sinlimo Posted January 22, 2019 Share Posted January 22, 2019 My travel rig is a Helix Stomp into a Tech 21 Power Engine - sounds great. However, I recently added a Line 6 G70 wireless unit to the mix, and when I plug the Stomp and G70 power adapters into the same conditioned power strip, or even the same circuit in the room, I get a very loud hum/buzz through the Power Engine. I then disconnected the G70 and tried using a Ditto looper (powered by a One-Spot adapter) and got the same loud hum/buzz. However, using a Helix LT with the G70 or Ditto works/sounds fine, so the issue seems to be with the Helix power supply. Any ideas? Quote Link to comment Share on other sites More sharing options...
deadlocked Posted January 23, 2019 Share Posted January 23, 2019 I had the same issue with the HX Stomp connected to... pretty much anything.... except when I plugged it into my computer. Apparently, the 2-prong US power adapter is not grounded, so the only way to stop the madness is to ground the HX Stomp either via a PC or by replacing the power supply with a grounded one. I actually took the power supply apart and moved it to a newer bigger case and added a 3-prong power cable with the ground pin (the third, round pin) going through a switch so that I could either ground the HX Stomp (when not connected to a PC) or lift it (when connected to a PC). I wouldn't recommend this, unless you are knowledgeable in working with power supplies, as the board inside is very small and crammed and one side is connected directly to 120V. One alternate solution, which is far safer and I tried it before deciding to mod the power supply would be to take a spare similar USB cable (not the one that came with the the HX Stomp, obviously) and cutting it near the end opposite the HX Stomp, peeling off the plastic sleeve to expose the metal braid and attaching it to the (usually the middle) screw that holds the wall power outlet in place. This *must* be ground, as per the US electrical code. Once you have that, when you plug the other end of the cable into the HX stomp, you are grounding it, without the need to plug the USB cable into a PC. Just make sure that none of the 4 wires inside the USB cable are touching the metal braid or each other. The wires are usually colored red, black, green and white. Red and black are USB power and ground, respectively and green and white are USB data. 1 Quote Link to comment Share on other sites More sharing options...
sinlimo Posted January 23, 2019 Author Share Posted January 23, 2019 awesome, thanks deadlocked! Glad to know it isn't just me, and great information! Since I'm not the handiest with electronics, I'll check the specs/power on the adapter and see if there's an aftermarket adapter that's grounded that supplies the correct power. Quote Link to comment Share on other sites More sharing options...
deadlocked Posted January 23, 2019 Share Posted January 23, 2019 The HX Stomp uses a non-standard 9V plug. Though you may be able to find a 9V 3A (or better) power supply for it, I think only a handful of them would fit the HX Stomp. Polarity is also crucial, if you get one that has reverse polarity, at best it won't work and at worst, it might damage something inside the HX Stomp. Without opening it, I am not sure whether it has a protection diode or something else that would prevent a wrong polarity power supply from frying the unit. If you have a 5v USB charger with a 3-prong (grounded) power cable, you may also try to plug the USB cable that came with the HXS into it while the charger plugged into the outlet. the HXS will NOT power from it, you are basically only using the ground on it. If your 5V charger only has a 2-prong power cable, it will almost certainly NOT work, you need the ground pin to make the hum go away. 1 Quote Link to comment Share on other sites More sharing options...
sinlimo Posted January 23, 2019 Author Share Posted January 23, 2019 super helpful, thanks again deadlocked! Looking at Amazon, I see some grounded power strips that also provide USB power... that might work. Quote Link to comment Share on other sites More sharing options...
deadlocked Posted January 24, 2019 Share Posted January 24, 2019 You're welcome. Give it a try. If what you are experiencing is a grounding issue, plugging the USB cable from the Helix into the USB strip should help with the hum levels, as long as the power strip grounds the USB ports appropriately. Quote Link to comment Share on other sites More sharing options...
sinlimo Posted January 28, 2019 Author Share Posted January 28, 2019 well, that didn't help. I don't know if the USB ports are connected to the overall grounding of the power strip, but plugging in the Helix (via USB) to the USB port on the power strip made the hum even worse. Quote Link to comment Share on other sites More sharing options...
deadlocked Posted January 29, 2019 Share Posted January 29, 2019 hmm... maybe the USB ports do not share the ground with the power strip? That would be odd, though not impossible. Also, if possible, did you try to reverse the HX Stomp power supply on the power outlet? I.e. if the brick is facing left, try facing right, or vice-versa. When I opened mine, there was a white wire (neutral) and a black wire (live). maybe reversing the way the brick is plugged into the outlet might help? Or try connecting the HX Stomp to a computer using the USB cable, just for testing purposes. If the hum goes away or reduces significantly, then you know you have a grounding issue somewhere. The computer would have to be a "desktop" model, with a 3-prong power supply cable or a laptop with a charger that is also grounded, a laptop with a 2-prong charger would not be truly grounded and therefore, it would not help. Quote Link to comment Share on other sites More sharing options...
sinlimo Posted January 29, 2019 Author Share Posted January 29, 2019 thanks again deadlocked. I too thought it would be odd if the USB ports didn't share the grounding of the overall strip. I'll try reversing the Helix Stomp power supply to see if that makes a difference. If that doesn't work, I'll at least test it with a USB going to a grounded PC. (and if you're still in MN, hope you're adversely affected by that deep freeze!) Quote Link to comment Share on other sites More sharing options...
sinlimo Posted January 31, 2019 Author Share Posted January 31, 2019 Problem appears to be SOLVED! (in fairness, the "problem" was I didn't RTFM.) I HAD been powering the base unit with a 9V power adapter (yes, of sufficient power for the G70 base unit) However, per the manual, the preferable way to power the unit is via the 5V USB port. Powering the unit via the USB ONLY eliminated the hum. Kudos to deadlocked who got me looking in the right direction! Quote Link to comment Share on other sites More sharing options...
deadlocked Posted February 2, 2019 Share Posted February 2, 2019 Awesome, glad you got your issue sorted out! Yes, I'm in MN, but I kept warm the old fashioned way: Warmest jacket I have, home -> car (heater on) -> work -> car (heater on) -> home :) no wandering about for no reason. Looks like your 9V adapter might've been the culprit, as most wall warts aren't grounded properly. Once you plugged it into the 5V USB port on the power strip, then it would be properly grounded and, through the 1/4" cable from the base unit to the LT, the LT would share its ground. so, likely the issue was two power adapters that weren't grounded, therefore having both grounds floating... bad news. Once you grounded the base unit (via USB port on grounded power strip), problem solved. 1 Quote Link to comment Share on other sites More sharing options...
chumbo Posted March 31, 2023 Share Posted March 31, 2023 I'm also having a +-60Hz cycle hum with my HX Stomp however in my case, I have nothing other than the HX Stomp straight into a PC. sinlimo, in your solution you speak of solving the problem by powering via USB...so the HX Stomp was not the problem in your case then? (You can't power the HX Stomp via USB...right??). Anyway, I noticed that it disappears completely when I disable the amp blocks in the preset. And I'm talking about a clean sound also, not even a hint of distortion and no pedals either! What's the solution there? An aftermarket PS with an earth prong? Is that what every HX Stomp user is doing or am I the only one bothered by this...or the only one with the problem!? Quote Link to comment Share on other sites More sharing options...
chumbo Posted March 31, 2023 Share Posted March 31, 2023 Wow! 80 USD! Yes, it might work but then so would an aftermarket PS which would be cheaper. Still, I'm curious about my more general question...anybody else notice this? Doesn't it bother you? Quote Link to comment Share on other sites More sharing options...
MayPRS Posted March 31, 2023 Share Posted March 31, 2023 This post reminded me a previous gig - the amp was buzzing as soon as I connect a cable to the Helix. I though "damn, something wrong with the Helix, I tested at home and it was nothing like this"... after changing cables, etc etc I just moved the outlet from the Helix and connected to same outlet where the amp was... buzz was gone, silent as it should! Connecting Helix and amp in the same outlet circuit prevented the buzz and humming. Don't ask me the technical of this :) It just worked! Quote Link to comment Share on other sites More sharing options...
chumbo Posted March 31, 2023 Share Posted March 31, 2023 Well, I guess the equivalent for me would be to try a different outlet than where my active studio monitors are connected...just tried that now, didn't help unfortunately :-( Quote Link to comment Share on other sites More sharing options...
chumbo Posted March 31, 2023 Share Posted March 31, 2023 Hmmm, interesting, as I'm browsing through my presets, I realise that most are silent! It actually comes down to one problematic preset that I unfortunately like a lot! I'd be curious if some of the more expert users (I've only had my HX Stomp for 2 days now) could try and figure out what's 'wrong' with the attached preset that causes the hum? (It's an 'Artist' presets from awesome guitarist Charlie Allen) Charlie's Amps.hlx Quote Link to comment Share on other sites More sharing options...
chumbo Posted April 27, 2023 Share Posted April 27, 2023 Bump...nobody has given this a try? Quote Link to comment Share on other sites More sharing options...
PierM Posted April 27, 2023 Share Posted April 27, 2023 Sorry not going to open unknown hlx files, but check if that preset is using an iR block, with a missing iR file. This is a possible cause for noise because the amp block is hitting the output without a cab or an iR. Quote Link to comment Share on other sites More sharing options...
chumbo Posted April 27, 2023 Share Posted April 27, 2023 Ok, I'll check later because I'm not at home right now. Not sure what you fear from loading the preset in your HX Stomp but you can download the file direct from Line 6 Custom Tone page. And here's Charlie Allen's demo of what it sounds like. 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.