Rupert Neve Designs 535 | Diode bridge compressor

THRESHOLD
A potentiometer with 31 positions that sets the level at which compression starts, from -25 dB to +20 dB. Turning this control counterclockwise increases the compression; turning it clockwise decreases the compression.

RATIO
The RATIO control has six selectable positions on a rotary switch that allows the user to adjust the slope of the compressor curve with preselected ratios from 1.5:1 to 8:1 for levels above the specified THRESHOLD. This range of compression ratios allows the user to compress as moderately or as much as desired.

TIMING
The uniform TIMING control is a rotary switch with six positions that is used to set the attack and release times of the compressor. The timing can be further changed using the FAST button.

FAST (TC1) – Fast Attack (750 μs), Fast Release (130 ms)
MF (TC2) – Medium Attack (2.25 ms), Fast Release (130 ms)
MED (TC3) – Medium Attack (2.25 ms), Medium Release (400 ms)
MS (TC4) – Medium Attack (4 ms), Slow Release (725 ms)
SLOW (TC5) – Slow Attack (10 ms), Slow Release (800 mS – 1 S)
AUTO (TC6) – Medium Attack (5 ms), Dual Release (T1 500 ms, T2 1s)
‘FAST’ Mode – Speeds up all compressor time constants by 30%

FAST
The FAST switch accelerates all compressor time constants by 30%, doubling the number of TIMING presets available to the user.

BLEND
The BLEND control has 31 detents and allows the user to mix the uncompressed (dry) signal with the compressed (wet) signal. Turning the knob towards 0% mixes the uncompressed dry signal, while turning the knob towards 100% mixes the fully compressed signal. This function enables parallel compression and therefore a wide range of compression finenesses.

GAIN
The GAIN control has 31 detents and allows the user to add extra gain to the compressed signal to bring its level back to that of the uncompressed input signal. It is much easier to judge the sonic effect of the compressor (via the COMP IN switch) when the compressed output level is matched to the uncompressed input level, avoiding potentially misleading level differences.

COMP IN
The COMP IN switch activates the compression circuit. By deactivating the COMP IN switch, the compressor is bypassed and the user can quickly compare the compressed sound with the dry input signal in order to obtain an objective assessment of the sonic effect of the compressor on the audio signal.

LINK
The LINK switch allows the compressor to be connected to another 535 compressor module via a side-chain control voltage. In link mode, the compressor that generates the higher side-chain voltage (resulting in higher compression) controls the compression of both audio signal paths to maintain a correct stereo center image during compression.

SIDE CHAIN HPF
The S/C HPF switch allows the user to insert a 12dB/octave 150Hz high-pass filter into the compressor side chain. When this filter is activated, the compressor reacts much less to information below 150 Hz. For example, on a drum kit, the low end of the kick drum would have a less proportional effect on the compression than a snare drum or cymbal, as a significant amount of the kick drum’s dynamic energy is concentrated below 150Hz.

LEVEL AND GAIN REDUCTION INDICATORS
These two LED indicators provide a highly precise