Part 6 - Turret board wiring

When adding the wiring that runs from the turret board to other components, you have a choice: you can solder the wires to the hole on the underside of the turret, or you can wrap the wire around the upper part of the turret, and then solder it in place. Some amp makers prefer the latter - because it's easier to rewire an amp in the future; others (myself included) prefer to wire to the underside of the turret (I find it slightly easier and a lot neater).
The diagram above shows the board, face up and with wires drawn as if they are soldered to the top of the turrets. At the bottom of the page, there's an equivalent diagram that shows the exact same scheme as viewed from the underside of the board. So you can choose for yourself.

Wire lengths

For each of the wires, I've shown how much wire you need (with a little allowance for trimming) for each connection. Before you start cutting wire and soldering, I strongly suggest that you do some 'dry runs' (this is, of course, essential if you bought the Basic kit and have your own chassis layout). To do this, add the mounting hardware for the turret board to the chassis. Add six M3 screws and M3 spacers to the holes circled in red in the photo below.

Now you can place the board (components facing up and diodes D1 and D2 closest to the power transformer) in the chassis and use the diagrams on this page to see where each wire runs. Most wires run to the valve sockets, grounding lugs and front panel components. Note that at this point, you're only soldering the wires to the turrets. Don't solder any of the wires to the other components just yet.

Adding the wiring

If you're new to amp building, I strongly suggest that you use the Amp Maker colour scheme shown in the photos and diagrams on this site to avoid any confusion. Every amp builder has their own preference, and some just go with what Fender or Marshall has used in the past. I've seen some amps which use the same colour for every single wire! If you do opt for your own wiring colour scheme, it's a good idea to print out the diagram and annotate it with the colours of the wires that you use for each of the connections.
NOTE: Before proceeding to the next stage, double-check that you have all these connections made. Remember to include the two wires which have both ends soldered to turrets: a yellow wire from C to D, and a red wire from A to B. NOTE: close to turret B is a hole that must be left clear for the board-mounting hardware; run the red wire to loop around this hole.

Soldering wires to turrets

Soldering to the turret's underside is much the same as soldering to the turret top. The same principles apply, so make sure that you get a good shiny and seamless solder joint. In addition, watch out for the following:
* Errant wire 'whiskers' - the wires have 16 individual strands, and it's important to make sure that the strands do not touch adjacent turrets or the chassis. Work in bright lighting so that you can easily spot any strands that stick out.
* Overheated wire insulation - if you inadvertently melt the PVC insulation as you solder the joint, check to see if there's any exposed wire. A little doesn't matter, but too much exposed wire risks a short against other turrets or the chassis. Be your own worst critic, and if you're in any doubt, desolder the offending wire and try again.
* One turret, two wires - some turrets must take two wires. If you twist the strands of the two wires together before inserting them into the turret hole (or wrapping them around the turret) it's easier to get a good solder joint.

SE-5a construction guide
1 - Kit contents
2 - Block diagram
3 - Reading your schematic
4 - Chassis assembly
5 - Turret board assembly
6 - Turret board wiring
7 - Chassis wiring guide I
8 - Chassis wiring guide II
9 - Chassis wiring guide III
10 - Initial testing
11 - Final test

Main diagrams:
Schematic
Control panel wiring
Turret board layout
Turret board wiring
Test-point diagram
Final chassis picture

SE-5a kit purchase page