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Sm 58 shock troubleshoot
- Thread starter Low_Ryder
- Start date
Just wanted to add - I had to bring some mics to a recent gig. One of the jacks of a SM57 pulled out and I was looking up how to fix it on youtube - and discovered two of my three SM57's are fakes! Bought off of eBay a few years ago. Lots of fake 58's out there too, many probably have questionable wiring.
If the PA and your amp are not properly grounded, or if one has a defeated ground, or is different ground potential, the chassis of one piece of equpment may have the line votage on it. Play your bass/guitar, and while holding the strings, touch the mic, and 120VAC will flow through your lips.
We ran into this A LOT before grounded outlets appeared, and grounded cords were put on amps. I learned, with our amps with two pronged plugs, and ground switches, to turn the amps and PA on, put a cord into the amp, turn up till I could hear the hum, then flip the ground switch. The postion with the least hum was the correct one. If it was on damp grass, or on concrete, I'd use a plastic comb to flip the switch. Later, I started using a meter to measure between the mic and amp chassis. The reading would either be 0 or 120vac.
There is nothing wrong with the mic.
We ran into this A LOT before grounded outlets appeared, and grounded cords were put on amps. I learned, with our amps with two pronged plugs, and ground switches, to turn the amps and PA on, put a cord into the amp, turn up till I could hear the hum, then flip the ground switch. The postion with the least hum was the correct one. If it was on damp grass, or on concrete, I'd use a plastic comb to flip the switch. Later, I started using a meter to measure between the mic and amp chassis. The reading would either be 0 or 120vac.
There is nothing wrong with the mic.
This was mentioned before, but not really highlighted, and is the simplest solution - go wireless on your bass. As you've pointed out, there are a ton of variables between the house current, outlet wiring, power strips, bass rig, pa rig and microphone. (With no insult intended), it seems the OP randomly testing individual moving pieces in a complicated whole will give more information than he / she is prepared to work with (it's more than I am prepared to work with, too, and from venue to venue, I don't have the time, ability or willingness to try). If it's house wiring (the most common in my experience), the problem could change from location to location, and the solution could be beyond their control.
At it's simplest, there's an electrical charge that is finding its easiest path to where it wants to go through his body, to his instrument, through his cable, and through his amp. Wireless breaks this (potentially deadly) path. I don't completely understand ground loops, and ground potential, but since I've been wireless, I simply don't need to.
At it's simplest, there's an electrical charge that is finding its easiest path to where it wants to go through his body, to his instrument, through his cable, and through his amp. Wireless breaks this (potentially deadly) path. I don't completely understand ground loops, and ground potential, but since I've been wireless, I simply don't need to.
