock bass players who want aggressive distorted bass tones”
— from the community notes
- bass
- aggressive
- modern
- eq
- transistor
- djent
- overdrive
Good for
- Live
- Silent Recording
- Studio
Price updated Oct 23, 2026
Genres the Demon FX Microtubes A7K Bass Preamp is commonly used in
- Metal
- Rock
- Djent
- Metalcore
cited
Inferred from shared tonal signals, not a stated genre tag. - Alternative
cited
Inferred from shared tonal signals, not a stated genre tag. - Hard Rock
cited
Inferred from shared tonal signals, not a stated genre tag.
Pedals that stack with the Demon FX Microtubes A7K Bass Preamp
Fjord Fuzz Odin
Fjord Fuzz
24% matchgain stackingStacks two gain stages for more saturation than either produces alone. (mid-forward → fuzzy)
Fjord Fuzz Odin layers fuzzy onto an already mid-forward signal
Comes earlier in the signal chain
Fjord Fuzz Berserk
Fjord Fuzz
23% matchgain stackingStacks two gain stages for more saturation than either produces alone. (mid-forward → fuzzy)
Fjord Fuzz Berserk layers fuzzy onto an already mid-forward signal
Comes earlier in the signal chain
Electro-Harmonix Bad
Electro-Harmonix
13% matchsits in the right chain slotPlaced for where it does its job cleanly in the chain, not for a tonal interaction with the anchor.
Run Electro-Harmonix Bad after Demon FX Microtubes A7K Bass Preamp in the signal chain, clear of Demon FX Microtubes A7K Bass Preamp's own gain stage
Comes earlier in the signal chain
Wren and Cuff Gold Comp
Wren And Cuff
10% matchshapes the dynamic responseShapes how the tone responds to picking dynamics rather than its frequency or gain.
Demon FX Microtubes A7K Bass Preamp's own aggressive character is the real reason this is worth trying
Comes earlier in the signal chain
Roland SDE-3000D
Roland
6% matchRoland SDE-3000D's pristine voice goes after Demon FX Microtubes A7K Bass Preamp in the signal chain — it's not there to compete with Demon FX Microtubes A7K Bass Preamp's own aggressive character — goes in the amp's FX loop (or last, into a clean amp)
Comes later in the signal chain
Empress Echosystem
Empress
6% matchKeep Demon FX Microtubes A7K Bass Preamp's aggressive voice out front: Empress Echosystem goes after Demon FX Microtubes A7K Bass Preamp in the signal chain so its pristine voice doesn't muddy it — goes in the amp's FX loop (or last, into a clean amp)
Comes later in the signal chain
Death By Audio Destruction
Death By Audio
tonal matchComes earlier in the signal chain
Death By Audio Destruction stacks fuzzy on top of the mid-forward already here
Dr. Scientist Frazz Dazzler V2
Dr Scientist
tonal matchComes earlier in the signal chain
Run mid-forward into Dr. Scientist Frazz Dazzler V2 for more fuzzy on top
Cheaper alternatives
Boutique & premium upgrades
Laney Digbeth Series Bass
Laney
49% similarityShared character: bass, overdrive
Ashdown Geezer Butler Signature
Ashdown
49% similarityShared character: middle, bass, aggressive playing
Electro-Harmonix Battalion Bass Preamp/DI
Electro-Harmonix
47% similarityShared character: middle, bass, overdrive
Ampeg Classic Analog Bass Preamp
Ampeg
43% similarityShared character: middle, bass
DSM & Humboldt Electronics Sub-Atomic X-Over Cmos Bass Preamp
Dsm Humboldt Electronics
43% similarityShared character: bass, aggressive playing, overdrive
Dunlop MXR M85 Bass Distortion
Dunlop
43% similarityShared character: metal, middle, bass
Similar character
Demon FX Microtube D7K "Bass" Preamp
Demon Fx
74% similarityShared character: bass, aggressive playing, overdrive
Electro-Harmonix Nano Operation Overlord
Electro-Harmonix
55% similarityShared character: middle, bass, overdrive
Ashdown James LoMenzo Mega Drive
Ashdown
49% similarityShared character: metal, middle, bass
Hotone B Station
Hotone
48% similarityShared character: middle, bass, overdrive
EarthQuaker Devices Scrolls V1
EarthQuaker Devices
45% similarityShared character: bass, aggressive playing, overdrive
Tech 21 Sansamp YYZ Shape-Shifter
Tech 21
44% similarityShared character: bass, aggressive playing
See all alternatives to the Demon FX Microtubes A7K Bass Preamp (cheaper + boutique) →
Questions people ask
What are good alternatives to the Demon FX Microtubes A7K Bass Preamp?+
The closest matches in character are the Demon FX Microtube D7K "Bass" Preamp, the Electro-Harmonix Nano Operation Overlord, the Ashdown James LoMenzo Mega Drive. Budget picks: Electro-Harmonix Bass Metaphors. Boutique upgrades: Laney Digbeth Series Bass, Ashdown Geezer Butler Signature, Electro-Harmonix Battalion Bass Preamp/DI.
What pairs well with the Demon FX Microtubes A7K Bass Preamp?+
Strong matches from rig and tone-complementarity evidence: Fjord Fuzz Odin, Fjord Fuzz Berserk, Electro-Harmonix Bad — Fjord Fuzz Odin layers fuzzy onto an already mid-forward signal.
How much does the Demon FX Microtubes A7K Bass Preamp cost?+
Around $67.88 (live listing price, updated Oct 23, 2026).