Variacs for my amp! I own an All-Tube (analog power) 100w guitar amp, and have recently been informed of a way to hook up a Variac to the amp.

Submitted byglx25v onFri, 08/17/2018 - 17:29

Variable transformers (Variacs®) are commonly used with various tube type amplifiers and other tube type devices.  The primary purpose is to bring the AC voltage up slowly in order to extend the life of the tubes.  Variable transformers have the unique ability to adjust their AC voltage without adding any noise or hum to the device that they power.  It may act somewhat as a volume control although it probably depends on the design of the amplifier.

Van Halen has been known to use Variacs to lower the voltage to his amp so that he could increase the volume without distortion.  He also used the Variac to create an effect that he called Brown Sound.  Brown Sound is sought by many professional guitarists.  Our Variacs are commonly used to create this effect.

Variable transformers are rated based on maximum amperage.  If there is a name plate on the device it may list the input amperage.  The variable transformer should be rated at least for the maximum amperage of the amp.  Links to common variable transformers that are used for this purpose are shown below.

 

10 Amp Portable Unit

5 Amp Portable Unit

 

These units simply plug into the wall and the amplifier can plug in to the receptacle that is provided.  Switch and fuse is also provided.

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