Full Wave Center Tapped Ground Question

[dbishopbliss]

All of which posed no particular problem as long as the guitar and amp and player were a little island unto themselves standing on stage.

One time a band mate handed me his guitar to hold while he ran to the bathroom real quick.  He was a little pissed when his SG went flying across the stage.  After that, I learned to tap the mic with one hand while holding the guitar strings with the other.  Then, tap the guitars of other band members in a similar manner.  If you felt a shock, you would switch the ground.

[JC]

Well, Doc, I don't think there was a review, but I would imagine there was a considerable amount of medicinal Jack Daniels applied to the injury!

You may recall that the chassis on that vintage of fender was hung into the cabinet with long screws that  went through two chromed steel "straps" on the top of the box which acted as big "washers".  These were also "grounded" by their attachment to the chassis, of course.  Bad idea to be leaning on two different amps at the same time, in other words!

Beefy, I've used a similar approach in the past, even on a Foreplay 2, although I usually find the cap to be unnecessary.  Of course, that is the ONLY point at which the Chassis/Safety ground can be connected to the Audio ground.  So, jacks must be of the insulated type, of course, for instance.

[Paul Joppa]

How do ground loop breakers figure in here?

With my PCB solid state gear, I am used to connecting safety/chassis ground to signal ground through a 10ohm, 5W resistor paralleled with a 0.1µF mains-rated capacitor. Signal ground including input and output jacks is otherwise isolated from the chassis. Could the same be done for P2P tube amps with the signal/circuit star ground point connected to the safety/chassis through a breaker?

There are many answers to these questions. Each of them is authoritative, and explains, patiently or not, why all the other answers are wrong. I have not yet succeeded in sorting them out into a consistent set of recommendations.

Part of the problem is that the answers are often based on experience with a variety of gear, and the gear itself is not consistent in how grounding and shielding are done. I conclude that there is no system that will work with all gear. In the end we've tried to implement the safety standards first - every piece of metal accessible from the outside is grounded to the power line safety ground.

Another part of the problem is that the grounding that works best for low-frequency (audio band) noises is not what works best for radio frequencies (cell phones, light dimmers, refrigerators, etc.)

[dbishopbliss]

So that explains why my 101dB horns hum when hooked up the ice dispenser of my refrigerator.  :-)

[Beefy]

Thankyou for the replies, gentlemen!

I have indeed read many different opinions for this, but it is good to know from you all that - at a very minimum - I would not blow anything up if I grounded a tube amp the same way as I do for my SS gear.