Mojotone Tweed Champ User manual

THE MOJOTONE
TWEED CHAMP
5F1 STYLE COMBO AMP
Mojotone’s Tweed Champ Style Amp Kit is based on the beloved 5 watt amp from the 1950s. These amps were
perfect for recording and were featured on a wide array
of recordings from Joe Walsh’s “Rocky Mountain Way” all
the way to Derek & the Dominos’ “Layla.” Modeled after
the historic Class-A 6V6 platform, this amp delivers warm
tones that are harmonically rich and have a beautiful low
volume crunch.
The amp utilizes one 6V6 power tube and one 12AX7
preamp tube, giving the amp its famed lush harmonic
composition. We chose our Mojotone American Vintage
AV8C 15 Watt speaker to complement the 5F1 style circuit
since it has a nice clean sound at its lowest volumes but
introduces an articulate and unique grit as you increase the
amp’s volume.
Don’t be fooled by the fact that this circuit features only a
single volume control; 5F1s have been used by some of the
greatest guitarists and on some of the greatest recordings
of all time. Our Tweed Champ style amplier is extremely
tactile and responds well to dynamic playing; so no matter
if you play jazz, classic rock, blues or anything in between,
you will not be disappointed.

CONTENTS
SECTION 1: SAFETY PG.3
SECTION 2: TOOLS PG.3
SECTION 3: PARTS INVENTORY PG.4
SECTION 4: COMPONENT IDENTITY & ORIENTATION PG.4
SECTION 5: CHASSIS PREPARATION PG.6
SECTION 6: TRANSFORMER WIRING PG.8
SECTION 7: BOARD ASSEMBLY PG.10
SECTION 8: BOARD INSTALLATION INTO CHASSIS PG.12
SECTION 9: WIRING THE SOCKETS, JACKS & POTS PG.13
SECTION 10: INITIAL CHASSIS TESTING PG.14
SECTION 11: CAB PREP & SPEAKER INSTALLATION PG.15
SECTION 12: CHASSIS INSTALLATION PG.16
SECTION 13: SOUND TEST PG.17
SECTION 14: TROUBLESHOOTING PG.17
MORE FROM MOJOTONE PG.18
Copyright © 2018 MojoTone, LLC
All content included in this book including text, graphics and images is the property of MojoTone, LLC and protected by U.S. and international copyright laws. The collection, arrangement and assembly of all
content in this book is the exclusive property of MojoTone, LLC and protected by U.S. and international copyright laws. You may not copy, reproduce, distribute, publish, display, perform, modify, create derivative
works, transmit, or in any other way exploit any part of copyrighted material without permission from MojoTone, LLC .

www.mojotone.com 3
SECTION 1:
SAFETY
SECTION 2:
Tools
SAFETY FIRST! ELECTRONICS CAN BE DANGEROUS AND MUST BE TREATED WITH RESPECT.
ANY CIRCUIT THAT WORKS WITH 120 VAC POWER FROM AN ELECTRICAL OUTLET
IS ESPECIALLY DANGEROUS AND COULD POTENTIALLY KILL YOU. HERE ARE SOME
SAFETY GUIDELINES TO KEEP YOU SAFE AS YOU WORK:
CERTAIN TOOLS ARE REQUIRED TO SUCCESSFULLY BUILD YOUR AMP. THE FOLLOWING
TOOLS ARE RECOMMENDED TO COMPLETE YOUR PROJECT:
• ½”NutDriver
• Setofneedlenosepliers (one with no grip and one with serrated edge)
• WireCutters
• WireStrippers
• SolderingIron&Solder
• AdjustableWrench
• PhillipsHeadScrewdriver
• Drillwith3/16”drillbitand5/32”drillbit
• SharpieMarker
• Ruler
• Multimeter
• Lotsofpatience
• Never work on a circuit while power is applied.
• Donot connect power to a circuit until the circuit is nished and you have carefully checked your work (twice).
• Ifyousmellanythingburning, immediately disconnect the power and examine your circuit to nd out what
went wrong.
• Keepyourworkareadryandorganized.
• Becarefularoundlargecapacitors; they can continue to hold voltage long after they are disconnected from
power. Discharge electrolytic capacitors if power has been applied to the unit.
• Beespeciallycarefulwhenyousolder. A hot soldering iron can easily burn you.
• Alwaysworkinawell-ventilatedspace.
• Havesafetyequipment such as a re extinguisher, a rst-aid kit and a phone nearby.
• BePatient! Rushing through any type of technical work just leads to frustration and compounds issues that can
easily be avoided.
NEED A TOOL? DO YOU SEE SOMETHING ON THIS LIST THAT YOU DON’T HAVE? TURN TO
PAGE 18 FOR A FULL LIST OF TOOLS, PARTS AND KITS TO ADD TO YOUR WORK BENCH.

BUILD. MODIFY. REPAIR.
4
SECTION 3:
PARTS INVENTORY *optional based on order
(1) Solid Pine Cabinet*
(1) Eyelet Board & Backer Board
Vacuum Tubes*
(1) 1MA Potentiometer
w/ hardware
(1) Chicken Head Knob (1) Fuse Holder & 2amp Fuse
w/ hardware
(1) J12A 1/4'' Shorting Jack
w/ hardware
(2) Octal Tube Socket & Tension Clamp (1) 9-Pin Tube Socket & Tube Shield
(1) MOJO 760 Power Transformer
w/ hardware
(1) NOS 771 Output Transformer
(1) Chrome Chassis
(1) 10'' Install Power Cord (1) 8'' Jensen C8R 25w 4Ω Speaker*
(1)
(1)
(1)
5Y3 6V6
12AX7
100Ω
1M
220K
68K
100K
22K
4.7K
1.5 K
470Ω
5Y3 6V6
12AX7
100Ω
1M
220K
68K
100K
22K
4.7K
1.5 K
470Ω
5Y3 6V6
12AX7
100 Ω
1M
220K
68K
100K
22K
4.7K
1.5 K
470Ω
5Y3 6V6
12AX7
100Ω
1M
220K
68K
100K
22K
4.7K
1.5 K
470Ω
5Y3 6V6
12AX7
100 Ω
1M
220K
68K
100K
22K
4.7K
1.5 K
470Ω
5Y3 6V6
12AX7
100 Ω
1M
220K
68K
100K
22K
4.7K
1.5 K
470Ω

www.mojotone.com 5
SECTION 4:
COMPONENT IDENTITY & ORIENTATION
ENSURE ALL POLARIZED CAPS ARE IN THE CORRECT ORIENTATION WHEN INSTALLING ONTO
THE BOARD. THIS IS TYPICALLY DENOTED BY AN ARROW POINTING TOWARDS THE NEG-
ATIVE SIDE, OR A SMALL INDENTION ON THE POSITIVE SIDE.
SAFETY FIRST! A CAP IN THE WRONG ORIENTATION CAN EXPLODE! SO FOLLOW YOUR SCHEMATIC
AND WIRING DIAGRAM AND PAY CLOSE ATTENTION WHEN ORIENTING YOUR POLARIZED CAPS.
POLARIZED NON-POLARIZED
++
--
--
(1) Indicator Lamp Assembly
w/ hardware
(1) Jewel Lens (2) Rubber Grommets(1) Speaker Jack
w/ hardware
(1) Pilot Light (1) Three-Lug Ground
RESISTORS CAPACITORS HARDWARE
WIRES
22 gauge Yellow Pre-Tinned
(4) 4-40 1/4'' Screw & Kep Nuts
(2) 8-32 1/4’’ Screw & Kep Nuts
(6) 4-40 3/8’’ Screw & Kep Nuts
(2) 6-32 1/2’’ Screw & Kep Nuts
(2) 10-32 11/2’’ Screw & Kep Nuts
18 gauge Green Pre-Tinned
22 gauge Black Stranded
22 gauge White Stranded
(2) .022µf @ 600v Orange Drop
(1) 2w 4.7k Metal Oxide
(1) .5w 220k Carbon Comp.
(2) .5w 22k Carbon Comp.
(1) .5w 1m Carbon Comp.
(2) .5w 1.5k Carbon Comp.
(2) .5w 100Ω Carbon Comp.
(2) .5w 68k Carbon Comp.
(1) 16µf @ 475v Electrolytic
(2) 8µf @ 475v Electrolytic
(2) .5w 100k Carbon Comp.
(1) 25µf @ 50v Sprague Atom
16uF
8uF
25uF
+
0.022uF

BUILD. MODIFY. REPAIR.
6
Mount the fuse holder using its pre-
assembled hardware and adjustable wrench.
Install fuse.
Solder the two 100Ω resistors on the
indicatorlampthen mount it using its pre-
assembled hardware and adjustable wrench.
1 2
1 AMP
FUSE
12AX76V65Y3
12
3
4
56
7
8
12
3
4
56
7
8
TWEED CHAMP Layout Model 5E3 Revision 2.1 12/03/2018
1
2
3
4
5
6
7
89
SECTION 5:
Chassis preparation
PLEASE NOTE: ALL PARTS LISTED IN THE CHASSIS PREP SECTION STARTS AT ONE END OF
THE CHASSIS AND COMPLETES ON THE OPPOSITE END, BOTH TOP AND BOTTOM.
Mount the power transformer
using its pre-assembled hardware and
your 1/2“ nut driver. The transformer
will be recessed through the
rectangular cutout in the “belly” of the
chassis.
Installrubbergrommets in holes for
output transformer leads.
Mount the output transformer
using the (2) 8-32 x 1⁄4” screws and
corresponding keps nuts onto the
outside of the chassis next to the power
transformer (output transformer is not
recessed). Install the transformer so that
the Red and Blue wires go through
the grommet closest to the power
transformer. The wire goes through
the grommet furthest from the power
transformer. The screws will go through
the outside of the chassis, and the nuts
will be installed in the inside. Use a
screwdriver and adjustable wrench to
tighten.
POTENTIOMETER
OCTAL TUBE SOCKETS
RUBBER GROMMETS
9-PIN TUBE SOCKET
SIDE
VIEW
BOTTOM
VIEW
POWER TRANSFORMER
INPUT JACKS
SPEAKER
JACK
FLATTENED VIEW OF INSIDE OF CHASSIS
FUSE
HOLDER
INDICATOR
LAMP
GROUND
LUG

www.mojotone.com 7
Mount the potentiometer using its pre-
assembled hardware and 1/2” nut driver.
Make sure potentiometers are mounted with
their lugs facing up towards the open end of
the chassis.
Quick Tip: When mounting the pots, make
sure the toothed locking washer goes between
the potentiometer and the chassis. The flat
washer will go on the outside of the chassis
and the nut will tighten down
Onceyouhavethepotssecurelyinstalled, turn the
shaft of the pot all the way counter-clockwise. Install
the chicken head knob on each pot, making sure the
pointer of the knob is pointing to “1” on the chassis.
Use a small at head screwdriver to tighten the set
screw in the back of the knob securely on the pot
shaft.
Solder the 1M resistor on the speaker
jack closeset to the potentiometer. using their
pre-assembled hardware and 1/2” nut driver and
adjustable wrench, mount the two input jacks. Be
sure to note their orientation on the wiring diagram.
Mount octal tube sockets and tension clamp
using the (4) 3⁄8” 4-40 screws and keps nuts. When
mounting, be sure to choose an orientation and
keep this orientation uniform throughout all octal
sockets. Install octal sockets with solder lugs facing
inside the chassis. While mounting octal sockets, it
is best to simultaneously mount tube clips. To do so,
use your hand to hold tube clip over mounting holes
on the outside of the chassis, while still holding tube
socket in place. Insert screw from the outside towards
the inside, fasten nut from the inside. Repeat with
second mounting hole, then tighten both nuts using
a screwdriver.
PRO Tip: Mount the ground lug on the 5Y3 tube
socket screw closest to the edge of chassis.
Mount9-pintubesockets using (2) 1⁄4” 4-40 screws
and keps nuts and tighten down with adjustable
wrench and screwdriver. Here again, make sure to
choose an orientation and keep it uniform throughout
all 9-pin sockets.
CHASSIS CROSS-SECTION FOR COMPONENT ASSEMBLY - INDICATES CHASSIS EDGE
OCTAL
SOCKET
9-PIN
SOCKET
POT. &
KNOB
INDICATOR
LAMP
FUSE
HOLDER
INPUT JACKS SPEAKER JACK
1M

BUILD. MODIFY. REPAIR.
8
POWER TRANSFORMER SCHEMATIC
INDICATOR
LAMP
VOLUME 1M
MOJO 760ex
FUSE
HOLDER J12A J12A
12AX7
SPEAKER
JACK
6V65Y3
100Ω
100Ω
12
3
4
56
7
8
12
3
4
56
7
8
TWEED CHAMP Layout Model 5E3 Revision 2.2 12/04/2018
1
2
3
4
5
6
7
89
SECTION 6:
TRANSFORMER WIRING
PLEASE NOTE: ONLY MAKE FINAL SOLDER CONNECTIONS IF ALL LEADS ARE CONNECTED
TO COMPONENT. IT IS BEST TO ONLY SOLDER EACH JOINT ONE TIME, SO UNLESS ALL
COMPONENTS ARE IN PLACE, WAIT TO SOLDER.
Twist all matching pairs of wires
coming out of the power transformer.
Measure length needed for each
wire, allow yourself extra lead and cut
to length. This will eliminate excess
wire and free up space in your chassis
. Apply this principle to all leads.
Strip (1/2”) and tin the two Red
wires from the power transformer
(HV secondary). Solder one wire to
pin 4 and the other to pin 6 of the 5Y3
rectier tube socket, the octal socket
that is closest to the power transformer.
These wires carry AC voltage, so either
wire can go to either pin 4 or 6.
Measure,strip, and tin thetwo
Yellow wires from the power
transformer (5v rectifier filament).
Connect these two wires to the top
opening of pins 8 and 2 of the 5Y3
rectifier tube socket. Solder pin 2 but don’t
solder pin 8 yet.
Measure,stripandtinthe2Greenwires from
the power transformer (6.3v tube lament). These
will go to your indicator light with the (2) 100Ω
resistors to ground.
Measure and strip the Black and White
wires coming from the power transformer. One of
these will go to your fuse and one will go to the
potentiometer on the bottom lug. (It doesn’t matter
which wire goes to either component)
Doublecheckyourwiring.
POWER TRANSFORMER
FROM OUTPUT TRANS.
0V
BLACK (10”)
120V
BLACK (10”) GREEN (10”)
GREEN (10”)
RED (10”)
RED (10”)
RED/YELLOW (10”)
YELLOW (10”)
YELLOW (10”)
5V AC @ 4A
6.3V @ 4A
330V @ 75MA
330V @ 75MA
FLATTENED VIEW OF INSIDE OF CHASSIS

www.mojotone.com 9
pro tip:
SOLDERING BASICS
Primary is Blue and Red. Secondary is Yellow.
SoldertheBluewire from the output transformer
to pin 3 of the 5Y3 octal socket closest to the rectier.
SoldertheRedwire from the output transformer
to pin 3 of the octal socket closest to the
speaker jacks.
Connect the Yellow wire from the output
transformer to the tip lug of the speaker jack.
Doublecheckyourwiring.
OUTPUT TRANSFORMER
OUTPUT TRANSFORMER SCHEMATIC
Prepare the joint to be soldered, i.e. twist leads
together, hook leads into eyelets, etc.
Tin(apply solder to)thetipofthesolderingiron.
This will keep it from oxidizing and prolong the life
of your soldering tip. Wipe excess on sponge.
Cleanthetipoftenwhilesoldering.This will help
the iron heat more consistently and evenly.
Be sure to use clamps or tweezers if needed to
hold the components to be soldered in place.
Touchtheirondirectlyonthejointto be soldered
for about two seconds to get it hot enough to melt
the solder.
Touchthesoldertothejoint. As it melts let it ow
onto the joint to create a solid bond.
Liftthe solder offrst and then remove the iron
from the component.
Anothermethod is to tin the stripped wire and then
touch it directly to the heated component.
Placesolderingironbackintotheholder.
5000 Ω 4 Ω
YELLOW (3.5”)
LEAD GROUNDED TO CASE
RED (5.5”)
BLUE (5.5”)
SOLDERING IS AN ESSENTIAL SKILL FOR EVERY LEVEL OF AMP BUILDER. HERE ARE A FEW
TIPS FROM THE AMP PROS AT MOJOTONE.
SAFETY FIRST! THE SOLDERING IRON TIP REACHES A TEMPERATURE OF 400˚C SO NEVER DIRECTLY
TOUCH IT OR ANY COMPONENT THAT YOU ARE SOLDERING WHEN IT IS HEATED. ALWAYS WORK IN A
WELL VENTILATED AREA OR USE A SMOKE ABSORBER.
SOLDER EXAMPLES
PROPER
SOLDER
PROPER
SOLDER
COLD
SOLDER
COLD
SOLDER