The HX Effects is legit

TubeStack

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CBMOD is an SD1-type OD (Custom Badass Modified OD, silly name).

This is with my Mesa Electra Dyne, crunch channel, or Marshall DSL100 at a rehearsal space, high gain channel,
 

CarlGuitarist

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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. :huh

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.
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.
 

ljholland

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@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.
 

guitarman3001

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@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.
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.
 

ljholland

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Good news - I may have a theory @guitarman3001.

I create a simple patch with a send/receive in loop 2 and a reverb - the rest of the HXFX/Amp1 wiring was the same. I tried a Jam Pedal Fuzz Phrase, Ramble Marvel Drive 3, and a Wampler Tumnus in loop 2. All sounded fine and behaved completely as I would expect. However, if I cranked up the level (not the gain) on the pedals too high, I heard a staticky noise. That noise makes complete sense as I had the level cranked way above unity. It's an effects loop, it's not meant to take signal levels that high. I then tried this experiment with my Friedman Dirty Shirley tube amp by putting one of the pedals in the loop and cranking up the level - I had the same result. If you want to push the level in front of your amp for dirt, that's fine - those inputs are meant to handle those levels...but an effects loop is not.

So - try setting the pedal in your loop at unity gain so that the volume doesn't perceptibly change, and let us know if that works.
 

ljholland

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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.
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.
 

guitarman3001

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11,087
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 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.
 
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guitarman3001

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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.
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.

1. Ran guitar > HX input. HX Output > amp's input (CR120's dirt channel). 6" jumper cable to bridge the HX loop send <> return. I didn't get the hum/buzz, but it did add a noticeable amount of hiss.

2. I deleted the HX loop from the signal chain and just ran Guitar > HX input, HX output > CR120 input. It added a tiny amount of hiss but not as much as when the HX's loop was on and jumpered (step 1 above).

3. Guitar > amp's input. Amp's FX send > HX Input. HX Output > amp's FX Return. HX effects send/return bridged with 6" patch cable. No added hiss or noise.

So, it would seem that at least part of the problem is that the HX is definitely adding some noise, in this case hiss, that is being amplified by the dirt channel. Seems that the HX loop's Send is responsible for most of it.

The hum/buzz you can hear in my video is only happening when I complete the 4CM connections. This may very well be some kind of ground loop, but from where? I've never had this problem with my regular pedalboard and I'm not doing anything unusual. Just amp, HXFX. 4CM exactly as described in the manual. Nothing else added. Tried three amps, a bunch of different cables, and connecting the amp and HX to different power circuits, and the same power circuit with no difference. The HX's power supply is an ungrounded two-prong, not three prong, so maybe this could be causing a ground loop?

So we may be looking at two problems - the HX "send" is definitely adding a loud hiss which is very noticeable when run into an amp's dirt channel (or into dirt pedals, as eoengineer is experiencing), and there may also be an internal ground issue within the HX. Combine those and it's a perfect storm of noise.
 

CarlGuitarist

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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.
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.
 

guitarman3001

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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 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?
 

CarlGuitarist

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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?
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.
 

guitarman3001

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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.
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....
 

eoengineer

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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.
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....
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.

I emailed support yesterday to reopen my ticket. I trust L6 to make this right. Still waiting to hear back.
 

eoengineer

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Still no response from support. Looks like I’m going to have to call today and ... sigh... speak to an actual human. :p
 

guitarman3001

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Still no response from support. Looks like I’m going to have to call today and ... sigh... speak to an actual human. :p
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.
Not sure if their system was supposed to automatically send me an email but I didn't see anything from them until I checked it myself after getting the email from UPS.

Interestingly, as I was writing this post I received an email update from L6.

BTW, I'm very close to ordering a Mooer GE300 Lite to either replace the HXFX or to have as a backup, or maybe I'll use the HX as the backup. The selection of dirt pedals on the Mooer looks much better than the choices on the HXFX, plus it has full amp and cab modeling.
 

Long2Play

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I’m building a new pedalboard rig with an HX Effects as the controller for MIDI. It’s been ran 4cm with a Mesa Mark V:25 and a Bogner Ecstacy 3534. So far so good. Because I intend on using expression pedals, I am going to use a Voodoo Lab Control Switcher to do amp switching. Sounds like that might avoid some grounding issues, along with clean power to my board, a Goodwood Audio pedalboard interface and hopefully good planning. I’m in early testing stages.
 

CarlGuitarist

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3,498
Confession time, the HXFX is gone. It’s the same story every damn time I try to go all digital. I start hearing ghosts, get option paralysis and basically stop playing and start tweaking. It really is a great unit but I just can’t vibe with it. Back to pedals with a loop switcher it is.
 

phil_m

Have you tried turning it off and on again?
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I think the noise issue that happened early on with the HX Effects has to do with the main inputs, not effects loops. Depending on the type of pedal (or amp preamp) in the loop, noise can be an issue. The effects loops themselves raise the noise floor a little bit. With clean stuff, you don’t really hear it because it’s still low. With high gain stuff, the noise floor gets elevated to the point you hear it as white noise. So if you’re running a high gain amp in the 4CM and put a gain pedal in front of it, that can be quite noisy. This is a white noise, hiss sort of noise, different from typical ground loop noise, which is more like 60Hz hum/buzz.
 




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