aion UBE SCREAMER User manual

RUNOFFGROOVE UBE SCREAMER 1
PROJECT NAME
UBE SCREAMER
BASED ON
EFFECT TYPE
PROJECT SUMMARY
DOCUMENT VERSION
Runoffgroove UBE Screamer
An original design from Runoffgroove with the goal of reproducing the sound of the Tube Screamer with
CMOS gain stages.
CMOS overdrive 1.0.0 (2022-04-08)
BUILD DIFFICULTY
Easy
Actual size is 2.3” x 1.86” (main board) and 1.78” x 0.87” (bypass board).

RUNOFFGROOVE UBE SCREAMER 2
TABLE OF CONTENTS
1Project Overview 7Enclosure Layout
2Introduction & Usage 8Wiring Diagram
3-4 Parts List 9Licensing
5Schematic 9Document Revisions
6Drill Template
INTRODUCTION
The UBE Screamer from Runoffgroove was originally developed as an experiment to see if something
tonally similar to the Ibanez Tube Screamer could be created with a series of CMOS hex-inverter stages.
CMOS hex inverters function somewhat similar to op-amps, albeit with much lower open-loop gain and
much different clipping characteristics. Craig Anderton’s famous Tube Sound Fuzz circuit (which the
Way Huge Red Llama is based on) also used hex inverters, as well as the Electro-Harmonix Hot Tubes
from 1979 and many other derivatives since that time.
Circuit-wise, the UBE Screamer has little in common with the Tube Screamer it’s named for, but it
succeeds in occupying a similar space in the tonal spectrum and is well worth your time to build it.
The Aion FX implementation of the UBE adds two modifications: a clipping diode switch and a second
switch to change out the global feedback resistor. The original Runoffgroove article recommends
selecting this resistor for based on whether you’ll be using single coil pickups or humbuckers, so we
took the step of putting it on a switch so the pedal can be used in any scenario without heating up the
soldering iron.
USAGE
The UBE Screamer has three knobs:
• Drive controls the amount of gain going into the feedback-clipping stage.
• Tone controls the treble response of the effect, cutting frequencies at 3dB/octave with a variable
cutoff frequency of between 1kHz and 10kHz.
• Volume controls the overall output of the effect.
In addition, there are two switch modifications included for added flexibility:
• Clipping selects between 2 diodes or 4 diodes in the feedback clipping stage.
• Frequency sets the mixing ratio of the clean path, which impacts the EQ or fullness of the overall
effect. Three options are available, with the down position being better suited for single-coil guitars
and the middle position being better for humbuckers. The top position is somewhere in between.

RUNOFFGROOVE UBE SCREAMER 3
PARTS LIST
This parts list is also available in a spreadsheet format which can be imported directly into Mouser for
easy parts ordering. Mouser doesn’t carry all the parts—notably potentiometers—so the second tab lists
all the non-Mouser parts as well as sources for each.
View parts list spreadsheet →
PART VALUE TYPE NOTES
R1 470k Metal film resistor, 1/4W
R2 470k Metal film resistor, 1/4W
R3 100k Metal film resistor, 1/4W
R4 100k Metal film resistor, 1/4W
R5 10k Metal film resistor, 1/4W
R6 1M Metal film resistor, 1/4W
R7 100k Metal film resistor, 1/4W
R8 10k Metal film resistor, 1/4W
R9 100k Metal film resistor, 1/4W
R10 100k Metal film resistor, 1/4W
R11 330k Metal film resistor, 1/4W
R12 680k Metal film resistor, 1/4W
R13 150k Metal film resistor, 1/4W
R14 220k Metal film resistor, 1/4W
R15 330R Metal film resistor, 1/4W Power supply filter resistor.
RPD 2M2 Metal film resistor, 1/4W Input pulldown resistor. Can be as low as 1M.
LEDR 4k7 Metal film resistor, 1/4W LED current-limiting resistor. Adjust value to change LED brightness.
C1 10n Film capacitor, 7.2 x 2.5mm
C2 2n2 Film capacitor, 7.2 x 2.5mm
C3 470n Film capacitor, 7.2 x 3mm
C4 OMIT MLCC capacitor, NP0/C0G Optional. Use 100pF if you experience feedback at high gain settings.
C5 100n Film capacitor, 7.2 x 2.5mm
C6 1n5 Film capacitor, 7.2 x 2.5mm
C7 150pF MLCC capacitor, NP0/C0G
C8 100n Film capacitor, 7.2 x 2.5mm
C9 100n Film capacitor, 7.2 x 2.5mm
C10 100n Film capacitor, 7.2 x 2.5mm
C11 220uF Electrolytic capacitor, 6.3mm Power supply filter capacitor.
C12 100n MLCC capacitor, X7R Power supply filter capacitor.
C13 100n MLCC capacitor, X7R Power supply filter capacitor.
D1 1N5817 Schottky diode, DO-41
D2 1N914 Fast-switching diode, DO-35

RUNOFFGROOVE UBE SCREAMER 4
PARTS LIST, CONT.
PART VALUE TYPE NOTES
D3 1N914 Switching diode, DO-35
D4 1N914 Switching diode, DO-35
D5 1N914 Switching diode, DO-35
D6 1N914 Switching diode, DO-35
D7 1N914 Switching diode, DO-35
IC1 CD4049UBE CMOS hex inverting buffer, DIP16
IC1-S DIP-16 socket IC socket, DIP-16
DRIVE 500kB 16mm right-angle PCB mount pot
TONE 500kB 16mm right-angle PCB mount pot
VOL. 100kA 16mm right-angle PCB mount pot
CLIP SPDT Toggle switch, SPDT on-on Can also use a center-off switch to add diode lift mode (untested)
FREQ SPDT cntr. off Toggle switch, SPDT on-off-on
LED 5mm LED, 5mm, red diffused
IN 1/4" stereo 1/4" phone jack, closed frame Switchcraft 112BX or equivalent.
OUT 1/4" mono 1/4" phone jack, closed frame Switchcraft 111X or equivalent.
DC 2.1mm DC jack, 2.1mm panel mount Mouser 163-4302-E or equivalent.
FSW 3PDT Stomp switch, 3PDT
ENC 125B Enclosure, die-cast aluminum Can also use a Hammond 1590N1.

SCHEMATIC
RUNOFFGROOVE UBE SCREAMER 5
GND
2M2
1N5817
220uF
GND
+9V
100n
VA
500kB
100kA
CD4049UBE CD4049UBE
CD4049UBE
CD4049UBE
CD4049UBE
CD4049UBE
330R
10n
470k
470k
2n2
100k
100k
10k
470n
1M
100n
100k
1n5
10k
GND
500kB
100k
150pF
100n
100k
100n
330k
680k
150k
220k
100n
GND
VA
GND
100n
GND
VA
100pF
RPD
D1
C11
IN
OUT
C13
DRIVE
1
2
3
VOLUME
1
2
3
IC1D
109
IC1E
1211
IC1C
67
IC1F
1514
IC1B
45
IC1A
23
IC1P
VDDVSS
8 1
R15
C1
R1
R2
C2
R3
R4
R5
C3
R6
C5
R7
C6
R8
TONE
1
2
3
R9
C7
C8
R10
C9
R11
R12
R13
R14
C10
D2
D3
D4
D7
D5
D6
FREQ
2
3
1
CLIP
2
3
1
C12
C4
GND

RUNOFFGROOVE UBE SCREAMER 6
DRILL TEMPLATE
Cut out this drill template, fold the edges and tape it to the enclosure. Before drilling, it’s recommended
to first use a center punch for each of the holes to help guide the drill bit.
Ensure that this template is printed at 100% or “Actual Size”. You can double-check this by measuring
the scale on the printed page.
Top jack layout assumes the use of closed-frame jacks like the Switchcraft 111X. If you’d rather use
open-frame jacks, please refer to the Open-Frame Jack Drill Template for the top side.
LED hole drill size assumes the use of a 5mm LED bezel, available from several parts suppliers. Adjust
size accordingly if using something different, such as a 3mm bezel, a plastic bezel, or just a plain LED.
x: -0.65, y: +1.71 x: 0.65, y: +1.71
ø9/32” ø9/32”
x: -0.85, y: +0.66
ø1/4”
x: 0, y: +0.66
ø9/32”
x: 0, y: -1.20
ø15/32”
x: -0.775, y: -1.20
ø5/16”
CENTER (0,0)
ø3/8” ø1/2”
0.385”
0.625” 0.625”
ø3/8”
OUT DC IN
125B
VOLUME
FREQ CLIPTONE
DRIVE
FOOTSWITCHLED
x: +0.85, y: +0.66
ø1/4”
0 1 2
CM
0 1
INCH

RUNOFFGROOVE UBE SCREAMER 7
ENCLOSURE LAYOUT
Enclosure is shown without jacks. See next page for jack layout and wiring.
125B

RUNOFFGROOVE UBE SCREAMER 8
WIRING DIAGRAM
125B
IN +VGND N.C. N.C. OUT
PCB
IN
GND +V +V JACK GND JACK
OUTIN
GND GND PCB
OUT

RUNOFFGROOVE UBE SCREAMER 9
LICENSE & USAGE
No direct support is offered for these projects beyond the provided documentation. It’s assumed
that you have at least some experience building pedals before starting one of these. Replacements and
refunds cannotbe offered unless it can be shown that the circuit or documentation are in error.
All of these circuits have been tested in good faith in their base configurations. However, not all the
modifications or variations have necessarily been tested. These are offered only as suggestions based
on the experience and opinions of others.
Runoffgroove circuit licensing
Runoffgroove circuits have special licensing that is different from standard Aion FX projects. These
projects are for personal use only and may not be used for commercial endeavors without approval
from Runoffgroove. Here are the terms of use from their site:
runoffgroove.com projects are provided free-of-charge to builders for personal, non-commercial use. We do offer
licensing for builders who wish to sell pedals based on, in whole or in part, our projects. As part of the licensing
agreement, the builder must clearly state that the circuit was developed by runoffgroove.com, both in promotional
literature and on the circuit board. If you see a pedal for sale that seems to be based on a runoffgroove.com project
and does not credit us, the builder may not be officially licensed by us and therefore, not compensating us as the
developer. Please contact us with the information and we will investigate the situation. Thank you.
DOCUMENT REVISIONS
1.0.0 (2022-04-08)
Initial release.