Hi all,
I've been doing some changes to my console (MCI528c), and experimented with swapping out the DBX 202c VCAs with DBX202x and That 2002. I made the appropriate resistor changes per the That datasheets, but I'm getting oscillation issues with 5534 opamps. There was no compensation cap in the original design w/ 5534, but I think these VCAs have higher bandwidth so the problems happens with them. I added a 22pf cap as pictured here, but still get oscillation. This happens with all the types of 5534 I tried, but I get no oscillation with opamps like the OPA 134, or MA332, which both don't need compensation caps.
Any ideas of what to try? I know SSL used the 202x a lot I think with 5534s, but I'm sure the VCA card design is a little different.
In the schematic 2003=5534, and the stock VCA is dbx202c
Including docs here. I can just use the OPA or MA332, but it's bugging me why this is happening.
I've been doing some changes to my console (MCI528c), and experimented with swapping out the DBX 202c VCAs with DBX202x and That 2002. I made the appropriate resistor changes per the That datasheets, but I'm getting oscillation issues with 5534 opamps. There was no compensation cap in the original design w/ 5534, but I think these VCAs have higher bandwidth so the problems happens with them. I added a 22pf cap as pictured here, but still get oscillation. This happens with all the types of 5534 I tried, but I get no oscillation with opamps like the OPA 134, or MA332, which both don't need compensation caps.
Any ideas of what to try? I know SSL used the 202x a lot I think with 5534s, but I'm sure the VCA card design is a little different.
In the schematic 2003=5534, and the stock VCA is dbx202c
Including docs here. I can just use the OPA or MA332, but it's bugging me why this is happening.