Mesa Boogie 5AR4 | GZ34 Rectifier Tube
Mesa Boogie 5AR4 / GZ34 Rectifier Tube
We love premium grade Mesa tubes for their unsurpassed quality, consistency and value. The GZ34 / 5AR4 has long been considered the king of the rectifier tubes. This powerful, sturdy rectifier tube makes more DC out of the AC it’s fed. It does this elegantly and with great efficiency, while still inducing many of the most-loved characteristics of tube rectification into an amplifier’s performance. Sonically, the 5AR4 Rectifier Tube produces a vintage feel with light to mild "sag". While it produces more "sag" than Silicon Diodes, it is the least "saggy" of all the Mesa rectifier tubes. Used in vintage-style MESA amps like the Heartbreaker, Blue Angel and Maverick as well as many other vintage, non-MESA amplifiers.
What is a rectifier tube? In basic terms, a rectifier is the diode component within a tube amplifier that converts AC voltage from the power transformer into a DC voltage required by preamp and output tubes to do their amplification business. The rectifier is not in the signal chain of the amp, and your guitar signal does not pass through the rectifier at any time. But this doesn’t mean that the rectifier has no impact on the sound of your amp. Preamp and output tubes perform differently at various voltage levels, so different rectifiers can offer a different tonal or performance characteristics. They affect the attack, compression, dynamics, and touch-sensitivity that any tube amp gives you, and is something players tend to notice most about how their rectifiers are performing—whether they know it or not.
In between the 5Y3 and GZ34 are a number of rectifier tubes—such as the 5R4, 5U4GB, 5U4, and 5V4 – which are generally found in mid-sized amps. Rectifier tubes can sometimes be swapped for a different type in cases where you find it preferable to run your tubes at slightly higher or lower voltages. Such a change should only be made after consulting with a qualified tech.