Capacitor on fuse holder?

[Tweedguy]

I built a '57 Tweed Twin and didn't hook up the ground switch because I used a modern 3 prong AC chord. Now, the ground switch had a .05uF cap on it going to ground. I was told by the guy who sold me the kit to put this cap on the fuse holder tab since I wasn't using the ground switch. I haven't seen too many other amps with a .05uF cap on the fuse holder, is this totally unnecessary or does it have some sort of advantage, protection, etc?

Thanks

[rooster]

Totally unnecessary. I have never seen or heard of such a thing, FWIW, and I have seen a few things. With the 3 prong AC cord you can skip the .05 to ground at this juncture. If you insisted on using it, you would install it on the positive side of the AC to ground.

[Firestorm]

That doesn't sound like the safest thing in the world. If the cap shorts, you'll have 117VAC on the chassis (even scarier in Europe). Technically, you want the fuse and the switch on the hot side of the AC. If you absolutely needed to have a ground cap (because you were in a studio and wanted to lift the ground so all the equipment chassis' could be grounded together to kill ground loops), you'd want that cap on the neutral wire, not the hot.

That said, I've seen amps with caps on both sides of the AC AND on the B+. Noise suppression, I suspect, was the intent. But it sounds like bad business.

[jjman]

My '74 V-Champ came with an orignal 3 prong cord and the death cap on the fuse holder (which is the hot leg) to ground. The neutral side was to the switch and had no such cap. The schematic shows otherwise however.

[Tweedguy]

OK, I disconnected the cap from the fuse holder. Thanks for the info.

I took a look at the new Fender Reissue schematic of this amp and it had a .1 cap across (connecting) the two AC wires just before the power tranny. What is this about... anybody?

[Tonegeek]

OK, I disconnected the cap from the fuse holder. Thanks for the info.

I took a look at the new Fender Reissue schematic of this amp and it had a .1 cap across (connecting) the two AC wires just before the power tranny. What is this about... anybody?

If it is between the neutral and hot ac input, it is probably just a teeny bit of filtering to supress RF before hitting the tranny. Not a safety issue.