Inspired by vintage solid-state studio microphone pre’s from the 70s and 80s, the 228 PRE is a unique design tuned for guitar using a discrete transistor topology.
The two gain controls, INPUT GAIN and OUTPUT GAIN both change the feel and character of the signal, giving a responsive feel under the fingers. The 228 PRE enhances the guitar tone like a great overdrive can, but without clipping the signal. Its like an overdrive for your clean tone.
Using the gentle-slope HF (high frequency) and LF (low frequency) shelving controls, the signal can be shaped to suit the amp and other pedals in the chain. Slight adjustments can make your tone fat and responsive, or make some more extreme adjustments to use the 228 PRE boosting the midrange into an overdrive. Everything from full range to treble boosting is available with these controls.
Controls
INPUT GAIN
The input gain simultaneously controls the gain (approximately 0-12 db) of the first gain stage while also controlling an attenuator further into the circuit. Increasing this control you’ll hear the increase in volume but also feel the guitar give more under the fingers and as you dig in with your pick attack, you’ll feel and hear a natural compression similar to an overdrive, but without any noticeable clipping of the signal. The high-end “sparkle” is also slightly enhanced as you increase this control.
LF
The LF controls is a switched capacitor, 3 db per octave shelving filter. The dial indicates the frequency (0-112 Hertz) of the -3 db point of the filter.  These values have been selected to give the ability to “tighten up” the guitar signal in the lower range, all the way up to the higher range emphasising the midrange character of the guitar signal. This makes the control very useful if you plan to use the 228 PRE to boost the guitar signal into an amp or  another overdrive.
HF
The HF control is a low-pass filter tuned for guitar, and is particularly useful for sweetening single coil guitars where the boosted signal can become overbearing. Some high-end “sparkle” is still allowed to pass through regardless of the setting. Note this control will have a more subtle effect on darker sounding guitars due to the tuned frequency of the filter.
OUTPUT GAIN
The output gain simultaneously controls the gain (approximately 0-18 db) of the last gain stage while also controlling the negative feedback of that stage. As the control is increased the volume increases, while the negative feedback reduces, making the sound more “loose” as it gets louder.
