FuzzDog GimpFX Ultr-Fk User manual

GimpFX Ultr-Fk
More sludgy bass fuzz than
you can shake a thigh-bone at
Contents of this document are ©2015 Pedal Parts Ltd.
No reproduction permitted without the express written
permission of Pedal Parts Ltd. All rights reserved.

Schematic
B M
R1 100K
R2 4K7
R3 47K
R4 47K
R5 10K
R6 51K
R7 33K
R8 330K
R9 51K
R10 4M7
R11 51K
R12 1M
CLR 2K2*
C1 22n
C2 4n7
C3 1n
C4 10n
C5 22n
C6 10n**
C7 470n
C8 10u elec
C9 47u elec
C10 47u elec
C11 47u elec
C12 47u elec
C13 47u elec
C14 100u elec
Q1,3 BC550
Q2 2N5088
D1 3mm rangeLED
D2 1N4001
INPUT 1MC
UTPUT 100KB
M RE 5KB
N TCH 50KA
SL PE 100KB
SHIFT 100KB***
SWITCH SPDT
N- FF- N
*2 x CLRs are required on the daughterboard. Use whatever you prefer as your
normal LED current limiter.
** nly required if using the Notch Shift switch rather than the pot.
***Not required if using the Notch Shift switch.
Switch marked in blue above is the optional Notch Shift control, which is
SPDT N- FF- N. This is not required if using the SHIFT pot.
Switch marked in orange is the M RE footswitch on the daughterboard.

Be very careful when soldering the diodes, 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 striped leg (cathode) of the diodes go into the square pads. For the LEDs, the
shorter leg goes into the square pad.
The long leg (anode) of the electrolytic capacitors go into the square pads.
These can all lay flat as shown in the image on the first page. This will give you
plenty of clearance in the enclosure.
Snap the small metal tag off the pots so they can be mounted flush in the box.
Pot mounts on the back side of the board. You can use vertical-mount pots or just wire
up ‘normal’ ones. It’s a good idea to place the pots in their holes in the enclosure when you’re soldering
them in place on the PCB. That way you know they’re going to line up ok. Best way to do it is to solder a
single pin of each pot in place, then do a visual check to see that they’re all sitting at the same height. If
not, melt the joints and re-adjust any that are off.
Similarly, for the toggle switch it’s best to solder a single lug then check it for position. If not straight or
flat, melt the joint and reposition before soldering the
other two lugs.
If your pots don’t have protective plastic covers you should place a strip of thick card between them and the
board when soldering to keep them a good distance from the pcb to avoid shorting other components.
You should solder all other board-mounted components before you solder the pots. nce they’re in place
you’ll have no access to much of the underside of the board.
Make sure your footswtich lugs are horizontal as shown above when soldering into the daugherboard. It’s a
good idea to place them in the holes in the enclosure when doing this to ensure they line up ok.
1 2 3
PCB Layout ©2015 Pedal Parts Ltd.

Ensure you mount the footswitches on
the right side of the daughterboard.
It’s clearly marked. therwise your
ribbon cable connections won’t line up.
The boards are designed for a 7-way
ribbon cable connection between
them, but you can use any wire you
want. just make sure you connect the
correct pads.
LEDs
You should leave these until you’re actually boxing up the circuit. They don’t need to be in place for the
circuit to work, so plug it in and test it before you add them.
Pull them up through the PCB (short leg to square pad), and slightly bend the legs out so they don’t fall
back through. Position your daughterboard into the enclosure and lightly secure the footswitches. You
should now push the LEDs down through the PCB and located them into their holes in the enclosure.
nce done, tighten the footswitches, check the LEDs are still in place, then solder them in.
WHY IS THERE AN EXTRA PAD F R THE ‘M RE’ F TSWITCH LED...?
Yes. You can use a bi-colour LED in there if you want, i.e. green for normal, red for M RE.
Use a common-anode LED.

IN OUT
WIRING
Couldn’t be much easier really. nce you have the daughterboard and main circuit connected (hopefully
you’ve used a 7-way ribbon cable for extra simplicity and neatness), there are only six wires to connect as
shown below.

Drilling template
Hammond 1590BB
91 x 116 x x 31mm
Ultr-Fk
Recommended drill sizes:
Pots 7mm
Jacks 10mm
Footswitch 12mm
DC Socket 12mm
Toggle Switch 6-7mm
This template is a rough guide only. You should ensure correct marking o your
enclosure be ore drilling. You use this template at your own risk.
Pedal Parts Ltd can accept no responsibility or incorrect drilling o enclosures.
PedalParts.co.uk
30mm
60mm
30mm
It’s a good idea to
drill the holes or
the pots 8mm to
give yoursel some
wiggle room unless
you’re a drill ninja