Amp gain.

[grandad]

"The main part of the problem though was that our 'singer' has absolutely zero mic technique and no interest in learning either".

Are you quite sure about that?

[Nobatron]

9 hours ago, 40hz said:

Weirdly enough my functions band had the opposite experience. We found maxing the volume on channels and adjusting overall volume using the gain control greatly reduced the feedback and cleared our stage sound up.

This discussion comes up quite often in live sound discussions like this reddit post and the general consensus is that gain is gain and it doesn’t matter where it is added with regards to gain before feedback.

The only way I can see boosting the gain causing more feedback than the fader is if the preamp doesn’t boost gain evenly across the frequency spectrum and I’m not aware of any desks with preamps that do this.

[Japhet]

43 minutes ago, Nobatron said:

This discussion comes up quite often in live sound discussions like this reddit post and the general consensus is that gain is gain and it doesn’t matter where it is added with regards to gain before feedback.

The only way I can see boosting the gain causing more feedback than the fader is if the preamp doesn’t boost gain evenly across the frequency spectrum and I’m not aware of any desks with preamps that do this.

We use a Mackie desk that doesn't have faders so the gain is the only control on the signal strength. It's not a great idea but it works OK now we've worked it out.

[Dan Dare]

8 hours ago, Nobatron said:

This discussion comes up quite often in live sound discussions like this reddit post and the general consensus is that gain is gain and it doesn’t matter where it is added with regards to gain before feedback.

The only way I can see boosting the gain causing more feedback than the fader is if the preamp doesn’t boost gain evenly across the frequency spectrum and I’m not aware of any desks with preamps that do this.

Where in the signal path you add gain is important to the sound. A guitarist will often add gain early in the chain, to drive the input stage hard, cause it to break up and add some grit to the sound. That's not a good idea on a PA mixer (or a bass amp unless you are aiming for a dirtier sound).

On a PA mixer, a good rule of thumb is to set vocal levels on headphones and aim to have them max at 0db, perhaps 3db on peaks. Then increase the master fader to achieve the desired level in the room.

Edited August 16, 2020 by Dan Dare

[Nobatron]

2 minutes ago, Dan Dare said:

Where in the signal path you add gain is important to the sound. A guitarist will often add gain early in the chain, to drive the input stage hard, cause it to break up and add some grit to the sound.

Yeah. I’m not arguing with that. With tube amps where you might want to introduce some clipping for taste different sounds but when recording or with live sound it is a bit more of a science. Especially if digital is involved.

[agedhorse]

12 hours ago, Nobatron said:

Depends on the amp. My last 2 took the DI after the preamp.

For post-eq DI, that would be always after the preamp.

For MOST pre eq-DI's it's before the gain stage. Of course there can be exceptions, but my experience it's about 95% give or take.

[agedhorse]

10 hours ago, Nobatron said:

This discussion comes up quite often in live sound discussions like this reddit post and the general consensus is that gain is gain and it doesn’t matter where it is added with regards to gain before feedback.

This is generally correct, gain is gain as far as gain before feedback is concerned.

[agedhorse]

10 hours ago, Japhet said:

We use a Mackie desk that doesn't have faders so the gain is the only control on the signal strength. It's not a great idea but it works OK now we've worked it out.

Which one is this? 

[Nobatron]

5 minutes ago, agedhorse said:

For post-eq DI, that would be always after the preamp.

For MOST pre eq-DI's it's before the gain stage. Of course there can be exceptions, but my experience it's about 95% give or take.

Yep, and if it’s switchable between the two it’ll almost certainly be be post gain.
Easy enough to put a DI box before the amp if the gain is a problem anyway.

[agedhorse]

1 hour ago, Nobatron said:

Yep, and if it’s switchable between the two it’ll almost certainly be be post gain.
Easy enough to put a DI box before the amp if the gain is a problem anyway.

It it's switchable, then in the pre-eq position it will almost always be BEFORE the gain control, not after.

[Nobatron]

3 minutes ago, agedhorse said:

It it's switchable, then in the pre-eq position it will almost always be BEFORE the gain control, not after.

My Markbass was after gain for both switch positions which fees like it would be easier to implement.

[agedhorse]

2 hours ago, Nobatron said:

My Markbass was after gain for both switch positions which fees like it would be easier to implement.

That's how that designer chooses to do it, in general it's the exception to the rule. It's no easier or harder to do it pre or post gain control, it's purely the designer's choice, which may relate to what else (voicing filters, effects loops, etc.) they may wish to include in  the pre-eq signal path. 

I'm just suggesting that most choose to take the signal post input buffer and pre gain stage. If it's an issue to have the signal pre or post gain stage, it's good to know this before buying the amp.

[Sparky Mark]

This is how Markbass used to do it. I doubt it's changed.

[NickA]

..

Edited August 18, 2020 by NickA
needs more thought this one!

[agedhorse]

On 15/08/2020 at 08:51, Sparky Mark said:

Thanks Andy. Do you think there would any difference in the longevity of a solid state amplifier used with the output control at max and volume set via the gain control verses one where the gain was set just below input clipping and volume set via the output control?

Virtually no difference IME. 

[bassmayhem]

My Fender Super Bassman - and the Bassman 100T I had - requires the gain set relatively high, since the noise level when cranking the power amp is immense.
My Vanderkley Spartan has no gain control at all. When I asked Marc Vanderkley about it, he answered: "There is nothing in there you can overdrive".
The little Quilter Bassblock 800 had no overload LED; Pat Quilter said: tweak with your ears - not with your eyes!

My personal standpoint: set the gain high enough to get a decent signal with as little noise as possible when opening up The Big Tap. Decent signal? That's up to me. Or you.
I prefer my Super Bassman to break up a bit when digging in, so gain at around 5, and master volume at 4 - 5. I tend to keep the Class D amps a bit cooler; no good idea letting them clip. No good tone comes out of that.  Any kind of dirt or grunt, I add a tad with a pedal in front...

Edited August 24, 2020 by bassmayhem

[NickA]

5 hours ago, bassmayhem said:

My Fender Super Bassman - and the Bassman 100T I had - requires the gain set relatively high, since the noise level when cranking the power amp is immense.
My Vanderkley Spartan has no gain control at all. When I asked Marc Vanderkley about it, he answered: "There is nothing in there you can overdrive".
The little Quilter Bassblock 800 had no overload LED; Pat Quilter said: tweak with your ears - not with your eyes!

My personal standpoint: set the gain high enough to get a decent signal with as little noise as possible when opening up The Big Tap. Decent signal? That's up to me. Or you.
I prefer my Super Bassman to break up a bit when digging in, so gain at around 5, and master volume at 4 - 5. I tend to keep the Class D amps a bit cooler; no good idea letting them clip. No good tone comes out of that.  Any kind of dirt or grunt, I add a tad with a pedal in front...

Can't argue with that!

Depends so much on the amp architecture that it's impossible to make one rule for all.  Turning up the gain gives a nice strong signal into the power amp, but not if you then turn the volume down.  If you want a clean sound turn up both gain and volume avoiding clipping in both, if you like the  sound of the pre clipping, turn up the gain and if you want to clip the power section, turn up the volume too ( but it will be unavoidably loud! )