Some time ago i broke one of the two op-amps which are running the snare. It happened by accident as we tried to fix a broken solderpoint of the newly integrated 2.2k resistor. These op-amps are part of the envelope-section. After we spend some time researching we found out that the big op-amps of the envolope-section is a quad-op amp produced by Texas Instruments, so we decided to use a similiar op-amp also made by Texas Instruments. We've chosen the single-op amp from the same series as the quad-op amp, which is the Texas Instruments LM321MF. We bought a bunch of them and replaced the broken one. The operation was a success! The sound is nearly the same, there are no sensible changes in the envelope of the snare.