I just bought an Ayre V5Xe amp and I notice a hiss when I connect it with my system. I talked To Ayre and they suggested it's because of the pre-amp. I don't quite understand why that is the case and would appreciate any help in understanding and solving this problem. Here are the details -
1) I hear the hiss when the pre-amp and amp are on and the pre-amp is "unmuted". I have used an SPL meter to measure the hiss - it's about 55 dB right next to the speakers (Maggie 1.6). The magnitude does not change if I change the volume using the pre-amp volume controls.
2) The pre-amp I have in the system is an Audible Illusions Modulus 3. It'a a tube pre-amp.
3) The Ayre has both balanced and unbalanced inputs. Since my pre-amp is unbalanced, I am using the unbalanced inputs. There's a switch in the back that toggles between balanced/unbalanced. I have the switch set to "unbalanced". If I set that switch to "balanced" the hiss increases.
4) If I take the pre-amp out of the signal path and connect the amp directly to a D/A converter (Benchmark DAC 1 USB) the hiss goes away. So the hiss is purely because of the pre-amp.
Previously, I had used a hybrid amp, the AMC CVT2100A. I never heard any hiss from that system. The Ayre amp has higher gain. Is that the problem? The pre-amp has a residual noise and I hear it because this amp has a higher gain? And is the only solution getting a new pre-amp?