Headroom feature on authentic page in amp block

neale dunham

Experienced
Hi,

Could somebody give me a quick breakdown of what the headroom feature within the Amp block authentic page in Axe edit is monitoring or metering?

Thanks.
 
Last edited:
Question on this... The release notes say:
Added “Headroom” monitoring meter to Amp block. The most common reason for “muddy” tones with high-gain amps is incorrect setting of the Master Volume control. The Headroom meter displays the voltage at the virtual power tubes in dB. If the Master Volume is too high the meter will be near 0 dB most of the time. Note that this only applies to amps where the power amp is intended to run “clean” like the 6160, Recto, etc. Non-Master Volume amps get their distortion from the power amp distorting so this recommendation does not apply.

After this firmware update, I always make sure the MV is set low enough so that the headroom meter isn't pegged around 0 when playing. However, I continually see presets from very knowledgeable players that have a high MV resulting in a pegged meter. An example would be @2112's recent demo of Cygnus.

More Cygnus Goodness - YouTube

See around 4:30 mark where the Brit800 is being used. Am I misunderstanding something? I know 'use your ears, not your eyes', but I'm just trying to understand the technical details a bit better.
 
Note that this only applies to amps where the power amp is intended to run “clean” like the 6160, Recto, etc.



More Cygnus Goodness - YouTube

See around 4:30 mark where the Brit800 is being used. Am I misunderstanding something? I know 'use your ears, not your eyes', but I'm just trying to understand the technical details a bit better.
The Brit800 needs the power amp overdriven.
https://wiki.fractalaudio.com/wiki/..._800_.28based_on_50W_Marshall_JCM_800_2204.29
 
Oh, ok - so I misinterpreted the notes. I initially read it as meaning that only Non-MV amps get their distortion from the power amp and that all MV amps should run a 'clean' power amp. I see now this is not what was actually written. Thanks!
 
There's no right or wrong with power amp distortion, it just has a particular character that is desirable for certain styles.

If you're trying to dial in a tight metal tone you may not want that character, and in that case the headroom parameter provides a nice piece of visual feedback.
 
It’s probably technically wrong to get power amp distortion on the SLO100, but both the real amp and the model do something special when pushed past 6 or 7
 
Exactly as others have said, it's just a visual reference for where the modelled power tubes start adding power tube distortion, like a cranked master on a real amp would also do. Because the Axe uses a custom taper for the master knob and a somewhat compensated output level from it, exactly where the "volume" stops going up and the "distortion" starts increasing can be tricky to find. Whether that helps or hurts your tone is for you to decide. I think mostly it's there so if you pull up an amp and it sound bad, you can really easily see if it's got all sorts of power amp distortion on note. More specifically, Mesa Rectifier amps fall apart when they don't have power amp headroom, so it's a really quick visual aid to see where about your should be on the Master knob.

It’s probably technically wrong to get power amp distortion on the SLO100, but both the real amp and the model do something special when pushed past 6 or 7

Nothing is "technically wrong" in music. And those are amps that are famous for needing to be loud enough to peel off your skin to sound their best. Lots of useful tones throughout the Master Volume range on them!
 
Exactly as others have said, it's just a visual reference for where the modelled power tubes start adding power tube distortion, like a cranked master on a real amp would also do. Because the Axe uses a custom taper for the master knob and a somewhat compensated output level from it, exactly where the "volume" stops going up and the "distortion" starts increasing can be tricky to find. Whether that helps or hurts your tone is for you to decide. I think mostly it's there so if you pull up an amp and it sound bad, you can really easily see if it's got all sorts of power amp distortion on note. More specifically, Mesa Rectifier amps fall apart when they don't have power amp headroom, so it's a really quick visual aid to see where about your should be on the Master knob.



Nothing is "technically wrong" in music. And those are amps that are famous for needing to be loud enough to peel off your skin to sound their best. Lots of useful tones throughout the Master Volume range on them!
No doubt. I really associate the soldano sound more with a more reasonable mv setting, TBH. The midrange bump is definitely different though. Radically different sounding and it happens fast on my amp, like in between 6 and 7 theres a distinct point.
 
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