FuzzDog Repeater V4 User manual

Repeater V4
Modded and updated
Vox Repeat Percussion
Contents of this document are ©2019 Pedal Parts Ltd.
No reproduction permitted without the express written
permission of Pedal Parts Ltd. All rights reserved.

mportant notes
If you’re using any of our footswitch daughterboards,
DOWNLOAD THE DA GHTERBOARD DOC MENT
•Download and read the appropriate build document for the daughterboard
as well as this one BEFORE you start.
•DO NOT solder the supplied Current Limiting Resistor (CLR) to the main
circuit board even if there is a place for it. This should be soldered to the
footswitch daughterboard.
POWER S PPLY
Unless otherwise stated in this document this circuit is designed to be
powered with 9V DC.
COMPONENT SPECS
Unless otherwise stated in this document:
•Resistors should be 0.25W. You can use those with higher ratings but
check the physical size of them.
•Electrolytics caps should be at least 25V for 9V circuits, 35V for 18V
circuits. Again, check physical size if using higher ratings.
LAYO T CONVENTIONS
Unless otherwise stated in this document, the following are used:
•Electrolytic capacitors:
Long leg (anode) to square pad.
•Diodes:
Striped leg (cathode) to square pad.
•ICs:
Square pad indicates pin 1.

Schematic + BOM
R1 22K
R2 1M
R3 330K
R4 33K
R5 1K5
R6 1M
R7 330K
R8 4K7
R9 82K
R10 Trimmer***
R11 1K
R12 470R
R14 330K
R15 Empty
(see page 5)
C1 100n (4n7*)
C2 100n
C3 68n
C4 100u elec
C5 10u elec
C6 2u2 elec**
Q1,2 2N5088‡
Q3 2N2646
DEPTH 500KC (or B)
RATE 100KC (or B)
VOL 47K Trimmer
Switch SPDT ON-ON
* Original was 4n7, but this gives a really thin sound.
Both caps are included, but any ticking may be more
pronounced with the bigger value.
** Added, along with switch, to give a bigger range.
***See notes on page five.
‡ Many high gain NPN wil work here, e.g. 2N3904, MPSA18,
2N5089
Solder C4 last. Once in place you’ll have difficulty getting at
the switch pads with your iron.

The power and signal pads on the PCB
conform to the FuzzDog Direct Connection
format, so can be paired with the appropriate
daughterboard for quick and easy offboard
wiring.
You can omit the depth pot altogether by
connecting DEPTH pads 2 and 3 with a
jumper.
You can mount the trimmers on either side of
the board, but putting it on the back with the
pots keeps it nicely out of the way.
Be very careful when soldering the LED and
transistors. They’re very sensitive to heat. You
should use some kind of heat sink (crocodile
clip or reverse action tweezers) on each leg as
you solder them. Keep exposure to heat to a
minimum (under 2 seconds).
The long leg (anode) of the electrolytic
capacitors go into the square pads.
Snap the small metal tag off the pots so they
can be mounted flush in the box.
The small metal tag on Q3 should be
positioned as shown above in red. the legs
will sit naturally in the holes in this position.
SW TCH
f you’re using a board-mounted micro toggle
you’re going to have to be very neat and
careful. Solder in C2 first, and ensure you
have very clean solder joints. Snip them down
as close to the board as you can.
The switch sits on the other side of the board
but there’s a metallic surface that can short
out the capacitor. Use something non-
conductive in between the switch and the
board, such as some flattened heat shrink.
Or you can just ensure there’s a gap between
the switch and the capacitor joints. We leave
the switch around 1mm away from the PCB.
Use your pre-drilled enclosure to line it up.
PCB layout ©2015 Pedal Parts Ltd.

f you’re using a wired switch, connect as shown >>>
gnore the two pads above C2 - they’re only there as extra
support for the board-mounted micro-toggle.
Things not quite Tickety-boo? R10 is there for you.
The board can accommodate a more readily
available 2N6027 PUT (Programmable
Unijunction Transistor) device instead of the
increasingly hard to find 2N2646 UJT.
To use the PUT device you need to change R10
to a 4K7-5K trimmer, and add R15 (3K9).
The PUT fits in the pads shown >>>
This feature is taken from the Moosapotamus Skippy.
The UJT in this circuit can produce an audible tick. t can be reduced, or even
eliminated, by adjusting the value of R10. This does have a trade-off, in that the circuit
may lock up at higher rates. For this reason we’ve changed R10 to a trimmer.
f using a 2N2646 for Q3, use 100R - 220R. You can use up to 1K but you’ll find it difficult
to fine tune.
Adjust this until you get a balance between effect depth, audible tick and useable rate
adjustment you’re happy with.

Test the board!
Check the relevant daughterboard document for more
info before you undertake this stage.
NDER NO CIRC MSTANCES will troubleshooting help
be offered if you have skipped this stage. No exceptions.
Once you’ve finished the circuit it makes sense to test is before starting on the switch and LED
wiring. t’ll cut down troubleshooting time in the long run. f the circuit works at this stage, but it
doesn’t once you wire up the switch - guess what? You’ve probably made a mistake with the switch.
Solder some nice, long lengths of wire to the board connections for 9V, GND, N and OUT. Connect
N and OUT to the jacks as shown. Connect all the GNDs together (twist them up and add a small
amount of solder to tack it). Connect the battery + lead to the 9V wire, same method. Plug in. Go!
f you’re using a ribbon cable you can tack the wires to the ends of that. t’s a lot easier to take them
off there than it is do desolder wires from the PCB pads.
f it works, carry on and do your switch wiring. f not... aw man. At least you know the problem is
with the circuit. Find out why, get it working, THEN worry about the switch etc.
Your completed circuit board
including pots

Wiring shown above will disconnect the battery when you remove the jack plug
from the input, and also when a DC plug is inserted.
The Board GND connections don’t all have to directly attach to the board. You
can run a couple of wires from the DC connector, one to the board, another to
the N jack, then daisy chain that over to the OUT jack.
t doesn’t matter how they all connect, as long as they do.
This circuit is standard, Negative GND. Your power supply should be Tip
Negative / Sleeve Positive. That’s the same as your standard pedals (Boss etc),
and you can safely daisy-chain your supply to this pedal.
L
E
D
BOARD
OUT
BOARD
9V
BOARD
GND
BOARD
GND
BOARD
GND
BOARD
INPUT
BATTERY
+
IN
OUT
L
E
D
BOARD
GND
BOARD
LED+
+
Wire it up (if using a daughterboard please refer to the relevant document)

This template is a rough guide only. You should ensure correct marking of your
enclosure before drilling. You use this template at your own risk.
Pedal Parts Ltd can accept no responsibility for incorrect drilling of enclosures.
FuzzDog.co.uk
Drilling template
Micro switch
Hammon 1590B
60 x 111 x 31mm
It’s a goo i ea to rill the potholes 1mm
bigger if you’re boar -mounting them.
Wiggle room = goo !
Recommen e rill sizes:
Pots 7mm
Jacks 10mm
Footswitch 12mm
DC Socket 12mm
Switch 5mm
8mm
32mm
If you mount the switch right
up against the PCB it woul be
9mm, but it’s best to leave a
gap so you on’t short out the
cap on the other si e.

6mm
32mm
This template is a rough guide only. You should ensure correct marking of your
enclosure before drilling. You use this template at your own risk.
Pedal Parts Ltd can accept no responsibility for incorrect drilling of enclosures.
FuzzDog.co.uk
Drilling template
Normal switch
Hammon 1590B
60 x 111 x 31mm
It’s a goo i ea to rill the potholes 1mm
bigger if you’re boar -mounting them.
Wiggle room = goo !
Recommen e rill sizes:
Pots 7mm
Jacks 10mm
Footswitch 12mm
DC Socket 12mm
Switch 6mm