too Much HUM told to re-post this message here guitars

[Doobs]

yeah, figured i'd come back to you, as a few of the guys stated you likely had a better handle... &...previous posts did Not get much thru the community, save those guys ...so in as small a nutshell as possible

the unit Tascam DP-008-EX , 8 track recording
all the guitars ( electric acoustic) do the same thing ...
HUM
a Breedlove, a Taylor and a lower end Martin

1 guitar cable, i know to be "better" than the other, and did try the XLR cable i have, with a TS on the other end,
so plugged all the guitars into that for a test = same = hum

now this occurs with A/C power only, no issue when using battery power
this is also a separate room, for my toying around w/ the instruments ....
so, unplugged everything else, and plugged the unit directly into the wall outlet,
( overhead light was left on, but nothing else on that room's circuit)
same = hum
it had been in a power strip, along w/ the speakers ... so... none of these different options
have even minimized, let alone, eliminate the humming ...

what does eliminate it is !
if i touch / pinch the guitar cable housing, as it enters the guitar's jack...? ? ?
does that with the 2 guitar cables , which are metal housings and the XLR / TS cable, which is plastic ?!?

now, my main room which has my home theatre 9.1 surround / OLED TV / etc ... never any hum or issues

ugggh ...

thanx

 

[R D Smith]

I have a Tascam DP-008-EX and have not noticed this. Are you are pluging the guitars directly into the Tascam? If your AC adapter has straight blades, try reversing it in the AC outlet. Some tube amplifiers have a two position power switch, or a hum switch that reverses the hot and neutral wires to reduce hum in the case an outlet is wired wrong or some appliance may be causing noise.

 

[rob aylestone]

The simple solution to many hum issues is to consider how the kit is grounded. It’s primarily supposed to be a safety thing nowadays, but equipment can have three pin connectors and the metalwork grounded to your electrical system and perhaps the real ground outside. That jack plug connector you touch which changes the hum suggests that your ’guitar ground’ is actually floating. Another bit of kit will have it’s ground connected to the real ground. Does the hum change when you rotate? It often does. Lots of gear nowadays is designed not to need a real ground. It’s double insulated for safety, but this means the ground might be floating a few bolts above real ground. Connect two of these together and you get hum. You touching it is adding grounding, via a new path - you! Get a bit of wire, or even just move around so you can touch the metal jack to the metalwork of your other kit. The interfaces, rack front panels, or the amplifier and see if you can replicate the silence. This connects the floating ground to real ground and that few volts gets passed harmlessly to ground.

there is a problem with this. Through no fault you have two different ground potentials. Connecting them sorts the hum, but compromises the equipment that WAS double insulated by design. You’ve possibly created a way for a real fault to become more serious if it ever happens. Worst case, your little bit of silencing wire carries a substantial fault current and hopefully when it fails you aren’t touching it!