Add tone, harmonic distortion and subtle dynamic control
The Rooster 2 is a 2 channel Tube Pre Amp EQ with distortion controls. It is designed for a wide range of applications and can produce a large range of tones, harmonic distortion and subtle dynamic control.
The pre-amp section can be used to add gain to mic, line or DI input signals. The double triode input valve (ECC81) provides a smooth sounding gain stage after the balancing input transformer.
48 volts can be applied to phantom powered mics by using the special toggle switch. The DI input bypasses the transformer to give a suitable high impedance unbalanced input.
The ‘Attitude’ section provides control over the amount of distortion inherently produced by the 5725 valve.
Tube Pre Amp EQ with Attitude
This valve is also found in the Culture Vulture circuit. In this case the distortion produced can be far more subtle giving specs of 0.01% distortion when the switched ‘Attitude’ control is at position 1. The distortion of the Tube Pre Amp EQ drastically as the ‘Attitude’ control is progressively switched from position ‘1’ to position ‘Max’.
Similarly to the Culture Vulture, the unit will tend to produce predominantly more 2nd order harmonics when in ‘Triode’ mode and 3rd order harmonics when in ‘Pentode’ mode. This provides a creative means of both tone and dynamics control over the input signal as well as allowing the user to select how much and what kind of harmonics are present in the signal.
The EQ section provides a simple yet powerful musical control over frequency content.
The Bass lift control gives a continuous control over the amount of bass using a unique ‘ vari slope’ curve which peaks at 60Hz.
The ‘mid/high’ lift control gives a bell type curve with variable gain peaking at either 2.5KHz / 4KHz or a ‘vari slope’ curve peaking at 12KHz, all selected by the frequency select switch.
The ‘Mid cut’ control provides a bell type curve centered at 700Hz with continuous control over the amount of cut.
The ‘Bass cut’ switched control provides 5 positions with different cutting curves. The curves start off as high pass filters which get progressively higher in frequency and then turn into a shelving type curve that will also increase in frequency as the switch is advanced. These controls are intended to interact with the other EQ controls for a very flexible control over the entire frequency range.
The ‘LPF’ or low pass filter switch control will allow the high frequencies to be cut at a frequency suitable to stop harsh sounding harmonics standing out when excessive distortion is used, smoothing the resulting sound.
The output level control adjusts the signal going to the PCF 80 output valve and the final signal is balanced by a Sowter custom made transformer.
The level of output signal is represented by the 3 LED display.
Measurements are made at typical ‘Attitude’ setting ‘2’. in Pentode mode with an output of +4dBu. Measurements made with AC mains input 236V 50Hz. Load resistance is 10kΩ. Available gain (dB) Mic Line 56 (87 with Attitude at max. (P)) 24 Frequency response ±1dB 20Hz to 45kHz Distortion (THD @ 1kHz) ≤0.05% Noise (unweighted, 30kHz filter) ≤95dB below MOL MOL (2% THD @1kHz) ≥+25dBu Phase shift 24º (6.6%) at 10kHz Input impedance Mic Line DI 1kΩ 10kΩ 100kΩ unbalanced Output impedance 200Ω 10kΩ is the ideal load impedance. The Rooster 2 will work into a load of 600Ω, but distortion will increase & MOL will be reduced.