A Low-Mu Triode Preamp

In this article, originally published in audioXpress, February 2004, the author describes how to achieve low distortion from power triodes. As he explains, his preamp is “a little different from most, using low-mu power triodes to get good performance with only one amplifier stage, and no negative feedback. This achieves the modest gain required along with very low output impedance.”

Here’s a do-it-yourselfer’s dream in tube amp design: four operating modes, high quality, low cost, and low distortion. An article originally published by audioXpress in May 2007. A true versatile project which we think deserves to be shared.

New from MOD Kits DIY for NAMM 2015 is The Wave, a tube driven analog spring reverb unit kit combining four dual triode tubes with a MOD three-spring reverb tank, a typical sixties design. The unit can be used in front of a guitar amp or as a line-level analog reverb effect for the recording studio. The Wave kit comes with a pre-punched powder coated steel chassis, easy-to-follow instructions and all necessary parts.

After over a decade of being dormant, Radial Engineering Ltd. purchased the Hafler brand in 2014 and announced it is re-launching a new series of high-fidelity audio products, already previewed at the 137th AES Convention in Los Angeles. One of the most interesting is the HA75 ‘Tube Head’ - a 12AX7 driven tube headphone amplifier with sufficient gain to power any type of headphone.

Everyone else’s doing it, so why shouldn’t an historic brand like dbx do it as well? With the new model 676 Tube Mic Pre Channel Strip, HARMAN’s dbx offers a Class A vacuum tube-based microphone preamplifier combined with its classic compressor/limiter designs and dynamics processing in a vintage-style solution.