With a high gain amp? I'm not sure what the CBMOD is. Is that a Carbon Copy mod?4cm, MXR CBMOD in the HXFX’s loop.
Sounds like a classic ground loop to me. Basically by using the fx-loop on your amp you’re introducing alternate paths to ground (the amp input+the fx loop send/return), ideally there should only be one. Try lifting the ground in the cable going to the amp input, either with an isolation transformer or by actually cutting the shield in one of your cables.That sucks but at least I feel a little better knowing it's not just me and I'm not imagining things.
Not sure how they're going to fix this. They sent me a replacement unit and fixed yours, but my replacement and your fixed one still have the problem. What's next? I already reopened my support ticket and messaged Frank.
I did another experiment just now. If I run guitar > HXFX input, then HXFX send > amp input, but don't connect the rest of the cables to the amp's FX loop, basically just what's placed in front of the amp, it's fine, no loud hum.
If I run guitar > amp's input, then amp's FX send > HXFX return, and HXFX out > amp's FX return, basically nothing from the HX in front of the amp, but the effects from the HX that I run in the loop connected, that also works fine, no loud hum.
But as soon as I complete the 4CM circuit and run both the effects placed in front of the amp and the effects placed in the loop all connected via 4CM, that's when I get the loud hum/hiss/noise.
If you're running your dirt pedals inside the HXFX's loop, you're basically doing the same thing. I'm running my amp's dirt channel inside the HX's loop. Whatever is going on inside the HXFX when everything is connected in this manner is causing hiss, hum, white noise, etc that gets amplified whenever you run anything with high gain inside its loop.
It has to be something in the implementation of the HXFX's internal loop. Or.... could we both be doing something wrong? Could it be a ground loop or other ground issue? I've tried with the amp and HXFX on the same power circuit and on different circuits and it made no difference.![]()
I'm always willing to accept that I'm missing or overlooking something....
Man, I've talked about this before and hate to say it again but I tried replacing my regular pedalboard with a Line 6 M13 years ago and regretted it. I went back to regular pedals and was perfectly happy for 7 or 8 years. I started reading up on the HXFX and against my better judgement decided to give an MFX unit another go. The HXFX wasn't cheap and I'm long past any return period so I'm in it for the long haul right now but I'm regretting having gone this route. I should have learned the first time.
I'm using mine the same way you use yours. I don't put additional pedals in the HX's loop. Just amp and HXFX. It's another poster who is putting pedals in the HX loop.@guitarman3001 ....I think I've missed something in my tests above. I'm not using my HXFX this way. I only use the HXFX with the Amp1 in 4CM and nothing else. I don't put pedals in the second Send/Return loop. I have put an OD or fuzz pedal in front of the HXFX and then used the HXFX/Amp1 that way. Let me try that and report back.
Seems like we're back to the original theory. You either have a bad unit or there's something else in your signal chain that's causing the noise.I'm using mine the same way you use yours. I don't put additional pedals in the HX's loop. Just amp and HXFX. It's another poster who is putting pedals in the HX loop.
That shouldn't be happening. If it is, it's an internal problem on the HX. It's advertised as being able to work in 4CM just like I'm doing without needing to cut my cables or use any additional hardware.Sounds like a classic ground loop to me. Basically by using the fx-loop on your amp you’re introducing alternate paths to ground (the amp input+the fx loop send/return), ideally there should only be one. Try lifting the ground in the cable going to the amp input, either with an isolation transformer or by actually cutting the shield in one of your cables.
So I tried a couple of new things. All with the CR120's dirt channel and all effects on the HX turned off. Inputs and outputs sent to instrument level.Seems like we're back to the original theory. You either have a bad unit or there's something else in your signal chain that's causing the noise.
You could argue that it’s an internal problem with the HX, but it’s also an inherent problem with any 4CM setup where the grounds can’t be properly isolated. The reason you don’t have issues with your regular setup is probably because you have physical separation between everything on your board (cable jacks, pedal chassis etc), or at least the stuff that matters. Now I’m not saying that your unit doesn’t have any issues, but the fact that you only experience problems when you complete the 4CM connections tells me that this is most likely a ground loop. There’s a reason rig builders exist, because they understand this stuff and can build around it.That shouldn't be happening. If it is, it's an internal problem on the HX. It's advertised as being able to work in 4CM just like I'm doing without needing to cut my cables or use any additional hardware.
And remember, I've tried a few different amps, different power circuits, and this is a relatively widely reported problem and has been acknowledged by L6 to be a hardware issue with some of the units. Something strange is going on. I'm still willing to consider that it could be something I'm doing but I have a very simple setup, just amp and HXFX, wired exactly as specified in the user manual.
I can understand that.You could argue that it’s an internal problem with the HX, but it’s also an inherent problem with any 4CM setup where the grounds can’t be properly isolated. The reason you don’t have issues with your regular setup is probably because you have physical separation between everything on your board (cable jacks, pedal chassis etc), or at least the stuff that matters. Now I’m not saying that your unit doesn’t have any issues, but the fact that you only experience problems when you complete the 4CM connections tells me that this is most likely a ground loop. There’s a reason rig builders exist, because they understand this stuff and can build around it.
Now the HXFX does have a HUGE design flaw; they didn’t isolate the switching jack ground from audio ground. This in my opinion is the biggest oversight in this unit, because you can’t fix that very easy.
I’ve heard of the dreaded loop hiss, and that certainly doesn’t come from any ground loop.I can understand that.
I've spent all morning working on this and it seems that the hum is separate from the added hiss. The hum is also worse on the Orange than on the Amp1. I don't have the time to pull out all my other amps right now but when I have a little more time I'll try it with my other amps too.
The hiss is being introduced by the HXFX's internal loop. Happens with the Orange's dirt channel, whether in 4CM or not, as long as the HX's internal loop is in the signal chain. Same with the Amp1's high gain channels, most noticeably on the Classic (JCM800) channel. But the hum isn't really an issue on the Amp1 for some reason.
Do you think the hum I'm getting with the Orange is a result of the design flaw you mentioned in the HXFX? Do you think one of those $20 Pyle Hum Eliminator boxes from Amazon might fix it?
Yeah, the hiss I'm getting from the HX's loop has nothing to do with a ground loop. In the video I posted earlier, you can hear the hiss AND the hum. It's really annoying. Imagine that being piped through the PA at a gig during our breaks or between songs!I’ve heard of the dreaded loop hiss, and that certainly doesn’t come from any ground loop.
The flaw I mentioned only comes into play if you’re using the “ext amp” jacks to switch channels on your amp. That’s easy to check, just pull that cable and see if the noise disappears.
I’ve heard of the dreaded loop hiss, and that certainly doesn’t come from any ground loop.
The flaw I mentioned only comes into play if you’re using the “ext amp” jacks to switch channels on your amp. That’s easy to check, just pull that cable and see if the noise disappears.
Just echoing that what I’m experiencing is in fact the loop hiss issue and not any sort of ground loop. It’s not as prevalent with my amp in 4cm, but every one of my mid to high gain ODs results in a crazy wash of broadband noise.Yeah, the hiss I'm getting from the HX's loop has nothing to do with a ground loop. In the video I posted earlier, you can hear the hiss AND the hum. It's really annoying. Imagine that being piped through the PA at a gig during our breaks or between songs!
I'm willing to put some time on my end into trying to fix the hum if it's a ground loop but L6 is going to have to figure out a way to fix the hiss. If they can't fix it, I'll have to live with it but if that's the case I'll probably eventually just box up the HX and stick it in the garage never to see the light of day again....
Have you checked your support ticket on their site? I hadn't seen any replies from them after their initial reply telling me the serial number on the replacement unit they sent me already had the fix installed, but yesterday I suddenly got an email from UPS that a shipping label was ready for me to download. I had no idea where it came from but I checked my support ticket on L6's site and they had updated it to show that they were sending me a label so I could send the unit in.Still no response from support. Looks like I’m going to have to call today and ... sigh... speak to an actual human.![]()