STEREO VU METER

This kit has two, 10 LED VU meters, which can be added to pretty much anything putting a stereo signal out and needs 10-15V to run.

I read about this particular piece of kit at Smokin’ MHz, a US site.  Obviously having been recently stung twice by HM Customs for Duty I need not have paid, I was keen to source something similar from the UK.  Maplins do 3 versions of the Vellman kits:

As I wanted the stereo output and size was important, the 10 LED stereo version was the winner, the 15 would almost fill the 5 1/4" blanking plate.

The kit comes in a rather sturdy transparent mini-briefcase affair; I use it for small components now.

I opened the box and nearly fainted.  I thought you just wired it into the source, gave it some power and away you go.  I was faced with two naked circuit boards and a massive pile of parts.  Doh!  Read on to discover how I became the Soldering King.

The wires, resistors, diodes & capacitors are laid out in between two strips of tape in the order the you install them, all the components for one board down to the middle then component one of the second (identical board) again in the right order.  There is a bag of LEDs, 4 IC mounts, 4 ICs, 2 resistor trimmers and a rather neat faceplate.

I read through the entire manual before I did anything.  This really does save misery later.  You simply open the manual and solder a component at a time to the board in the order shown.  There is even a tick box for each component enabling you to keep track.  Each item is marked on the circuit board, i.e. R1, R2 and so on for resistors.  Diodes & capacitors MUST be soldered the correct way round and the manual clearly show this & the boards have the polarity marked on them making this simple.  Well, simple apart from jumper 2 – it took me 5 minutes to find it, as it is tiny and J2 is marked on the bottom right corner.  You actually solder it half way up in the middle of the board on the right hand side, it is a 2 or 3 mm jumper, whereas the J1 is about 15mm long and easy to spot.  The remaining markings are foolproof though.

It is time consuming; I counted 83 odd solders on the first board!  It took me about 2 hours for the first one, and about half that for the second.  The manual even gives you advice on how to solder, follow it.  The components get taller as you work through them:

• Jumpers
• Diodes
• Resistors
• IC Sockets
• Resistor trimmers
• Capacitors
• Big resistor!
• LEDs

I fluffed two or 3 solders where they merged with another one that was close.  What you are supposed to do is melt the solder & use a solder sucker (a rubber pump thing) to lift off the excess.  I don’t have one so I melted it and blew it off.  I must add that this is a very stupid method.  Red-hot solder flying round the place is dangerous.  Solder well or buy a solder sucker fro a pound.  I take no responsibility for you melting your keyboard/favourite pants/Mums carpet/dog/eyes…

Once you have soldered the lot, you plug in the chips and you are done (hopefully).  Then you start again on the second board…

Reading the manual, checking the components and actual assembly took an entire evening; don’t expect to complete this in an hour or two.

OK, you have two boards smothered in components what next?  The manual has a guide to making brackets & spacers complete with measurements.  I sacrificed a spare 5 1/2 bay blanking plate as a base.  A plastic tube with internal struts obtained from some building block set of the kids made an ideal spacer.  Looking something like this bad picture, the internal struts meant that:

a.               Screws had something to bite on.

b.               The side next to on of the ICs was tight, so I cut 1/3 out of the side of the tube and it fit perfectly.

Of course, if you have no children’s toys to steal borrow; you could cut down some wooden doweling, or maybe some big raw plugs.  Poke around your kid’s bedrooms toolbox and see what you can find!

When cut to size, you screw the two circuit boards together to make a sandwich like this:

Being the cool, calm collected person that I am, I couldn’t wait until everything was assembled and hotwired it into the PC!  It worked first time, so I am the Soldering King!

The blanking plate was murder to cut, I measured it carefully, see the dimensions in the VU meter manual before you start cutting holes.  What I did was drill a load of 6mm holes and then use a Stanley Knife to join them together.  Remember kids – get a grown up to help you with this one.  It took ages, as the plastic is about 4mm thick.  Take your time; it’s not a race.

See my Baybus article to find out how this was incorporated into the finished RUV! ;-)