@wolverine1 The scenario you describe sounds unusual. I have the same preamp as you, the HPA4 (LA4 + with headphone amp). My Benchmark DAC3B has no volume control but if I were to have a DAC with volume I would set the DAC's volume to fixed. The manner to set it to fixed differs by DAC.
This flutter sound you hear should be investigated with Benchmark technical support. Give them a call and they will help you get sorted out.
You should also hookup your DAC by XLR (if supported) to the LA4's input #1. That input has some optimizations for DAC's.
My only complaint about this preamp is the RCA inputs, I wish they were all XLR's.
BTW - the LA4 is an incredible preamp. If you want a great volume control, a few source inputs, and total silence. I do not think you can find a better preamp. Almost all DAC's are noisier than this preamp.
This flutter sound you hear should be investigated with Benchmark technical support. Give them a call and they will help you get sorted out.
You should also hookup your DAC by XLR (if supported) to the LA4's input #1. That input has some optimizations for DAC's.
My only complaint about this preamp is the RCA inputs, I wish they were all XLR's.
BTW - the LA4 is an incredible preamp. If you want a great volume control, a few source inputs, and total silence. I do not think you can find a better preamp. Almost all DAC's are noisier than this preamp.