2. amps-preamps
  3. 1133926640

I'm SHOCKED literally .

I put a couple of new components in, and generally shuffled things around in my system last night - and after listening for a couple of hours today - got SERIOUSLY zapped (it was audible) as I touched the Volume knob on the preamp to turn it down. There was some kind of charge build up, and it took a while to drain it all down - I had to (gingerly) touch the knob a couple more times and then hold it until the charge was drained off. My finger still hurts!

This has never happened before - so it's not static from my rug or something. I'll be doing some careful testing tonight, but in the meantime - Any ideas what could cause this???

Possible explanatory variables:

---The "new" items were the preamp (tube) itself, the processor which connects through the Pre's Tape loop, and a Granite Audio power cord with toroidal noise filters at each end connecting the Pre to a surge protector (temporarily). The surge protector has been in use elsewhere with no trouble.

---The new processor is a two prong plug - Polarity?

Tonight I will try running a couple of hours with the processor unplugged and the Tape Monitor OFF to see if I have the same problem. Or if any other equipment has the charge buildup.

Any ideas? Is there a plausible explanation without there being an actual equipment problem?

opalchip
avguygeorge
2,300 posts
 
In the past I got such a shock from my amp. In my case it was because the amp wasn't grounded, a cheater plug/ adaptor was in place. When it's windy and dry I still get mini shocks;and don't use those cheater adaptors. I live in Southern Ca.
aball
2,016 posts
 
Sounds like you have a floating ground on your preamp. You can lift the ground by using a three-to-two prong adapter plug. If there are only two prongs on the preamps plug already, then check to see if you are using balanced cables. It could be that the balanced ground connection is causing the floating voltage from another component, connecting between chassis ground and earth ground.
stereo_spencer's avatar
stereo_spencer
6 posts
 
If it is static charge, I would suggest two simple answers which I do now as I am in the "dry season" and have a woodstove nearby to make things worse. First, touch the wall, wood furniture or metal object to help to neutralize the charge before touching your components and/or second, take your shoes off before touching the stereo system.
jond's avatar
jond
5,807 posts
 
It sounds like static to me. This time of year I always touch one of the metal supports of my rack before I touch any gear, to drain the charge.
opalchip OP
355 posts
 
Thanks for all the suggestions so far - I'm pretty sure it wasn't static, since this has never happened before and my room has been the same for 5 years. The processor has a simple two-prong plug and I reversed it's polarity in the outlet then tried to recreate the situation again and couldn't. So somehow, it may have been that.

I'm going to test the equipment chassis' to see if there is any slight current flow going on. But for now, I'll just have to be careful. Or I'll just ask my wife to change the volume - she's the one who always wants it lowered anyway!
More to discover