Buttons functioning as on amps

[FractalAudio]

I think I remember another exception that has been mentioned - 5 band Mark graphic sliders.

Being an amp tweaker and builder for going on 35 years, parts tolerances (especially on 'budget' parts) can explain a lot of variations. The knob positions required for the AxeFX3 to mimic, for example, David Gilmour's HIWATT tone are likely sorta close to the photos available of his touring rig, but likely need some small adjustments to shine on....

Yes, the graphic EQ sliders aren't accurate in terms of position but they ARE accurate in dB and response. If you've ever used Mark series graphic EQ you'd notice that the sliders do very little in the middle and then rapidly change as you get near the top/bottom. This sucks so the Axe-Fx uses proper linear-in-dB controls.

 

[yek]

I got this question because , for me , when you try to simulate an amp , you start doing his basics controls perfectly first . As I see them doing crazy feature , like changing the wattage (!!!) , super complex options on them , I just ask myself “but how can you go so far skipping the first step”. Then it’s just a guitarist talking . Once again I don’t imagine the craziness doing what he does , it is a really hard and amazing work . As I know the kemper by heart too , a lot of kemper users like this plug and play thing , changing the buttons in the front pannel as the real head and that’s all . Me I like to get in the advanced parameter because I am a sound geek , but most of guitarist just want to have heads simulated , without the original noise , some effects and that’s all . I prefer the sound of the axe 3 , for me it’s better , more define. If one day I can “profile “ my head with the axe , then I have it all . This is another wish

Not handy to bring the Kemper into this discussion, because their amp controls are nowhere near the controls on the original amps.

 

[sprint]

Do some math.

Let’s say part 1 is off by 8%, part 2 by 6%, part 3 by 5% and part 4 by 3%,

it would yield .92 x 2(.94) x 3(.95) x 4(.97) = 20.79

versus 1x2x3x4 = 24

Seems like a 13% difference across the first four parts.

yes - but what are the chances that all 4 parts of 3 randomly selected new MBMkVs will be off that much given the tolerances of manufacture etc. My point is that if the "two amps never sound the same" statement were consistently true to a dramatic extent, we would not have the nuanced level of agreement on reference tones that we have (ie: a MkIIC+ sounds like this versus a JP MkIIC+ which sounds like that - knowledgable experienced people passionately spit hairs with precision on this type of stuff - if no two of the same amp are usually somewhat close to the same in tone/operation, this type of precise communication could not happen, and I would even venture to say that amp modelling might not even be a thing in the way we know it).

 

[My name is mud]

I don’t have to go back as I play with both . But thank you for you post . Very interesting. I speak about the details I want to see , not that I am “not happy with the axe”.

 

[ElectricPhase]

yes - but what are the chances that all 4 parts of 3 randomly selected new MBMkVs will be off that much given the tolerances of manufacture etc. My point is that if the "two amps never sound the same" statement were consistently true to a dramatic extent, we would not have the nuanced level of agreement on reference tones that we have (ie: a MkIIC+ sounds like this versus a JP MkIIC+ which sounds like that - knowledgable experienced people passionately spit hairs with precision of this type of stuff - if no two of the same amp are usually close to the same in tone/operation, this type of precise communication could not happen, and I would even venture to say that amp modelling might not even be a thing in the way we know it).

I seem to remember that there were amazing JCM800s and utterly terrible ones. Variances are undoubtedly less on newer amps, and maintenance also is a factor. Given the results they've achieved, I trust that Fractal has picked very good and well maintained specimens to model.

 

[My name is mud]

With luck if you buy 3 same new amps they won’t be so different . The amps manufacturers are not here to do random things , they have a reputation too . When you hear these guys it seems that the difference is huuuuuge .

 

[sprint]

I trust that Fractal has picked very good and well maintained specimens to model.

That's a key point - picking an amp to model that well represents itself as a "reference tone" - particularly for the more iconic ones like JCM800.

 

[chris]

With luck if you buy 3 same new amps they won’t be so different . The amps manufacturers are not here to do random things , they have a reputation too . When you hear these guys it seems that the difference is huuuuuge .

It can be huge. The top players don’t just buy an amp. They go to the factory, try many amps of the same model and choose the one they like best because they can be very different.

My friend and I both bought identical VH4S Diezel amps a long time ago. They were like $4000. His amp had more bass, mine had more treble at the same settings, same guitar, same cab. The difference was huge.

 

[My name is mud]

Strange . Ok

 

[FractalAudio]

I seem to remember that there were amazing JCM800s and utterly terrible ones. Variances are undoubtedly less on newer amps, and maintenance also is a factor. Given the results they've achieved, I trust that Fractal has picked very good and well maintained specimens to model.

We have two of them. One sounds amazing, the other not so much. The model is based, naturally, on the amazing sounding one.

 

[FractalAudio]

Strange . Ok

It's not strange.

The sensitivity to pot value is very high. Consumer potentiometers have a 20% tolerance on end-to-end resistance and another 20% on midscale resistance. If the taper of the pot is Log10A and the pot is a nominal 1M then the midscale resistance should be 100K. If the pot is 20% low on end-to-end resistance (800K) and then another 20% low on midscale resistance then it's value at midscale would be only 64K. That's nearly half the nominal value.

The potentiometer values used in the models use "nominal" values. If the amp was designed with 1M pots then we use 1M for the pot value. When comparing the models to the amps I routinely have to change the B/M/T controls +/-20% to get the model to match the amp. And this is expected. For example on my 5150 I have to set the model's bass control to 4 to match the amp at 5 (-20%). This is unsurprising since when we measured the pot in the amp it was about 20% low at mid-scale.

You can shout at the clouds all you want demanding the models match your particular amp but it's simply impossible because of the aforementioned tolerances. What you get with the models represents the "nominal" amp if it had ideal potentiometers in it which is exactly what the designer intended.

 

[Andrew Male]

Even if it were an issue, and I don't believe it is, I think development time is better spent elsewhere, personally.

 

[guitarnerdswe]

It's not strange.

The sensitivity to pot value is very high. Consumer potentiometers have a 20% tolerance on end-to-end resistance and another 20% on midscale resistance. If the taper of the pot is Log10A and the pot is a nominal 1M then the midscale resistance should be 100K. If the pot is 20% low on end-to-end resistance (800K) and then another 20% low on midscale resistance then it's value at midscale would be only 64K. That's nearly half the nominal value.

The potentiometer values used in the models use "nominal" values. If the amp was designed with 1M pots then we use 1M for the pot value. When comparing the models to the amps I routinely have to change the B/M/T controls +/-20% to get the model to match the amp. And this is expected. For example on my 5150 I have to set the model's bass control to 4 to match the amp at 5 (-20%). This is unsurprising since when we measured the pot in the amp it was about 20% low at mid-scale.

You can shout at the clouds all you want demanding the models match your particular amp but it's simply impossible because of the aforementioned tolerances. What you get with the models represents the "nominal" amp if it had ideal potentiometers in it which is exactly what the designer intended.

THANK YOU!

I wish people would just crasp this very simple concept.

 

[chris]

The basic tone controls match the specific modeled amps.

Due to variances, they may not match your specific amp or your memory of knobs on a specific amp.

That’s pretty much it.

 

[jefferski]

Exactly. And the overall point is that the 5150 sounds and feels like a 5150. Not a Soldano, not a Recto. The JCM800 doesn't sound like a Plexi... etc.

OP can "shout at the clouds" (I like that phrase ;-) but does it really matter if your treble is at 4 or 5, especially when my 800 isn't exactly the same as yours to begin with? Survey says... "no."

 

[My name is mud]

I hope this is finally a sign of acceptance of the facts instead of more dismissal of them

I never been against facts. I just don’t believe words or what I read as soon as I read it , I prefer to see it with my eyes or ears , or with a video or whatever . Then when is it someone who is on it all day long , his comment is “more important” to me . We read so much things in the net ... I think I never really compared 2 same amps in the same room , and even in the music shop , when I was ordering a new model , I never said “wow this one sound different!” That why I was sceptic about that . But ok cliff explain it well . I m here to learn to . Never said I know everything

 

[My name is mud]

I believed that differences can be with amps built in different years or ...

 

[AndrewJay]

We have two models of the Carvin Legacy amp. One is a based off a production model, the other is a one of a kind one made specifically for Steve Vai. They are different, perhaps not drastically, but if all we had was the special version made just for Steve Vai, then if you are familiar with the production version of the Legacy, you may not like the one modeled in the Axe. Also, the JP2C that we have modeled is based off of John Petrucci's favorite recording amp. This amp may or may not be different in some small way, it could have something peculiar about it that JP really likes for recording that his other JP2Cs in his collection don't have. The point being, even the artists whose amps are made and designed specifically for them have favorites and preferences. But lucky us Axe FX users, we get to have a modeled version of those very special amps! How cool is that? Anyone can get a JP2C, but only JP has that particular one that he uses to record. Only JP and well, us Axe FX users. I think that's really special, that out of all the production ones we could have gotten, we got one that the man himself prefers. Same thing with Steve Vai, or any of the other artist amp models that were lent to Cliff to model. What is different about them is quite cool I think.

 

[Joe Bfstplk]

It can be huge. The top players don’t just buy an amp. They go to the factory, try many amps of the same model and choose the one they like best because they can be very different.

My friend and I both bought identical VH4S Diezel amps a long time ago. They were like $4000. His amp had more bass, mine had more treble at the same settings, same guitar, same cab. The difference was huge.

I bet you could get them sounding pretty close with a few knob tweaks away from identical knob positions. Pots are usually the loosest tolerance parts in any amp.

Strange . Ok

Factory-built amps are generally built with the least expensive parts that will do the job. Resistors and capacitors have manufacturing tolerances, and in many older amps (Leo was famous for this), +/- 10% resistors were de rigeur, and caps were often +/- 20%. 5% resistors were used in more critical locations only, such as phase inverter plate loads and output tube signal grid resistors. The tubes themselves are also all over the place in specs, and drift as they age. I don't think @FractalAudio models tube wear/drift, though.

Amps from a particular production run will generally sound similar, unless a critical part ran out and was resupplied from a different batch. We should be amazed that the amps sound as close to each other as they do, really. Tight grouping on a target with that many variables involved is pretty impressive, actually.

I generally start from recommended or copied settings and adjust until it sounds right for the desired result.

 

[chris]

I bet you could get them sounding pretty close with a few knob tweaks away from identical knob positions. Pots are usually the loosest tolerance parts in any amp.

yup, we could. but at the same settings they sounded different.

i'm sure it's happened, but i don't think people bought the same amp as their guitar hero, copied their settings from a picture, heard it wasn't exactly the same, then returned the amp or tried to have it modified because it didn't match. they would probably just... adjust it slightly to sound good for their uses.

same thing here. match your former amp or guitar hero's settings. play and listen. too bassy? turn down the bass. not enough treble? turn up the treble.