Tell me about the Death Cap

[conky]

I just picked up a 2nd gen Model T and I'm paranoid about the death cap that a lot of the older amps had. This one has a 3 prong cord but I think it came stock. Has a ground switch too, but I haven't messed with it. I'll try to post gut shots soon.

[fever606]

In for second gen T knowledge...

[braaandooon]

Death cap in my old Ampeg J12 went bad recently. Symptoms displayed were ghost notes and the occasional tripping of breaker in my home, probably due to the faulty cap leaking AC to the amp chassis. Ended up removing cap and adding a proper cord and now good as new. Was always under the impression that amps that came stock with 3 prong cords didn't utilize a death cap but I could be wrong.

[potatofarmer]

It's a cap from one side of the mains power to the chassis ground to filter out noise. Usually there'll be a switch so you can select which is getting filtered (live or neutral) - or more accurately so you can compensate for reversed wiring at the venue.

If the cap starts shorting, AC power goes through the chassis. If you have a 3-prong plug and you're plugged into a properly-wired 3-prong outlet, the ground prong will probably look like a more attractive path to ground than through your guitar and body, so it'll probably trip the breaker before you die.

Still a good idea to remove them, as that's a whole lot of "if" and "probably" and most venues were wired by hacks.

If you've already got the 3-prong, it's just a matter of snipping out the cap. It may have been done already.

edit: found the schematic here, just because I've never looked at it: http://music-electronics-forum.com/t34524/#post321027

[ShaunNecro]

This can happen. This is bad. You can get safety caps now that don't do this if they blow.

[chillerthanmost]

First thing I do with ALL my amps is a three prong and remove that cap. It's as easy as clipping it off, or you can solder it off if you want a cleaner look. Very simple job that should be a must, although I've never experienced the negative side of why it should be done. My first gen model T came with a three prong and I don't remember if it had a death cap or not. I'm gonna open it up today to bias the new tubes I just put in, so I'll see if I took it out or not.

[ShaunNecro]

The only reason why you should keep it in with a three prong cable is because you can never be sure that the ground is going to be hooked up at every single place you play at, and you sure as hell want that cap in there for those unlikely situations.

[crochambeau]

Yeah, just clip the cap out. The issue is that when they fail, they fail short.

If noise appears because of this (like periodic motor noise, dirty on the AC mains, etc) simply slap a safety cap ACROSS hot and neutral, I don't reference chassis at all where mains is concerned. Has to be a safety cap though, which fail open.

http://www.justradios.com/X1Y2capacitors.html

The only reason why you should keep it in with a three prong cable is because you can never be sure that the ground is going to be hooked up at every single place you play at, and you sure as hell want that cap in there for those unlikely situations.

For noise issues? I can't think of a single instance this has bitten me (though I have indeed been hit with mains a time or three), but I'll give you the benefit of the doubt. If for whatever reason you need a cap referencing the chassis, snip the OE piece of shit out and plant an X1Y2 in its place.

[D.o.S.]

Death Cap for Cutie?

[CyaNitrate]

The only reason why you should keep it in with a three prong cable is because you can never be sure that the ground is going to be hooked up at every single place you play at, and you sure as hell want that cap in there for those unlikely situations.

You can be sure actually. When I first got into vintage Fender amps, one of the first things I bought was an outlet tester. You can get them at just about any hardware store for pretty cheap, and a huge peace of mind. Just plug it into an outlet and it will tell you if it's wired properly, and it's small enough, like golf ball sized, to keep in a gigbag, case, or the bottom of your amp.

Death cap needs to go. You can keep it in storage if all original parts are important to you, but it's called a death cap for a reason.

[ShaunNecro]

The only reason why you should keep it in with a three prong cable is because you can never be sure that the ground is going to be hooked up at every single place you play at, and you sure as hell want that cap in there for those unlikely situations.

You can be sure actually. When I first got into vintage Fender amps, one of the first things I bought was an outlet tester. You can get them at just about any hardware store for pretty cheap, and a huge peace of mind. Just plug it into an outlet and it will tell you if it's wired properly, and it's small enough, like golf ball sized, to keep in a gigbag, case, or the bottom of your amp.

Death cap needs to go. You can keep it in storage if all original parts are important to you, but it's called a death cap for a reason.

Allow me to rephrase; aside from personally being there with an outlet tester, you cannot be sure that every venue has the ground connection. And hell no should you keep the original caps in there, that's why I suggested replacing them with a safety cap. Some things should be kept original, some things like a three prong cable and the death cap should be replaced with the safer modern alternative.

[potatofarmer]

There's also the "Reverse Bootleg Ground" which a 3-light outlet tester won't detect, but a non-contact voltage tester will: http://ecmweb.com/contractor/failures-o ... ng-exposed

[kbit]

Death Cap for Cutie?

[gnomethrone]