Altec 1591A Threshold Mod.

[Lalaland]

Can anyone give me advice on how to add a threshold to an 1591a Compressor.
I have seen this mod around but not entirely sure how to do it, I imagine a volume control on the sidechain signal ?

Thanks for your time.

 

[mjrippe]

Can anyone give me advice on how to add a threshold to an 1591a Compressor.
I have seen this mod around but not entirely sure how to do it, I imagine a volume control on the sidechain signal ?

Thanks for your time.

From the schematic it appears that the only difference between the 0dBm and +8dBm settings is R3, a 22k resistor on the lower left side of the page. It would make sense that one could replace this with a 25k pot and adjust the threshold between 0 and +8 (or a bit higher).

Please let us know if you try this out