Shock Hazard?

[hesamadman]

Im experimenting with ways that I can power a backlit badge on my speaker cabinets from my amplifier. Right now I have a backlit badge powered by the heater winding via an RCA jack on both the back of a cabinet and rear of the amp. So when the amp comes on, the badge lights up. I know the RCA jack is not ideal due to the ends being live when the amp is turned on. I realize its only 6.3 volts but given the right circumstances this could possibly be bad. Potentially shorting out the heater winding. Etc. Etc.


I am extremely happy with the results of this. There is no noise. I am using LED tape so its basically an unfiltered DC supply. Is there any other jacks that someone could recommend to keep this a little more safe. I truthfully don't know the safety hazards of this. Again its only 6.3 volts, however, this is a high gain 100 watt amp with tube fx loop so we have 4 output tubes and 5 12ax7. Thats a bit of current going through the same circuit the badge is on. If I had a 5v winding, I could fuse it? Or maybe I could still fuse the LED's? Or is this even necessary? I am also using a +15 -15 volt TL072 for the reverb. Would it be safer to tap off this +15vdc? Id have to drop voltage a tad as this is a 12v LED strip.

[jjasilli]

I think the basic point is that a plug (male) should never be live, because it is exposed (until plugged-in).  A female RCA output jack on the back of the amp is OK.  The jack's outer ground ring is presumably chassis grounded.  No different from the heater supply.  The RCA jack's inner tip connection is unexposed and inaccessible except by a male pug.  But, terminating the other end of the lead with a male plug is wrong, because it is live & exposed.

One solution is to permanently attach the lead to the LED's on one end, with a male plug on the other end to plug into the amp's female output.  Other solutions are Neutrik, or DIN connectors.  These offer insulated connectors to guard against shocks or short circuits.

[hesamadman]

Thanks for the input. I'll check around for some more connector options. I'm trying to eliminate the need to make a specialty cable, but will if I have to.

[Tony Bones]

You might also consider fusing that connector so that short won't take out a valuable PT.

[pompeiisneaks]

Is there any reason you can't just put a bushing in the hole through the chassis, and do a permanently soldered connection covered with heatshrink over it?  That would be loads safer and more permanent as well.  Or would the badge not come off when pulling the chassis?  Is that the reasoning?  If so, I have  used threaded connections before like this: http://www.newark.com/conxall/17282-2sg-300/circular-connector-receptacle/dp/93F7299?mckv=sNGIcBLBP_dc|pcrid|81515568741|plid||kword||match||slid||product|93F7299|&gross_price=true&CATCI=aud-106011026661:pla-325659264201&CAAGID=20376566901&CMP=KNC-GUSA-GEN-SHOPPING-93F7299&CAGPSPN=pla&gclid=CjwKCAjwtdbLBRALEiwAm8pA5eqIL2VdkTWuduSiaVg4gKrxWr2LeW-ekXGjM8ujMH4Yv-wMZUk6jhoCRisQAvD_BwE&DM_PersistentCookieCreated=true&CAWELAID=120185550001335854

they're not cheap here, but I got mine a long time ago and can't remember the source.  They thread tight and then you're safe for it to be easily removed if needed when the time comes.

~Phil

[hesamadman]

The badge is wired directly to an RCA jack in the same jack plate on rear of cabinet as the speaker jack.

[pompeiisneaks]

Then yes as others have said, it should be okay due to the way the rca jack is when disconnected, you'd have a hard time getting fingers inside it.  Also it seems that at 6.3v you're not at high risk of doing major damage to anyone, so that alone means it's probably not a big deal, but it still leaves a potential for shock.  If you feel comfortable with that risk then it's likely fine, but as mentioned a screw on type jack would ensure it can't accidentally come loose and cause someone a jolt.

~Phil

[drgonzonm]

Probably not, 

To reduce the hazard, modify the speaker rca jack and put in a male plug.    Then your led power cable is male female, and the shock hazard is reduced.  (think of the IEC plugs on amps,

I will guess that there are other shock hazards associated with the speaker. plus other exposed current issues.  What kind of plugs are you using on the amp and the cabinet to connect, male 1/4 plugs?  Find the schematic to your amp, and look at the b rail voltage on the power tubes,  300 plus volts? maybe higher?   you are likely plus 20 volts feeding the speakers.