Line 6 Helix Stadium Talk

[Orvillain]

Yeah agreed. The amp graphics are a waste of time, and is a poor attempt at adding some skueomorphism and realism that the platform just does not inherently support.

If they wanted the "real" experience, then they should've made their amp knob layouts truly represent the amp, and hid the non-realistic stuff away on an advanced tab.

Not a big deal. But also on some level, we have to wait for amps because now one of their checklist items is some dodgy 3D graphics that offers zero functionality.

 

[MirrorProfiles]

Real amps could offer it. But they don't. So no, this isn't a particularly "faithful" control, which is odd that they'd include it at all, given their stance on doing warts-and-all modelling.

Are you sure? this is the part that doesn’t add up in my head and the description doesn’t make things any clearer. The description honestly reads like it was written by someone who doesn’t really know either.

Can you name any examples of amps that have the negative feedback path coming back into different parts of the amp (to each other, not in the same amp)?

Pretty sure I’ve only ever seen it coming back into the inverted side of a phase inverter. My understanding of NFB has been that it always goes there if you use it.

 

[Orvillain]

Are you sure? this is the part that doesn’t add up in my head and the description doesn’t make things any clearer. The description honestly reads like it was written by someone who doesn’t really know either.

Can you name any examples of amps that have the negative feedback path coming back into different parts of the amp (to each other, not in the same amp)?

Pretty sure I’ve only ever seen it coming back into the inverted side of a phase inverter. My understanding of NFB has been that it always goes there if you use it.

As I said - they could. But they don't.

You'd need a mixing matrix in the NFB circuit, which would tap various parts of the circuit and allow you to mix signals into the NFB. That would give you pre/post Z control. Whether it is desirable or not, I don't know. But you could build that in the real world.

Potentially another way to do it would be to have dual feedback paths, and a blend between them.

 

[dbfretz]

The graphics really do cheapen it, does not look good in the slightest. Some stylised knobs or 2D panel might have looked cooler but the weird angle graphics are whack.

 

[[Nathan]]

The picture actually doesn't show the real controls. I think the pictures aren't meant to be taken too seriously, but the controls in the amp blocks seem to be pretty accurate. I like how they included all the switches on certain amps, like the XTC. One thing that is confusing is that on the unit, the master vol should really be on the second tab for the plexi with the "extra" controls and the presence should be on the main tab, since it really does have a presence but not a master (unless it was modded and really does have one).

I was confused and thought the MV knob was controlling one of the normal gain stages on the amp, and then the 2 gain knobs were weirdly sharing the other one... yeah if the MV knob wasnt there it would have been clearer by default. Oh well, got there in the end. And yeah the graphic doesnt help either.

 

[[Nathan]]

Real amps could offer it. But they don't. So no, this isn't a particularly "faithful" control, which is odd that they'd include it at all, given their stance on doing warts-and-all modelling.

But personally, if its a choice between 50 knobs that all do various things I don't understand, and 1 knob that is a kind of macro knob that I do understand, I'll take the macro knob. Likewise with hype. I think hype is actually kind of cool on a few of the amps. A bit poopy on some others.

I'm a fan of the hype knob, this one im just indifferent about. I guess it fattens things up a bit when its over to the right, thats about as much as I've noticed.

 

[Orvillain]

I'm a fan of the hype knob, this one im just indifferent about. I guess it fattens things up a bit when its over to the right, thats about as much as I've noticed.

I've noticed in various positions, more high frequency content at certain positions. But I guess it would differ based on the amp. Haven't looked into it too much yet, because I'm more focused on figuring out if I like the core modelling or not first!

 

[Orvillain]

Can you name any examples of amps that have the negative feedback path coming back into different parts of the amp (to each other, not in the same amp)?

I had to check this:

https://schematicheaven.net/boogieamps/boogie_mkiv.pdf

But it looks like to me the feedback path passes through the presence circuit before it goes to the phase inverter??? Would that answer your question??

Not the same as selectable/blendable pre/post Z at all. But I just thought it was interesting; because it does seem odd to me that the claim would be NFB always goes back to a specific place. Seems like there would be tons of possibility for tone adjustments just by running it into different parts of the amp, prior to the PI, and it would be easy to do???

 

[MirrorProfiles]

As I said - they could. But they don't.

You'd need a mixing matrix in the NFB circuit, which would tap various parts of the circuit and allow you to mix signals into the NFB. That would give you pre/post Z control. Whether it is desirable or not, I don't know. But you could build that in the real world.

Potentially another way to do it would be to have dual feedback paths, and a blend between them.

Yeah, no one is doing that. IMO it should have just been a global NFB control - it makes much more sense to people (because it’s something that actually exists in the real world) and it’s a more useful control.

I’m still curious why they chose to go with Z pre post instead, and what that potentially offers/fixes over a NFB control.

As I said, the concept of inserting NFB anywhere other than the PI doesn’t really add up to me

 

[Orvillain]

Yeah, no one is doing that.

Yes. I said that.

 

[MirrorProfiles]

I had to check this:

https://schematicheaven.net/boogieamps/boogie_mkiv.pdf

But it looks like to me the feedback path passes through the presence circuit before it goes to the phase inverter??? Would that answer your question??

Not the same as selectable/blendable pre/post Z at all. But I just thought it was interesting; because it does seem odd to me that the claim would be NFB always goes back to a specific place. Seems like there would be tons of possibility for tone adjustments just by running it into different parts of the amp, prior to the PI, and it would be easy to do???

No. The presence (and depth if amps have it) always comes off the NFB. That’s why they’re considered part of the poweramp.

The presence pots actually work in reverse and you are cancelling out high frequencies as you move towards 0. 10 allows everything through

 

[molul]

I just saw the Fractal Icons plugin announcement. Here's hoping this encourages Line6 to make the new Native standalone (and to deliver it soon).

 

[Orvillain]

No. The presence (and depth if amps have it) always comes off the NFB. That’s why they’re considered part of the poweramp.

The presence pots actually work in reverse and you are cancelling out high frequencies as you move towards 0. 10 allows everything through

I'm no amp designer, it just seems odd to me. It's one wire that you could send anywhere. There has to be at least one amp out there that sends the NFB back into another part of the circuit. Surely?!

 

[MirrorProfiles]

I'm no amp designer, it just seems odd to me. It's one wire that you could send anywhere. There has to be at least one amp out there that sends the NFB back into another part of the circuit. Surely?!

Well the way it works is by cancelling out the nasty hashy noise. So it needs to be out of phase. Phase inverter is kind of the obvious place to handle that. Doesn’t really make sense to do it anywhere else, if it’s even possible. It’s always designed around going there and that’s how people expect it to work.

As I said, I can’t really imagine what would happen or why you’d even move it anywhere else. Just doesn’t make sense to me. No one has really been able to explain the logic in that control yet.

 

[Orvillain]

Well the way it works is by cancelling out the nasty hashy noise. So it needs to be out of phase. Phase inverter is kind of the obvious place to handle that. Doesn’t really make sense to do it anywhere else, if it’s even possible. It’s always designed around going there and that’s how people expect it to work.

As I said, I can’t really imagine what would happen or why you’d even move it anywhere else. Just doesn’t make sense to me. No one has really been able to explain the logic in that control yet.

Well the real amps convo is just a side quest.

The real question is, why have a prePost-Z control in Stadium at all? All I can think is, one of the DSP engineers said "we don't want to pull a Fractal and unlock all of the controls in the UI, but maybe we can invent an original control that gives people some of the customisation they are used to on other platforms" and there you have it.

You can be sure as shit that under the hood, their amp models have all the same kinds of controls that Fractal does; hell, even Fractal probably have a lot more that they're not showing too.

Likewise with the hype control. Someone went "hey, we noticed this other platform consistently gives their amps more gain than the real thing, and a smiley EQ curve.... let's make a knob for that" ....

It is where the distinction between accuracy and product design becomes a thing.

 

[[Nathan]]

Well the real amps convo is just a side quest.

The real question is, why have a prePost-Z control in Stadium at all? All I can think is, one of the DSP engineers said "we don't want to pull a Fractal and unlock all of the controls in the UI, but maybe we can invent an original control that gives people some of the customisation they are used to on other platforms"

Listen up Kevin you're a great dev but you've thrown us like 50 ideas, you get ONE knob choose wisely..... PrePostZ !!!!!

 

[MirrorProfiles]

Well the real amps convo is just a side quest.

The real question is, why have a prePost-Z control in Stadium at all? All I can think is, one of the DSP engineers said "we don't want to pull a Fractal and unlock all of the controls in the UI, but maybe we can invent an original control that gives people some of the customisation they are used to on other platforms" and there you have it.

You can be sure as shit that under the hood, their amp models have all the same kinds of controls that Fractal does; hell, even Fractal probably have a lot more that they're not showing too.

Likewise with the hype control. Someone went "hey, we noticed this other platform consistently gives their amps more gain than the real thing, and a smiley EQ curve.... let's make a knob for that" ....

It is where the distinction between accuracy and product design becomes a thing.

Yeah, not disputing this. Not arsed about accuracy even on this one (as it can just be left at stock), im only curious about the design choice. My question is - what does Z Pre Post actually achieve? what was the reason for offering it? What does it accomplish to the poweramp response that a global NFB would've have achieved? I'm curious as to why that became the choice parameter for poweramp behaviours. Particularly as I feel a bog standard NFB would have done the job very well.

We know Z Pre Post changes the tone and response in some kind of way, but its hard to put a finger on, and there isn't really any understanding of why you'd use it, what results to expect etc. With the current understanding of it, it could literally be called "slight tonal tweak" and we'd have the same understanding of what's happening.

Listen up Kevin you're a great dev but you've thrown us like 50 ideas, you get ONE knob choose wisely..... PrePostZ !!!!!

This all over.

 

[dean701]

Listen up Kevin you're a great dev but you've thrown us like 50 ideas, you get ONE knob choose wisely..... PrePostZ !!!!!

Poor Kevin should have picked a customizable XY (draw your own) SIC curve feature instead.

 

[Orvillain]

We need to talk about Kevin....

 

[Chocol8]

I'm no amp designer, it just seems odd to me. It's one wire that you could send anywhere. There has to be at least one amp out there that sends the NFB back into another part of the circuit. Surely?!

There are plenty of amps with NFB in the preamp. They take the output of a gain stage and feed it back to the input of that stage inverted.

To do that with the power tubes in a push pull amp would require splitting the NFB signal and inverting it for one tube. It makes way more sense to feed it back before the PI. But...it needs to come after any loops, tone stacks and other tone shaping in the preamp, and preferably after any volume controls. The only place that makes sense is at the PI input.