So I just spent the last few hours listening to my hhf1s on this amp. Some Diana Krall live followed by Stan Getz - Jazz Samba. Chain was airport express->Luxman D112 integrated amp acting as a dac->rca tape loop out to the balanced m3 (transformer balanced inputs)->hhf1. There was no delay, everything got out of the way, and I was just absorbed by the music. This is such a spectactular combination. I will have to pair it up with the apogee at some point, but wow. Now I just need a comfortable way to sleep with the grados on