HRK 500 Series Colour Modules
Modules come in an array of flavours these days. How do you know which to go for? HRK are here to help with their cost-effective ‘Colour’ range
The basic principle behind the Colour modules is that you can select your choice of flavours and install them in an appropriate host. This keeps the cost down, and provides a massive amount of flexibility and tonal variation. The C544 builds on DIYRE’s original Colour Palette Module concept by upping the slot count to four. Although there is a Master Output LED, it is quite a shame that the coloured LED module indicator system has been dropped. Both here and on the Stereo Processor, this makes it harder to see when individual Colours have been selected. That being said, this is a clean-sounding, good value starting point into this chromatic world of sound. VERDICT 8.9
This module is the only one on review that mentions any form of harder sonic mangling in its name, though most of the others exhibit this tendency when the input gain is dialled-up. In fact, as it is driven harder, the sonic breakup is smooth and with a pleasant character. HRK claim that this module provides a tone similar to that of vintage recording consoles. We found it to be a great all-rounder. VERDICT 9.0
All three modules represent different designs based on mixing desks from the ’60s and ’70s. As elsewhere, NOS transistors are used, with the Line Driver also benefiting from a small custom audio transformer and configurable feedback and low boost modes. British Console, based on the Neve 1073 mic preamp, has three gain modes across its two discrete op-amp stages. Pushed further, the GT adds additional harmonics and opens into a well-populated spectrum (even and odd). VERDICT 8.9
For those on a limited budget or with no room in their 500 chassis, the C2584 Stereo Colour Processor squeezes two channels, each with two Colour slots, into a single-width space, using two front-panel TRS jacks for the inputs and the rear XLRs as outputs (with an included adapter). Control is given over overall input and output gain for each channel, which is less flexible than its four-slot mono sibling. VERDICT 8.4
This trio of EQ flavours gives greater frequencybased shaping than the other Colour modules. In circuit topology, the Ge (Germanium) and Si(Silicon) are largely the same, except for the type of transistors used (resulting in different tonal balance). EQ is set using two trimmers, while the British EQ adds selectable bands. Though all are fine-sounding, it’s hard to make real-time changes to the EQ and calibrate these in stereo. VERDICT 8.5
Some say the true ‘vintage’ sound is best seen in valve circuitry, and its harmonic richness. HRK spoil us with two flavours using sub-miniature low-voltage NOS (New Old Stock) valves from the US and USSR. Each offers Pentode and Triode modes (via a PCB jumper) for further variation. Both work well, with the warmer Triode tone being our favourite. barthrk.com VERDICT 8.4