Helix Amp Models Producing DC

[Boudoir Guitar]

Nah, I'm not here to entertain you, this is a bug report thread.
Digital Igloo wanted us to "BE BRUTAL", the least we can do is post a few graphs and tell them that this particular model sounds like fuzzy diarrhea.

I don't think he meant "assume you're right even without verification". The least you can do is verify that your graphs show what you think they show before asserting that they definitely show what you think they show. I'm not asking to be entertained, I'm asking for folks not to be misled.

 

[KingsXJJ]

There was clearly enough suggestion of DC that it warranted looking at. I felt it helpful to show that the noise caused by Ripple is different to the DC. The other tests are probably less helpful to the vast majority of musicians who visit this forum.

You’re the only person here who wanted a higher burden of proof, even though you can’t actually do anything more to look into it or fix it. The post has led to it actually getting looked at and hopefully fixed, if you think that is some kind of failure then I think you should re-examine what your priorities are and what kind of forum you’re spending time on. All I know (and really care about) is that there shouldn’t be DC, and that could have negative consequences on the behaviour of the modelling.

It’s a forum of musicians, not electrical engineers. Maybe consider that others may not post bugs in the same manner you might.

Hey man, nice shot. Nice shot, man.

 

[Orvillain]

I'm asking for folks not to be misled.

Probably the best way to ensure that people aren't misled is to keep things calm, factual, respectful, and above all else, analytical and forthcoming.

If Jay has problems with the methodology, then I think the correct response is to educate people - not belittle them.

If you’re going to step into a thread just to condescend and tell everyone how wrong they are without offering a clear explanation or correction, you're not helping — you’re just posturing.

It’s one thing to point out a mistake. It’s another to walk in, throw around superiority, and leave people confused rather than informed. If you truly understand the issue, explain it. Share your knowledge. That’s how we all learn and get better.

Otherwise, it just looks like you're more interested in flexing than contributing.

 

[MirrorProfiles]

doesn't seem to me to matter to the accuracy of a digital model since we offset levels after-the-modeling-is-done at several points anyway?

What happens if you run a signal with DC offset into a non linear process? At what stage is the DC happening?

I'm asking for folks not to be misled.

I mean, the graphs in this thread do suggest the presence of DC in the signal. And there is DC. Jays issue was that an FFT doesn’t show beyond any doubt that it is 100% DC, because the FFT does not unequivocally show DC. What the FFT does show is consistent with the presence of DC, and more than enough to show that it’s not an intended behaviour.

The fact is there is clearly DC and the bug exists.

 

[Boudoir Guitar]

Probably the best way to ensure that people aren't misled is to keep things calm, factual, respectful, and above all else, analytical and forthcoming.

See my edit. "calm, respectful" may make people LISTEN to you more, but they don't do anything to stop the spread of misinformation. Indeed, they can result in wider spread of misinformation. Also, being factual requires being careful about asserting only things known to be facts as facts, and those that are assumptions being put forth CLEARLY as assumptions, not as facts.

 

[partytrain]

I’d like to sign up for the class. I’m always up for learning new stuff.

View attachment 46996

I’ll teach it. After all, I did solder a new pickup selector in one of my guitars, so I’m somewhat of a genius. When the switch stopped working a few weeks later, the luthier I took it to said it’s “one of” the worst soldering jobs he’s ever seen…but not the worst, so I’m thinking I’m pretty good.

 

[Orvillain]

See my edit. "calm, respectful" may make people LISTEN to you more, but they don't do anything to stop the spread of misinformation. Indeed, they can result in wider spread of misinformation. Also, being factual requires being careful about asserting only things known to be facts as facts, and those that are assumptions being put forth CLEARLY as assumptions, not as facts.

I do not agree, and actually, I think that is quite dismissive of people like Ed and James who have a strong reputation for being scientific and analytical, and also open to changing their minds and correcting the record.

You're not dealing with a couple of chucklefucks here.

And now, we're discussing this instead of the actual topic. Because Jay couldn't communicate effectively.

 

[Boudoir Guitar]

I do not agree, and actually, I think that is quite dismissive of people like Ed and James who have a strong reputation for being scientific and analytical, and also open to changing their minds and correcting the record.

You're not dealing with a couple of chucklefucks here.

Changing your mind and correcting the record is fine; what would be significantly better is recognizing that "hey, I've had to change my mind and correct the record enough times that maybe instead of asserting that an amp model is broken, I should just share my findings and see what other people think"

 

[Orvillain]

Changing your mind and correcting the record is fine; what would be significantly better is recognizing that "hey, I've had to change my mind and correct the record enough times that maybe instead of asserting that an amp model is broken, I should just share my findings and see what other people think"

Are you keeping score?

I'm not. So I don't know if you have a point or not. I suspect you don't, but couldn't prove otherwise.

Your entire argument presupposes that the two guys in question have racked up enough anti-points to break your threshold of acceptability.

I think it is a bit weird tbh. Almost like you're saying it in order to avoid having to correct yourself. Which is quite ironic.

 

[MirrorProfiles]

"hey, I've had to change my mind and correct the record enough times that maybe instead of asserting that an amp model is broken, I should just share my findings and see what other people think"

Thread is about the Helix amp models producing DC. And do we agree that’s the case?

Line 6 saw enough from the post to warrant looking at it, thread has achieved what it set out.

 

[KingsXJJ]

I’ll teach it. After all, I did solder a new pickup selector in one of my guitars, so I’m somewhat of a genius. When the switch stopped working a few weeks later, the luthier I took it to said it’s “one of” the worst soldering jobs he’s ever seen…but not the worst, so I’m thinking I’m pretty good.

I’m in!

 

[jay mitchell]

It’s a forum of musicians, not electrical engineers.

And yet some of these musicians insist on presenting data that will only be understood by someone with an engineering background. And, more importantly, these musicians don't really understand the data they're presenting.

Maybe consider that others may not post bugs in the same manner you might.

A single-sentence post with the results of a DC offset test - which requires nothing more than calculating the arithmetic mean of a sample sequence of sufficient length - would have established the existence of the bug. FYI, you're still only batting .500, since your original conclusion was that there's also a DC offset on the analog outs.

 

[fr8_trane]

Ripple definitely creates subharmonic ghost notes on some models. OP, Have you tried turning the the hum parameter off? I always disable hum and ripple.

 

[KingsXJJ]

Ripple definitely creates subharmonic ghost notes on some models. OP, Have you tried turning the the hum parameter off? I always disable hum and ripple.

I was never a big fan of U2’s “Ripple and Hum”

 

[MirrorProfiles]

And yet some of these musicians insist on presenting data that will only be understood by someone with an engineering background. And, more importantly, these musicians don't really understand the data they're presenting.

All that needs doing is present enough reason for it to be looked into. We are end users, if there is enough reason to suspect a bug then it’s worth mentioning. It really doesn’t need to be more involved than that, otherwise bugs would never get fixed.

A single-sentence post with the results of a DC offset test - which requires nothing more than calculating the arithmetic mean of a sample sequence of sufficient length - would have established the existence of the bug.

It really doesn’t matter because L6 would have to look into it anyway. All that needed doing was to show enough for Line 6 to take a closer look. There was more than enough here for that to happen. People with a better understanding can now do what they need.

My assertion was that the bug was caused by the amp modelling. I use Helix Native and that’s my primary concern. I validated that the same bug occurs in the hardware, and is not just a bug present in Native. I thought I detected it on the outputs, but couldn’t recreate it. If one upping me on that is some kind of medal for you, great.

I have no issue with being proven wrong, especially if it’s with the intention of helping and improving things for others.

Ripple definitely creates subharmonic ghost notes on some models. OP, Have you tried turning the the hum parameter off? I always disable hum and ripple.

Yep, those are off. The DC is seperate to those.

 

[Lysander]

The spectral display you show does not show DC.

I... have to concur. The model is clearly doing something wonky when the Bias controls are adjusted, but that does not mean you're getting DC at the output. This happening only happens with a handful models is even more proof - you'd have a serious hardware issue involved otherwise.

The only way to properly measure DC offset is to plug the output to proper equipment, such as a multi-meter, or even better, a recording digital oscilloscope. If there is DC in the output, and it's transient, most DMMs will not be able to measure it properly. And an audio interface will definitely won't be able to measure it. at all, just due to the fact that audio inputs are pretty much always DC-decoupled.

 

[MirrorProfiles]

I... have to concur. The model is clearly doing something wonky when the Bias controls are adjusted, but that does not mean you're getting DC at the output. This happening only happens with a handful models is even more proof - you'd have a serious hardware issue involved otherwise.

The only way to properly measure DC offset on outputs is to plug them to proper equipment, such as a multi-meter, or even better, a recording digital oscilloscope. If there is DC in the output, and it's transient, most DMMs will not be able to measure it properly.

The DC on outputs discussion is a bit of a distraction now though, because the issue is to do with DC being produced in the amp modelling. If it gets filtered at the analog outputs, it doesn’t fix any potential issues it may be causing to the modelling, or any digital processes happening after the amp modelling. Or for anyone using the modelling digitally. My concern was that the presence of DC could be causing some negative sonic effects to the modelling process. It may be benign but it does not seem right.

The thread’s assertion is that some of Helix’s amp models are causing DC artefacts. And it’s not just when the controls are being adjusted

 

[Lysander]

The DC on outputs discussion is a bit of a distraction now though, because the issue is to do with DC being produced in the amp modelling. If it gets filtered at the analog outputs, it doesn’t fix any potential issues it may be causing to the modelling, or any digital processes happening after the amp modelling. Or for anyone using the modelling digitally. My concern was that the presence of DC could be causing some negative sonic effects to the modelling process. It may be benign but it does not seem right.

Ahhh, gotcha. Still, that still looks like an artifact of how the FFT for the spectral display is computed to me.

Shifting the bias controls around should not behave like that thou, so there's likely some other issue with those models.

 

[KingsXJJ]

All joking aside and I’ve been doing that to lighten things up. I have purposely not taken any cheap shots that I recall. If I did, that was wrong.

I truly respect and appreciate the sentiment and activity taken to help and improve things for all. It’s very commendable and speaks highly of the people who do.

Folks can disagree about many things but I hope it’s not that.

 

[Chocol8]

The way I see it, MP made two initial assertions, one seems correct, the other was false. Overall, I think his discovery may prove to be beneficial.

JM provided a helpful correction communicated in his usual manner, which some people have trouble with. I get the complaints, but some people have better communication skills than others and in my experience, some of the smartest most knowledgeable people are often soft in their people skills. It is a mistake to dismiss them because of that shortcoming.