Gain or master?

[Aloe]

why not both?

some amps are clean-only, they're best used when the gain is just sub-clipping.

some amps have lots of grit, so if you need cleanest sound, you max up the master volume and then use the gain as the volume.

some amps (and desired tones) are in between, so use your ears.

at the end the proper way to set your amp should be written in your amp's manual. other amps might have it differently.

 

[Wasnex]

It depends on the amp and it also depends on your tone goals. The reality is you might make a different choice to better suit changing tone goals.

Increasing gain can have an impact on compression, tone, damping, and distortion. The exact way gain impacts the sound varies from one amp model to the next. Some preamps produce usable drive and some sound awful pushed over the edge.

A useful concept is signal to noise ratio. The circuits in an amp produce a certain amount of self-noise. EQ sections, in particular, tend to be fairly noisy. EQ is usually located in the middle of a preamp, after gain but before the master. The output of the EQ section will contain a certain level of noise, which can vary depending on how the tone controls are adjusted. This is called the noise floor. Adjusting the Master will change how much of this noise is sent to your speaker.

Many amps suggest turning up the Gain till you get distortion on peaks or light a signal LED. Back off on the gain a bit and your are good to go. The point of this procedure is to maximize the signal to noise ratio at the output of the EQ section. Adjusting the gain to be right on the edge of clipping is done so the EQ section receives a nice hot signal. The idea is for the signal to be much hotter than the self-noise produced by the EQ section. If the signal is really hot, you can run the Master at a lower level. Turning down the master reduces both the signal and the noise.

With some amps you may wind up having to choose a compromise between the tone your want and the level of noise you are willing to accept.

The output section responds to signal levels more so than the position of the knobs. For example, you can run the preamp gain high and the master low and the output section will see a certain signal level. If you turn the gain down and turn the master up, the output section may see the same nominal signal level, but the tone and note envelope may be a bit different.

As with preamps, some output sections have nice drive qualities and some sound awful pushed to clipping. Most player who are into all-tube rigs prefer output drive to input drive. The tone and feel of an amp can change as it approaches the power level where it breaks into drive. The window for this transition is typically wider with tube output sections than solid state. But this is not a hard fast rule. Some solid state amps sound good pushed over the edge and some tube amps do not. Some solid state amps maintain a very consistent tone and feel right up the point where they clip and completely fall apart.

 

[agedhorse]

Some designs are... designed to let you use the gain control as a character control. More gain = more dirt. If you want the cleanest tone distortion-wise, max the master volume and turn the gain up until you get the volume you want.

Other designs instead do not overdrive gracefully, and in these designs, the gain control should be set in order to maximise SNR (signal-to-noise ratio) - the stronger signal you have earlier on in the chain, the less noise you amplify. These designs usually feature a clip light, and you are supposed to set the gain where the clip light barely turns on the hardest peaks (and then turn it down slightly, perhaps).

To tell the truth, maximising SNR on guitar or bass matters relatively little (it does matter, especially for high-gain guitar tones, but not much for how to set gain-master volume controls); electric guitars and basses are inherently noisy, especially if equipped with single coils. A guitar or bass's self-noise is bound to be higher than that of an amplifier.

By the way, there are also designs that are closer to the first type that feature a clip light, rather confusingly, and you might be tempted to set the gain as in the second case; one such design is the Ampeg SVT3-PRO II, where you actually lose out on a variety of mildly overdriven tones if you keep the clip light off.

In general, especially with most modern amps, operating with the master volume all the way up will be noisy and restrict the input gain control to a much narrower range towards the bottom of the control.

No practical benefits with some very real world drawbacks.

 

[Wasnex]

In general, especially with most modern amps, operating with the master volume all the way up will be noisy and restrict the input gain control to a much narrower range towards the bottom of the control.

No practical benefits with some very real world drawbacks.

There are exceptions of course.

Maxing the Master on my Orange AD200B Mk III works really well. My guess is this was an intentional choice by the amp's designer.

I would have to check to confirm, but I believe my Ashdown CTM 300 also works pretty well with the Master at or near max.

Both of these amps have relatively gainy preamp designs.

 

[Boneless]

In general, especially with most modern amps, operating with the master volume all the way up will be noisy and restrict the input gain control to a much narrower range towards the bottom of the control.

No practical benefits with some very real world drawbacks.

That's the way it basically is with volume control-only amps, though. (For example, the Hartke LH heads, or lots of guitar amps). And on older GK amps, the manual actually encourages you to do so, even though it sounds worse to me (what I do is set the gain as far up as it makes sense, and then adjust the master for volume; on my 800RB, the DI outputs a line level signal, pre-boost, so I actually use the mixer's meter to set the gain).

I think the best arrangement would be to have a set of signal level lights like on mixers (but not as fine-grained). Green for "adequate", yellow for "beginning of overdrive" and red for "overload". You set the level so that the signal has to be in the green all the time and then you make your own choices after that. There used to be a Hughes & Kettner amp, if I'm not mistaken (huge!), that was designed in such a way (or something similar).

 

[agedhorse]

There are exceptions of course.

Maxing the Master on my Orange AD200B Mk III works really well. My guess is this was an intentional choice by the amp's designer.

I would have to check to confirm, but I believe my Ashdown CTM 300 also works pretty well with the Master at or near max.

Both of these amps have relatively gainy preamp designs.

I should have mentioned “with solid state power amps” in my description.

That's the way it basically is with volume control-only amps, though. (For example, the Hartke LH heads, or lots of guitar amps). And on older GK amps, the manual actually encourages you to do so, even though it sounds worse to me

I think the best arrangement would be to have a set of signal level lights like on mixers (but not as fine-grained). Green for "adequate", yellow for "beginning of overdrive" and red for "overload". You set the level so that the signal has to be in the green all the time and then you make your own choices after that. There used to be a Hughes & Kettner amp, if I'm not mistaken (huge!), that was designed in such a way (or something similar).

When no master volume control is present, the designer will set the effective master volume control to where they think it’s appropriate. Rarely is it effectively “all the way up”.

Some amps do include input gain stage signal level LEDs. How they work is described in the respective manuals.

 

[S-Bigbottom]

I think the best arrangement would be to have a set of signal level lights like on mixers (but not as fine-grained). Green for "adequate", yellow for "beginning of overdrive" and red for "overload". You set the level so that the signal has to be in the green all the time and then you make your own choices after that. There used to be a Hughes & Kettner amp, if I'm not mistaken (huge!), that was designed in such a way (or something similar).

Most well known solid state amps have a gain over load/clip light.
There are a few in this thread that have mentioned turning up the gain until the light flickers, then back it down a bit for setting a strong yet clean signal.

 

[Redridge]

gain is a low level amplified signal to the preamp (tone, fx, compression etc) afterwards, that signal is sent to the power amplifier amplifying the signal even more (which the master volume controls). Finally the signal is sent to the speakers.

 

[ReidK]

This EQ setting here is perhaps a little dramatic, but clearly illustrates a mid scoop.
View attachment 7293109

Only if you ignore the labels.

 

[MCS4]

Back in my day we had to scoop the mids if we didn't want to be heard in the band mix, nowadays kids can just scoop the gain and master knobs...

 

[NKBassman]

Wow 30 posts to explain the relationship between Preamp Gain and Master Volume.

@Strane, has anyone actually asked you what amp you're using yet?

 

[Strane]

I think everyone answered your question well enough, but that depends on what you mean by, “push gain all straight,” and “scoop the gain?” What does “straight” and “scoop” mean in this scenario?

My mistake. I meant 'boost' the gain, sorry.

 

[Strane]

Wow 30 posts to explain the relationship between Preamp Gain and Master Volume.

@Strane, has anyone actually asked you what amp you're using yet?

I appreciate all the answers, I really do. All the explanations, helpful tips... I'm really grateful.
I use MarkBass Combo CMD 121 58R, by the way.

 

[N. Kentucky Bass]

Let me ask one permutation of OP's question...

I run a Noble preamp into my Genz Benz Shuttle 3.0's effects loop. This essentially cuts out the Shuttle's preamp/EQ section, letting me balance the total output with the Noble's volume knob and the Shuttle's Master. Adjusting these works as described above.

However, I have the option to run the Noble into the Shuttle's instrument jack to take advantage of the built-in EQ. Because the Shuttle's preamp has no coloration, blending it into the equation does not seem to affect tone. What advice do wiser TBers have for considering how much to crank the Noble's and Shuttle's respective preamp volumes (there are now two), and then the Shuttle's Master?

 

[NKBassman]

in that scenario I would suggest running the Nobel where it sounds the best, adjusting the Shuttle gain low enough to avoid wanted clipping, and master volume as required.

 

[Super Bass]

Really, are bass amps really that complicated?

 

[Boneless]

Technically you want to avoid increasing gain stages. The more gain stages, the more noise. It can be academic though. Keep in mind that a lot of effects (for instance, FET compressors, diode compressors, etc.) actually attenuate the signal a lot (like, really a lot: sometimes you need to contain the whole dynamics of the signal within 30mV or so - a hot bass guitar signal can have peaks of 1V even). And then they amplify it back to the desired level. Also, a DI, depending on design, can attenuate the signal a lot, especially a passive unit. (This basically presents a much higher impedance to the source compared to what a mixer input would present).

 

[N. Kentucky Bass]

in that scenario I would suggest running the Nobel where it sounds the best, adjusting the Shuttle gain low enough to avoid wanted clipping, and master volume as required.

I wonder if the low setting on the Shuttle's preamp would affect the relative volume boosts or cuts in EQ? It's going to be a few weeks before I can test this as I'm traveling.

 

[coyote1]

Is it right to push gain all straight as long as it doesn't clip? I usually scoop the gain much more than the master and I'm not sure if that is okay.
Does it affect to the sound? and if it does, in what way?

Thnx in advance.

Whatever generates the sound in your head without frying your gear is okay. Load the input gain? Why not? Crank the master? Fine!

Experiment, and let your ears be your guide.

 

[agedhorse]

I wonder if the low setting on the Shuttle's preamp would affect the relative volume boosts or cuts in EQ? It's going to be a few weeks before I can test this as I'm traveling.

On the Shuttle 3.0 specifically, and because it's also quite neutrally voiced, you can use the front input. The gain range is quite wide so based on what I know about the Noble, set the input of the Shuttle to about 10:30-11:00 set the master around 1:00 and then set the Noble's level accordingly.

The gain on the Shuttle amp does not alter the eq operation in any way.