Originally Posted by: blueradish ... I'd rather have a 15 or 18 cranked to 7 or 8 than a 30 at 4. ...
Ah, the light comes on... :cool:
This is why so many people have put so much time and effort into finding a way to adjust the output of a tube amp without losing that tone. So far, all of the techniques being used appear to have some trade-offs.
Most of the classic Master Volume circuits simply reduce the level of the preamp signal that reaches the power amp. This is OK if your distortion tone originates in a stompbox, or in the preamp. If you crave the sound of raging power tubes, MV amps don't make it.
Attenuators like the Hot Plate, Power Brake, and the MASS all take the full output of the amp, dissipate most of it internally, and pass the remainder to the speaker(s). This allows you to crank up the amp to where the power tubes are singing, but that reduced signal doesn't push the speakers as hard, and some speakers need to be driven at a certain level in order to hit that 'sweet spot' where they sound best. All attenuators affect the tone, and you also lose that interraction between the amp and the speaker. Acoustic feedback? Fugedabowdit! And because the power tubes are still being driven hard, they wear out fast.
Power Scaling has some distinct advantages over MV or attenuator setups, but it isn't perfect either. By reducing all of the voltages applied to the tubes, the life expectancy is greatly extended. There is some effect on the tone, but its certainly no worse than attenuators. There's still the issues of 'sweet spot' speakers and the reduced feedback sustain, but the amp does interract with the speaker.
A technique sometimes used in studios is to install a speaker inside a completely sealed cabinet lined with sound absorbent material. A microphone is also installed in the cab, which allows the sound of the speaker to be recorded without having to deal with high SPL in the room. The sound is not very natural. There's no room ambience, or interraction between the speaker and guitar.
The trend is definitely towards smaller amps, with a mic and/or a DI feed to the PA system. But not every club has a decent PA, and I know a lot of guys who insist on keeping their 100 Watt monster amps. Hell, I ain't selling my VT-22, even if I don't have anywhere I can really crank it up.
Ya pays yer money, an ya makes yer choices.
Lordathestrings
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