Shock From Bogan AP250 Update

[Ray7027]

I had written about this problem a few weeks ago. Thanks to those who responded. I did put the amp away. I ordered the ST-70 kit from Bob Latino. I
really enjoy it, Thanks Bob.

A few minutes ago I tried the suggestion from Tom Bavis. I removed the capacitor from the input. No more shock from the amp. I included that section
of the schematic. Is the capacitor needed?

 

[JonL]

Assume you mean the cap on the AC power input. If you leave that cap in place and you are getting shocks, simply reverse the AC plug in the outlet. No more shock, and probably less hum if you are getting any now. The cap is there to bleed off high frequency noise from the AC power. There is a special grade of capacitor that should be used there, I forget what it is... something like Y2 I think.

 

[Ray7027]

The markings on it are GE 750 X4

I had tried reversing the plug when this first happened and it still shocked me.
Thanks for the info. I will try a new one.

 

[JonL]

It shouldn't shock you when reversed. When it's shocking you it means the side of the plug with the cap is on the hot leg of the mains. Switch it over in the socket and the cap will be going from neutral of the mains to the chassis. If you are still getting a shock I think it might mean that you have another piece of equipment somewhere that has a similar cap on the hot leg. It might also mean that you have a problem with your house wiring to that outlet. I'm no expert on this, but us guitar players get shocked like that all the time because Fender (and many other makers') amps use a similar setup. Usually they have a "ground" switch that flips that cap from one side of the mains to the other. Basically, you switch the ground switch so that you have the least hum (and reduced effect on hum from touching the chassis), then you hope that the PA and the other players have set their mains the same way. It's really special when your lips graze the mic when the polarities don't match. I guess if you have no noise issues without the cap, you could leave it out. You can also get a smaller value cap that will pass less of the 60Hz current thus reducing the pain if you do get a shock.