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Posted by: bmh1109 Sep 20 2007, 09:03 AM

If an amp has a master volume like many multi channel tube amps do, does this feature allow you to drive the tubes hard and keep volume reasonable? Ive never owned a master volume amp and was just curious.

Posted by: JVM Sep 20 2007, 09:09 AM

You'll never get a true cranked tube sound with out actually cranking them I think, if it has a preamp gain knob you can get decent distortion at low levels with one, but unless you buy a solid state or a really low wattage tube amp it'll be hard to get great tone at bedroom levels unfortunately. Or you can use an attenuator, but those cost a lot of money.

There may be some workarounds, but basically, you have to turn the volume up to get that tube sound.

Posted by: tonymiro Sep 20 2007, 10:03 AM

+1 as JVM says. Powersoak/attenuator will help an awful lot but they do have tendency to leach the treble a bit.

Cheers,
Tony

Posted by: Andrew Cockburn Sep 20 2007, 05:59 PM

All the master volume achieves is to let you overdrive the preamp stage and keep the overall volume level low. An overdriven preamp is a different sound to an ocerdriven power amp - a lot of high gain amps like Mesas' get most of their sound from the preamp, so in that case its probably ok to turn the main volume down without sacrificing tone, but most amps really hit a sweet spot when everything is sweating, and that includes the power amp section - if you have a 100W amp, the only way to get that all tube sound is to play it up to the max so the power tubes really are on the edge (and man, 100W of tube power is seriously loud - they were developed in the 60s for Stadiums!).

So, no, the master volume won't let you get that special tube sound at low volumes - there are a few ways to get this though. Attenuators, Tony & JVM have already mentioned, power scaling is another option but it has to be built in to the amp or later added as a mod. Another way for recording is to use an isolation box - basically the speaker goes in a sound proof box with a mic and you can crank it up without destroying your ears. Finally, you can make a lot of difference to the volume by using more or less sensitive speakers - surprisingly, you can change a speaker and get variations as much as 50% or more in the output energy (although due to the logarithmic nature of the human ear, the percieved variation in loudness is less).

For all of these reasons, the current fashion in boutique amps is for lower powered outputs - 5, 10, 15 watts. the idea is that at that level you can crank it for practice or recording, 15 watts will get you through a rehearsal with unmiked drums probably, and for those big gigs, you would just mic it up and put it through the PA.

Posted by: Hungus Sep 20 2007, 07:25 PM

Oh man I guess I will have to be very lucky to experience my tube amp properly as it is 130 watts....

It does have a switch to change it to 75 watts though but I dont think it sounds as good on that setting. I could be wrong and just being paranoid though.....