What is the difference between Volume and Master Volume

Bill McCloskey · Post by **Bill McCloskey** » 26 Mar 2023 6:52 pm

I have a Boss Katana and it has a Volume Knob and a Master Volume knob. I searched the forum and only go more confused as to settings, purpose of the master etc, but no clarity.

1. What is the difference/purpose of the Master volume vs the volume.

2. What do different settings/combinations get me.

Apologize for the dumb question.

David Wren · Post by **David Wren** » 26 Mar 2023 7:04 pm

As I understand it, the "volume", (or first gain knob) sets the level of the amp's preamp... and the "Master" volume or gain, sets the level of the main amplification, after the preamp signal is fed into it.

My rule of thumb for solid state amps is to dial the "preamp" setting, just under the "Master", as this will just give a hint of overdrive when picking hard. Setting the preamp higher than the master can result in continuous overdrive... as I understand it.

Now I will let the tech fellows follow up on this theory

Bill McCloskey · Post by **Bill McCloskey** » 26 Mar 2023 7:25 pm

I also have a Gain knob.

Gain knob, Volume, Master Volume.

I look forward to being educated.

Dave Grafe · Post by **Dave Grafe** » 27 Mar 2023 3:50 am

Jim Webb did this but called the controls by their proper names, Sensitivity and Volume. The channel volume knob controls the "sensitivity" i.e. how hot the signal entering the preamp is, while the master volume controls how much of that preamp signsl goes to the power amp section. This allows the front end to be adjusted for "hair" or lack thereof at all volume levels.

Webb recommends the Sensitivity (input level) at 10 and Volume (output level) as required, but other amps will call for other settings. On my SF Vibrosonic I ran channel at 7 or 8 and the master volume adjusted for the room. There is no interference between the two, so set the levels however it best serves your needs. Channel volume high and master volume low tends crunchy, channel volune low with master volume high yields maximum clean sound.

Hope that gets you there.

Bill McCloskey · Post by **Bill McCloskey** » 27 Mar 2023 5:38 am

Dave, where does the gain knob come in?

Howard Parker · Post by **Howard Parker** » 27 Mar 2023 6:41 am

I checked the owners manual and apparently the gain/volume stages do react like a channel strip, also driving the direct out, for recording & PA purposes.

The master controls how much signal goes to the final, power amp stages, ie..the speaker. In this amp, the gain/Vol stages are independent of the master so you can essentially turn the speaker "off" and still drive the DI output for recording and other purposes.

I gather that the Gain control acts as a "clean/distortion" control, the Vol controls level to the DI/Master and the Master controls speaker volume.

That's my take after 10 minutes with the manual.

Hope that helps.

h

Dave Grafe · Post by **Dave Grafe** » 27 Mar 2023 6:52 am

Bill McCloskey wrote:Dave, where does the gain knob come in?

What Howard said, from actually reading the manual no less

Generally the "Gain" label is attached to the initial input level control, an unfortunate choice of nomenclature as in reality "gain" occurs at every stage of an amplifier's design from instrument input to speaker output. Again, Jim Webb's use of the word "Sensitivity" is appropriate for this control.

Howard Parker · Post by **Howard Parker** » 27 Mar 2023 7:10 am

In practice, all of my amps with DI/Line Out react in a similar fashion.

At gigs, I'll send a DI/Line Out feed to the PA, adjusting that level with Gain/Vol (depends on how it's labeled). Once the correct level is established, I turn up the master for the desired stage/speaker level.

h

Tony Prior · Post by **Tony Prior** » 28 Mar 2023 2:18 am

Master volume sets the total ( final) OUPUT Level of the amp, Channel Volume/Gain sets the output level of an independent channel

A two channel amp for example can have two separate volumes and EQ's independent of each other - the final output level is determined by the Master volume . IF you need to turn up or down without changing your channel settings, use the Master volume.

Maybe start with the channel volume at 75 % or heck even 100% - Master at 50% .

You didn't ask , so here is the difference between Channel GAIN / VOLUME.

Set Gain at 100% and then set volume to achieve an OVERDRIVE tone. Set Gain at zero and Volume at 100% for the CLEAN tone. The more Gain you add, the more overdrive.

Many players using amps with MASTER volume set it a MAX and use channel volume to control amp volume, like we did with the old school Fender amps which had NO Master volume. Then Fender decided to be like Marshall and Mesa Boogie , they added channel GAIN/Volume and Master Volume . It confused the hell out of everyone who were using a Deluxe Reverb , Bandmaster , Super Reverb and even a Twin. Today the GOLD standard for all amps is apparantly channel Gain/Volume and Master Volume.

have fun

tp

Christopher Kux · Post by **Christopher Kux** » 28 Mar 2023 4:29 am

Might look at where the MV is in the circuit, too. Circuits with pre-phase inverter master volume controls are not going to yield the same tone with the MV turned down as they will with the control turned up. Just had this conversation last night, and demoed it for a friend on his amp, which he was about to sell.

You could have more or less flexibility depending on what you want the amp to sound like. It’s six to one, half a dozen the other if you have to crank the MV to take it out of the circuit, but I generally prefer an amp without an MV.