Whitestone Audio Instruments is the brainchild of Kim and Dave Rosen. Dave, a tech, was given the challenge of building a mastering-grade device for adding subtle harmonics by his wife, Grammy-nominated mastering engineer, Kim Rosen of Knack Mastering. The original device was designed as a custom unit to live in Kim’s mastering studio but now they’re bringing it to the world at large.
Instead of offering an obvious tube sound, the P331 Tube Loading Amplifier aims more for subtle colouration akin to the sound of running your signal through a Pultec in bypass mode. There are various different options available to the user, all of which can be bypassed or perfectly recalled thanks to over 60 relays in the front panel, both features ideal for mastering. The tubes employed in the circuit aren’t your run-of-the-mill 12AX7 tube found in guitar amps either, but the 6SN7, a tube more commonly found in audiophile hi-fi amplifiers. These can be loaded in different ways for subtle or less subtle non-linearities and even order harmonics.
Transformers can also be switched in and out to change the texture of you signal further. Although the P331 has been designed for the mastering chain, it has already found users in the mixing world who are using it on their mix bus. It will be available in January and has an expected price of $4500.