Miscellaneous Rumbles

Just how dangerous is doing your own amp work?

1

I hear it all the time about how electrical shock can kill, and I know it's true and can happen. But if you're careful to check if the unit is plugged in, understand grounding, and know how to discharge caps, should I still shy away from doing cap jobs and building an amp from a kit? I love the idea of doing this work myself. I have an uncle who used to work on TVs as a hobby, and he's 88 and still talks about how much pleasure he got from that. Although I value all opinions, I'd especially like to hear from Don the Toneman on the subject.

2

Only you can make that decision. Familiarize yourself with the dangers and address them every time you open the amp. The most dangerous part in my opinion is during biasing or chop-sticking when you're working with live voltages. If the amp is off and you've discharged the caps, everything else is pretty low risk.

Maybe try building some pedals to get your technique down before approaching the high voltage stuff.

5

Always keep your free hand in your pocket ;)

– charlie chitlins

Yes. Keep your left hand in pocket. Sucks for me as I'm a lefty.

6

https://www.premierguitar.c...

I have always liked this video...

– Twangmeisternyc

This is an excellent, de-mystifying video. Great breakdown. Now I'm not afraid to work on them.

If only I knew how to work on them...

Paul/FF909

7

No more dangerous than gigging on a wet stage with the amp grounded but the PA mic ground-lifted.

Sorry, that was a slightly morbid jest.

8

I pay to have my amps worked on.

Tree service, too.

And roofing.

9

I pay to have my amps worked on.

Tree service, too.

And roofing.

– crowbone

Come on, I do all that stuff myself. Call me next time and I'll give you a quote on how much it would cost you. Cash only no receipt

10

It's not all that dangerous, but it's unlikely that you'll get a first class job. It takes many years of experience to get good at it.

11

That I completely agree with....

Hey, Billy, is that your cousin in that vid?

Twins? I smile every time I watch it...

12

This thread reminds me....

What's black and crispy and hangs from the ceiling?

Non Union electrician.

Be careful, Sparky, and don't let the smoke out!

13

Red to red, black to black, blue to bits...

14

It's true that it tales years to get good at this stuff. But you have to start somewhere. If you have doubts you probably shouldn't fix your amp. You just have to have a logical mind and approach. You have to understand how a circuit works - I don't mean how everything works, but how a circuit needs to be complete to work and not shorted.

The trick with audio circuits in particular is that unlike working on a motorbike (which I also do) it is crucially important where you ground things. Motorbikes don't care about ground loops but amps do. And don't let yourself become the ground!

15

It's not all that dangerous, but it's unlikely that you'll get a first class job. It takes many years of experience to get good at it.

– Billy Zoom

Billy, you have pictures all over the internet.

I have just one:

16

The "be careful" warning can be applied to any hobby. I do wood working, have a band saw, router, etc. It only takes ONE distracted moment to lose a finger.

Working on electrical gear is not necessarily more or less dangerous, but you DO need to respect the voltages involved, especially in tube amps where connections can be at hundreds of volts. That said, by all means get an amp kit and try building a simple Champ clone. Lots of people do it successfully. There aren't a lot of components in a Champ and you can focus on your soldering and wiring techniques, testing, using a voltmeter, installation in a cabinet, etc.

And remember - it's a hobby. Be safe and have fun.!

17

Yes. Keep your left hand in pocket. Sucks for me as I'm a lefty.

– Otter

Otter, you are a lefty, but you build right handed guitars?

18

Yes, I play guitar and most sports (baseball, hockey) righty, but I write with my left hand. You don't want your left hand near live voltages, because any sick would go through your heart.

19

The reason people say stick your left hand in the pocket is because you should only use one hand and most people are right handed. If you are left handed use your left hand. The whole thing about the current hitting your heart is if you use BOTH hands. Then if you complete the circuit through your hands the current will go from hand to hand - ie across your heart. Your heart is in the middle of your chest, not on the left.

Now disregard everything I just said if you were being facetious.

20

The reason people say stick your left hand in the pocket is because you should only use one hand and most people are right handed. If you are left handed use your left hand. The whole thing about the current hitting your heart is if you use BOTH hands. Then if you complete the circuit through your hands the current will go from hand to hand - ie across your heart. Your heart is in the middle of your chest, not on the left.

Now disregard everything I just said if you were being facetious.

– JimmyR

Yes I've heard that (the current path through the heart when using both hands) but also that your feet are grounded, so that any shock through the left arm will go that way (up the arm then downwards) past the heart. Maybe a wive's tale, but it's easy enough to just use the right hand.

21

Its funny, they say that about 70% of Men are color blind to one extent or another. Personally, I'm a 70% failant, (US Navy word) in distinguishing red and green, Pretty important when dealing with electrical wiring. I use one hand to drop my Amp off at the Billy Zoom Custom shop and then use it again to shake his hand before I split.....Find yourself an Amp Tech who is good and that you like and trust and stick with him.

22

Re: current takes the path of least resistance. Electroshock used to get your heart back in sync uses this principal. Going from one hand to another is a far shorter path than down the length of your body. Keep you left hand in your pocket, use a rubber mat under your feet, avoid metal bench work. Having had a couple of good jolts, I know why they say electric shock is the most painful thing that you can go thru. That's why tasers work---electric chairs, too.

I've had very large capacitors in 2KW xenon lamphouses blow. Sounds like a rifle going of next to you. Learn how to discharge them properly and safely. Never work on high voltage alone. You can't be too safe.

23

20+ years ago my old Frigidaire garage Beer Fridge started to have a quirky problem. Every now and then it would trip the GFI at the outlet.

Very intermittent...

I checked it each time every way I knew how and could, no cause or answers found, then pushed the button back in.

Fine for another couple months...

I brewed beer from grain for a decade or so, traveling a lot at the same time. I basically had a small but complete brewery. My great-grandfather was a BrewMaster...family tradition. Eventually, I just plugged the fridge into a non-GFI outlet so as to not come home after a trip and find everything soured.

So, it's hot outside, bare feet, T-shirt, shorts weather. Time for a beer.

Out to the garage, concrete floor, grab the handle........Electrocution begins!!!!!!!!!!

I was locked on for about 15 seconds until my wife heard my scream and unplugged the damn thing.

Final analysis was when in the infrequent self-defrost mode, if the conditions in the garage were moist enough, the sweating inside could bypass the drip pan as the rubber door insulation wasn't keeping a good, solid seal, and then leak out and make a weak but adequate connection to the floor at the door hinge-side adjustable foot.

I think I would have eventually freed myself, but then maybe not...

A drier day, a different time, no thirst, a pair of flip-flops...would have never happened.

25

Certainly analog...

It was an old one but perfect for the kegs and carboys and such. It was an Over Fridge side-ways open, Lower Freezer drawer-style open model. I kept supplies down below.

Moral to my story, ...on a bad day even just getting a Beer can kill you.


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