Why should I ever use MV instead of level?

[krcassid]

OK. I've been happily playing my Axe for 3+ years and never wanted to ask this question because it just sounds....well....dumb!

I come from 40 years of playing tube amps where MVs were considered "evil", only to be used in the most dire of circumstances when the club owner is headed your way with smoke coming out of his ears and you just have to keep your distortion with 1/2 the volume. But, since we have a level control, why would I ever want to use MV? I think (ignorance showing clearly here) that it has something to do with power amp distortion (IE you can run your power high and cut it back?) but I've owned 30+ amps in my life, many of the classics from Fender tweeds to modern Boutiques, and very few had MVs. Actually, I always thought that the MV versions of non-MV amps (IE later twins Vs original blackfaces) were considered inferior for this reason (amongst others).

Being a simple fellow, I get my distorion from my preamp (&/or stomps), run my MV at 10, and control overall volume with level, like I've always done with my amps (albeit my amps had no level hence, attenuators, MVs, 18 watt Boutiques...).

So, what am I missing here? What is the secret of the MV? I've goofed around with it a bit and, honestly, I can't hear a huge difference between adjusting volume with MV or level. But, my old ears are pretty shot (nobody wore earplugs or IEMs in my day!). Maybe it's just that the amps I use in the Axe are not traditionally MV amps so this control is similar to level?

Thanks!

 

[Sebastian]

Obviously it depends on the modeled amp, but to make it short and simplified:

1. MV = gain knob for the power amp. Like with the drive knob of the preamp, there are settings that sound better than others.
2. Just fool around with it and listen! You'll get to know what it does.

 

[Rex]

Gain and Master Volume interact with each other to change the characteristics of your distortion. Depending on how you set them, you can get more or less distortion from your preamp or from your power amp. They both have a different sound and feel. Even for clean tones, pushing the power amp a little bit can sweeten the sound without introducing anything your ears would call "distortion."

At high gain, a lot of amps can get flubby with too much MV. At lower gains, sometimes the tone can sound dry if you don't push the master a bit.

"Real" amps have no Level control, so you have to use their Master Volume knobs to turn them down and still keep some distortion. But as you noted, that's a compromise, if you've already set Gain and MV to where it sounds right. The Axe-FX gives you a Level control that just changes the level, without messing with your gain structure.


Side note: The Axe-FX is set up so that setting MV to 9 will give you the most accurate response when you're using non-MV amp models. When you crank it to 10, you're actually hitting the power amp harder than the "real" amp would.

 

[MaxTwang]

The MV controls power amp distortion and affects overall tone. I recently Tone Matched a Vox AC15 and noticed increasing the MV from 6 to 9 warmed up the tone but also lost the chime (I performed the tone match with the MV at 6.5), the MV also added a different type of distortion than the Gain control. I also found that small adjustments to MV can help in final shaping of a preset.

Many high gain amps rely on preamp distortion and a very clean/accurate power amp so it's appropriate to set the MV to a low setting on these (3 or 4 on a Mesa can keep things from getting flubby). An exception would be a Diezel VH4 which is designed to have a clean/accurate power amp at lower MV settings but is also designed to produce power amp distortion at higher MV settings. With the new VH4 channel 2 model a high MV setting can get cool vintage tones.

 

[zentman]

The MV controls power amp distortion and affects overall tone. I recently Tone Matched a Vox AC15 and noticed increasing the MV from 6 to 9 warmed up the tone but also lost the chime (I performed the tone match with the MV at 6.5), the MV also added a different type of distortion than the Gain control. I also found that small adjustments to MV can help in final shaping of a preset.

Many high gain amps rely on preamp distortion and a very clean/accurate power amp so it's appropriate to set the MV to a low setting on these (3 or 4 on a Mesa can keep things from getting flubby). An exception would be a Diezel VH4 which is designed to have a clean/accurate power amp at lower MV settings but produce a vintage type power amp distortion at higher MV settings.

Yo...when you gonna upload all those TM's you been doing?

 

[Funeral]

"Why should I ever use MV instead of level?"
Because it changes the way the amp sounds.
Period.

 

[MaxTwang]

Yo...when you gonna upload all those TM's you been doing?

I got a new mic pre and the TM of the Vox AC15H1TV really captured the warmth and character of that particular AC-15 model, I want to try another mic but will probably upload this week.

I'm going to re-TM the Boogie with the new mic pre and a different mic to see how that turns out before I upload the Boogie.

We need a thread on gear your TM'ing your amp with.

EDIT: Just TM'd the ef86 channel. Both AC15H1TV Top Boost and ef86 TM's are uploaded.

 

[bkrodgers]

My understanding is that MV will affect how the amp model reacts, just as they affected how the real amp reacted in most (all?) amps with one. The level control should not change the overall sound of the model, beyond the normal Fletcher-Munson stuff that happens with changes in volume.

That's also what makes the level control important for balancing out patches and avoiding digital output clipping.