[rajacat]

Need advice and  on purchasing gloves for electrical work. 500v to 1000v ok for tube amp? Since I'm not a pro, I would like to keep the cost low without compromising safety.

-Roy

[Haoleb]

1000v would be fine for anything in a tube amp, Although dont rely on the gloves as something to protect you. The best thing you can do is follow good safe procedures while messing with electronics while they are on. Such as taking off rings and watches, keeping one hand behind your back so you dont accidently set it on something while not really paying attention (hard when your working with meter probes i know) and knowing whats not safe to touch.

You may also want to consider getting an Isolation transformer which would make it safer.

Basically, good common sense will go alot further than gloves would. But they certainly can offer peace of mind. Just dont rely on only them to keep you safe.

[rajacat]

I don't plan to work on my amp while it's connected to AC. These gloves would be used to avoid possible shocks when working near loaded capacitors.

-Roy

[Haoleb]

Well if thats the case just get yourself a resistor and some alligator clips. I would say a screwdriver but some people say its not good to do that. I always just touch a screwdriver or something across the leads before I work on something. I let it sit for a minute or so after powering down too because most discharge in circuit anyway.

[rajacat]

So it takes just a few seconds to discharge a loaded cap? Please excuse me for my newbie questions.

[Haoleb]

Yes, depending on what size resistor you put across it. If you used a screwdriver it would discharge almost instantly and then if you wanted to be absolutely sure just put your multimeter leads on it and see if there is any voltage.

You could use like a 50 ohm 5 watt resistor and it would discharge pretty quickly. Personally, one of the only downsides i see to using a screwdriver is that it will spark and can sort of arc weld just leaving a little mark on your screwdriver or the terminals.

If you go the resistor route still touch the screwdriver across after a minute or so to be sure they are fully discharged if you havent got a meter to test with.

[KS]

I've done some work wearing electrician's gloves.  Forget about any sense of feeling or doing any delicate work.

[mgalusha]

Please get a resistor with some insulated clip leads and don't use a screwdriver. A large cap discharged via a screwdriver can actually take a chunk out of the screwdriver blade. When discharging the caps in an amp clip one end of the resistor to the circuit ground, a speaker binding post is a good spot, and then you will only need one hand to connect the resistor.

The same procedure can be used for measuring many of the voltages present in the circuit as they will be referenced to ground. Clip one of the meter leads to ground and probe with only one hand. As previously suggested using only one hand is the safest way to go. Always probe for residual voltage before working on the amp, even after you have discharged the caps. Some circuits have a bleeder resistor that will discharge the PS caps but not all. I have seen some hold hundreds of volts for days, you have to measure to be sure.

[rajacat]

Thanks for all your answers. I have the resistor with the alligator clips and will check the large caps with a multimeter too. If you never hear from me again you'll know that I've gone to audiophool heaven .

-Roy

[jneutron]

Once the capacitors have discharged, keep the resistors connected to them while you do work.

All capacitors will recover a bit after they have been discharged to zero.

If you choose to use v rated gloves, you'll have to have them tested every 6 months.  This is a PITA.

Best bet is remove the voltage, and keep it down while working.

Cheers, John

[whubbard]

Ironically I remember reading this thread on Thursday...

So this weekend I'm working inside my Tube Pre-Amp (Aspen GK-1m) while talking on the phone and then Zap. I believe I was lucky enough to touch one of the lower voltage sections of the preamp, but none the less it was a bit scary considering if I had touched other places it would have been bad, very bad.

Now, I don't think I will be investing in a pair of gloves, but I sure am going to be much more careful from now on. It's now the third time I've been seriously shocked. The first was 120V from the outlet on a split cable into my leg, the second was holding two terminals on a power amp while it was playing, and now this. So I'm really hoping to avoid further injury in the future as my arm was sore for an entire day after it happened.

Thought I would just share that will all others looking at this thread.

-West

[G Georgopoulos]

using gloves is wise thought especially when having no experience
alternatively just remember to use one hand, this of course wont
work with live parts...

[whubbard]

just remember to use one hand, this of course wont
work with live parts...

Even I remembered that...
which is why only my left forearm felt funny the next day.

However, when I grabbed the two amp output terminals I felt the current pass across my chest; it was a very bizarre feeling.

-West

[TomW16]

I have never had any current go through me, however, I have scared myself with home wiring by inadvertantly shorting it out.  I was testing a 3-way switch that wasn't working properly and I inadvertently touched the voltmeter to the metal box.  It blew the circuit with a flash of blue light followed by a grown man dropping the voltmeter and screaming like a scared school girl. 

I am happy to hear that you are OK.  You might want to check out the arm if you are feeling pain so long after the incident.

Tom