XXX Master Volume

[Genius Gone Insane]

If I have the XXX Master Volume at full and the channel volume way down, it sounds great.

Conversely, if I turn the Master Volume way down and the channel volume up, I can get the same loudness as above, but I lose a lot of tone, particularly in the high end.

Why?

 

[Noumenon]

The channel volume is the preamp out and master volume is the power amp out. You're probably driving the input of the power amp too hard.

 

[Genius Gone Insane]

So if I've got the Master up higher, then I'm driving the tubes more?

 

[Wolfeman]

The channel volumes are simply master volumes before the master volume.

They 'should' sound the same either way you do it. Either the loop is changing your tone or the way the pots are placed/valued is affecting how the amp is loaded down in that area, which could affect the tone.

Edit- See my post below, the XXX does things a bit differently than most amps.

 

[egan.]

Where is Wolfeman? You are driving the poweramp about the same in both scenarios but you're driving the preamp much harder by turning down the master.

 

[Wolfeman]

Just took a look at the schematic. If you look, the channel volumes are pre EQ, then the signal goes through or around the loop, and into another driver tube before hitting the master volume. So yes, doing what you did will make a huge difference on tone.

If it helps any, when I had my XXX I used to set the channel volumes to about half way, and then adjust each to match volume based on what I had in the loop. Then I wouldn't touch them, and just use the master to control volume.

 

[Genius Gone Insane]

Ok thanks guys. The manual made it sound like it doesn't make a difference, but clearly that is incorrect.

Sounds like I'm going to get the most tube tone by having the Master at full. Which is what my ears have been telling me.

 

[Joelegend]

Brought my XXX to the repairguy last week for maintance and retubing. Asking if he wanted to put EL34's in it. He disadvised me it and told me abit history of tubeamps and stuff. He also said to turn the master all the way open to let the beast really out. At max mastervolume the Powertubes are also bringing extra overdrive to the sound. Never did it in 10 years. Very curious how it is going sound when i get him back.

 

[guitarguru777]

I always had my master at full on my 333XL (XXX / JSX Clone) and used the channel volume as my volume controls.