Setting the Master Volume

FractalAudio said:
A little trick you can do to get the "bounce" of high MV without the muddy bass is to reduce the LF Res value on the Spkr tab. This will reduce the amount of bass clipping in the virtual power amp allowing you to turn the MV up. You can also reduce the HF Res to reduce the amount of treble clipping.
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Cool. Are you referring to the 'low resonance' dial (in AXE-Edit), or Q Res, Freq Res?
[Edit]
After looking at the HF Res panel, i'm assuming it's the 'low resonance' dial. :confused::D
 
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DropTheSun said:
Hmm. This makes me wonder. Do we need "Ideal Master Volume" option? :)

Edit :
Fixed Authentic to Ideal, cause that's what i ment.
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Actually, I think I know what you mean in both ways. By authentic, you didn't mean 'technical' authenticity, you meant authentic as a sort of range that users would typically set that MV of that amp to. And I do think at least a list of such ranges would be a great undertaking. But I don't know how much different pickups and use of real cabs and such will effect it, but FRFR players could certainly use such a list!

This thread made me inquire as to what a phase inverter is (PI = Phase Inverter?). I think I'm learning amp-speak.

http://www.300guitars.com/articles/article-demystifying-the-phase-inverter/

And I quote, "Of all the circuits in a tube amplifier, the Phase Inverter, also known is the Phase Splitter, is the most difficult to understand by even some experienced techs..."
 
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The output balance of the phase splitter is another ingredient in the overall distortion/harmonic eco-system. Might be an interesting parameter to have exposed to tweak on the AFX.
 
Tried it. Works just like you said. This is nice simple real world test to see and hear how it changes the tone.
Thanks Cliff.
 
As of Firmware 19 the Master Volume knob was on a very gentle taper, meaning that setting it to 5 was like setting it to 2 on the real amp.
At least, that was how I read things.
Has this changed, or was I reading the post "#1 Biggest User Error" incorrectly?

Either way, I'm still going to be that psycho who turns the MV on the 5150's up to 6 :smilingimp:
 
The Last Romantic said:
As of Firmware 19 the Master Volume knob was on a very gentle taper, meaning that setting it to 5 was like setting it to 2 on the real amp.
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That's news to me. From post #1:
FractalAudio said:
Our modeling is accurate and with the MV on 10 you will get the same amount of power amp distortion as the real amp when set to 10.
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The Last Romantic said:
At least, that was how I read things.
Has this changed, or was I reading the post "#1 Biggest User Error" incorrectly?
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The point of post #1 is that a lot of people set Master Volume too high.


The Last Romantic said:
Either way, I'm still going to be that psycho who turns the MV on the 5150's up to 6 :smilingimp:
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Go with whatever works for you. For me, that much MV farts out too much .
 
DLC86 said:
That's not news, always been like that, master volume in the axe fx has a LOG10A taper while most amps have linear pots...
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That I knew.


DLC86 said:
...that means that MV set to 5 is like setting real amp to 1.
http://wiki.fractalaudio.com/axefx2/index.php?title=AMP_block_parameters#AMP_controls_behavior
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I'm not sure how you gleaned that info from the link you posted. Setting a real amp's MV to 1 virtually guarantees you're operating the power amp in the linear region. Setting any Fractal model's MV to 5 puts the power amp well into saturation, as long as the original amp has an MV knob.
 
Rex said:
That I knew.



I'm not sure how you gleaned that info from the link you posted. Setting a real amp's MV to 1 virtually guarantees you're operating the power amp in the linear region. Setting any Fractal model's MV to 5 puts the power amp well into saturation, as long as the original amp has an MV knob.
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In the link there are just various quotes from Cliff stating that the MV taper on the axe is LOG10A, that means that at 50% of its rotation its (virtual) resistance will be 10% of the pot value. If an amp has a linear taper you'll find 10% of its resistance at, well, 10% of its rotation. :)
I think it's a pretty straightforward assumption..

EDIT: if it's operating in the linear region or not I think it depends on the amp design, also consider that not all amps have linear pots
 
DLC86 said:
In the link there are just various quotes from Cliff stating that the MV taper on the axe is LOG10A, that means that at 50% of its rotation its (virtual) resistance will be 10% of the pot value. If an amp has a linear taper you'll find 10% of its resistance at, well, 10% of its rotation. :)
I think it's a pretty straightforward assumption..
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The assumption is that real amps use linear pots for their MV controls, but I don't know of any that do.


DLC86 said:
EDIT: if it's operating in the linear region or not I think it depends on the amp design, also consider that not all amps have linear pots
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Linear pots and linear amplifier operation are different things with different meanings. Setting a real amp's MV at 1 pretty much guarantees that the power amp isn't being overdriven (is operating in the linear region). Setting MV to 5 on any Fractal model of an MV amp pretty much guarantees that the power amp is being overdriven (is no longer operating in the linear region). In other words, 5 on the model isn't the same thing as 1 on the real amp.
 
Rex said:
The assumption is that real amps use linear pots for their MV controls, but I don't know of any that do
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There are many, trust me ;)
Rex said:
Linear pots and linear amplifier operation are different things with different meanings. Setting a real amp's MV at 1 pretty much guarantees that the power amp isn't being overdriven (is operating in the linear region). Setting MV to 5 on any Fractal model of an MV amp pretty much guarantees that the power amp is being overdriven (is no longer operating in the linear region). In other words, 5 on the model isn't the same thing as 1 on the real amp.
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Yes I know they're two different things, thanks for the unnecessary explanation. I added "also consider that not all amps have linear pots" just to point out that maybe the real amps you have experience with don't have linear pots. The amp I had (hiwatt) surely has a linear 500k pot.
And you can't say that a MV set at 1 guarantees a linear operation, it depends on the signal level the power amp is receiving from the preamp and many other factors (like bias for example). A preamp with MV set at 10% could be putting out the same signal voltage of another preamp with MV fully clockwise, or a power amp receiving a certain voltage could be overdriven while another with same voltage applied could be perfectly clean. It really depends on the design.

EDIT: I just found a post by Cliff stating exactly what I say: http://forum.fractalaudio.com/threads/18beta-kick-in-the-balls.96781/page-3#post-1162192
 
DLC86 said:
There are many, trust me ;)
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If that's the case, it wouldn't be the first time I learned something new.


DLC86 said:
Yes I know they're two different things, thanks for the unnecessary explanation.
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Chill, brother. No need for that.


DLC86 said:
The amp I had (hiwatt) surely has a linear 500k pot.
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Thanks for letting me know. Seriously.


DLC86 said:
And you can't say that a MV set at 1 guarantees a linear operation...
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I said "virtually," for the reason you outlned later in the post. On most amps, MV at 1 renders a clean-running power amp that only starts to fatten as you approach 3 or so.


I'll concede that you have a point, and that in some cases, 5 on the model is equivalent to 1 on the dust-burner.
 
Rex said:
Chill, brother. No need for that.
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Sorry I didn't want to be rude, just a little sarcastic ;)
Rex said:
I'll concede that you have a point, and that in some cases, 5 on the model is equivalent to 1 on the dust-burner.
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From the amps and schematics I've seen (I have also built a few) I assume that's true for most vintage low gain amps.
In high gain amps, that produce distortion mainly from the preamp, it probably makes more sense to use a log pot so that the power amp works linearly for a wider range on the pot rotation
 
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DLC86 said:
Sorry I didn't want to be rude, just a little sarcastic ;)
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No worries. We're cool.

Cliff's choice of MV taper works really well for a lot of different amp types. You can often get good results just leaving it at 5.
 
This was, so far, the single most helpful post I have read. Thank you!! Across the board, my tones are so much better now.

Now if I can wrap my head around the math in your "Negative Feedback" tutorial, I'll be ready to sculpt more powerfully yet. :)

Thanks, Cliff!
 
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