4KCC - SSL 4000 Dynamics (PCB)

High quality recreation of the legendary SSL channel compressor for 500 series.
 

• AD536 (original) or THAT2252 RMS Detector Runs at +/-16V (API500) or +/-24V (51X)
• Optional Stereo Link GATE and EXPANDER switchable

What You Need To Complete The Build
1. This PCB 
2. 6 knobs for 16mm pots
3. Front Panel and L-Bracket
4. A 500 series rack!

Support Thread: https://groupdiy.com/index.php?topic=45348

Documentation from Igor:
https://www.dropbox.com/s/ltafvf9foruzv7o/4KCC_docs_v2.rar?dl=0

Calibration procedure:  (taken from the SSL Manual)
Inject 1KHz into the channel Line Input and increase the input level to +14dB so as to obtain +10dB at the Insert Send.
Set the Compressor controls as follows:

THRESHOLD +10dB
ATTACK Fast (pull Release knob up)
RELEASE Fast (fully ACW)
RATIO Infinity

Press the Dynamics to Channel Input button (CH IN) and check that the output level at the Insert Send drops by 4dB. This can be adjusted with the preset marked '0dBm'. Confirm that, when the Attack switch (on the Release pot) is pushed back in, the output level increases by 1.5dB approx (no adjustment available). Decrease the input level to approximately -20dB, and with the Threshold pot set to -20dB, increase the input signal level so that the compressor starts to limit. Check that once limiting is achieved, the output level remains reasonably constant (within +1dB). If not, use the 'Gain' preset to correct. Now set the compressor Ratio pot to its minimum setting (1:1). Set the Expander controls as follows:

THRESHOLD 10dB
ATTACK Fast (pull Release knob up)
RELEASE Fast (fully ACW)
RANGE 40dB
GATE SWITCH In

Increase the input level to +14dB and adjust VR3 so that the channel just begins to pass audio (all the Green LEDs should extinguish). The gating level can then be confirmed either by adjusting the Line Trim around ist indent position or by increasing and decreasing the oscillator Input.
Set the Expander Range control to the minimum setting and adjust the 'Symmetry' preset for minimum distortion measured at the Insert Send. Release the Gate Switch. Set all other expander controls ACW.

This item includes just the pcb. Nothing else.
Frontpanels and brackets are available in this shop.