The law of averages is a lay term used to express a belief that outcomes of a random event will “even out” within a small sample.
Roughly translated, if you play your equipment enough times, at some point it WILL eventually break. This holds true for your guitar, your drums, your mixing desk and even your unbreakable, Sherman Tank encased Orange Tiny Terror Valve Amplifier.
So what are you going to do when disaster strikes and your trusty steed decides it’s had enough?
Well if you’re smart, you’ll have a spare? No? That’s right ask the tech guy in the band to fix it for you, if your are lucky enough to have one. Otherwise, pay through the nose to get it repaired or replaced.
Well perhaps it’s just as well I used to disassemble my Xmas presents as a kid to see how they worked instead of playing with them!
Before I begin, the usual disclaimer. Valve amps are very dangerous and operate AND store high voltages that can kill. I/We take no responsibility for any disasters if you try any of this.
So Lees’ (Rhythm Guitarist/Cool dude) amp, the aforementioned Orange Tiny Terror, developed a problemo. The GAIN knob started becoming ‘scratchy’ and losing gain, not working, cracking. Basically all sorts of nasty stuff. So he stuck it in the cupboard and bought another amp. Until one day I asked for a shot to to test as a backup. It sounded poor.
So I decided it was time to change the GAIN CONTROL for a new one. This would require stripping the amp down, taking out the main board and removing the old pot. Something I have done many times before.
There are TEN screws to remove on the top cover AND FOUR screws on the bottom cover. Take the top off first and then remove the valves carefully.
BEFORE you do anything, DISCHARGE the capacitors and OBVIOUSLY MAKE SURE IT IS NOT PLUGGED IN!!!
Remove the control knobs and the nuts from the pots, the input jacks and the speaker jacks. Remove the speaker jack PCB, the remove the screws from the PCB. It is pretty easy to get the main board out.
Here it is.
And the board.
The pics were taken randomly hence the pot has already been opened. So the easiest way to get this off is to open the pot and cut it off. This will allow you to de-solder and remove the six pins one at a time. Much easier. Bend the metal lugs back to get the metal sleeve off.
Now we can see what the problem is, the carbon tracks are worn AND right at the point where the pot was crackling.
Now it’s time to remove the old pot. Cut off the legs with side cutters CAREFULLY.
Heat up the solder till it melts, then grip the legs and pull out when the solder melts.
Once you suck up all the solder with a solder sucker then it’s time to give the site a little clean. I use the wives nail polish remover, but you can use any ethanol based product.
Nice and CLEAN!!! Ready for new pot
And here it is. The new pot! A shiny Dual Ganged 500k Audio Taper bought from eBay for only £4.99.
And finally installed.
And the verdict. It’s just like brand new and sounds as good as it was before it broke.
Just a one hour job if you have the skills and tools. All for only £4.99 (cause my time is free for the band of course). Now we have a spare amp again!