Akashic Guitar effects PCB lookup
COLORINTENSITYBLENDATTACKDECAY

1590XX · 5 knobs

Aion FX

SpectronDynamic Filter

Based on the Lovetone Meatball

Category
Wah / Envelope· Envelope filter
Controls
Color · Intensity · Blend · Attack · Decay
Difficulty
Advanced
Price
$22.00in stock

From the vendor

A full-featured envelope filter originally based on the Mu-Tron III with several modifications and additions. Used by The Edge, J Mascis, and Kevin Shields among others.

The Spectron Envelope Filter is based on the Lovetone Meatball, the first of Lovetone’s legendary big-box modulation effects that was initially released in 1995. It has been used by a number of high-profile artists including Kirk Hammett, Dan Auerbach, The Edge, Kevin Shields and J Mascis.

Unlike Lovetone’s later offerings, the Meatball was not a fully original circuit, but rather a heavily tweaked version of the very first commercial envelope filter pedal, the Mu-tron III. While the core circuit is the very similar, the Meatball adds several new features including a clean blend, attack/decay controls, two extra range modes in between Hi and Lo, two expression controls, and an effects loop.

The Spectron is a faithful adaptation of the Meatball, with the only changes being cosmetic. The rotary switches are certainly part of Lovetone’s trademark aesthetic, but two of the switches can easily be replaced with standard toggles, so we’ve simplified the switching accordingly.

The Spectron also includes a new optional modification for an external trigger source. The original Meatball allows similar functionality with the Send/Receive loop, but there are a few limitations with the way it is implemented. Because of this, we’ve added the capacity for an external signal source to be fed to the trigger circuit. The limitations of the original and the benefits of the external trigger modification are described in the build documentation if you’re curious about the particulars.

Special thanks to Ian (LaceSensor / Gigahearts FX), the DIY community’s resident Lovetone expert, for help verifying the Spectron prototype against an original Meatball for accuracy.

Schematic

The schematic is in the vendor's build document, page 13. Open the build document. No KiCad fragment has been drawn for this circuit yet.

Parts list 81 rows

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RefValueNormalizedTypeNotes
Resistors 25
R11k51.5kMetal film resistor, 1/4W
R21M81.8MMetal film resistor, 1/4W
R3100k100kMetal film resistor, 1/4W
R4330R330Metal film resistor, 1/4W
R54k74.7kMetal film resistor, 1/4W
R622k22kMetal film resistor, 1/4W
R71M81.8MMetal film resistor, 1/4W
R8100R100Metal film resistor, 1/4W
R91k51.5kMetal film resistor, 1/4W
R10330R330Metal film resistor, 1/4W
R11330R330Metal film resistor, 1/4W
R12330R330Metal film resistor, 1/4W
R1310k10kMetal film resistor, 1/4W
R1410k10kMetal film resistor, 1/4W
R151k51.5kMetal film resistor, 1/4W
R16100k100kMetal film resistor, 1/4WPart of the Moog filter mod. See build notes.
R1710k10kMetal film resistor, 1/4W
R18220k220kMetal film resistor, 1/4W
R19120k120kMetal film resistor, 1/4W
R2022k22kMetal film resistor, 1/4W
R2122k22kMetal film resistor, 1/4W
R22330R330Metal film resistor, 1/4W
R2322k22kMetal film resistor, 1/4WOptional. Added in v1.2 for bias modification. See build notes.
RPD2M22.2MMetal film resistor, 1/4W
LEDR10k10kMetal film resistor, 1/4W
Capacitors 20
C1470n470nFilm capacitor, 7.2 x 3mm
C22n22.2nFilm capacitor, 7.2 x 2.5mm
C310uF10uElectrolytic capacitor, 5mm
C410uF10uElectrolytic capacitor, 5mm
C522n22nFilm capacitor, 7.2 x 2.5mm
C6470n470nFilm capacitor, 7.2 x 3mm
C710uF10uElectrolytic capacitor, 5mm
C810uF10uElectrolytic capacitor, 5mm
C9470n470nFilm capacitor, 7.2 x 3mmPart of the Moog filter mod. See build notes.
C102n22.2nFilm capacitor, 7.2 x 2.5mm
C113n33.3nFilm capacitor, 7.2 x 2.5mm
C126n86.8nFilm capacitor, 7.2 x 2.5mm
C1315n15nFilm capacitor, 7.2 x 2.5mm
C142n22.2nFilm capacitor, 7.2 x 2.5mm
C153n33.3nFilm capacitor, 7.2 x 2.5mm
C166n86.8nFilm capacitor, 7.2 x 2.5mm
C1715n15nFilm capacitor, 7.2 x 2.5mm
C1847uF47uElectrolytic capacitor, 5mm
C19100uF100uElectrolytic capacitor, 6.3mm
C20100n100nMLCC capacitor, X7R
Diodes 5
D11N58171N5817Schottky diode, DO-41
D21N9141N914Fast-switching diode, DO-35
D31N9141N914Fast-switching diode, DO-35
D41N9141N914Fast-switching diode, DO-35
D51N9141N914Fast-switching diode, DO-35
ICs 3
IC1TL072TL072Operational amplifier, dual, DIP-8
IC2LM358NLM358NOperational amplifier, dual, DIP-8
IC3TL072TL072Operational amplifier, dual, DIP-8
Opto 2
LDR1GL5537-1GL5537-1LDR, 20-30k light, 2M darkSee build notes for LED/LDR information.
LDR2GL5537-1GL5537-1LDR, 20-30k light, 2M darkSee build notes for LED/LDR information.
Potentiometers 6
ATK.5kBB5k16mm right-angle PCB mount pot
BLEND10kBB10k16mm right-angle PCB mount pot
DECAY100kAA100k16mm right-angle PCB mount pot
INT.1kBB1k16mm right-angle PCB mount pot
SENS.10kBB10k16mm right-angle PCB mount pot
BIAS100k trimmer T100K TRIMMER Trimmer, 10%, 1/4”, Bourns 3362POptional. Added in v1.2 for bias modification. See build notes.
Switches 9
BAND.SPDT cntr offSPDT CNTR OFFToggle switch, SPDT on-off-on
FILTERSPDTSPDTToggle switch, SPDT on-onOptional modification. See build notes if you want to omit it.
MODEDPDT on-on-on ToDPDT ON-ON-ON TOggle switch, DPDT on-on-onSee build notes to make sure you use the correct toggle type.
LOOP SND.NMJ6HC-SNMJ6HC-S1/4” phone jack, stereo, switchedNeutrik NMJ6HC-S
LOOP RET.NMJ6HC-SNMJ6HC-S1/4” phone jack, stereo, switchedNeutrik NMJ6HC-S
INT. EXPR.NMJ6HC-SNMJ6HC-S1/4” phone jack, stereo, switchedNeutrik NMJ6HC-S
DEC. EXPR.NMJ6HC-SNMJ6HC-S1/4” phone jack, stereo, switchedNeutrik NMJ6HC-S
EXT. TRIGR.NMJ6HCD2NMJ6HCD21/4” phone jack, stereo, switchedNeutrik NMJ6HCD2 (the PCB-mount variant of the HC-S).
BYPASS3PDT3PDTStomp switch, 3PDTAvailable from Aion FX.
LEDs 4
LED5mm5MMLED, 5mm, red diffused
SENSE5mm green5MM GREENLED, 5mm, green diffused
LED15mm green5MM GREENLED, 5mm, green diffusedSee build notes for LED/LDR information.
LED25mm green5MM GREENLED, 5mm, green diffusedSee build notes for LED/LDR information.
Jacks & sockets 6
IC1-SDIP8 socketDIP8 SOCKETIC socket, DIP-8
IC2-SDIP8 socketDIP8 SOCKETIC socket, DIP-8
IC3-SDIP8 socketDIP8 SOCKETIC socket, DIP-8
IN1/4" mono1/4" MONO1/4" phone jack, closed frameSwitchcraft 111X or equivalent.
OUT1/4" mono1/4" MONO1/4" phone jack, closed frameSwitchcraft 111X or equivalent.
DC2.1mm2.1MMDC jack, 2.1mm panel mountLumberg NEB/J 21 C or equivalent.
Hardware 1
ENC1590XX1590XXEnclosure, die-cast aluminum1790NS equivalent.