All they do is change the output. I believe Theta makes the dac with higher output because in most situations it gives you more dynamics. Beyond that you will not hear anything different with the gain lowered. Hooked up to the CAT you will get a bit more control of the volume increments if you lower the Theta's gain, but their stepped attenuator volume pot should not show different balance at different levels. BTW, I love my Gen Va and just had it updated to 24/96.
THETA GEN 5A OUTPUT GAIN CHANGE MOD
THE THETA GEN 5A HAS A FACTORY SET OUTPUT LEVEL THAT IS HIGHER THAN AVERAGE. THIS RESTRICTS THE NUMBER OF CLICKS THAT I CAN TURN ON THE VOLUME CONTROL OF MY PREAMP (C.A.T. SIGNITURE MK3). THETA HAS A GAIN REDUCTION MODIFICATION. HAS ANYONE DONE THIS MOD? WILL IT AFFECT SOUND QUALITY?