1176 Rev A - external sidechain using a DPDT Switch

[juleselipse]

I'm currently building a Rev A with the mnats PCB:  http://mnats.net/files/1176REVA_125_VOLTAGES.pdf

The internal side chain voltage comes from R23 CCW lug - instead of soldering it straigt to the ratio PCB I solder it to pole 2 of a DPDT switch. On pole 1 I solder the hot wire from the external XLR input used as an external sidechain (see attachement)

Should I process the external side chain signal before sending it to the ratio PCB or can I just send it as is?

 

[abbey road d enfer]

Should I process the external side chain signal before sending it to the ratio PCB or can I just send it as is?

It depends what you expect. If you just want to make a signal "pump" under control from another, processing is not always necessary, although it helps eliminating unwanted triggering. If you want to do selective compression, you need to process the signal.

 

[juleselipse]

Any advice on what I should run it through before it reached the ratio board? HPF, LPF? I have to say I am bit worried about damaging the 2N5457 in the circuit, even if the MC76 insert loop function comforts me a bit.

 

[abbey road d enfer]

Any advice on what I should run it through before it reached the ratio board? HPF, LPF? I have to say I am bit worried about damaging the 2N5457 in the circuit, even if the MC76 insert loop function comforts me a bit.

Some kind of EQ that would allow frequency-shaping the signal. Even a simple Baxandall type is useful, or a cheap graphic.

 

[juleselipse]

thanks! does the filter has to wired to the power supply?

 

[abbey road d enfer]

thanks! does the filter has to wired to the power supply?

It can be a passive filter, but the choice of response is rather limited. However, passive high-pass is easy and works well enough in many cases to prevent low fequencies triggering too heavy compression.