Your Woodface WF-55 amplifier kit contains all of the electronics and hardware parts needed to make a
great-sounding valve amplifier. Before jumping in, clear a space on your workbench and unpack all of
Your kit's contents
Start by checking the Kit contents listing supplied with the kit package. Look through the electronic
components and check them off.
If this is your first electronics build, familiarise yourself with the component
values. In some cases, it's as simple as reading the value from the body of component
(most capacitors, for example). However, most resistors are too small to have printed values, and
instead colour coded bands on the resistor indicate the resistor's value. You can decipher the code
using the Resistor colour codes table at the bottom of this page.
Some of the components have a polarity, meaning that the component needs to be
inserted in one particular direction for the circuit to work. For example, if you look closely at
the larger capacitors, you'll see a small '-' (minus) mark close to (or pointing at) one of the
capacitor's two leads. This marks the negative terminal. In the WF-55, all of the capacitors'
negative terminals point towards ground.
The rectifier (D1-D4) and zener (D5) diodes also have a polarity, indicated by a
silver band around one end of the diode's black body. Where the diodes are used to rectify AC
voltage into DC voltage (D1 to D4) the silver band points away from ground. The zener diode (D5)
is a special case, and in this amplifier, the silver band points towards ground. Don't worry if you're not
clear of the reasons - the turret board photos on the next few pages show exactly which way to use these
Go through the components in the WF-55 Kit contents list and tick them off. Get in touch
with Amp Maker if there's any discrepancy or confusion.
|Capacitor voltage ratings|
|All components have a voltage rating - a maximum voltage for the component. The resistors
supplied in your kit are rated well over the maximum voltage present inside this amplifier. It's
a different story for the capacitors, however. Here, they are rated according to their place in
the circuit and the voltages present at that position.|
For example, the large power supply capacitors will be faced with the highest voltages
in your amp - up to about 370V. So they must be rated for at least this voltage; the parts supplied with your
kit are rated at 450V - plenty. Some other capacitors may be rated at a lower voltage - for example,
capacitor C3 is rated according to its position in the circuit and it never sees the high voltages that
the other capacitors see.