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Vintage threads from the first ten years

Re: 3 prong AC plug for old Fender amp: addition

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6/19/2000 2:47 PM

Re: 3 prong AC plug for old Fender amp: addition

I'm not experienced enough to give an answer on that (whether the "death cap" is prone to failure or not) but I do feel confident that the advice I gave is unconditionally safe.

I never give advice on AC wiring in these fora unless I feel confident in it, I would hate to be half-assed on this particular subject and hurt somebody.

The three-position, normally-off switch idea makes sense to me, make sure the cap and switch are rated for AC service of course.

-j

6/19/2000 11:57 PM

No amp leaves my shop without one, unless the owner insists on maintaining the originality. Even at that they get a stern warning of the hazards. I think most reputable shops would have the same practice.

FWIW, I've never seen a bad one either. Also, I know I've heard static for this before but I always recommend leaving the ground reverse in the circuit. The wiring you'll see out there can be pretty sorry at times. "Electrical code...what's that? My brother Darryl and my other brother Darryl wired this place and they only charged me a case of beer."

Get the idea?

Carl Z

7/27/2000 8:33 PM

Carl,Bruce.
No amp leaves my shop without one either.....they are warned when they drop the amp off that the 3 wire grounded cord will be installed. If they don't like this mod they can take their amp elsewhere. I have never seen a bad "ground cap" either. I always leave it in, but disconnect the hot side of the ground switch. This way if you run into one of Darryl and Darryl's wiring jobs and they have the ground disconnected you'll still be able to have a ground connection. If the AC is wired backwards, I won't plug into the circuit until I rewire it properly anyway so I don't want the hot on the ground switch.

Peter S

7/30/2000 8:10 PM

Peter:

No amp leaves my shop without one either...

A good policy in view of all of the lawsuits going on these days! Most judges would ignore any verbal or written warnings you had given to the customer... if it was in an unsafe condition when it left your shop and someone was injured or killed the lawyers will come looking for you!

Steve Ahola

P.S. What 3-prong cords do you use? Lots of people like the universal (IEC?) computer power cords since they are so inexpensive; they are also skinny enough to fit inside the original cord restraints.

7/31/2000 2:31 AM

Steve,
I generally use the heavy 3 wire 9' or 12' cords, I get either from a local electrical supplier, or I order 'em from Magic parts or one of the other Amp/Guitar parts suppliers. I always replace the strain relief when I install a new cord. On the amps I'm building now, I've switche to using the computer type cords and sockets, that way you just unplug the cord from the back of the amp when you want to pack up and go.....no more long dangling cord hanging off the amp. I like this arrangement.

Peter S

8/9/2000 4:05 AM
Andy Fuchs	I buy surplus 10 footers. Minimum 18/3. The computer cords are nice, but often are shielded, which makes working with them a bit of a pain.

6/20/2000 7:44 AM

quote:
"How many of you have actually found a bad ground cap in an old Fender BF or SF amp."

Well, it only takes one!!! And if you live to tell about it consider yourself lucky.
I was working on a cheap amp with no p/t one fine day. It used a voltage doubler right off the ac line. The amp was working o.k. and I was about to call the customer when I decided to "test" the grounding by touching the tuning key of my Les Paul (a '52) to the grounded outlet box on my bench.
"CAPTAIN, CAPTAIN, all the STARS have gone out!"
After resetting the breaker in my fuse box I discovered that my high e-srting had been blown off my guitar. I was lucky that that was the only damage done. Turns out that an AC wire on a terinal strip was poking over and contacting another terminal which was connected to the chassis. If the plug had been the other way in the socket I might have sent this amp out to the customer without realizing the shock hazzard.

RE

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