jalam71 Posted August 31, 2013 Share Posted August 31, 2013 Hi all, just got my HD500 unit. Its was used. Works great but when playing directly through the unit using headphones I can hear a relatively loud hum that is constant. When I touch my effects buttons it goes away and is crystal clear. When I touch the looper or up down buttons on the left it goes away by about half. Of course its more pronounced on tones having heavy distortion effects. Seems to be a ground problem. I've checked and its not the cord, nor my guitar. Its definately the POD. Hum if affected only when i touch the pod. Question is how can I fix this without having to run a ground wire to my toe? Thanks. Quote Link to comment Share on other sites More sharing options...
guitarplayer0376 Posted August 31, 2013 Share Posted August 31, 2013 Try the ground/lift switch next to the expression pedal. Other than that, it is probably noise coming from the wall, dirty power....I actually use a Furman P-1800 PF....works really well. Quote Link to comment Share on other sites More sharing options...
singlecut69 Posted September 1, 2013 Share Posted September 1, 2013 The HD500 has a ground lift switch? Quote Link to comment Share on other sites More sharing options...
Mr_Arkadin Posted September 1, 2013 Share Posted September 1, 2013 The HD500 has a ground lift switch? Yes, but it affects the XLRs only. There is definitely an earth (ground) loop going on from your description. They are a pain to track down. For instance, if you have the USB connected, try disconnecting that. Also try powering all of your equipment from the same outlet. Other options may include using a DI box. Quote Link to comment Share on other sites More sharing options...
toneman2121 Posted September 1, 2013 Share Posted September 1, 2013 just through the cans? try different cans Quote Link to comment Share on other sites More sharing options...
jalam71 Posted September 2, 2013 Author Share Posted September 2, 2013 OK, did some more testing. Its certainly a grounding issue with the POD. If I'm plugged into the wall with the provided power transformer, then play using the headphones directly though the unit without an amp connected, it hums like a church choir. But when I play normally through the amp, all is well. I then had the unit sitting on top of my amp after I had shut the amp power off but still had the cable connecting pod to amp plugged in. Issue found! When monitoring through the headphones, the cable connecting the amp to pod was now allowing the signal to go to ground by going through the amp system and into the house power outlet - as it should. I could touch the guitar cable into any of the pod's 1/4" jacks on the back and hear the buzz disappear when i did. So technically nothing is wrong with the unit internally. ... but things could be better. Suggestion for Line 6: Improve the POD power supply adapter. Sometimes late at night its nice to use headphones to practice and not wake the neighbors. All that is needed to solve the humm/ground problem when using the POD as a stand alone unit is for line 6 to change the power supply transformer cord into one that has the three prong type plug so that the unit can get a true ground through the power outlet. Hasn't anyone had this issue before? seems odd no one else has mentioned this. Maybe something is wrong with my unit after all. For now I'm going to get a negative tip 9V-3A power adapter off ebay that has the ground circuit. That should fix the hum when going ampless with cans. Quote Link to comment Share on other sites More sharing options...
GTLazer Posted September 2, 2013 Share Posted September 2, 2013 The grounding thing is because the POD sits behind a DC transformer from which it doesn't take an earth reference; this is not required because the internal voltage is low enough that it is not considered to be dangerous. Ordinarily, the POD would take it's earth reference from something plugged into it, whether it is via USB to a PC or via TS or XLR to mixer/monitors/etc. (This is also why connecting a USB sometimes creates a ground loop through the POD to your monitors) It is designed, however, such that it can be used without an earth reference and it shouldn't need the case to be grounded (except internally) to prevent hum. I would say, therefore, that there's something wrong with it. Quote Link to comment Share on other sites More sharing options...
bjnette Posted September 3, 2013 Share Posted September 3, 2013 Well done. Let me get this straight. You have a 3 pin cord from outlet that has an earth. The other end earth has a jack connected and the POD's PSU is plugged in the remaining 2pins. Clever! Quote Link to comment Share on other sites More sharing options...
jalam71 Posted September 5, 2013 Author Share Posted September 5, 2013 rootmusic, thanks for that idea. I was thinking or doing something similar by modding the original power supply, but before I cut into it I wanted to see if i can find a compatible power supply and just buy a new unit online. I found several that have the correct negative tip 9v 3A power but none so far have a three prong grounded power cord. Still looking. For now I may just make me one of the aformentioned ground cords. Thanks. Quote Link to comment Share on other sites More sharing options...
bjnette Posted September 5, 2013 Share Posted September 5, 2013 You could just tie a copper lead to a water pipe and run it to your jack or chassis. Re reading I see what you've done now you have a plug that just connects only to earth in a power strip or wall and that goes to your jack. I might just see if it quietens mine down with a long to the waterpipe cable first. Damn I just chucked out one of those protective covers. Quote Link to comment Share on other sites More sharing options...
PerS Posted September 5, 2013 Share Posted September 5, 2013 Hi Had the same probem and found three issues. Groundloop was one, that coverd above. I have two lamps in my music room one flourescent lamp and a halogen lamp. One plugd in the same outlet as my poodhd pro. Bothe caused a backround hum. The flourescent lamp was easy as it was only heard turned on. The halogen lamp was not that easy as it was no corelation turend on or off. I found it when I moved the pluggs around and forgot to connect the transformer... / Per Quote Link to comment Share on other sites More sharing options...
bjnette Posted September 5, 2013 Share Posted September 5, 2013 Didn't work for me, not that there was a hum to begin with anyway. Quote Link to comment Share on other sites More sharing options...
Guitarwildman Posted September 16, 2013 Share Posted September 16, 2013 If it's truly a ground loop hum... First, I would use an Ebtech hum eliminator (cheap) or the HD500 for the 1/4" cables (see if it get's rid of the hum). If it doesn't, then my next step would be to start checking the other stuff plugged into your wall receptacles and try using an Ebtech Hum-X (it could be another beast is messing up the HD500 ground path). Oh actually, step one is to get a cheap receptacle tester form the hardware store to test all of the receptacles. I had ground loop hums for years, now I don't... oh yeah.. as a LAST ditch effort (only if you're playing a gig that has crappy receptacles) you can you can use 3 prong to 2 prong for other gear - It get's rid of the hum for the evening gig, however, you lose your ground derr... Oh yeah... it could be that you need to use a noise gate on some of your patches, they are sort of a necessary evil sometimes... reduce hum.. but lose some tone gusto?... If you run out of room on your patch because you have a volume pedal in it, I usually delete the volume pedal effect, and make the EXP-2 controller have the amp channel volume controlled by EXP-2 to free up enough room for a noise gate. Quote Link to comment Share on other sites More sharing options...
r2v2 Posted February 27, 2015 Share Posted February 27, 2015 BUMP HD500X has definitelly serious grounding issue when its not plugged into amp (using headphones only) - the amp ussually does the grounding duty in the rig i guess (i dont know i dont have any amp)... I actually have the same problem as OP... i ran GUITAR -> HD500X -> HEADPHONES (no amp cause i have simulations in HD500X, duhh): 1) brand new HD500X from local guitar centre 2) plugged in a guitar and get constant anoying buzz in my headphones 3) when i touch with my finger any metalic surface on my guitar (knobs, cord connector, high strings, bridge) OR HD500X UNIT (the stomp buttons, the metalic rail below LCD display) the buzz dissapears immediatelly... grounding issue for sure but where exactly is the buzz coming from... prior to taking my entire setup to local guitar centre i tried all wall power outlets in my flat, pluging directly to wall socket with no other equipment, also tried some anti-surge multi-socket adaptors i use in my home recording studio... no improvement... took my whole setup (guitar, cable, fx, headphones) to local guitar centre service we tried everything - shop's spare HD500X with a spare power supply - different guitar cables - 2 different guitars - quite expensive models (1500$) with good grounding (Gibson Les Paul and some expensive Gretsch) - guitar technician/repair man measured my guitars grounding and its correctly shielded !!! = so 3 guitars with correct grounding all generated same buzz and it always dissapeared when i touched anything metalic on guitar or on the HD500X unit... between the 3 guitars tested it was a mix of single-coils, humbuckers, noiseless single-coils... everything buzzed the same... the technician even remembered another customer who had the same buzz problem with his HD500X = so thats total 3 HD500X units that do it (mine, the spare test unit in the shop, this other reported customer's unit) HD500X comes with a standard 2 pin power plug adaptor (without null/grounding pin) such as you find on your cheap notebook or ipod/ipad charger... i hope someone from Line 6 found out a hack how to ground the HD500X unit... this is definitelly a HD500X grounding issue... the HD500X has no ground connection when its not connected to amp... between GUITAR -> HD500X -> HEADPHONES there is no grounding at all in such a rig without amp (because the HD500X only has 2 pin power adaptor)... so any suggestions ? its a major design ommision on the Line 6 product - it should have been grounded via 3-pin power plug or some separate grounding of the chassis via a grounding lug... iam sorry to say but HD500X is pretty much unusable with only headphones (without amp)... and i did the best to locate and eliminate the problem (see above)... its HD500X without any doubt... sorry Line 6... but give us solution or this is a major deal-breaker... Quote Link to comment Share on other sites More sharing options...
Charlie_Watt Posted February 27, 2015 Share Posted February 27, 2015 Try grounding your HD500. It's not grounded when nothing is connected but the power supply. Quote Link to comment Share on other sites More sharing options...
phil_m Posted February 28, 2015 Share Posted February 28, 2015 HD500X comes with a standard 2 pin power plug adaptor (without null/grounding pin) such as you find on your cheap notebook or ipod/ipad charger... i hope someone from Line 6 found out a hack how to ground the HD500X unit... this is definitelly a HD500X grounding issue... the HD500X has no ground connection when its not connected to amp... between GUITAR -> HD500X -> HEADPHONES there is no grounding at all in such a rig without amp (because the HD500X only has 2 pin power adaptor)... so any suggestions ? its a major design ommision on the Line 6 product - it should have been grounded via 3-pin power plug or some separate grounding of the chassis via a grounding lug... iam sorry to say but HD500X is pretty much unusable with only headphones (without amp)... and i did the best to locate and eliminate the problem (see above)... its HD500X without any doubt... sorry Line 6... but give us solution or this is a major deal-breaker... The whole issue of grounding in electrical systems is confusing. I'm a registered engineer who's designed power distribution systems and the concepts are tricky for me sometimes. But I think the main thing I'll say is that having a three prong adapter probably wouldn't solve your problem. The main purpose of grounding electrical systems is safety - clearing faults so people don't get electrocuted. Devices like the HD500X don't need to be grounded in the same way an amplifier does simply there's not enough fault current available to really hurt someone. However, when your connect a bunch of audio equipment together, there should be a common signal ground (not necessarily the same thing as the ground connection in an electrical distribution system). When you are using the HD500 with just headphones, the chassis the ground, or common connection. There is a little ground wire connecting the circuit board to the chassis. It sounds to me like that wire is probably loose in yours. So when you have your guitar connected, you're getting nuisance current showing up in the signal that has no where to drain. When you touch the strings, you become the path of least resistance for it drain to. I don't believe this is a common problem, otherwise I'm sure it would be brought up here a lot more. Using these units with headphones is very common. I've never had an issue with noise when I play through headphones. Quote Link to comment Share on other sites More sharing options...
cruisinon2 Posted February 28, 2015 Share Posted February 28, 2015 I don't believe this is a common problem, otherwise I'm sure it would be brought up here a lot more. Using these units with headphones is very common. I've never had an issue with noise when I play through headphones. I'm an apartment dweller, so aside from gigs and rehearsals, almost all of my playing is with headphones...never had a grounding issue. Quote Link to comment Share on other sites More sharing options...
r2v2 Posted February 28, 2015 Share Posted February 28, 2015 Try grounding your HD500. It's not grounded when nothing is connected but the power supply. how exactly do you ground an FX pedal board without an amp ? thats sums the question of this entire thread (including the OP) :) There is a little ground wire connecting the circuit board to the chassis. It sounds to me like that wire is probably loose in yours. I don't believe this is a common problem, otherwise I'm sure it would be brought up here a lot more. tomorrow ill open the unit and locate that wire you talk about to check if it is loose... but the probability of 3 different units (mine, the test unit i tried in the shop, the other customer who had the same problem) all having loose wire is pretty low... i dont know how frequent this is... but in my post i tried 3 different quitars with 3 different pickup types with 2 different cables on 2 different HD500X in about 5 different wall sockets in 2 different venues (all around home and in the guitar centre - 1st floor with a sales person, basement with a technician) - you do the math :) it buzzed every single time... right now i came up with a quasi-solution which is pretty silly... iam just posting it so someone may figure out whats the problem and how to solve it PROFFESIONALLY 1) connect an XLR --> 1/4 TRS cable into MIC IN of the HD500X and just stand with your bare foot on the naked TRS ending of the cable... that way you dont have to touch any metal parts on guitar or pedalboard with your hands yet your body is grounding the rig via your foot on the cable - the only benefit of this is that you have free hands and your foot is the grounding lead of the rig (your foot is connected via the XLR --> TRS cable into MIC IN of the HD500X)... eliminates the buzz entirelly just like touching with your hand... 2) DISCLAIMER - WARNING !!! DONT TRY THIS AT HOME YOU ARE RISKING ELECTROCUTION - THIS IS NOT SAFE WAY TO HANDLE ELECTRIC DEVICES. THIS METHOD MAY NOT APPLY TO YOUR SETUP RIG OR YOUR COUNTRY ELECTRICAL WIRING. Instead of steping on the TRS ending with my foot i pressed the TRS connector carefully against the NULL/GROUNDING/EARTH pin in the wall socket (iam in europe we have Type E sockets with massive protruding EARTH pin). This will "drain" the buzz into the earth. Unfortunatelly and to my suprise this method removes only 85% of the buzz while still leaving an audiable 15% buzz that can only be further decreased to 0% by again touching any metal part of your guitar or HD500X pedal board. so right now i am using method 1) my foot touching the loose TRS end of the XLR --> TRS cable attached to MIC IN of the HD500X and the buzz is gone and i can play the guitar as long as i step on the loose end of the cable... its pretty silly... to quote the OP (posted back in Aug 2013): Question is how can I fix this without having to run a ground wire to my toe? Thanks. Quote Link to comment Share on other sites More sharing options...
r2v2 Posted February 28, 2015 Share Posted February 28, 2015 I'm an apartment dweller, so aside from gigs and rehearsals, almost all of my playing is with headphones...never had a grounding issue. you are lucky :) i tried 3 different quitars with 3 different pickup types with 2 different cables on 2 different HD500X in about 5 different wall sockets in 2 different venues (all around home and in the guitar centre - 1st floor with a sales person, basement with a technician)... buzzes every single time... its sadly logical... the whole rig (GUITAR --> HD500X --> HEADPHONES) has nowhere to drain the buzz or ground itself since the only attachment to the outside world is via power supply brick adaptor with 2 pins (without ground pin)... i believe that connecting to amp might drain the buzz (ground the whole rig) via the amp power socket which iam guessing is ussually 3 pin... but the point of HD500X is that you shouldnt need and amp (hence the simulations and headphone/line outputs)... Quote Link to comment Share on other sites More sharing options...
r2v2 Posted February 28, 2015 Share Posted February 28, 2015 btw there is 3650 threads in Forum Line 6 / POD HD and this thread How To Remove Hum From Hd500 is 67th most viewed topic (3501 views) yet only 19 replies and no working solution so far (since August 2013)... i guess this issue may be more common than expected... Quote Link to comment Share on other sites More sharing options...
phil_m Posted February 28, 2015 Share Posted February 28, 2015 I went and double-checked my HD500 tonight with headphones, and there is a very slight difference in the noise/hum level when I touch the strings versus when I don't. It's very dependent on the amount of gain in the tone and the overall volume of the headphones. Had I not been specifically looking for something, I'm pretty sure I wouldn't have noticed anything. Quote Link to comment Share on other sites More sharing options...
Charlie_Watt Posted February 28, 2015 Share Posted February 28, 2015 Guitar pickups are great noise receivers. That is why I love my Variax guitars. Dead silent. My guitars with magnetic pickups all get some buzz from stuff in my house. Lamp Dimmers, Fans with speed controls, Florescent lights are all nasty noise generators. If your noise changes when you touch the strings, that is most likely noise picked up by your guitar. If it goes away when you turn your guitar volume to zero, it's definitely coming from your guitar. Quote Link to comment Share on other sites More sharing options...
pianoguyy Posted February 28, 2015 Share Posted February 28, 2015 I went and double-checked my HD500 tonight with headphones, and there is a very slight difference in the noise/hum level when I touch the strings versus when I don't. It's very dependent on the amount of gain in the tone and the overall volume of the headphones. Had I not been specifically looking for something, I'm pretty sure I wouldn't have noticed anything. not just gain --- but more specifically, amp gain. Quote Link to comment Share on other sites More sharing options...
powerwindows Posted February 28, 2015 Share Posted February 28, 2015 Just get a Behringer Micro HD400. 19 English pounds. Worked for me. Quote Link to comment Share on other sites More sharing options...
r2v2 Posted February 28, 2015 Share Posted February 28, 2015 OK day 3 trying to get rid of the hum other than the OPs early suggestion having to run a ground wire to my toe Some new discoveries and semi-solutions found while fiddling with the rig 1) connecting my ungrounded rig (GUITAR --> POD --> HEADPHONES) into any device that has grounded 3 PIN POWER SOCKET reduces the hum by about 70-80%... in my case i connected POD's BALANCED XLR OUTPUTS into my HIFI STEREO AMPLIFIER - i left the headphones in the POD... just passively interconnecting my rig with the grounded HIFI STEREO AMPLIFIER was sufficient to drain 70-80% of the hum "out of the POD and out of the rig"... thats a proof that POD itself is totally ungrounded and thus useless on its own (with headphones only)... you need an external device with 3 PIN POWER SOCKET to interconnect with POD and thus provide a drainage of the hum... this only reduces hum by 70-80% but its sufficient reason that POD SHOULD HAVE A 3 PIN POWER SOCKET BY DEFAULT !!! but even grounding the original rig (GUITAR --> POD --> HEADPHONES) to a grounded device with a 3 PIN POWER SOCKET left about 15-20% of hum yet to be removed... to remove the last 10-20% of hum that is still left after grounding the rig you still need to TOUCH ANY METALIC PART ON THE RIG - only touching with your bare hand/foot you get 0% hum... complete hum cancelation... at that time i realised one thing by testing and touching various surfaces around me... 1) when the guitar is connected to grounded rig (via any device with 3 PIN POWER SOCKET) the buzz is reduced down to 10-20% 2) when the guitar is connected to grounded rig but its standing on its own in a stand the buzz is down to 0% - no buzz 3) when the guitar is connected to grounded rig and i pickup the guitar and place it on my lap, touching my belly the buzz is back up to 10-20% so after grounding the rig and eliminating 80% of the hum the remaining 20% hum IS STATIC GENERATED BY MY LIVING BODY and it only leaks into the signal path when i touch my guitar against my lap and belly... the only way to eliminate this 20% BODY STATIC is the old trick - touching anything metalic on the rig - closing the loop cancels out the remaining 20% of hum... and the rig is DEAD SILENT... so what does that leave us with ? to get rid of 80% of hum, ground the POD via any device with 3 PIN POWER SOCKET - interconnect via UNBALANCED 1/4" or the BALANCED XLR to get rid of 20% of hum remaining (static generated by your body when holding the guitar) touch anything metalic on the grounded rig now if you are fine with 80% reduction the solution is easy but once you taste the "sweet silence" you never settle down with second best... I KNOW MY RIG CAN BE DEAD SILENT and i invested honest money to buy only the best equipment so why should i accept 20% hum... the solution i came up with for now is not ideal but better than living with a constant ghost hum in your music: 1) buy 2 meters of wire in home depot (you can use any cheap wire (1$ per meter) - i used basic solid copper wire) 2) attach one end to any metalic part of the grounded rig - i used the metalic bar/rail under the POD's LCD display / 1,2,3,4 knobs 3) either step on the other loose end of the wire with your foot but if you are used to tap your feet in the rhythm or fidget with your feet you may use following alternatives 4) unwrap a square sheet of aluminium cooking foil (30x30cm) lay it under your feet like a carpet and attach/wrap the wire's loose end into the corner of the foil - stand on the foil sheet while playing 5) sit on a metalic chair or stool and attach the loose end to the metalic frame of your stool/chair - your bare body must touch the stool - no cushions or thick clothes, thats why this solution is not ideal - the aluminium cooking foil "carpet" is better QUEST FOR PROFESSIONAL SOLUTION CONTINUES... i dont want to stand on a cooking foil for the rest of my life :)) Quote Link to comment Share on other sites More sharing options...
Charlie_Watt Posted February 28, 2015 Share Posted February 28, 2015 You are wrong that the Pod should be grounded. When plugging into a grounded amp, it is much better that it isn't grounded. You don't want extra grounds - or you have a new source of hum in a ground loop. The pod is designed to plug into an amp. If you are working with headphones only, provide a ground somehow. Quote Link to comment Share on other sites More sharing options...
r2v2 Posted February 28, 2015 Share Posted February 28, 2015 iam sure POD was designed for both amp and sans-amp usage... world is full of people using it sans-amp... it doesnt say "AMP REQUIRED" anywhere... the fact that this topic is no. 67 out of 3650 threads on POD HD forum is a proof that Line 6 should do something about the grounding (hardware switch or grounding lug) or at least explain sufficiently how to ground a sans-amp setup using external grounded devices... both amp and sans-amp users should have an easy way to achieve clean sound and not to resort to googling around and spend days figuring out on their own... i believe many just use it with that horrible hum and think its how its supposed to sound ("its a cab sim buzz")... i was troubleshooting the POD with several members of guitar centre staff - all skilled guitarists - and no-one suggested the correct solution... i had to figure out on my own... given how many false solutions was suggested in this thread alone, shows that many users are wandering in darkness and try random solutions and suggestions from google - while all it takes is connecting to a grounded device with 3 PIN POWER SOCKET even if you dont use that device for anything (passive interconnection only to drain the hum)... Quote Link to comment Share on other sites More sharing options...
r2v2 Posted February 28, 2015 Share Posted February 28, 2015 ok to be fair with Line 6 i think that connecting to a grounded device with 3 PIN POWER SOCKET reduces ALL the hum caused by the GROUNDING all the remaining hum that is left after connecting to a grounded device is unrelated to GROUNDING that remaining 20% hum that appears only when i press the guitar to my lap/belly is most likely not caused by GROUNDING at all and there is nothing Line 6 or POD can do with it - BUT I MAY BE WRONG AGAIN IMHO it may be the case that the last 20% hum in my rig is most likely insufficient pickup SHIELDING because the hum comes in and out when i put my guitar in a stand and just hover my palm near the pickups - my body magnetic field is amplified by the pickups - even without holding the guitar - only hovering my palm around the pickups introduces that 20% hum... STILL touching a metal components on the rig makes everything silent... so its hard to say what is the cause of the last 20% hum in my rig... my guitar and rig may be properly GROUNDED now but the pickup still pickup hum from my body magnetic field due to insufficient SHIELDING until i figure out ill use the "aluminium foil carpet" trick or run a wire from the bridge to my pants (just tug the loose end under your belt touching your waist bare skin) ANY OTHER SUGGESTIONS HOW TO GET RID OF THAT REMAINING BODY GENERATED STATIC Quote Link to comment Share on other sites More sharing options...
Charlie_Watt Posted March 1, 2015 Share Posted March 1, 2015 Get a Variax or a guitar with Active pickups. Magnetic pickups are hum receivers. Quote Link to comment Share on other sites More sharing options...
panaman Posted March 1, 2015 Share Posted March 1, 2015 i havent seen the op mention using a different set of headphones, they could make a great antenna. the hum you hear could be a demodulated hf signal. since xlr jacks are balanced (to avoid ground loops) it may be a better idea to use any other jack on the pod for grounding. i dont believe the ground/lift switch is for the xlr at all, they are balanced and dont need it, it is for the guitar in, try that rather than grounding which i wouldnt recommend at all. try different z settings. try aux in make sure the mic input is not turned up if the pod is sitting on the floor in the middle of the room, chances are the cables from the ceiling lights in the room below are right below the pod or yourself. this close they can induce hum easily. you need to empty your mind. the hum is coming from your brains. you want to enter an alpha state of mind where the hum gradually turns into ommmmm Quote Link to comment Share on other sites More sharing options...
Charlie_Watt Posted March 1, 2015 Share Posted March 1, 2015 The XLR ground lift is to potentially reduce hum if you have a long XLR run to a PA or board that has a very different power ground. In that case, the lift can be quieter. Believe me when plugging into a regular amp, the fact that the pod is not grounded to the power ground is a blessing! Quote Link to comment Share on other sites More sharing options...
r2v2 Posted March 1, 2015 Share Posted March 1, 2015 i agree with Charlie_Watt there are general cases when a device is better ungrounded itself as it takes its "ground refrence" from other devices down the chain... but on a universal device such as POD there should A CHOICE if you want it to operate in grounded mode (POD solo with its own grounding) or ungrounded mode (POD in a chain without its own grounding)... but grounding mismatch can be solved various way... for example i have ALL my studio recording gear connected to a single wall socket - that way all the devices share same "ground plane" from that single wall socket... i never experienced any grounding-related hum ever this way (not that there are not other causes of hum in a audio system)... POD used solo was my first time i had to deal with horrible hum caused by ungrounded device... Quote Link to comment Share on other sites More sharing options...
phil_m Posted March 1, 2015 Share Posted March 1, 2015 i agree with Charlie_Watt there are general cases when a device is better ungrounded itself as it takes its "ground refrence" from other devices down the chain... but on a universal device such as POD there should A CHOICE if you want it to operate in grounded mode (POD solo with its own grounding) or ungrounded mode (POD in a chain without its own grounding)... but grounding mismatch can be solved various way... for example i have ALL my studio recording gear connected to a single wall socket - that way all the devices share same "ground plane" from that single wall socket... i never experienced any grounding-related hum ever this way (not that there are not other causes of hum in a audio system)... POD used solo was my first time i had to deal with horrible hum caused by ungrounded device... In a house, or really any modern electrical installation, all the outlets share the same "ground plane" (not really the best terminology). But, they are all tied into the the same grounding system (unless you actually have isolated ground receptacles - even those, though, go back to the same system grounding electrode eventually. You're correct on one hand - having everything plugged into one outlet is a good practice. Although, it doesn't mean you'll never have noise issues. There are other ways noise can pop up in audio equipment. Perhaps a little ironic, but, having everything sharing a common ground is actually the thing that leads to one of the most common noise issues - the ground loop. Ground loops happen when there's a difference in voltage between two or more pieces of equipment and small currents travel between them via the ground wire. This current flows through the shielding of audio cable and generate noise. A ground lift in an audio is a little resistor that is placed somewhere in the grounding circuit that provides enough resistance to stop that current from flowing. It doesn't get rid of the ground altogether, though. In the HD, the ground lift is at the ground pin of the XLR outs (balanced outs are still grounded). Quote Link to comment Share on other sites More sharing options...
r2v2 Posted March 2, 2015 Share Posted March 2, 2015 ok some more info: so previously we sucesfully got rid of 80% of hum caused by POD HD500 total lack of grounding in sans-amp setup (GUITAR --> CABLE --> POD --> HEADPHONES) you eliminiate it just by passively pluging POD XLR outputs into a grounded device with 3 PIN POWER SOCKET in my case it was a plain HIFI STEREO AMPLIFIER i use for my CD player but i guess anything will work as long as its connected to a wall socket with 3 PIN POWER SOCKET... no from this post onwards... iam trying to hunt down and eliminate remaining 20% hum that i still have in the audio... since i dont know what causes it exactly and it only dissapears when i touch something metalic on my rig (GUITAR, POD, HIFI STEREO AMP) iam not going to judge now if its a GROUNDING issue or SHIELDING issue... i also cant rule out any cause so far, including POD... i just dont know what causes it... today i found another piece in the puzzle but i cant say that it cleared things up, quite opposite, now iam not sure i understand anything about grounding... i connected the guitar into my notebook and used Overloud TH2 software on very high gain (similar to PodFarm, Amplitube, GuitarRig, GTR) GUITAR --> CABLE --> APOGEE DUET AUDIO INTERFACE --> MACBOOK AIR (OVERLOUD TH2) --> HEADPHONES when i run the notebook on battery (therefore iam not connected to the power grid) i get ABSOLUTELLY 0% HUM - CLEANEST SOUND I EVER HAD. PERIOD. it doesnt matter if i touch the guitar or not, or if iam touching anything metal or not... whether i hold the guitar or place it in a stand the sound is always same and with 0% hum... its like playing in heaven... but when i plug my notebook to an AC adapter (which has 2 prongs - damn you Apple) i get 50% increase in HUM which is constant even when the guitar is in a stand and when i hold the guitar and place it on my lap, belly or i hover my hand in front of the pickups the hum even increase to 70-80% NOW GO FIGURE... pluging my notebook to an AC wall socket introduces 2 different kinds of HUM 1) 50% constant hum (probably comes from grid) 2) 20% additional hum when you place the guitar near your body or when you hover your palm in front of pickups MIND YOU that when you run the notebook ON BATTERY the audio has 0% HUM... CLEANEST SOUND EVER... this for me rules out guitar pickups as a "common cause" of most hum... that old "yeah pickups work like giant antennas and they amplify all sorts of garbage in the room"... nope... not my pickups... by running on notebook battery i know my pickups can deliver totally clean sound with SUPER HIGH GAIN when the rig is not connected to power grid (aka wall socket)... i read this article the other day You're just a big ole' Bucket O' Noise and it says that body generates a lot of noise and generally works like a big antenna and all this garbage and static in your body is transfered to guitar pickups when you hold a guitar near your body... well how come none of that garbage and static that your body is supposed to contain and accumulate is NOT TRANSFERED TO GUITAR PICKUPS when you run through a notebook with a battery power... the article's main premise just dont verify in this setup (battery powered notebook)... if the article was true in all that it says (it also talks about grounding your body to earth via guitar strings and amp) than running on a notebook battery - not attached to grid - not grounded to grid - not grounded to anything at all - your audio should be swirling with noise, hum, buzz, magnetic fields, radio static... everything at once... your BODY should work like a giant ungrounded antenna, your PICKUPS should work like giant ungrounded antennas... your CABLES should also pickup garbage... your whole rig including your body should be 1 GIANT RADIO STATION AND EMI/RFI AMPLIFIER... but actually the opposite is true... without connection to power grid... running on a battery... with no grounding to anything... you get the CLEANEST SOUND EVER FROM YOUR GUITAR... NOW GO FIGURE... Quote Link to comment Share on other sites More sharing options...
scottyo78 Posted March 2, 2015 Share Posted March 2, 2015 MIND YOU that when you run the notebook ON BATTERY the audio has 0% HUM... CLEANEST SOUND EVER... I had hum issues which was solved by plugging my (laptop) PC into a ground lift plug... best find ever. ;) With the PC essentially the heart of all the processing when running an Audio Interface and a DAW this is an easy fix. Quote Link to comment Share on other sites More sharing options...
DarkEdge Posted March 2, 2015 Share Posted March 2, 2015 So how old is the house/apartment that you are plugging into wall outlets?? Also have you tried a surge protector (which has a proper ground plug for the wall outlet)? Quote Link to comment Share on other sites More sharing options...
spaceatl Posted March 2, 2015 Share Posted March 2, 2015 Power Conditioning and Surge Protection only offer partial protection and can do little about a ground loop... My suggestion would be to get a power isolation transformer....You can kill three birds with one shot by getting a transformer based AVR (Automatic Voltage Regulator)...switching type (non-transformer) AVRs are NOT the same thing. Something like a Tripp Lite LCR1200 will give you stable regulated voltage, power conditioning and isolation...It's the isolation property of a transformer that can be most helpful...Ground loops will not go thru a transformer since there is no physical connection.... Here's a good paper on the subject... http://web.mit.edu/jhawk/www/tmp/p/EST016_Ground_Loops_handout.pdf 2 Quote Link to comment Share on other sites More sharing options...
r2v2 Posted March 2, 2015 Share Posted March 2, 2015 scottyo78> what is "ground lift plug" maybe i could use that on line 6... whatever it is... your laptop has 2 prong power brick or 3 prong power brick ??? not that it gets rid of all the hum but 3 prong power brick will most likely have less hum than 2 prong brick used by Apple... battery powered notebook for me righ now is HOLY GRAIL of guitar amp simulation... DarkEdge> my house is a 10 years old development project with 5 flats... basically a new house (10 years) with very high standards in everything in a nice residential area... i dont say that the electricity may not cause the problems but right now all this is very very very confusing... surge protectors are in my opinion useless in this scenario not that i dont have them on my other recording equipment and i tried them way back with POD 500 when i started chaising the hum and they didnt change anything... afterall they are what they are - SURGE protection... thats not ground/buzz protection... iam not having SURGES here... thats like a super fast but super strong spike in electricity caused by lightning etc. thats absolutelly not my situation... spaceatl> i agree that surge protection is useless here and power conditioning most likely too... power conditioning should be more about the quality of the POSITIVE/NEGATIVE charge being perfectly constant rather than grounding... power "isolation" sounds promising... the paper looks like great read for a physics profesor or a nerd... i dont understand this stuff... could you post some examples of the units i could buy ? unfortunatelly iam in Europe 240V 50Hz... isolation transformer... hmm we are getting bit spacey but i remember reading somewhere a while back that transformers are used to get rid of hum/buzz when interconnecting unbalanced with balanced studio equipment... like say old synthesizers with mixing desks... i dont know exactly... but "transformers = no buzz" rings a bell... stuff like this: http://www.ebtechaudio.com/hedes.html but this is used on audio cables not on power cables... i guess what you suggest is something like the EBTECH Hum Eliminator but instead of TRS audio connectors it would have power supply connectors... right ? iam lost here... any link to actual power isolation transformer for sale ? Quote Link to comment Share on other sites More sharing options...
r2v2 Posted March 2, 2015 Share Posted March 2, 2015 playing around further... unfortunatelly once i fix 1 kind of buzz another kind of buzz re-apears in the signal... replacing 2 prong plug on the Macbook Air charger with a 3 prong cable got rid of the constant buzz... unfortunatelly this fix reintroduces the 20% buzz which: 1) appears ONLY when i touch the guitar 2) dissapears when i touch any metalic part of guitar seems like i have no luck eliminating both types of buzz at the same time EXCEPT RUNNING MACBOOK ON BATTERY which is still the only way to get rid of both buzz types at once: 1) 50% constant buzz (probably comes from grid) 2) 20% additional buzz when you place the guitar near your body or when you hover your palm in front of pickups the simple observation that both types of buzz (1 and 2) are non-present when running ON BATTERY, tells me that both types of buzz are related to power grid and grounding rather than GUITAR PICKUPS or BODY STATIC CHARGE (unlike it is suggested by You're just a big ole' Bucket O' Noise)... Quote Link to comment Share on other sites More sharing options...
scottyo78 Posted March 2, 2015 Share Posted March 2, 2015 scottyo78> what is "ground lift plug" maybe i could use that on line 6... whatever it is... your laptop has 2 prong power brick or 3 prong power brick ??? not that it gets rid of all the hum but 3 prong power brick will most likely have less hum than 2 prong brick used by Apple... battery powered notebook for me righ now is HOLY GRAIL of guitar amp simulation... DarkEdge> my house is a 10 years old development project with 5 flats... basically a new house (10 years) with very high standards in everything in a nice residential area... i dont say that the electricity may not cause the problems but right now all this is very very very confusing... surge protectors are in my opinion useless in this scenario not that i dont have them on my other recording equipment and i tried them way back with POD 500 when i started chaising the hum and they didnt change anything... afterall they are what they are - SURGE protection... thats not ground/buzz protection... iam not having SURGES here... thats like a super fast but super strong spike in electricity caused by lightning etc. thats absolutelly not my situation... spaceatl> i agree that surge protection is useless here and power conditioning most likely too... power conditioning should be more about the quality of the POSITIVE/NEGATIVE charge being perfectly constant rather than grounding... power "isolation" sounds promising... the paper looks like great read for a physics profesor or a nerd... i dont understand this stuff... could you post some examples of the units i could buy ? unfortunatelly iam in Europe 240V 50Hz... isolation transformer... hmm we are getting bit spacey but i remember reading somewhere a while back that transformers are used to get rid of hum/buzz when interconnecting unbalanced with balanced studio equipment... like say old synthesizers with mixing desks... i dont know exactly... but "transformers = no buzz" rings a bell... stuff like this: http://www.ebtechaudio.com/hedes.html but this is used on audio cables not on power cables... i guess what you suggest is something like the EBTECH Hum Eliminator but instead of TRS audio connectors it would have power supply connectors... right ? iam lost here... any link to actual power isolation transformer for sale ? Well with noise created from hum, ground loop, etc., there's no "silver bullet". My older Acer laptop had a 3 prong plug for the power supply and using a ground lift plug eliminated my noise (maybe that's where my loop was broken?). A ground lift plug can be bought for 1-3 dollars at a hardware store (Lowes, Fred Meyer, etc.) What they look like is on one side you can plug in the "3-prong" plug and on the side that goes into the wall there is only 2 prongs... the 2 blades. With my new laptop PC I have no noise issue. :D The only trouble I have is if I stand with my guitar pickups right in front of my monitors. :( Don't do that and I'm golden. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.