April 1, 2004

Tested By Terry Buddingh
If you’ve been keeping up with the latest trends and developments in elite multi-channel high-gain amplifiers, you’ve surely heard of Diezel. Hand-crafted in Munich, Germany,

these wicked-sounding tone machines have been a force to be reckoned with ever since the impressive four-channel VH4 (reviewed December, 1999) debuted in the U.S. several years ago. The latest offering to spring from the mind of Peter Diezel is the Herbert, which, if you’re familiar with the VH4, differs by featuring three independent channels, six output tubes (two more than the VH4), and an in-line front panel. In addition, the Herbert boasts a powerful two-knob Mid Cut tone-shaping function, a handy alternate master volume, and MIDI capability.

Herb Garden

The Herbert can serve up a wide range of tonal colors and textures courtesy of its three channels, each of which is voiced differently and optimized for a specific range of gain and tones.

Channel 1’s two gain stages are voiced to deliver clean tones with maximum headroom, while channel 2’s three gain stages cover the low- to moderately high-gain territory. Channel 2 also sports a Gain-Boost switch that can kick-up the burn for more singing sustain, and Channel 3 employs four gain stages for the most extreme overdriven tones.

The Herbert’s two-knob Mid Cut circuit, the amp’s most unique and powerful tone-shaping function, features an Intensity knob that controls the severity of the midrange scoop (centered at approximately 400Hz), and a Volume control that provides an appropriate cut (or boost) in overall amplifier level. While obviously useful for obtaining extreme scooped-mid metal tones, you can alternately use Mid Cut as a programmable lead-boost option. And, thanks to the Herbert’s MIDI capability, the circuit can be assigned to any, or all, of the channels. (The Herbert doesn’t come with a footswitch, so you’ll need to use a MIDI controller such as the Digital Music Ground Control or the Rocktron All Access to control the footswitchable functions.)

The Herbert also features unusually powerful (but non-programmable) global Presence and Deep controls. Affecting frequencies above 2kHz, the inductor-based Presence control is voiced deeper into the treble range than traditional presence circuits. This voicing provides more bite and cutting power, as well as increasing the control’s perceived effectiveness. The Deep control also uses an unusual inductor-based circuit to increase the output stage’s low-frequency response. This powerful circuit boosts in the 120Hz range to provide bone rattling low-end that stays tight and controlled thanks to the abundance of power provided by the six output tubes.

The Herbert’s output stage can accept a wide range of output tubes, and each pair of sockets is equipped with an independent bias control so that you can mix different tube types.

For example, it’s possible to run 6L6s, EL34s, and 6550s simultaneously, with the bias current for each pair of tubes optimized for their own dynamic “sweet spot.” How cool!

Diezel Power

The Herbert’s three channels cover an impressive range of sounds. While some multi-channel amps favor higher-gain textures, the Herbert is remarkable in its ability to provide impressive clean tones as well. Channel 1 conveys clean with astounding headroom and punch, yet there’s always a sense of resiliency in the dynamic response that keeps the feel from becoming stiff or sterile.

Channel 2 is the versatility champ thanks to the additional range provided by its Gain-Boost switch. In low-gain mode, it can cover tweed-like grind, Brit-flavored crunch, and even totally nail the Van Halen “brown” sound. Activate the Gain-Boost and there’s enough rage for old-school metal or shred solos. Channel 3 delivers the extreme gain demanded by today’s nu-metal players, while the Mid Cut control lets you dial-in the perfect amount of scoop. And, thanks to the Mid Cut’s programmability, you can preset it for wicked rhythm chunk, and then bypass the scoop for more forceful solos.

The highest-gain tones reveal the true value of the Herbert’s extra horsepower. Yes, six output tubes can produce authoritative tones at frighteningly loud levels, but the real benefit here is enhanced low-end control. There’s simply no substitute for raw power when you’re talking about low-end slam.

Homage to Herbert

Paving the way for a new breed of 21st-century super amps, the Herbert boldly ventures into uncharted territory with a spectrum of sounds that leaves little to be desired.

This German tone machine would rule on the basis of its second channel alone, and when you consider its plethora of hip features, and its ability to sound impressive even at low volumes, it’s clear that the Herbert has few rivals. For those who seek a truly ¨ber high-gain tube amp, and have the bank to afford it, there’s no substitute for the Herbert.


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