2 - Kit contents
barry (Administrator) 12-30-2013 at 12:24 AM.
Post: #1
Your N5X 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 the components. Start by checking the Kit contents listing supplied with the kit package.

[Image: n5xkc.jpg]

Look through the electronic components and check them off. If this is your first amplifier project take a little time to familiarise yourself each type of component, its shape, size and connections (leads, solder lugs, etc).

The Kit contents page lists the resistors first. Most resistors are too small to have printed values, and instead the manufacturers use a standard set of colour coded bands to indicate the resistor's value. You can decipher the code using the Resistor colour codes table below.

[Image: rescols.jpg]

TIP: Depending on the colour of the resistor's body, some colour bands may be tricky to read; dark green, for example, may appear to be almost black. If in doubt, to avoid any mistakes use your digital multimeter (DMM) to check the resistance. There's a tolerance in all components, and in the resistors, values will be within +/- 5% of the specified value, such as 98.2Ω for the 100Ω resistor.

[Image: n5xres.jpg]

It's also very apparent that a few resistors are bigger than others. The resistor size is related to its power rating: the smaller ones being rated for a maximum of 0.5W, the slightly larger ones for 1W, the medium-sized ones for up to 3W and the largest for up to 5W. This will be very apparent when you lay them out side by side. There's only one value which is present in two ratings - 100kΩ, with the 3W version being much bigger than the 0.5W version.

Resistors do not have a polarity; so it does not matter which way around they are connected in the circuit.

(Note that supplies of parts do vary over time, and a resistor shown in the build guide may be a different colour to what's supplied in your kit, or it may be printed with a written value instead of colour bands. If you're in any doubt, get in touch with Amp Maker.)
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barry (Administrator) 12-30-2013 at 12:29 AM.
Post: #2
Almost all modern capacitors have their values and ratings printed somewhere on their body. This written information makes it easy to work out which capacitor is which. (There is a colour coding system for certain types of small capacitor but none of those are included in this project.)

The first part of the text is the capacitance value itself. This is shown in units of microFarads (uF), nanoFarads (nF) or picoFarad (pF). When comparing what you see with the Kit contents list bear in mind that 1000pF = 1nF = 0.001uF. The smallest caps are the silver mica ones, usually reddish brown or tan in colour. These may not have a unit printed, but these capacitors are always in the picoFarad range, so "500 500V" means 500pF.

[Image: n5xcaps.jpg]

You'll also see from the printed information that capacitors have a voltage rating. This is a maximum working voltage for the component, and it's very important. Whereas all of the resistors in your kit are rated well over the maximum voltage present inside any part of this amplifier, it's a different story for the capacitors. They are all specified and rated according to their place in the circuit and the voltages present in that position.

For example, the large power supply capacitors will be faced with the highest voltages in your amp - which can be almost 300V. So these capacitors must be rated for at least this voltage; the parts supplied with your kit are rated at 350V or more (see below). This is plenty. Likewise, there are some signal caps inside the amplifier that are rated at 500V and 630V - more than enough.

Not all capacitors need to be rated at such a high voltage. And it would be very wasteful of money and space to have every capacitor rated for the full voltage range of the amplifier. For example, capacitor C1 is rated according to its position at the cathode of the ECC83 preamp valve, and it never undergoes a high voltage - perhaps 2V at most. So any rating of 25V or more is fine (I usually supply 100V as they are far more readily available, and still quite small).

[Image: n5xcapol.jpg]

Some capacitors have a polarity - a positive terminal and a negative terminal. In this amplifier kit, the blue/black electrolytic capacitors are all polarised. Look closely at the printing and you will see that one of the leads on each of these capacitors is marked by a minus sign (-). This is often contained within an arrow printed on the side of the capacitor, where the direction shows the negative terminal.
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barry (Administrator) 12-30-2013 at 01:03 AM.
Post: #3
Variable resistors in the form of potentiometers (also known as pots) are supplied for the amplifier's main controls. In all cases, the value and type is printed somewhere on the pot's body. Suppliers differ in how they mark the value/type. For some, it is stamped on the back of the pot, and for others it's printed on the front of the pot. On the second type, you can only see the value when you view the pot from the shaft of the pot - you can just make out 'B1M' in the picture below.

[Image: n5xpot1.jpg]

The text will also indicate the pot type. You may see 'Lin' or 'Log'. If you don't see either of these, look for the a code letter next to the pot's value: A1M means 1MΩ log; B22k means 22kΩ lin.

The pots have three lugs, and it's important to know which is which, so the diagram below shows the numbering convention. I always refer to the pot's lugs with reference to the back of the pots and with the lugs uppermost - as that's always the side you will look at when you are soldering.

[Image: n5xpot2.jpg]
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barry (Administrator) 12-30-2013 at 01:10 AM.
Post: #4
Diodes and MOSFET
These are the kit's semiconductors, and they are all used in the power supply (not the signal path, which is 100 percent valve). There are two types of diode, with the zener diode being much smaller and reddish/pinkish in colour.

Look closely and you will see that the diodes all have a small band around one end: silver on the black diodes and black on the pink zener diode. This shows the polarity of the diode - the banded end is the cathode. To do its job properly and safely, a diode MUST be fitted the correct way around as shown in the build guide diagrams that follow.

WARNING! The MOSFET needs special handling, so do not take it out of its anti-static bag until you are ready to use it. For now, just check that it's present in your kit.

[Image: n5xstatic.jpg]
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barry (Administrator) 12-30-2013 at 01:16 AM.
Post: #5
Turret boards
The N5X uses two turret boards, the smaller one is for the power supply and the larger one for the amplifier's signal path. Most of the smaller components will be mounted to the turrets on these boards.

[Image: n5xtb.jpg]
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barry (Administrator) 12-30-2013 at 01:20 AM.
Post: #6
Other components
The rest of the kit contents list spells out the sockets, switches, etc you use to make up the rest of the circuit. Check the contents against the list and let Amp Maker know of any problems or missing parts.

[Image: n5xcomps.jpg]

Wire and Hardware
There's also a bag of wire with several types and colours of wire: solid, stranded, insulated, bare and shielded. Don't worry, there's more than enough cable to build the amplifier. In addition, a bag of hardware includes all of the fasteners you need to mount the parts to the chassis.

[Image: n5xwire.jpg]

[Image: n5xhw.jpg]

Chassis and control panels
These aluminium parts should be pretty obvious! Smile The control panels are both anodised, so they won't show any fingerprints from handling. The chassis is not anodised, so once you have removed the plastic covering the outer surface, it will be easily marked by handling. Of course, it's harmless and out of sight once the chassis is installed in your cabinet.
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barry (Administrator) 01-20-2014 at 05:03 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
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barry (Administrator) 01-20-2014 at 06:25 AM.
Post: #8
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