October 2024: Fractal Audio's VP4 Virtual Pedalboard has been added to the wiki.
Difference between revisions of "Amp block"
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* The preamp and power amp sections of the amp sims cannot be separated. | * The preamp and power amp sections of the amp sims cannot be separated. | ||
* The Amp block now contains a graphic EQ. It's fixed in position at the very output. [http://forum.fractalaudio.com/axe-fx-ii/35997-axe-fx-ii-technical-questions-thread-30.html#post491401 Source] | * The Amp block now contains a graphic EQ. It's fixed in position at the very output. [http://forum.fractalaudio.com/axe-fx-ii/35997-axe-fx-ii-technical-questions-thread-30.html#post491401 Source] | ||
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| + | The amp modeling in the Axe-Fx II is called G2 and Virtual Vaccuum Modeling modeling, see Fractal Audio website. | ||
| + | A part of it has been ported to Standard/Ultra firmware (firmware 11). | ||
| + | |||
| + | Cliff: "As you listen to clips from modelers what you start to recognize is a certain "stationary" aspect to the tone compared to the every-changing tonality of a tube amp. Another thing is finger response. With a good tube amp you can vary the tone quite a bit just by how you fret the note and attack it. Modelers tend to make every note sound the same. So I tested some hypotheses and came to the conclusion that it's because a real vacuum tube has a transfer function that is not static. The transfer function is dependent on time, frequency and amplitude. Where you really hear it is in the in-between regions where the tube is just starting to distort. At first I tried some dynamic transfer functions but that was a lesson in futility. So then I created the VVT stuff. In VVT there is an actual vacuum-tube replica in software. You enter the values of the resistors and capacitors on the grid, cathode, etc. and it behaves just like a tube complete with Miller effect, cathode memory, etc. The problem is that it requires an obscene amount of horsepower so the only solution was a dedicated DSP. The other big part of the G2 sound is the output transformer modeling. The OT distorts and as it distorts its inductance decreases which changes the bandwidth and loop characteristics." [http://forum.fractalaudio.com/axe-fx-ii/36159-where-axe-ii-samples-come-beta-testers-18.html#post497893 Source] | ||
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| + | One Amp block uses about 40%. One of the two DSPs is dedicated to Amp blocks. So you can run 2 of those while the other DSP is used for other effects. | ||
[[category:Effect blocks]] | [[category:Effect blocks]] | ||
Revision as of 07:24, 20 June 2011
test
- Cliff:
- "Almost all the amps in the AFXII are based on actual amps. The amps I haven't ported yet are because I don't have the real amp yet. I could use theoretical values but I would rather not." Source
- "The amps I haven't ported yet are because I don't have the real amp yet. I could use theoretical values but I would rather not." Source
- The preamp and power amp sections of the amp sims cannot be separated.
- The Amp block now contains a graphic EQ. It's fixed in position at the very output. Source
The amp modeling in the Axe-Fx II is called G2 and Virtual Vaccuum Modeling modeling, see Fractal Audio website. A part of it has been ported to Standard/Ultra firmware (firmware 11).
Cliff: "As you listen to clips from modelers what you start to recognize is a certain "stationary" aspect to the tone compared to the every-changing tonality of a tube amp. Another thing is finger response. With a good tube amp you can vary the tone quite a bit just by how you fret the note and attack it. Modelers tend to make every note sound the same. So I tested some hypotheses and came to the conclusion that it's because a real vacuum tube has a transfer function that is not static. The transfer function is dependent on time, frequency and amplitude. Where you really hear it is in the in-between regions where the tube is just starting to distort. At first I tried some dynamic transfer functions but that was a lesson in futility. So then I created the VVT stuff. In VVT there is an actual vacuum-tube replica in software. You enter the values of the resistors and capacitors on the grid, cathode, etc. and it behaves just like a tube complete with Miller effect, cathode memory, etc. The problem is that it requires an obscene amount of horsepower so the only solution was a dedicated DSP. The other big part of the G2 sound is the output transformer modeling. The OT distorts and as it distorts its inductance decreases which changes the bandwidth and loop characteristics." Source
One Amp block uses about 40%. One of the two DSPs is dedicated to Amp blocks. So you can run 2 of those while the other DSP is used for other effects.
