The information below was taken from discussions at The Lab involving different resistor values being needed depending on which model VCA is used in Gyraf Audio's GSSL Compressor. Much of the information is taken directly from THAT Corporations datasheet entitled "Substituting THAT 2180- and 2181-Series VCAs for THAT 2150-Series VCAs in Existing Designs".

As a homage to Gyraf for this awesome project, I would like to take the time to steal his disclaimer in a slightly modified form.

Disclaimer: Notice that all information is supplied "as is", and that I can in no way be held responsible for its accurateness, functionality or even safety. In other words, if you break something, it's not my fault.

-Matt

VCA used in GSSL
Original Value 2180LA 2180LB 2180LC 2181LA 2181LB 2181LC 2155
100K (Ratio Adjustment) ? ? ? 120K 120K ? ?
10K (based on THAT's Datasheet) Remove (no jumper) Remove (no jumper) Remove (no jumper) Jumper Jumper Jumper ?
68R (based on THAT's Datasheet) Remove (no jumper) Remove (no jumper) Remove (no jumper) Remove (no jumper) Remove (no jumper) Remove (no jumper) ?
3K9 (based on THAT's Datasheet) 5K1 5K1 5K1 5K1 5K1 5K1 5K1
10K (based on THAT's Datasheet) Remove (no jumper) Remove (no jumper) Remove (no jumper) Remove (no jumper) Remove (no jumper) Remove (no jumper) ?
1M (based on THAT's Datasheet) Remove (no jumper) Remove (no jumper) Remove (no jumper) 680K 220K 130K 300k?
50K Trimmer Mounted? No No No Yes Yes Yes ?
2 X 47K ? ? ? ? 120K ? ?

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