Grounding an amplifier...

[kegmcnabb]

A while back my father scored me a 1957 Fender Champ. She is an absolute tweed beauty in nearly flawless condition. He found it at a garage sale and the guy wanted $5.00 for it. Dad asked if it worked and the seller had nothing to plug into it so my father (ever the bargain-hunter) asked if he would accept $2.50 for it as there was no way to see if it even functioned. The seller said "sure" and I ended up with a wonderful little piece that I intend to use as a harp (harmonica) amp.

My question is about grounding. I have been told that it is very important for safety purposes to convert the two-prong ungrounded plug to a three-prong grounded. I have an amp specialist that can do that but he is a couple hours away and I won't be going there for a while. So my question is...

Will plugging the two-prong cord into a three-prong power strip/surge protector offer the same (or indeed, any) level of ground protection or should I avoid connecting my harp and mic (and therefore, my mouth) until I have the conversion done?

Thanks!

[lgb&dtuba]

http://www.regiscoyne.com/tech/3prongconversion/" target="_blank

[kegmcnabb]

Wow...that was freakin' fast!

[lgb&dtuba]

Behold the power of Google. Google "fender champ grounding".

Actually, I was curious and it was a quick lookup.

Good luck with the conversion.

[kegmcnabb]

Thanks,

I am a little unsure of a couple things...

The Champ's wiring differs a bit from the diagram as it has no accessory outlet or ground switch. While I am generally comfortable making wiring changes myself if I have specific instructions, I don't feel confident making adaptations considering the potentially lethal voltage involved.

I will do a bit of "googling" myself.

Thanks for pointing me in the right direction, but the question remains...will a power strip/surge protector give any protection in the meantime?

[lgb&dtuba]

I don't think a power strip and surge protector will do anything for you.

Here's a site with the schematics for many amps, including Fender Champs. There are quite a few models of Fender Champs. Pick the one that matches your model number.

I looked at several and the older models seem to all be the same on the transformer wiring, but check the one that goes with your amp.

The black wire should be connected to the fuse. The white wire should be connected to the other leg, which is where the power switch should be. The green wire should be screwed to the metal chassis.

Since I'm not looking at your specific amp, then consider all this a guideline. I accept no responsibility if you don't double check everything I wrote in light of what's in the schematic that matches your amp.

[iiipopes]

Bottom line: NO.

I have had amps over the years that had the two prong plugs. I've also been badly shocked when the old Bogen PA head (before polarized plugs) I used for a gig once decades ago got tripped over (long story) and the person, wanting to be "helpful," plugged it back in, upside down, and I touched my guitar and the mike at the same time. The house lights even dimmed momentarily.

So after that, all the amps I've ever had that had 2-prong plugs I changed out to a three-prong cord and plug. It is easy to put a three-prong cord on an old amp. Just buy one, replace one wire at a time, solder the hot to the hot, the neutral to the neutral, and attach the ground with a machine screw and lug drilled into the chassis. That's how all modern amps are grounded. If you can't find one, just purchase a short industrial grade 3-prong extension cord, cut off the jack end, and go for it.

[iiipopes]

Yeah, but that's transistor, not tube! But I have to tell you, I was a tube purist until this Christmas when I got a new Vox Pathfinder 15R to go with my Rickenbacker 12-string. Up to the point it gets pushed totally over the edge and starts fizzing, a person would be hard pressed in a blind test to tell the difference between this amp and the "real deal" AC15. Great little practice/bedroom/small gig/mike it up/has a line out amp that brings out the Rick jangle in spades for only @$125, instead of $5-600 or more for the AC15.

[tubatooter1940]

Bottom line: NO.

I've also been badly shocked when the old Bogen PA head (before polarized plugs) I used for a gig once decades ago got tripped over (long story) and the person, wanting to be "helpful," plugged it back in, upside down, and I touched my guitar and the mike at the same time. The house lights even dimmed momentarily.

The same thing happened to me on a damp cement floor with my hand on the guitar strings when my lip touched the mike.
Yowie!

[tubatom91]

If I've learned anything through my years of garage band playing and jazz playing it's that electricity does not feel too good going up one arm and down the other. I have been electricuted by two amps, one at school. That one was a modified Yamaha 115 bass amp, I went to move a music stand and grabbed it and zapped myself. I am not sure what caused either of the incidents but neither were "fun", I would definatly advise checking out that amp before putting your face in any danger of electricution. Best of luck!