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Ripple, Hum, Sag, Bias, Bias-x questions


tjbassoon
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I've read the manual but the descriptions don't really mean much to me. I adjust these settings and I don't ever really hear a difference - what am I missing? What do these actually change the sound like? Lots of discussion that have these terms on the forum, but I can't find anyone describing what these things do directly.

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When you adjust those settings on your real world amp, do you hear a difference?

 

WHAT? You say that REAL WORLD amps don't HAVE those settings?

 

Hmmm....

 

Methinks the answer to the question "What am I missing?" is "NOTHING of any great import!" :-)

 

Okay Golden Eared Tone Sniffers - READY - SET - GO!

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3 hours ago, tjbassoon said:

I've read the manual but the descriptions don't really mean much to me. I adjust these settings and I don't ever really hear a difference - what am I missing? What do these actually change the sound like? Lots of discussion that have these terms on the forum, but I can't find anyone describing what these things do directly.

 

I definitely hear/feel a difference, particularly on Sag and Bias. My suggestion is to use the looper to record a loop with some clean and overdriven guitar. Dig in and then lessen your attack. Play back the loop and work the various amp/tube parameters. It can help you home in on how these controls modify the sound, somewhat dependent on how and what you are playing. The looper can however remove the "feeling" of responses like sag.

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I definately hear a difference with bias in terms of when an amp breaks up and how, and I often set hum at zero (I have no need for atrifical/modelled noise in my amps, and couldn't get rid of noise for a while until I discovered this).

 

The rest - hmmm not so much for me but for a god demo of them - see Mr S

 

 

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3 hours ago, rd2rk said:

When you adjust those settings on your real world amp, do you hear a difference?

 

WHAT? You say that REAL WORLD amps don't HAVE those settings?

 

Hmmm....

 

Methinks the answer to the question "What am I missing?" is "NOTHING of any great import!" :-)

 

Okay Golden Eared Tone Sniffers - READY - SET - GO!

Well, a lot of amps have the bias adjustment, don't they. ;)

What are they missing? Ooh, a whole heap of expense when the amp goes bang.

L6 should change the setting from numbers to 'Right, Wrong and F***ed'

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Hum and Ripple are the first things I turn down completely, they don't serve any purpose than simulating what would make me send my amp to a service in real life. Bias can do quite something, it does occasionally help me to tighten up an amp (or soften it, which I usually don't want). Bias-X is something I only notice differences with when turning Bias itself way up or down. And that's it for me.

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3 hours ago, SaschaFranck said:

they don't serve any purpose than simulating what would make me send my amp to a service in real life.

 

I wondered about that. I don't want my amp to "hum" - that's part of what makes modeled amps nice: you can take problematic parts of the sound away.

 

 

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21 minutes ago, tjbassoon said:

I wondered about that. I don't want my amp to "hum"

 

Well, there's actually a few "good" things to say about hum, such as it masking dynamics. Whether you'd need that in a guitar amp is highly debatable, though.

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18 hours ago, waymda said:

I definately hear a difference with bias in terms of when an amp breaks up and how, and I often set hum at zero (I have no need for atrifical/modelled noise in my amps, and couldn't get rid of noise for a while until I discovered this).

 

The rest - hmmm not so much for me but for a god demo of them - see Mr S

 

 

 

OK, so based on this video I have personal preferences I would probably put on every amp, although it seems like if you don't dime a few of the main controls it doesn't matter all that much. For my own reference later:

Sag 5

Hum 0

Ripple 0 (doesn't matter with hum at 0?)

Bias 10

BiasX 10

 

Smooth and clear distortions when set this way?

 

Emulate an old tired amp with ancient and well worn tubes:
sag <5

hum <7

ripple <7

Bias >5

BiasX >5

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1 hour ago, tjbassoon said:

 

OK, so based on this video I have personal preferences I would probably put on every amp, although it seems like if you don't dime a few of the main controls it doesn't matter all that much. For my own reference later:

Sag 5

Hum 0

Ripple 0 (doesn't matter with hum at 0?)

Bias 10

BiasX 10

 

Smooth and clear distortions when set this way?

 

Emulate an old tired amp with ancient and well worn tubes:
sag <5

hum <7

ripple <7

Bias >5

BiasX >5

 

You could always set some amp blocks up as Favorites or User Model (Defaults) with your preferred settings. I find that changing these parameters to my perceived sweet spots results in a more satisfactory sound and "feel", easy now with Favorites and Defaults to save those for future use.

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Well getting all technical, Bias is the only thing you can alter on a real amp and it's not a user adjustment because if done incorrectly you'll need a new set of output tubes.

Sag is inherent to the power supply design but it will increase over time.

Hum and Ripple get worse as an amp ages or get better as it grows some mojo depending on your viewpoint.

I'm not sure about BiasX but it probably relates to the biasing and crossover distortion which never sounds good.

 

Real valve amps all have some hum and ripple but mine hum at 50/100Hz not 60/120Hz so the modelled versions sound wrong.

 

 

 

 

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Bias and bias X are functions of the tubes in a tube amp. Tubes have a bias. It is a DC current applied to the tube that is part of how the tube actually operates. Tubes have an optimal bias setting (amoutn of current) so it can run efficiently but often people will change it in an tube amp so it runs inefficiently because it does change how it sounds. Changing the rules so to speak. This article will help to understand the bias thing a bit better. It did for me anyway

 

https://www.sweetwater.com/insync/what-is-tube-amp-bias/

 

BUT, describing what it does physically doesn't really help you find out what it does to the sound, does it? To me changing the bias affects the amount of "distortion saturation' I hear.  A clean sound it seems to, well, it's subtle and hard to explain. It gives it more or less ooomph. You know that technical term, ooomph don't you? That's the best way I can come up with to describe it but no words will really work. It's easier to just hear what it does than use a description to come up with how it will sound.

 

Sag is a bit easier. I think of it as a kind of compressor. Higher settings will compress it more, kind of like a harder rock sound via Scorpions or Metallica. Make it a bit tighter  Lower will loosen it more like Stevie Ray Vaughn or maybe Robin Trower.

 

As has been mentioned before, hum and ripple are essentially flaws inherent in a guitar amp circuit that get worse as time goes on and electronic components deteriorate. They are both subtle things you may hear in an old amp and so you may want them because they do contribute to the sound you hear. Subtly but it's there. Nothing wrong with turning them down either.

 

These are all subtle things that many will probably not even notice. Take an amp with a lot of amp distortion and mess with them on that so you can hear what these things do. But just note that they are subtle and are there more for the tube, cork sniffing thing which I do have in me, just not as much as others. Just a few more tools to help dial in your perfect sound. Not everyone will use them but they are there for those that want them. Hope this helps in some way.

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6 hours ago, brue58ski said:

Sag is a bit easier. I think of it as a kind of compressor. Higher settings will compress it more, kind of like a harder rock sound via Scorpions or Metallica. Make it a bit tighter  Lower will loosen it more like Stevie Ray Vaughn or maybe Robin Trower.

 

Guess we strongly disagree here. As you say, when you turn up Sag, the amp will also compress more. And more compression rarely results in a tighter hard rock sound. That's why modern high gain amps used for styles where tightness is a must, usually offer loads of headroom so their power amps always stay clean and don''t produce any "sag" - hence resulting in the tightest possible sound.

A "sagging" amp may feel more dynamic but it's certainly not more tight.

The Helix models prove that quite nicely. Turn up sag and you'll get a sort of squishy tone - which, don't get me wrong, could be just what the doctor ordered, but it's certainly not what you want for tight rock tones.

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From page 37 of the manual:
 
Bias       "Changes the Bias of the power tubes. Lower values achieve a “cold"
                Class AB biasing. At maximum, the amp is operating in Class A."

 

I believe operating at Class A is pretty much the opposite of raising the bias on a Class AB amp.  

The elimination of the crossover in a Class A amp s generally thought to make for a sweeter clean sound.  

In the real world a class A Marshall Super Lead is impossible, but we're not in Kansas anymore are we.

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