8 - Turret board wiring
barry (Administrator) 12-30-2013 at 10:02 PM.
Post: #1
The next step is to add wires to connect the turret board with the valve sockets and front panel controls. In each case, keep it as neat and direct as possible. When soldering to valve socket pins, make sure that you avoid wire 'whiskers' where one strand of wire misses its hole and shorts against a neighbouring pin or the chassis.

Start with the V1 connections. Two red wires connect to the anodes of V1, pins 1 and 6, and two yellow wires to connect to their cathodes, pins 3 and 8. That completes the V1 wiring and it should look like this:

[Image: n5xtbw01.jpg]

Then make the two yellow wire connections for V2 and V3. This connects their cathodes to the turret board. Pay special attention to V3 - you must strip a little extra wire so that you can extend the connection from pin 1 to 8, soldering the wire at both pins.

[Image: n5xtbw02.jpg]

Now there are two wires that connect V2 directly to V3. These also complete the R15 and R18 connections (which were left unsoldered from the previous page):
* add a blue wire to connect R15 at pin 2 of V2 to pin 5 of V3
* add a red wire to connect R18 at pin 9 of V2 to pin 4 of V3

Solder all four pins and V2 and V3 should now look like this:

[Image: n5xtbw03.jpg]

Note that there are several unused pins on V2 and V3 - we'll return to some of these a little later.
- - Quote -
barry (Administrator) 12-30-2013 at 10:03 PM.
Post: #2
Front panel controls I
We now get to the most 'busy' part of the wiring layout - the control panel, with its input, pots and switches. There are dozens of wires and it would look chaotic if all were done at once, so I've broken it down into several steps to make it easy to follow. Take your time and, once again, double check each connection. Start by wiring up the input socket.

TIP: Many experienced amp builders find it easier to do the initial wires for the input socket and some other individual components outside of the chassis. You can temporarily mount the socket to the front side of the front panel. This gives you full access to the lugs and keeps it stable while you solder.

You need R1, some shielded wire and some black wire. First, trim and bend the leads of R1 so that it connects lugs 1, 2 and 4 of the input socket (the lug numbering is shown in red here). Note: one of the resistor's leads passes through lug 4 and passes back diagonally to attach to lug 2. The other end is connected only to lug 1. Don't solder any of the lugs yet.

[Image: n5xtbw04.jpg]

Now take about 12cm of the shielded wire and strip one end of it, so that you have a short length of shield (twisted together to make a single wire) and the separate centre conductor. Solder the centre conductor to lug 1 of the socket and the shield to lug 4.

[Image: n5xtbw05.jpg]

We'll ground the input socket, but it's easier if we add the necessary wire to the chassis first (it's a very crowded space if we leave it until later). Take about 8cm of black wire and solder one end to the ground lug on the bottom of the chassis, shown here. Bend the other end of the wire out of the way for a moment.

[Image: n5xtbw06.jpg]

Now install the input socket inside the chassis. Take that black wire you added to the ground lug and connect the end of it to lug 2 of the input socket. Solder this lug. Note: there is nothing to solder on lug 3 of the socket.

[Image: n5xtbw07.jpg]

At the other end of the shielded wire, strip back the outer insulation and the shield. Discard both and then use some heatshrink to cover the exposed end of the shield (this ensures that it cannot short against any other part of the circuit). Connect and solder the inner conductor to the turret that's connected to R2.

[Image: n5xtbw08.jpg]
- - Quote -
barry (Administrator) 12-30-2013 at 10:30 PM.
Post: #3
Front panel controls II
Now it's time to do wire up the pots. Take a deep breath before diving in. Smile The first diagram shows the pot wiring with all other wires temporarily hidden from view so you can concentrate on the steps you have to take.

[Image: n5xtbw09l.jpg]

CLICK HERE to see the same diagram in a higher resolution.

A few things to note:

1) Use shielded wire for the connection of lug 2 of the Gain pot (VR1) lug to the turret board (R8). Use the same technique as with the shielded wire you just added to the input socket, but this time you will attach and solder the shield to lug 3 of the Gain pot.

2) The Bypass switch (S2) is also included here because it makes/breaks the connection of the Middle pot (VR4) to ground. For the two black wires for this switch, use the black solid insulated wire - it's much easier to get into the solder lugs (see the tip below).

3) When soldering to the long row of solder lugs and turrets with many wires that cross each other, be VERY careful not to accidentally burn through the wires that you've already added.
- - Quote -
barry (Administrator) 12-30-2013 at 10:37 PM.
Post: #4
Soldering with mini-toggle switches
The mini-toggle switches used for the Boost and Bypass functions are small enough to look right on the amplifier's front panel, but that means they're small and fiddly to work with inside the chassis! Here are some tips for success:

1) It’s sometimes easier to wire them up out of the chassis, as with the Input socket

2) The solder lugs are too small for the full diameter of the stranded wire, and worse still, the solder lugs are so close that it's very easy to get an accidental short with a loose strand of wire For this reason, I've supplied thinner solid insulated wire - use the black wire for the Bypass switch.

3) The plastic bodies of mini-toggle switches are vulnerable to excessive heat – if you apply the soldering iron for too long, the heat will transfer to the plastic which will deform and ruin the switch. The thinner wire absorbs less heat and therefore requires a shorter soldering time.

4) Solder the two black wires at the Bypass switch FIRST, then mount the switch in the chassis, and then trim and solder the other ends of these wires at their destinations (lug 3 of the Middle pot and lug 3 of the Master pot)

[Image: n5xtbw10.jpg]
- - Quote -
barry (Administrator) 12-30-2013 at 10:42 PM.
Post: #5
Connecting the Boost switch
The technique you've applied to the Bypass switch is even more important for the Boost switch (S1), because it has six lugs instead of two! But take the same approach and it will work out just fine.

Once again, for clarity I have hidden all other wires so that you can concentrate on the wires and connections we're making here.

First, add a black wire that connects both centre lugs at one end and connects to the turret shown here.

[Image: n5xtbw11.jpg]

Now add two orange wires and two brown wires to the remaining four lugs of the switch. If necessary, use a magnifying glass to check that all wires are separate and there are no shorts from one lug to another.

Connect the other ends of these four wires to the turrets shown here. The orange ones connect to the 1uF capacitors and the brown ones connect to the 47uF capacitors.

[Image: n5xtbw12.jpg]
- - Quote -
barry (Administrator) 01-19-2014 at 01:38 AM.
Post: #6
At this point, your main turret board and its wiring should look like this:

[Image: n5xtbw13.jpg]
- - Quote -
barry (Administrator) 01-20-2014 at 04:54 AM.
Post: #7
Direct links to reference diagrams
This guide is written in several sections, ranging from a basic description of the N5X to very detailed instructions on how to build each and every part of the amplifier. I recommend following it step-by-step and paying attention to the tips and suggestions.

However, if you're an experienced amp builder, you may just want to dive into the build and do it your own way. To make that easier - and for easy reference for all builders - this, the last entry on each page, lists the important reference diagrams:

* Schematic
* Power supply board
* Main board
* Finished layout
- - Quote -
barry (Administrator) 01-20-2014 at 06:07 AM.
Post: #8
- - Quote -
Post Reply