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Dual Recto with the LB-2 vs the Axe-Fx III and more

shatteredsquare

Fractal Fanatic
are these tests being done with the loop active on the 3 channel DR? with the loop active it makes a huge difference how you gain stage the master level into the output level, it has a huge effect on the final tone. low master into high output, or high master into low output. also if the loop is active it makes a big difference what the FX send knob is set at on the back. if you bypass the loop, the master pots have such a quick taper that you can only barely crack it before the power amp would start to fold, it's a lot better tone to use the loop active and find the sweet spot on the output, then feed it master level until the bottom fills in. my Dual rectifier model tone search is over, i just got brainworx mega dual and mega single today, beats amplitube mesa by a long shot, brainworx modeled the loop circuit so you can dial in the sweet spot right between output and masters, and has a built in power soak. between that and the new two notes mesa pack i am a happy camper now.
 

Guitarjon

Power User
are these tests being done with the loop active on the 3 channel DR? with the loop active it makes a huge difference how you gain stage the master level into the output level, it has a huge effect on the final tone. low master into high output, or high master into low output. also if the loop is active it makes a big difference what the FX send knob is set at on the back. if you bypass the loop, the master pots have such a quick taper that you can only barely crack it before the power amp would start to fold, it's a lot better tone to use the loop active and find the sweet spot on the output, then feed it master level until the bottom fills in. my Dual rectifier model tone search is over, i just got brainworx mega dual and mega single today, beats amplitube mesa by a long shot, brainworx modeled the loop circuit so you can dial in the sweet spot right between output and masters, and has a built in power soak. between that and the new two notes mesa pack i am a happy camper now.
Good question!
I did in fact A/B the amp with the loop on and off because a few guys told me that the amp sounds worse with the loop on.
With the gain, master and eq settings of my choice I decided to bypass the loop because it didn't make much of a difference.
I set the master control to taste on the amp because it's easily compensated with the LB2's level control.
 

ML SOUND LAB

Cab Pack Wizard
Vendor
EDIT: Corrected information based on other threads development.

Among doing some other tests at my studio I started to work with my Dual Rectifier and I found some "issues" with the amp input impedance. When I was running my guitar straight into the amp it sounded very different than pre-recording a clip and then running it through the amps. I did a comparison clip with my Dual Recto in this thread: https://forum.fractalaudio.com/thre...s-axe-fx-iii-and-input-impedance-woes.143963/

Here's the clip and my Dual Recto sounds almost identical to the Axe-Fx Dual Recto. I have an original 3 channel one without the new multiwatt options.


1. Guitar straight into the Mesa Dual Rectifier with all knobs on noon. Red channel, modern.
2. Running the signal through the Axe-Fx III <--- notice how it's about 4dB darker although the signal was way hotter in real life
3. Trying to volume match that signal
4. Axe-Fx III Dual Recto amp sim with default settings
5. Axe-Fx III Dual Recto amp sim with master setting at 5 just like on the real amp.

Comparing 1 vs 5 makes me agree with Cliff, that something's wrong in Jon's video. If done correctly, they sound nearly identical.
 
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BillyZeppa

Power User
Among doing some other tests at my studio I started to work with my Dual Rectifier and I found some "issues" with the amp input impedance. This is something that we definitely don't talk enough about here. Running your guitar straight into the amp sounds very different than pre-recording a clip and then running it through the amps. I did a comparison clip with my Dual Recto in this thread: https://forum.fractalaudio.com/thre...s-axe-fx-iii-and-input-impedance-woes.143963/

Here's the clip and my Dual Recto sounds almost identical to the Axe-Fx Dual Recto. I have an original 3 channel one without the new multiwatt options.


1. Guitar straight into the Mesa Dual Rectifier with all knobs on noon. Red channel, modern.
2. Running the signal through the Axe-Fx III <--- notice how it's about 4dB darker although the signal was way hotter in real life
3. Trying to volume match that signal
4. Axe-Fx III Dual Recto amp sim with default settings
5. Axe-Fx III Dual Recto amp sim with master setting at 5 just like on the real amp.

Comparing 1 vs 5 makes me agree with Cliff, that something's wrong in Jon's video. If done correctly, they sound nearly identical. Remember that it's not the same thing if you've recorded a DI track that you run to the real amp, you are not getting the impedance pull thingy to your guitar. The Axe-Fx simulates this... so I'm thinking that since Jon recorded the DI tracks using the Axe-Fx which simulates this pull, we're hearing that simulation twice which is causing the Axe-Fx (and all other modelers as well) sound darker in comparison. Just a thought because I sure wasn't experiencing this when comparing my Dual Recto with the Axe-Fx III today.
So the impedance pull is applied to the direct signal whenever recording both at the same time? So that when reamping from a recorded AXE-FX direct signal, the signal gets pulled twice? Can the impendence pull be bypassed?
 

ML SOUND LAB

Cab Pack Wizard
Vendor
So the impedance pull is applied to the direct signal whenever recording both at the same time? So that when reamping from a recorded AXE-FX direct signal, the signal gets pulled twice? Can the impendence pull be bypassed?
EDIT: Need to do some more tests just to be sure.
 
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shatteredsquare

Fractal Fanatic
Even though the waveform is the same, even if it was level matched, a DI straight out of a pickup reacts with the distortion circuit, because it's an electromagnet pushing voltage...the same DI signal wouldn't do that coming from a digital audio file, no? doesn't the impedance fluctuate with an electromagnet when it's part of a circuit?
 

BillyZeppa

Power User
EDIT: Need to do some more tests just to be sure.
I just realized, as long as the 'pulling' is an analog function, it has to happen prior to digitization, and all is well for reamping via SPDIF.
When reamping analog you want a buffered signal that won't relent to the 'pulling' this second time around going into through analog.
Is that about right?
 

ML SOUND LAB

Cab Pack Wizard
Vendor
Honestly there are many complicated things you can run into when working with real tube amps, loadboxes and digital units together. In my case I was able to get rid of that impedance problem by getting rid of "the loop" so instead of having my loadbox send the signal back to my PC I get my output using the slave out of my Dual Recto. Anyways, nothing wrong with the Fractal. The Dual Recto model sounds pretty much identical to my Dual Recto when both are running correctly.
 
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