aion Dryad Transparent Overdrive User manual

DRYAD TRANSPARENT OVERDRIVE 1
PROJECT NAME
DRYAD
BASED ON
EFFECT TYPE
PROJECT SUMMARY
DOCUMENT VERSION
Catalinbread Silver Kiss Mk. 2
A stripped-down Tube Screamer circuit with an active 3-band EQ which provides amp-like control over
the tone.
Transparent overdrive 1.0.0 (2023-11-24)
Actual size is 2.3” x 1.86” (main board) and 2.3” x 0.86” (bypass board).
BUILD DIFFICULTY
Easy

DRYAD TRANSPARENT OVERDRIVE 2
TABLE OF CONTENTS
1Project Overview 7Drill Template
2Introduction & Usage 8Enclosure Layout
3-4 Parts List 9Wiring Diagram
5Build Notes 10 Licensing
6Schematic 10 Document Revisions
INTRODUCTION
The Dryad Transparent Overdrive is based on the Catalinbread Silver Kiss, originally released in 2007
and traced by Aion FX in 2023. There were at least five different versions of the circuit, but this project
is based on the Mk. 2, which was the most widely available.
The Silver Kiss is a simplified Tube Screamer-style overdrive, not dissimilar in concept to the Jack
Orman Son of Screamer or the Lovepedal Eternity. The major departure is the addition of an active
3-band tone control, which offers a significant amount of tone-shaping.
As with the Timmy, the Silver Kiss doesn’t color the tone with a lot of its own character, instead bringing
out the best of your rig but allowing for a high degree of control before it hits the amp.
The Dryad is a direct adaptation of the Silver Kiss Mk. 2 based on our trace.
USAGE
The Dryad has the following controls:
• Treble, Middle and Bass form an active 3-band tone control for flexible tone shaping.
• Gain controls the amount of gain in the op-amp clipping stage.
• Volume controls the overall output of the effect.

DRYAD TRANSPARENT OVERDRIVE 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 1M Metal film resistor, 1/4W
R2 1k Metal film resistor, 1/4W
R3 1k Metal film resistor, 1/4W
R4 2k2 Metal film resistor, 1/4W
R5 2k2 Metal film resistor, 1/4W
R6 2k2 Metal film resistor, 1/4W
R7 1k Metal film resistor, 1/4W
R8 2k2 Metal film resistor, 1/4W
R9 2k2 Metal film resistor, 1/4W
R10 2k2 Metal film resistor, 1/4W
R11 2k2 Metal film resistor, 1/4W
R12 100k Metal film resistor, 1/4W
R13 100k Metal film resistor, 1/4W
R14 47R 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 10k Metal film resistor, 1/4W LED current-limiting resistor. Adjust value to change LED brightness.
C1 47n Film capacitor, 7.2 x 2.5mm
C2 200pF MLCC capacitor, NP0/C0G
C3 220n Film capacitor, 7.2 x 2.5mm
C4 100n Film capacitor, 7.2 x 2.5mm
C5 1uF Film capacitor, 7.2 x 3.5mm Can omit and use 4.7uF tantalum for C6. See build notes.
C6 OMIT Tantalum capacitor, 044A Can use 4.7uF tantalum here and leave C5 empty. See build notes.
C7 47n Film capacitor, 7.2 x 2.5mm
C8 22n Film capacitor, 7.2 x 2.5mm
C9 47n Film capacitor, 7.2 x 2.5mm
C10 47n Film capacitor, 7.2 x 2.5mm
C11 1uF Film capacitor, 7.2 x 3.5mm Can omit and use 4.7uF tantalum for C12. See build notes.
C12 OMIT Tantalum capacitor, 044A Can use 4.7uF tantalum here and leave C11 empty. See build notes.
C13 47uF Electrolytic capacitor, 5mm Reference voltage filter capacitor.
C14 100uF Electrolytic capacitor, 6.3mm Power supply filter capacitor.
C15 100n MLCC capacitor, X7R Power supply filter capacitor.

DRYAD TRANSPARENT OVERDRIVE 4
PARTS LIST, CONT.
PART VALUE TYPE NOTES
D1 1N5817 Schottky diode, DO-41
D2 1N914 Fast-switching diode, DO-35
D3 1N914 Fast-switching diode, DO-35
IC1 TL072 Operational amplifier, dual, DIP8
IC1-S DIP-8 socket IC socket, DIP-8
GAIN 100kA 16mm right-angle PCB mount pot Audio (log) taper.
BASS 50kB 16mm right-angle PCB mount pot Linear taper.
MID 50kB 16mm right-angle PCB mount pot Linear taper.
TREBLE 100kB 16mm right-angle PCB mount pot Linear taper.
VOLUME 10kB 16mm right-angle PCB mount pot Linear taper.
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.
BATT Battery snap 9V battery snap Optional. Use the soft plastic type—the hard-shell type will not fit.
FSW 3PDT Stomp switch, 3PDT
ENC 125B Enclosure, die-cast aluminum Can also use a Hammond 1590N1.

DRYAD TRANSPARENT OVERDRIVE 5
BUILD NOTES
C5/C6 and C11/C12 capacitors
The Silver Kiss uses 4.7uF tantalum capacitors (C6 and C12) as signal couplers immediately after both
of the op-amp stages. We recommend keeping tantalum capacitors out of the signal path wherever
possible. This PCB includes space for an alternate film capacitor (C5 and C11) in each of these positions,
in which case C6 and C12 can be omitted entirely.
Due to the low source impedance of the op-amp stages, 1uF is more than enough to pass all useful
bass frequencies. However, if you want to stick as closely as possible to the original circuit, use 4.7uF
tantalum capacitors for C6 and C12 and omit C5 and C11.

DRYAD TRANSPARENT OVERDRIVE 6
SCHEMATIC
IN
OUT
GND
2M2
1N5817
100uF
50kB
50kB
GND
10kB
100kB
+9V
100n
VA
47n
1M
VB
TL072P
TL072P
VA
GND
200pF
2k2
100kA
1N914
1k
220n
GND
1k
1uF
2k2 2k2
2k2 2k2
2k2 2k2
1k 47n22nF
47n
47n
VB
1uF
GND
4.7uF
4.7uF
100k
100k
47uF
GND GND
VB
47R
RPD
D1
C14
BASS
1
2
3
MID
1
2
3
VOLUME
1
2
3
TREBLE
1
2
3
C15
C1
R1
2
3
1
IC1A
IC1B
6
5
7
84
C2
R4
1
2
3
GAIN
D2
D3
R2
C3
R3
C5
R5 R6
R8 R9
R10 R11
R7 C7C8
C9
C10
C11
C6
C12
R12
R13
C13
R14
GND
100n
GND
C4

DRYAD TRANSPARENT OVERDRIVE 7
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.
0 1 2
CM
0 1
INCH
x: -0.775, y: +1.71 x: +0.775, y: +1.71
ø9/32” ø9/32”
x: -0.775, y: +0.41
ø9/32”
x: 0, y: +1.71
ø9/32”
x: +0.775, y: +0.41
ø9/32”
x: 0, y: -1.20
ø15/32”
x: -0.775, y: -1.20
ø5/16”
CENTER (0,0)
125B
TREBLEMIDBASS
GAINVOLUME
FOOTSWITCHLED
ø3/8” ø1/2”
0.385”
0.625” 0.625”
ø3/8”
OUT DC IN

DRYAD TRANSPARENT OVERDRIVE 8
ENCLOSURE LAYOUT
Enclosure is shown without jacks. See next page for jack layout and wiring.
125B

DRYAD TRANSPARENT OVERDRIVE 9
WIRING DIAGRAM
125B
IN +VGND N.C. N.C. OUT
PCB
IN
GND +V +V JACK GND JACK
OUTIN
GND GND PCB
OUT
Shown with optional 9V battery. If battery is omitted, both jacks can be mono rather than one being stereo.
Leave the far-right lug of the DC jack unconnected.

DRYAD TRANSPARENT OVERDRIVE 10
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.
Projects may be used for commercial endeavors in any quantity unless specifically noted. No
attribution is necessary, though a link back is always greatly appreciated. The only usage restrictions
are that (1) you cannot resell the PCB as part of a kit without prior arrangement, and (2) you cannot
“goop” the circuit, scratch off the screenprint, or otherwise obfuscate the circuit to disguise its source.
(In other words: you don’t have to go out of your way to advertise the fact that you use these PCBs, but
please don’t go out of your way to hide it. The guitar effects industry needs more transparency, not less!)
DOCUMENT REVISIONS
1.0.0 (2023-11-24)
Initial release.