Grounding Hum from FOH

[Harpman]

This issue doesn't happen all the time, but still annoying.  I get an occasional hum coming from the FOH.  I know it's a grounding issue. Maybe even a "ground lift" issue.  A buddy of mine Jeff (also a DL1608 user and member of this forum) suggested lifting the ground by using a 3-to-2 AC adapter to remove the ground. I'm using a GC LiveWire Power Conditioner (PC1100) to plug all the components into, including the DL1608.  I've thought of isolating the DL1608 on it's own power conditioner or removing the ground from the DL1608 using the adapter.  Any suggestions would be very welcomed here.  We have a gig tonight and it may not be an issue at this venue, but I don't want any surprises either .

[Wynnd]

I like all my amps and mixer on the same circuit.  (Not always a possibility.)  I've noticed that most of the time when getting a hum, it's frequently on a single channel from a mic or instrument.  Bear in mind that plugs in the same outlet, can come from different circuits.  I bought a tester to keep the lights away from the sound equipment and now with LEDs, we don't need that anymore.  I'm not a fan of dropping the ground from the circuit.  It's there to protect you from electrocution.  (And you need it for surge suppressors.)  You should have a circuit tester to verify that the circuit is wired correctly.  They only cost a couple of bucks and don't take up much space.  Two of my power strips have nag lights on them when the circuit is bad.  (Bad or non-existant ground, incorrect hot and neutral.)   I've found bad circuits in Casino buildings that were less than 10 years old, so new isn't a guarantee that it was done correctly.  (And in spite of my better judgement, incorrectly wired circuits usually work anyway.)

[WK154]

Based on your description of 1 AC source you should not encounter hum issues unless you are using unbalanced input or output devices or worst unbalanced cable to balanced devices. I would pack a few DI boxes. I'm enjoying Cyberhippie's Sonoma and Russian River Wine samples. One of these days I'll get down to your neck of the woods.

[Harpman]

In this case the hum happens when all instruments and vocal mics are muted. I do have and carry a voltmeter for my IT business and work a lot with AC.  Ground-to-Neutral should be under .5 VAC, but I have seen it creep.  They certainly have "Ground Lift" on certain devices for a reason.  The issue I'm definitely getting is the 60Hz hum.  I will check it out.  It wouldn't matter if I moved the mixer to another receptacle anyway since in all likelihood, they are probably on the same 20A circuit breaker.  Thanks for you input.

[Wynnd]

Balanced connections should help a lot!  Also, your gain structure can be used to minimize this issue.  Hopefully this is only something that you notice. 

[Harpman]

Based on your description of 1 AC source you should not encounter hum issues unless you are using unbalanced input or output devices or worst unbalanced cable to balanced devices. I would pack a few DI boxes. I'm enjoying Cyberhippie's Sonoma and Russian River Wine samples. One of these days I'll get down to your neck of the woods.

Now I'm jealous.  I'm from No. Cal and love the Sonoma / Russian River wines!!  So is Cyberhippie a Winemaker?  I am using a new configuration since my last gig.  All my mics/instruments go into a Focusrite Scarlett 18i20 XLR/1/4" combo inputs (8 of them) and then are fed to the DL1608 via the 1/4" outputs (8 of them).  I'm doing this so I can multitrack record the event tonight.  3 vocals, 2 guitars and my 2 harmonica mics. 

[Harpman]

Balanced connections should help a lot!  Also, your gain structure can be used to minimize this issue.  Hopefully this is only something that you notice.

We were practicing at my house this week and both guitarists were running 1/4" balanced into my 18i20.  We will have DI's though at the gig.  Had to alter the gain structure a bit due to lack of DI's.

[WK154]

Hey what with that X32 on your facebook page? You wouldn't need the hassle your going thru. I may take a trip on the 19th to sample cab. Listened to Kepi's other songs on the web.

[Harpman]

Hey what with that X32 on your facebook page? You wouldn't need the hassle your going thru. I may take a trip on the 19th to sample cab. Listened to Kepi's other songs on the web.

LOL, your right!!  If you come down on the 19th, we will be performing at Fazeli Cellars in Old Town Temecula from 6-9pm.  If you come down earlier, we can meet up for a glass or two.  Let me know.  We are trying to meet the deadline for the next season "Voice" audition.  Have to record two songs for Kepi and a video bio to send in before 12/15.  Not enough hours in a day 

[WK154]

Gio I called you today. Better than forum for this. Can Kepi join us for lunch? Our treat.

[Harpman]

Hate to bring this subject up again, but had rehearsal last night at the drummers house.  Brought just the DL and my Bose L1's.  Keyboardist was having an issue with his amp/monitor, so I hooked him up in the DL (upper / lower keyboards).  The upper keyboard was fine, however, the lower keyboard produced that 60Hz cycle oscillation that was driving me nuts.  Between that and the bass players amp causing an annoying hum, it was enough to cause any soundman to leave the room .  So the DL was plugged into the same power strip as the lower keyboard, so I moved the DL to another outlet.  Issue was not a prominent but still there. Now another buddy of mine who is on this forum and has a local band here in town, has also experienced this issue.  He removes the ground from his DL via the gray adapter (i.e. Lowes / Home Depot) and the issue goes away.  Now, I can either do this or remove the ground from the lower keyboard.  If experienced this issue only a handful of times and it always seems to come from the keyboardist.  Why is that?  Also, any suggestions on the bass players amp.  We have a gig tonight and this will drive me crazy if I have to deal with these issues!!

[WK154]

See pin 1 problem on forum. Solution is a different DL power supply or DI boxes for the offending KB's. Most keyboards are unbalanced connections. Same problem probably with the Bass amp. I can bring some gear for test when I see you but that won't help you tonight.
We definitely have to talk about some of the gear you're  picking up!

[Harpman]

See pin 1 problem on forum. Solution is a different DL power supply or DI boxes for the offending KB's. Most keyboards are unbalanced connections. Same problem probably with the Bass amp. I can bring some gear for test when I see you but that won't help you tonight.

Thanks William, I'll check it out.  Looking forward to meeting you and Janice next week!!

[WK154]

Here's the link if you can't find it.
 http://cacophony.aspinock.com/index.php?topic=383.0
RR didn't think it was important for FAQ's.

[Harpman]

Here's the link if you can't find it.
 http://cacophony.aspinock.com/index.php?topic=383.0
RR didn't think it was important for FAQ's.

I think it's real important!!  Bought a couple of passive DI's by LiveWire.  Worked great on the Keyboards.  Also, picked up a couple of HumX units by Ebtech.  Worked really well.