Download Mojotone Tweed Deluxe Style Amp Kit Instruction

Mojotone® Tweed Deluxe Style Amp Kit
Instruction Manual
Tools needed for build: (Photo 1)
40 watt soldering iron
Wire cutters/ stripper
Needle nose pliers
Phillips head screwdriver
Small flat head screwdriver
AC/DC multimeter with resistance reading
44 Rosin core solder
Photo 1 - Lay out parts for a quick inventory
1. Layout parts for a quick inventory (Photo 1)
Compare physical inventory to the included bill of materials. (Packaging mistakes are
rare for Mojo but double check us before you start your build.)
2. Install chassis mounted hardware
3. Tube Sockets - Install so that they all face the same direction, noting pin #1
orientation.
4. Power Transformer - Make sure to mount the PT so that the label faces toward tube
sockets. This will be helpful for anyone looking at the transformer mod. number
without having to take the chassis out of the amp.
5. Output transformer - feed wires through grommets and note wire locations
6. Install the Potentiometers
7. Install Input and Output Jacks
8. Fuse Holder (install fuse at same time so you won’t forget)
9. Pilot Light Assembly
©Mojotone® Tweed Deluxe Style Amp Kit Manual 2012
Page 1
Photo 2 - Chassis Mounted Hardware Installed
Photo 3 - Chassis Mounted Hardware Installed
Photo 4 - Fiberboard Assembly
©Mojotone® Tweed Deluxe Style Amp Kit Manual 2012
Page 2
1. Fiberboard Assembly (Photos 4 and 5)
a) Always try to rely more on the schematic than the wiring diagram in any circuit.
b) Solder (1) ½ Watt 1.5k resistor to pin 5 and 6 on each power tube socket.
c) (2) ½ w 100 Ohm resistors - Solder from the pilot light to ground.
d) ½ w 1 Meg resistor from Input 1 to ground tied to Input 2. This accomplishes signal or
noise back to ground when unplugged. This is duplicated for the two bright inputs.
e) Be sure of component placement and orientation, especially capacitors (positive,
negative)
f)
If you plan on doing modifications such as “hot-rodding” (ie. adding a bright switch
etc.) and have never put a kit together before, it is suggested that you assemble the
basic amp and have it functioning properly, to have an understanding of how the amp
works before you start modifying it.
g) Check and double check the traces on the back of the fiberboard. (this is one of the
most common areas that mistakes are made.)
Photo 5 - Fiberboard Assembly
2. Internal Wiring
a) Always try to rely more on the schematic than the wiring diagram in any circuit.
b) Solder (1) ½ Watt 1.5k resistor to pin 5 and 6 on each power tube socket.
c) (2) ½ Watt 100 Ohm Resistors - Solder from the pilot light to ground.
d) ½ Watt 1 Meg resistor from Input 1 to ground tied to Input 2. This accomplishes signal
or noise back to ground when unplugged. This is duplicated for the two bright inputs.
e) Be sure of component placement and orientation, especially capacitors (positive,
negative)
f) If you plan on doing modifications such as “hot-rodding” (ie. adding a bright switch etc.)
and have never put a kit together before, it is suggested that you assemble the basic
amp and have it functioning properly, to have an understanding of how the amp works
before you start modifying it.
g) Check and double check the traces on the back of the fiberboard. (this is one of the
most common areas that mistakes are made.)
h) Try to avoid crossing wires over each other, (other than filament wires)
i) Before you plug the amp in check and re-check your wiring. If you are not clear on any part of
the circuit, ask someone.
©Mojotone® Tweed Deluxe Style Amp Kit Manual 2012
Page 3
©Mojotone® Tweed Deluxe Style Amp Kit Manual 2012
Page 4
3. Testing the Amp
a) *WARNING* Never stick your hands inside amplifier especially while power is on!
b) Test tube socket voltage with a multimeter to ensure correct operation.
c) Plug in speaker
d) Turn amp on without tubes installed first, checking transformers and components for shorting,
excessive heat, arcing, smoking, etc.
e) Turn amp off before putting tubes in proper location, and allow tubes to heat up for approx. 30
seconds before playing at volume.
f)
Listen. The best way to tell if there any problems with the circuit of the amp and/or tubes is just to
listen for excessive noise - popping/ crackling, hum, loud squeals, as well as ghost-echo sounds.
These are all symptoms of many common problems in tube amps.
g) If you need to service the amp after having it on, you must “discharge” the capacitors. This is
done by unplugging the amp, turning the power and standby to the on position and letting it sit for
30 mins. or so. If you do not have a standby switch, you will need to short the capacitor positive
leads to ground with a pair of pliers or an insulated wire. It is common to hear a pop when this is
done. This is just the cap discharging itself. Always use a multimeter to check the residual voltage
in the cap to make sure it is fully discharged.
h) Feel free to call Mojo at 1-800-927-Mojo (6656) at any time if you any questions regarding your
kit.
i)
Thanks for choosing Mojo and don’t forget to crank it up!!
**WARNING**
The Voltages found inside your amp can cause serious harm or even death. Never
attempt to service your amp while a power source is connected.
Online Resources
Grounding principles: www.aikenamps.com/StarGround.html & www.el34world.com/charts/grounds.htm
Signal Flow Diagram: www.el34world.com/charts/currentflow.htm
Printed Resources
"The Tube Amp Book" by Aspen Pittman
"A Desktop Reference of Hip Vintage Guitar Amps" By Gerald Weber
"All About Vacuum Tube Guitar Amplifiers" By Gerald Weber
©Mojotone® Tweed Deluxe Style Amp Kit Manual 2012
Page 5