Stupid tube question?

[bbqjoe]

This might sound as stupid as my friend asking if the tubes got brighter with volume,
but here goes anyways.

I have the VTA 120 running with a VTA SP-14.
The 120 has a volume pot, which I just leave wide open, volume of course is controlled by the preamp.

Since the amp is wide open all the time, does the tube actually work any harder with increased preamp volume?

Thanks.

 

[gadget73]

The louder it gets, the more current flows through the tubes but that happens no matter what combination of controls you use.

 

[zackthedog]

Sometimes output tubes exhibit a blue glow just inside the glass envelope. This is called flourescence and is a natural result of what's going on physics-wise inside the tube. On power peaks, sometimes you'll see this flourescence change or increase. That's the only time a tube should get "brighter" during normal operation. A blue glow within the internal metal plate structure, OTOH, is sign of a gassy tube and is not good.

 

[century tek]

Basically, that volume pot is just a level control to the input. When your volume (level) pot is all the way up, its just as if it didn't have one at all. Just like a straight power amplifier. No controls. This is different with powered preamps and/or tone controls.

 

[bbqjoe]

Basically, that volume pot is just a level control to the input. When your volume (level) pot is all the way up, its just as if it didn't have one at all. Just like a straight power amplifier. No controls. This is different with powered preamps and/or tone controls.

Thanks.
I forget to think about it that way.
It's controlling the input, not the output.

 

[Pio1980]

To be clear, the amount of input determines the amount of output.

 

[primosounds]

This might sound as stupid as my friend asking if the tubes got brighter with volume,
but here goes anyways.

I have the VTA 120 running with a VTA SP-14.
The 120 has a volume pot, which I just leave wide open, volume of course is controlled by the preamp.

Since the amp is wide open all the time, does the tube actually work any harder with increased preamp volume?

Thanks.

Of course, the answer is yes, since you can't get more of something without a corresponding increase in something else. The increased loudness from the speakers is because of increased current, as Gadget said, by the output transformers which received their current from the output tubes which received their voltage from the driver tube for a single ended amp or the phase splitter tubes for a push pull amp which received their signal from the the input or driver tube. Obviously, i don't have "Grammerly" since that sentence ran on far too long.