On The Bench: 10 Stupid Things You Shouldn’t Do!

1: FUSES ARE NOTHING BUT TROUBLE

There is no single component that consumes more time on my ‘free advice’ hotline than questions about fuses. I hear all too often the frustration that gives rise to the industry standard approach to a blown fuse: ‘wrap foil around it and jam it back in’. Sure we’ve probably all done this – it’s 10:50pm on a Saturday night, the band’s on stage at 11 and the Marshall head has just popped a fuse. What else are you supposed to do?

Well, regardless of the old adage, ‘the show must go on’, and despite what it seems, fuses aren’t just there to drive us all to despair. They actually serve to protect both the equipment and the people using it. This fact was made all too clear to me only last week in spectacular fashion when my workshop bench power supply caught fire. I bought it secondhand about 10 years ago and it’s always done its job well, so I’ve never had reason to look inside or question its construction. This week it was sitting there powering up some nice Electrodyne modules when I looked up to see smoke billowing from the unit’s slotted lid, quickly followed by a small lick of flame. Once the pressing need to pull the mains power out of the unit and get it outside had passed, I had the chance to pull it apart and look inside to see what had happened. Lo and behold, this thing had been built without incorporating any mains fuse. This is not only illegal, it’s downright stupid. In this instance the transformer had failed, and since there was no fuse to blow, it just kept sucking mains current, heating everything up to the point where it finally caught fire. This story highlights one of the fundamental and practical roles of a fuse: it prevents things failing with catastrophic results.

Of course, the thing about fuses that leads to frustration is that sometimes they blow for seemingly no apparent reason, or at least no reason that coincides with an apparent fault within the equipment. Also, just like anything else, a fuse can simply be faulty in and of itself. Not all fuses are created equal and sometimes that hair-thin wire inside just snaps off. This leads to the proposition that replacing a blown or broken fuse is an entirely reasonable step to take. Now back to our gig: it’s 10:55pm and you need a fuse pronto. Of course you have a couple of spares in the gig bag, don’t you? I mean, you have spare strings and probably even a spare guitar lead so naturally you’ll carry a couple of spare fuses of the correct type for your amp, right? Forget the Alfoil – you only use Alfoil for cooking!

3: HO HUM

We’ve all heard of (ie, read or talked about) earth loops and plenty of us have actually experienced them. Like so many problems in life, there are usually a couple of solutions available that eliminate earth loops. One of these is exceedingly dangerous and downright idiotic: cutting off the earth pin on the offending power lead. For those afraid of commitment, yet predisposed to electrocution, you might just choose instead to fold the earth pin over. Either way, you risk killing yourself or others. Mains power earths exist for a reason that has nothing to do with audio quality and everything to do with safety. Every earth loop problem can be solved in a way that is safe and leaves the mains earth pin intact. Feel free to fiddle about with the wires inside XLRs and TRS plugs; just don’t fiddle with mains plugs.

5: THE GREY IMPORT

I know, I’ve harped on about this before but it’s such a common occurrence that I need to slap you all again. The simple fact is that in the USA mains power is 115Vac. In Australia it is 230Vac. That’s double the Volts folks and if your grey import is set for 115Vac when it lands fresh from the USA and you plug it into Australia’s mains supply, the experience will be overwhelming… for your new shiny toy and your pocket as well. If fortune is still on your side, you’ll blow a fuse. However, chances are you’ll do a lot more damage than that, damage that’s not covered by any sort of warranty. Oh, and please also note: simply using an Australian power lead or changing the rating of the fuse does not magically convert the unit’s operating voltage. Stop and think before plugging in anything you’ve imported from the USA, unless it’s a Twinkie.

7: DUST BUSTER

The manufacture of condenser microphones has transformed from an esoteric European black art into a mass factory production, with the resulting benefit of them becoming available at low cost. However, nothing has changed as to their capsule’s sensitivity to contamination by dust. The high voltages, gigaohm impedances and microscopic dimensions involved in condenser capsules means that a tiny amount of dust, particles or general crud can stop them working, or at least working noiselessly and consistently. If you have a condenser mic and you like to leave it on a stand ready for action 24 hours a day, at least find a nice plastic bag to slip over it when you’re not using it. If your mic came with one of those slip-on foam pop filters then give serious thought to throwing it away and getting a real pop filter. Not because it might sound better but because most foam filters degrade quite quickly and begin to rain tiny foam particles down through the grille and onto the capsule. This is aggravated even further when you slide the pop filter on and off regularly – the grille screen typically acts like a cheese grater, scraping off the foam particles through the grille and onto the capsule.

9: POWER ON

Okay, I admit this one seems unbelievable, but I’ve seen the evidence and got the photos here to prove it. Fate has allowed the humble figure-eight mains power lead to mate seamlessly with the male XLR plug leading to catastrophic results. If the authorities catch wind of this it could mean the demise of the male XLR as, by the book, nothing should physically mate with any sort of mains power connector unless it’s designed to accept mains voltages. Just because a plug and socket seem like a match made in heaven doesn’t mean you should bring them together. If you have figure-eight mains leads don’t be tempted to plug them into male XLRs, it’s unnatural.

11: ROCK ’N’ ROLL

Sure, the title of this article may have convinced some AT readers that this ’ere list would only go to 10, but it wouldn’t be rock ’n’ roll if a list of ‘10 dumb things’ didn’t crank up to 11, so let me just close with something that, if nothing else, is a reminder to myself: don’t make assumptions. We work in a complex world that combines technology with technique, machinery with magic, all of it creating lots of potential for things to go wrong. And it’s when things go wrong that we often make our biggest mistake – we make assumptions. Whether troubleshooting a faulty piece of equipment or mixing a masterpiece, assumptions can divert us from seeing or hearing the truth, wasting time, effort and sanity. Rule number one: assume nothing.