muso saver

[CJ]

maybe put a GFI in the amp?

no, economics dominates music amplifiers,

you can isolate the input jack from ground but there might be hum problems depending on the circuit, or where you are playing,

our bass player got hauled off in the meat wagon last Friday,

shock?

no, low blood sugar   
told him no swiggin and giggin,  but no,  hit the ground like a sack of dead flour,
had to cover his bacon on bass, no play, no pay, the show must go on,

what we need instead of a tip jar is one of those change makers so people could insert folding money only, the results could be tallied and displayed above the band stand in a green LED display, thus prompting further injections and preventing "change makers" 

 

[JohnRoberts]

maybe put a GFI in the amp?

On a live sound forum I have long advocated for using GFCI protected portable power drops for back line (guitar amps and stage gear).  I even experimented with inserting a cap in series with the ground lead inside these GFCI power drops. I sized the cap large enough that the GFCI would still trip in case of a fault but the current was limited to low enough that human injury was avoided.  Note: a GFCI will still work even with a ground lift but I do not advocate that, while far better than a ground lift and no GFCI. 

no, economics dominates music amplifiers,

indeed

you can isolate the input jack from ground but there might be hum problems depending on the circuit, or where you are playing,

I have speculated about this too. Any impedance in series with input ground would appear in series with the pickup. But a differential input circuit could grab the signal relative to that higher impedance ground. Could fairly easily be low enough to mitigate hum pickup. A secondary issue is to protect input circuitry from failure in case of high voltage exposure. In an ideal world no shock, and no device failure.

I have a friend who designs that kind of gear but I couldn't get him very interested. (still trying).

JR

our bass player got hauled off in the meat wagon last Friday,

shock?

no, low blood sugar   
told him no swiggin and giggin,  but no,  hit the ground like a sack of dead flour,
had to cover his bacon on bass, no play, no pay, the show must go on,

what we need instead of a tip jar is one of those change makers so people could insert folding money only, the results could be tallied and displayed above the band stand in a green LED display, thus prompting further injections and preventing "change makers" 

 

[CJ]

VOX uses a semi isolated input jack on there practice amp , still has the .1 cardio cap to chassis,

notice the ARRL symbols violation

no wait, there is only 47ohms and a .6 volt drop, never mind, 

 

[JohnRoberts]

Years ago I tried that trick of anti-parallel diodes to allow small voltage differences between grounds  while still being bonded for significant voltage faults but......  1n4002 diodes will vaporize if hit with a full 120V mains hit...  so  not UL friendly for ground bonding.

Maybe just the cap without the 47 ohm and 2 diodes. (I used 0.15uF to limit current below human muscle clamping). 


I'm working on some experiments and I'll share the results I get..

JR