In the first part of the series of articles about this amp the schematic was shown and explained. The second part showed all the components used. Today we will see the first steps of the construction.
The photo above shows all the components and the tools needed. Let's start with the mounting of the tube sockets. For these we use two 4mm screws.
Since the screw head is visible from the top, a type with a head for hexagonal allen keys is used. To avoid direct contact between the ceramic socket and the metal plate a rubber ring is placed in between:
Then the socket is added with two more rubber rings before the nuts are screwed on:
The socket fully mounted:
Next the switches for ground lift and mains on/ff. These are screwed on with a ring from the top:
For the mains connection, a IES socket with integrated filter is used:
Next the rubber dampers which are mounted on top of the plate and which will later carry the power transformer:
T secure their connection some varnish is applied. It makes sense to use that on every metal screw. This avoids that they get loos over time or if the amp is transported or shipped.
The preassembled metal plate:
Now the power transformer is added:
A close up showing how the transformer rests on the rubber damper:
The single black wire coming from the transformer is connected to the screen between primary and secondary windings. This will later be connected to signal ground.
The only connection to the power transformer which remains to be done is the high voltage to the rectifier:
Each of the two wires has it's own protection sleeve due to the high voltage. Like the other AC carrying wires they get twisted together and connected to the plate pins of the rectifier socket.
In the photo above the two cathodes of the rectifier are connected together and to one side of the heater. On the signal tube sockets some pins which are connected in parallel are tied together with a short piece of wire inside some insulation sleeve.
The rest of the assembly process will be covered in part 4. Stay tuned!