Neve 33609A (Vintage) Metal Knob Stereo Compressor/Limiter
The original all discrete “Metal Knob” version Neve 33609A inlcudes original BA440 Discrete Output Amplifiers and Maranair/St.Ives Transformers,
The 33609 is divided into two sections, with all stepped controls for instant recall. Limiter controls, and then compression controls Threshold and recovery controls are present with six release times available, two of which achieve program-dependent release, much like the Fairchild. The limiter also features a slow and fast attack switch. The compressor has similar threshold and recovery controls as the limiter, plus ratio selection and makeup gain. The unit also has global gain reduction bypass, and both compressor and limiter sections have individual bypass.
Dual Mono, or can be linked for stereo. both channels may be by-passed. Both mono, stereo and by-pass functions are switched by logic-controlled relays. Depending on the position of an EXTernal – INTernal switch, these functions are either operated by front panel switches or externally controlled by a rear panel connector.
Frequency Response Noise
Limit Ratio Attack Time
20Hz to 20kHz +/-0.5dB, measured at 0dBu relative to 1kHz.
-75dBu with input terminated in 600 ohms, by-passed IN, compress and limit OFF;
-55dBu with compress IN and gain make-up at maximum.
+4dBu to +15dBu, measured with limit recovery set at 50ms, level at +8dBu using a 1kHz sine-wave at +20dBu and +8 control adjusted to give +8dBu output.
with input level at 10dBu, increased to +20dBu the change in output level should be 0.1dB, +/-0.1dB.
slow: 4ms, +/-1ms
fast: 2ms, +/-1ms
being the time taken for a signal to return to within 1dB of its original value, using an increase in input level of 10dB on an input adjusted to +10dBu at 1kHz.
this is the time taken by the control voltage to reach a new value when an input at +20dBu is reduced in value by 10dB. The recovery times can be set to 50ms, 100ms, 200ms, 800ms, AUTO 1 1500ms, AUTO 2 3000ms (all +/-50%).
settings 0 to 20dB correspond with output level +/-0.5dB.
Limiter/Compressor Technical Handbook Page 2
recovery set to 100ms
threshold to -20dBu
input 1kHz at 0dBu
for each setting of the Compress Ratio Switch the input level is increased by 10dB and the change in output level should be:
Compress Recovery Distortion
Power Consumption Dimensions
100ms, 400ms, 800ms, 1500ms
AUTO 1 800ms AUTO 2 1500ms
Limiter/Compressor Technical Handbook
Compress Ratio Switch 1.5:1 2:1 3:1 4:1 5:1
O/P Level Change (dBu) 6.5
0.075% maximum (bypass IN, Compress and Limit OUT, input level at +9dBu, 1KHz).
0.2% maximum (Compress IN ratio 6:1, Gain make-up to MAX, Recovery 800ms, Threshold –18dBu).
0.45% maximum (Limit IN, Compress OUT, Recovery 800ms. Input level +22dBu, Threshold –18dBu).
Length: Height: Depth:
482mm (19in) 88mm (3.26in) 255mm (10.03in)