Ampt ANALOGER ADG-1 User manual

100% Analog Bucket Brigade Delay
User Manual Version 1.0 - Draft
Last Revision 11/20/2020

<2>
Introduction
Thank you for your purchase of Asheville Music Tool’s ADG-1 Analog
Delay. This pedal, engineered by renowned analog delay designer Hawker,
features two reissue Bucket Brigade Delay lines, for up to 700mS of delay.
It is coupled with a Low Frequency Oscillator and uses control voltage
topology to give you the best sound, features, and control available in any
fully analog delay currently on the market. We hope you enjoy many years
of use from your delay and find it as inspiring and fun to play as we have.
The ADG-1 is a marriage of vintage audio processing techniques and
advanced, high-tech electronics. It is designed using modern quality
components for uncompromising sound, musical expression, features, and
reliability. We started with a high voltage 15V power supply powering a
pair of studio grade MN3005 BBDs, unlike the lower cost MN320x pedal
grade BBDs found in most stompboxes. We then added a special blend of
two tightly tuned 5th order anti-alias and reconstruction filters, a unique 5
amp high current BBD driver, with an analog clock and exponential
modulation technology to obtain unprecedented sound, richness, clean tails
and true fractional delay in a compact footprint.
This is the first in what we hope to be a long line of time, phase, frequency,
control voltage based modulation, and synthesizer heritage inspired effects
from Hawker. The ADG-1 comes from and is inspired by delay-based
effects that Hawker has previously designed for other companies and
builds on his experience and expertise.
A special thank you and mention is needed for two people:
Kelly Bowers, my life partner, land-mate and co fur-parent for her love,
faith and dedication, and for pushing me to start designing products for
myself rather than others.
John Snyder, from Electronic Audio Experiments, for his friendship,
collaboration and help in bringing this pedal to market. Your experience,
patient advice, handholding and support were what made this possible. I
could not have done it without you.

<3>
About BBDs
I am often asked what gives analog delays their characteristic sound. The
answers I usually see given are not what makes them sound different to me.
A BBD (Bucket Brigade Delay) works by storing a momentary snapshot
“sample” or charge in a capacitor isolated by a FET network. It passes this
sample from one capacitor to the next via a BBD clock until it reaches the
output. These capacitors are like water in a bucket brigade line, passing the
audio sample from one “bucket” to the other until it reaches the “fire” at
the end. BBDs were originally designed for use in radar to determine the
distance to objects. By sending out radar signals, and delaying it through a
BBD one can adjust the delay time compared to the reflection. When the
reflection phase cancels out the delayed sample you have 1/4 the delay
time/distance. Early digital oscilloscopes, like the Tektronix 2440, also
used them as temporary storage since Analog to Digital converters of the
time were too slow. Digital cameras still do this today for the same reason.
Now they are used for audio in delays, chorus and flangers.
The ADG-1 uses a recreation of the Matsushita/Panasonic MN3005 PMOS
BBD from Xvive™. The MN30xx series BBDs use a higher voltage for
more clarity, lower noise, more headroom and lower distortion than the
MN320x NMOS types usually found in most stomp boxes, however they
have lower range of delay time (cannot clock as fast) compared to MN320x
BBDs. These BBDs sound very close to the Panasonic parts but are more
transparent, less animated and appear to have a lower noise floor. In
addition, the clock speed does not change the sound as much as their
predecessors do.
Perhaps the biggest reason BBDs can do what digital often cannot is due to
Fractional Delay, often referenced as the Doppler Effect. Since the clock
moves continuously, the delay time has every single continuous time delay
between each rate. That is why analog delays make great dive bombing
sounds. The ear is very sensitive to this and perceives this as distance and
movement. This trick is how movies pan sound or make you think a bullet
just whizzed over your head. Most digital delays simply cannot do this.

<4>
With a fixed clock frequency, they can only take a sample every 48 or
96KHz and step at that increment. They can only simulate fractional delay
and cannot do true fractional delay. The ear can perceive this and so it does
not feel right to the brain. Note early digital delays like the Lexicon PCM
41/42 did change the clock using different process, but these are the
exception not the rule. Most hybrid analog delays that use a MPU digital
clock do not use steps small enough for true fractional delay, so while they
may use a BBD the modulation does not sound as natural as some
picosecond step clocks or true analog modulation.
In addition, BBDs have some other “artifacts” that give them a unique
sound. The transfer characteristics, noise, distortion and frequency
response vary depending on the bias voltage and clock frequency making
the sound change as the delay time changes. They also do not put out the
entire signal at the same time. Half the signal is ½ clocks behind the rest of
the signal, yet combined at the same time, making for a strange time
domain merger and mixing of the signals slightly out of time.
Other components also affect the sound. The design of the companding and
emphasis/de-emphasis network (designed to improve the signal to noise
ratio) affects the animation, breathing, overshoot and tightness of the sound
like a compressor with a slow attack and fast release. The design of the
filters affects the frequency response, peaking or ringing, and potential
aliasing or ring modulation. There are many more parts of the analog
design often overlooked in digital recreations that affect the sound as well
including the clipping, feedback network, clock stability modulation wave
shaping/curves (exponential or linear, etc.) that are all important to get that
great analog delay sound.
For more reading about BBDs check out these great websites:
https://www.electrosmash.com/mn3007-bucket-brigade-devices
https://www.premierguitar.com/articles/25035-behind-the-bucket-brigade
https://pedals.thedelimagazine.com/bbd-chips-the-magic-behind-analog-
delay-pedals/

<5>
About the Firemen and the ADG-1 Artwork
Our pedal artwork, drawn by artist Geoff Sebesta, is homage to Hawker’s
past pedals and old modular synthesizers. The lines and boxes around
function blocks lend themselves to how classic modular synths were
organized by function. You may notice the use of synthesizer terms such as
“LFO, VCO, CV” and very literal function knob names rather than the
more sonic based names of guitar pedals (Feedback and Time rather than
Regeneration and Manual for example). It helps the user see the logical
function blocks, signal flow and understand what is happening.
Our firemen, also drawn by Geoff, have a historical background. In the
1990s Panasonic released an applications note and data sheet book about
BBDs (and Digikey used in in their marketing). On the cover and back of
this book was a picture of firemen in a bucket brigade line. This represents
the BBDs function of passing the sound from one capacitor or “bucket” to
another and 4096 times before it goes out (8192 times for us) by varying
the clock, thus delaying the sound.
Panasonic drew the men inspired by how the core of the product behaves.
Alas, I do not have that manual anymore and I cannot find it on the internet
but I did scan it once as shown below. Note the distortion where the book
was damaged.
I used this on the back of the PCB of a certain well-known analog delay I
previously designed. I felt it would be a nice tribute to use a re-drawn
version here for our BBD based delay.

<6>
Set up
Use only standard, REGULATED, 9VDC, center-negative power supplies
rated for at least 200mA from a reputable vendor for all your Asheville
Music Tools effects. Classic old style, rectified & filtered, but unregulated,
supplies are not acceptable for use with this product. We like the
Truetone™ One Spot® and similar products.
The ADG-1 will draw up to 125mA when engaged so be careful when
using multi output supplies that are rated for only 100mA. Use the higher
current outputs when using this type of supply. Never use a higher
voltage supply with this product. There are no sonic benefits and you will
risk damaging the pedal and void the warranty. The pedal will not turn on
if it detects an overvoltage supply. The Analoger Series of pedals high
current draw make it impractical to use with a conventional 9V battery.
The ADG-1 has an input level control and flexible bypass making it able to
be used in various configurations for guitar, synthesizer or line level
applications, including:
Standard pedal use: ADG-1 connected into an amplifier input,
with or without other pedals. You may use the pedal in either
Buffered or True bypass mode in this configuration.
Insert Effect: Connect the ADG-1 to the effects send/return of
your power amp or mixing console. Or use the ADG-1 to replace
the existing preamp if connected to just the return. Use this in
buffered Bypass mode only.
DI (Direct Input): The ADG-1 can be used to impedance match
to a mixer or DAW input for the correct drive and impedance
conversion from the guitar’s high impedance out to the low
impedance of a console or DAW line in. It can also be used as a
buffered drive pedal placed before other pedals. For best results
use with 10K or higher input impedance. Not suitable for
600ohm input impedance of some classic consoles. Use this in
buffered Bypass mode only.

<7>
Getting Started
Let’s explore the range of controls of your ADG-1.
Connect your guitar or other instrument to the INput jack. Connect an
amplifier to the OUTput jack, and if you have an expression pedal (or 0-
5V control voltage source like a synthesizer output), connect it to the
EXPression input.
Use a 9V regulated 2.1mm, center-negative, power supply, capable of
providing at least 200mA of power and connect it to the 9V DC input.
Be sure to power up your ADG-1 BEFORE turning on your amplifier to
prevent speaker pop and the potential to damage your speakers or
headphones.
Note: If not using the expression input; be sure the expression switch is
NOT SET TO THE TIME POSITION to start. We recommend setting it
to AMT if not using this feature.
To start, set the ADG-1 to the
Home position as shown in the
graphics to the right.
Set TIME, MIX & TONE
straight up (12:00).
Set FEEDBACK,RATE &
AMOUNT switch fully counter-
clockwise (7:00).
Set DRIVE slightly up, around 9:00.
Set the Bucket and LFO switches to the down position.
There is no way to damage the ADG-1 through knob settings so feel free to
explore how the controls work. Go ahead, play with your ADG-1 and have
fun. There are some gotchas and advanced possibilities so once you are
done having fun read on to learn more about the ADG-1.

<8>
Operation
The ADG-1 is laid out in homage to modular synthesizers with three main
modules. They are the DELAY Module, the LFO (Low Frequency
Oscillator) and the LEVEL Module. Let’s look closer at these modules.
DELAY MODULE
TIME: The Time knob adjusts the delay
time clock from 35mS to 700mS. If you
change the delay time while playing you
will also notice a pitch change as the signal
currently captured in the BBDs gets spit out
faster or slower compressing or expanding
the delay time. This is how analog delays
make that great pitch-up or dive-bomb
sound. Try playing with a short delay then
quickly turning the knob clock-wise for
massive dive bombs.
BUCKET SWITCH: selects whether the sound you are hearing travels
through 1 or 2 BBDs (4096 or 8192 stages) and so halves or doubles the
delay time (35mS –700mS or 17-350ms). And while there is clearly some
overlap, as you can often get the same delay time from either setting, the
tone is slightly different, so you may have a preference for one position or
the other. In general, use the down position for long reverberant delays.
Use the up position for more sparkly shimmering delays, or when doing
chorus or flange-like sounds.
FEEDBACK: The Feedback knob affects how much post EQ delayed
signal is fed back into the buckets. This affects the number of repeats and
fade-out time. Above about 3:00 it puts the ADG-1 into self-oscillation for
some wild swishing sounds that change as you move the time knob. Try it
out, get lost. Come back after and read the next section.
Be sure to read the control voltage section for information on this module
with expression pedals or control voltages.

<9>
MIX MODULE
The Level module provides level matching, wet/dry blending, and tonal
control of the ADG-1.
DRIVE: The DRIVE knob
provides up to +23dB of drive
and level matching as well as
some attenuation for hot input
signals. Unity gain is at about
9:00 but try cranking it for
some soft clipping and limiting
or to drive the BBDs hard. The drive affects both the wet and dry signals
and each have separate limiters with a different knee and threshold.
MIX:The MIX knob is designed to give you a cross-faded wet/dry mix
between the delayed and clean tone. In order to make it easier to adjust this
knob does not go 100% wet or 100% dry but very close. It gets to almost
100% wet with only a slight “ghost” dry signal but it does not approach as
close to fully dry so you will still hear a slight delay sound in the mix. This
is to make the knob easier to adjust and dial in an exact mix.
Note: If you’re applying a sustained steady pitch to the ADG-1 and have the MIX knob set near
12:00, you may find that the direct and delayed signals alternately reinforce and cancel each
other in rapid succession as the DELAY TIME is varied. This is a normal result of mixing a
steady pitch with a delayed replica of itself. It is the analog delay equivalent of “standing
waves” in a reverberant room.
TONE: The TONE knob is Hawker’s new touch for delays. It is a
modified “tilt type” filter with a soft curve that provides both high pass and
low pass control with a knee around 600Hz. It is placed INSIDE the
feedback loop so may be used to make each repeat sound progressively
more different with each repeat. You can use it in Low Pass mode to make
the sound fold under your playing or in high pass mode to make each
repeat punch and stand out more with a bright metallic sound.

<10>
LFO MODULE
The Low Frequency Oscillator (LFO) module is a modulation source for
animating your delay time and varying the pitch and time. Unlike
traditional delays, our LFO uses exponential modulation for musical and
balanced movement in a musical frequency domain, the way the ear and
brain want to hear it. In the synthesizer world this is the familiar
Volt/Octave tracking used for pitch and amplitude. Our modulation is
symmetrical around the time setting, changing above and below it. This
means that as you reduce the LFO amount the pitch and time will stay
centered where you have it and not shift one direction as with traditional
modulation.
RATE: The RATE knob adjusts the speed
or rate of modulation from about 0.08Hz
to 40Hz (wider range via control voltages).
Lower settings provide slow whoosh or a
rhythmic pitch shift. Medium speeds are a
chorus like effect while faster rates
provide a gargle, bubble or vibrato sounds.
AMOUNT: The Amount knob controls the
range of pitch movement at the speed of
the LFO aka the amount of effect. Use low amounts for subtle shimmer and
larger amounts for octave or greater pitch shifts or spaceship warbles.
LFO SHAPE SWITCH: Selects a slewed square wave or a rounded
triangle wave. At higher speeds the shape becomes more and more rounded
or slewed. Use triangle wave for traditional modulation and square waves
for pitch jumps above and below the note played.
Be sure to read the control voltage section for information on this module
with expression pedals or control voltages.

<11>
CONTROL VOLTAGE or EXPRESSION SECTION:
Using an external control voltage or EXPression pedal with your ADG-1
will greatly increase your dynamic playing and tonal possibilities as well as
expand the control range beyond the extent of the knobs. Use a standard
10-50K linear expression pedal that takes the +5V voltage supplied on the
ring jack and outputs the control voltage on the tip, or use a 0-5V external
CV voltage from a Eurorack module, Synthesizer, DAW or similar source.
CAUTION: Voltages over +5V or below 0V may damage your ADG-1.
Use only standard 0-5V control voltages. If your expression pedal has a
trim knob you may find it helpful to use this feature to reduce the range of
the expression pedal to less than a full knob sweep to make it easier to dial
in the exact sound you seek.
Please note in order to give a wider playing capability with expression
inputs the control setting selected by the Expression switch will reduce the
minimum knob setting slightly. The FEEDBACK, RATE and AMOUNT
control voltages are additive. This means that the knob position is added to
the expression position. For full control voltage range set the knob to the
most Counter Clock-Wise (CCW) setting.
TIME behaves differently as it is bi-polar. This means that, as the time
level is decreased around a 2.5V midpoint, the pitch will not shift resulting
in not having to re-adjust the center delay time based on the modulation
amount. This means that for full expression range the time knob must
be set to the center position when using an expression pedal.
Use only your fingers, a plastic screwdriver, guitar pick or similar plastic
device to turn the 4 position EXP rotary switch. Never use a metal object
that could damage the shaft. If you use this feature frequently we have
included a knob, C&K part number 297F02000. Note this knob will turn
the shaft but there is not enough shaft length through the enclosure to
permanently secure the knob to the shaft and it may fall off. Do not glue
the knob to the shaft or your ADG-1 will not be serviceable.

<12>
FOOT SWITCHES
BYPASS FOOTSWITCH: Turns the effect on or off. The LED is lit
when engaged. The switch is user selectable for true bypass or buffered
bypass by a selector switch inside the ADG-1.
TAILS / MOD FOOTSWITCH: Depending on the mode (set internally),
this switch will either engage or disengage the LFO modulation or provide
Tails (also known as Spill Over or Trails). In tails mode any sound in the
buckets and feedback loop will continue to sound or fade out (depending
on the FEEDBACK setting), however any new sound will play over this
sound and not add to the delay. The LED will flash at the LFO rate
(triangle only) while either of these modes are engaged and turn off when
not engaged.
UNDER THE HOOD SWITCHES
If you carefully remove the 4 screws holding the cover on to the back of
your ADG1 you will see 2 switches underneath the jack board on the edges
of the PCB. These are the ONLY user accessible options on your ADG-1.
They select two functional options for the pedal’s behavior. Do not adjust
any of the carefully calibrated factory set trim pots.
TRUE BYPASS / BUFFERED BYPASS: Use this switch, on the left
side of the jack board, to select true bypass (Default) or buffered bypass. In
true bypass when the effect is not engaged the input is coupled directly to
the output and does not pass through any electronics. This could be a
potential tone or noise issue for long cable runs. In this case select buffered
bypass to use the internal JFET as a simple buffered output with
approximately a 4K ohm output impedance. Non buffered bypass may have
a slight gain loss depending on the impedance match. This is normal.
MOD / TAILS: Use this switch to select if the 2nd stomp switch acts as a
modulation kill switch (default) or engages tails mode. See above for an
explanation of how these two modes behave.

<13>
Technical Overview
Utilizing over 400 carefully selected components, the entire ADG-1 was
designed for a 100% analog signal chain. We began with a classic delay
architecture using a pair of Xvive™ MN3005 reissue BBDs and a step up
power supply to power our premium audio-grade op amps and high-
tolerance, non-microphonic capacitors, providing performance, temperature
stability, low noise and maximum headroom.
We then implemented a vintage-style compander with emphasis/de-
emphasis coupled with two discrete transistor, 5th-order, anti-aliasing and
reconstruction filters to provide a familiar character with superior clarity,
noise reduction and dynamic feel. The feedback circuit uses a voltage-
controlled transconductance amplifier, to provide classic, warm feedback
tone while offering an accurate method of dialing in infinite repeats
without runaway or for achieving total feedback overload.
The input preamplifier consists of a discrete, high impedance, JFET input
stage that can be used as an always-on buffer. The preamplifier circuit can
be used for gain matching or to overdrive the delay line and mixer section
for unique artifacts and character that only an analog delay can provide.
The analog clock generation, modulation, oscillator, and even the switch
logic are all fully analog. Our VCO with temperature compensated
exponential modulation drives the BBDs at extremely high current to
eliminate artifacts for a clear tight sound. An assignable Expression/CV
input expands the flexibility and control available to the user.
The ADG-1 was designed using a multi-layer PCB with dedicated split
power and ground planes for the lowest noise and cross talk. The power
input is fully protected from reverse polarity and over-voltage conditions.
Our MHz range, step up high voltage power supply is designed to eliminate
sources of noise and radio frequency interference (RFI/EMI) and the IE is
designed to protect from electrostatic discharge (ESD) spikes to ensure
carefree operation in any studio or performance environment.

<14>
Functional Specifications:
Note: All specifications subject to change.
Time, Feedback, Rate and Amount control range all extended with the
use of Expression Pedal or control voltage input.
Delay Time: 35mS –700mS Bucket switch down (all BBDs),
17.5mS –350mS with switch up.
Feedback: 0 to greater than infinite. Capable of self-oscillation.
Rate: LFO RATE, from 0.08Hz to 40Hz
Amount: LFO amount control from OFF to 40% of Time sweep.
Drive: up to +23dB of control or level matching.
Mix: Center 50%. Adjust from full 100% wet to - 44dB
Tone: ~600Hz center tilt like filter.
HPF +6dB - -15dB, LPF +4dB - -7dB.
Bucket Toggle: 1 or 2 BBDs (4096 or 8192 buckets)
LFO toggle: Triangle or slewed Square wave
Bypass Footswitch: effect on/off user selectable True Bypass or
JFET Buffered
Tails/Mod Footswitch: User selectable modulation kill or engage
trails bypass (sometimes called Spillover).
Expression Switch: 4 position rotary selects Time, Feedback,
Rate or Amount controlled by expression pedal. Time is bi-polar
modulation (0V=-50%, 5V=+50%) all others are additive control.
Under the hood Switches: (Accessible by removing ADG-1 Cover)
True Bypass / Buffered bypass: Selects between true bypass a
classic JFET buffered bypass
2nd Stomp Switch function: Selects if 2nd stomp switch
enables/disables modulation or is tails mode.

<15>
Electrical Specifications: (subject to change)
100% Analog signal path
Switchable true bypass or JFET-buffered bypass with switchable
tails
Power: 9VDC @ <150mA (80mA Nominal)
Expression / CV input. TRS input assignable to Time, Feedback,
Mod Amount, or Mod Rate (CV range is 0-5V). Ring supplied
current limited 5V. Control on Tip.
Delay time: <35mS –700mS Dual BBD mode, 17 - 350mS
single bucket mode.
Input impedance: >1MΩ
Output impedance: 1KΩ Max (5k max for buffered bypass)
Max input level: +15dBµ (4.3V RMS)
Max output level: +14dBµ (3.9V RMS)
Maximum drive: >23dB (covers attenuation to gain)
Noise Reduction 2:1 broadband with 12dB HF emphasis
Physical Specifications:
Genuine Hammond™ die-cast aluminum enclosure
Dimensions: D=4.90” (12.5 cm), W=3.70” (9.4 cm), H=2.25”
(5.8 cm)
Weight: 15oz (0.425kg)

<16>
Tools To Inspire Your Creative Muse
Proudly Designed, Manufactured, Machined & Assembled in the
mountains of Western North Carolina
Changelog
Revision
Date
Notes
Rev A
xx/xx/2020
Production Release –shipped
with first Rev A units.
Rev 1
11/20/2020
Prototype Manual released
before product shipping
Visit our website for more information, mods, hacks, and presets.
www.AshevilleMusicTools.com

<17>
Presets:
The following are ideas of settings for your ADG-1. Since all analog
products have some variability the exact knob setting may be slightly
different than shown in these presets. Experiment and enjoy.
Reverberant Lead: Subtly modulated
long delay with overdrive. Great for
lead licks. Crank up the drive for an
even more aggressive sound or dial it
back and try it with arpeggios.
Cavernous Hallway: Hello? Hello?
Hello? Is there anybody in there? Do
we have an echo in there? Reverberant
echoes. Try dialing up some
modulation for more fun.
Fold Under (low pass) Delay: Long
repeat delay, where each echo slowly
becomes less and pronounced as they
fade out. Each repeat loses detail and
folds under your mix allowing you to
play over without delay tails getting in
the way. Perfect for late night ambient
jams.

<18>
Springy Bubbles: Silly gurgling
nonsense. Have fun and don’t laugh
to hard, especially if you dial up the
amount more. Pro Tip: Use an
expression pedal on the rate or
amount to get audio rate modulation.
Adjust amount or flip the wave shape
for stuttering warbles like a broken
film projector (younger players, ask
your parents about 16mm school projectors)
Faux Flanger: Phased hollow delay
with peaky and present movement. It
is similar to a Flanger, yet with
longer delay times. Adjust the
feedback to that sweet spot right
before oscillation and the amount to
bring out the tone the best.
Wet Pseudo Chorus: A long drippy,
lush, chorused sound with longer
than average delay times. Dial in rate
and amount until you get it just right.
Time sets the level of trip. Way out
dude. Only use a chorus pedal on one
song? You're covered!

<19>
Tin Pan Alley. A unique hollow,
peaky sound that is more tonal than
delay. Sounds like you are at the end
of a tunnel talking through an old
telephone. (Modulation off)
Square Jumps: Tune this by ear
(using amount and time controls) for
a bouncy, whimsical octave echo or a
chaotic, atonal warble!
Tape Wash: Bright repeats fade
away into the ether. No motor repair
necessary. Wow others with the
flutter. (Modulation off)

<20>
Lead Fattener: Make your solo
stand out of the mix. Bonus points if
you turn your amp to 11.
(Modulation off)
Lofi Vibes: Take advantage of the
ADG-1's lush filter to construct a lo-fi
vibrato evocative of vintage
recordings.
Slap Back Delay: Short delay
doubling. Chicken-Pickin’ and finger
licken’good. (Modulation off)