Why would you want to reduce your amp’s volume?
There are valid reasons, but rarely is it simply about making things quieter. Guitarists typically want to keep their amp sounding as good as it does when cranked up but without the problems caused by overwhelming decibel levels. Relatively few guitarists really need 100-watt stacks any more, and many are finding that even 50-, 30-, and 20-watt combos are still too loud for many situations.
So sounding cranked up while actually cranking down decibel-wise is the real conundrum. Luckily, there are several good ways to achieve it.
1. OUTPUT ATTENUATORS
Having come a long way from the days when a power attenuator essentially used a toaster element to rob your amp of output power (and threatened to blow your tubes and output transformer with every slash chord or unison bend), a new generation of output attenuators are available that bring volumes way down without excessively altering amp tone.
Some amp makers—Matchless and TopHat among them—still advise against using such devices, but Dr. Z, Kendrick, Marshall, Rivera, THD, and others offer their own attenuators and are obviously confident of their capabilities when used correctly.
2. HALF-POWER SWITCHES
These power-reducing functions come in a range of formats, and are factory equipment on some amps. A common type is the pentode/triode switch, which reduces the power tubes’ output by reconfiguring them to the less efficient triode mode. (Actually mock triode but who’s counting?)
Another is a switch that cuts two of four output tubes from the circuit to reduce output power from, for example, 30 watts to 15 watts. Be aware, however, that “half power” doesn’t actually mean “half volume”, since the human ear’s perception of loudness doesn’t chart in a straight line.
3. LOWER THE VOLTAGE, LOWER THE VOLUME
Reduce the voltages inside the amp on which the preamp and power tubes feed, and you reduce output power and, hence, volume. Make this governable by the player, and you have a nifty solution to wattage and volume levels, one that several manufacturers have pursued successfully.
Available as a factory feature on amps by makers such as 65amps, Mojave, Reeves, Suhr and others, and as a modification by London Power and Hall Amplification, this solution enables the player to find the sweet in an amp’s gain and EQ settings, then to globally reduce the output power by reigning in the internal DC voltages to the desired level.
4. HOW ABOUT A LESS EFFICIENT SPEAKER?
For years players have reveled in the ability of very efficient speakers such as Celestion’s Alnico Blue and G12H-30 and several Eminence models and others to convert a smaller amp with low wattage into a giggable tone machine.
Lately, however, plenty of guitarists have discovered the beauty of going the other way: replace a punchy, aggressive speaker with one that converts your amp’s wattage into fewer decibels and you have, in a sense, tapped the most efficient attenuator available. Manufacturers Eminence and Fluxtone have built this principle—in very different ways—right into speakers that allow you to manually vary their efficiency to reduce volume as desired.