Many of you
Let’s have a look shall we? If you’ll recall from my previous post, the rectifying circuit in the GA-5 looks like this :
The death cap, a .022 mF is there to help suppress hum. Have that removed!! It is actually very dangerous, and is no longer allowed in circuit designs (in fact, I think it was outlawed in the mid sixties). I found my first reference to the death cap here and a subsequent conversation with somebody with a lot more experience than I do made the problem clear.
When that cap goes, and it will, it will do one of two things. It will blow open, or it will short. Open is no problem, but shorted means that there is now a direct path from power to ground. Just touching your metal cord shield should be enough to put you in the circuit (I hate metal plug assemblies on cords). If you are touching your strings or metal on the guitar, your odds of being electrocuted are much better.
Remove the death cap and ground your amp with a three prong plug first. More details on the way.
I should point out that I have now done the same mod (and the three prong mod that is coming soon) to my daily player GA-5 and I got some noise. Popping when I touch the strings mostly.
Those are ground loops likely, and you’ll have to go checking your grounds (star grounding etc) if this happens to you. I’ll write about that eventually.
Hello from Madrid, Spain!
I did it in my 2 skylarks and 2 kalamazoos, and no problems. The amp is quieter than before the mod. Very easy to do and works fine!
This is a beautiful useful site ! Thank you !
Ignacio
By the way, if you have a capacitor tester, you can check and save the “black beauty” death cap and use it for replacements in other amps.
The 0.02 mfd “death cap” in the skylark , if still in healthy condition, can be a perfect coupling cap for the kalamazoo´s, and other amps (I think, in Fender Champs, also).
Outstanding. I actually ended up having to dress a few connections after removing the death cap.
While it is true that you can reuse that cap, it’s a 40 year old cap and they have a definite expected lifetime. Back then, they overbuilt, but still.. that thing will go.
Any reason that this “Death CAP” could not be used in a guitar? Is this not the same as the .022 PIO CAPS you see on eBay all the time? The Black Beauties?
Well.. they are usually pretty good sized. You don’t need a 400 or 600v cap in a guitar. I don’t know about the .022s you are seeing but mine was nearly the size of an M80.
i just purchased a mint epiphone ea 50 do you just remove the cap and add the 3prong thats it? nothing in its place?
@cobbo
In place of the death cap? That is correct. When it shorts, that cap causes a straight line from high voltage to you to ground.
Build a little IEC + 2 prong socket box and run a heavy gauge wire from the earth ground (middle) post on the IEC to the PT ground lug. Solder that wire in and you are good to go. At least you are safe. If it’s mint, save everything and keep the cap leads as long as you can when you clip them, in case you have to put it back.
Of course, if it’s mint.. you’ll be replacing power supply caps very soon.