Either way, fantastic roundup!!! I've found the same myself with 'synergy' It is pretty irritating, especially if a good amp brings out the true nature of a can that has been shielded by mushy amping. What it does mean is that the Predator is probably the least neutral in shaping cans to it's own image. But that can be a good thing - until you plug in something that already has the sonic qualities of the predator and they start to double up in effect. HD650+predator might only exagerate HD650 'issues' if you find it's sound signature an 'issue'.
Was this the D2 boa in the review????
I must say that what people should remember is that it's safer to try the D2 and then upgrade rather than shortcircuit the discovery process by going straight to the $500 amp XD
For the realists and impoverished ------->
ibasso D2 - £83.
2Move - £156
Pico+DAC - £260
Predator - £260
You might save money and not mind with a D2, or you might always be wondering 'what if' though if you go the cheapest option...then again, the sensation of being so happy with something so cheap is also incredible.
p.s. I've never personally like the LM6171/2 opamp based devices. Had terrible oscillation with GV5. Never liked the sound even when it worked.
AD8599, AD8656, AD8397, LM4562, LMH6643 are the gems imo from memory. OPA2111 apparently is nice too for soundstage on D2.
Shame with the boa there are no dip sockets, then again most chips are soic anyway.
See my post #2 about rolling opamps in the D2 for the Freq Show. For Freq Show I swapped the LM6172 into the ground channel and THS4032 into the main channel. I have to swap the opamps back to the other way when using the Grado RS-1, as the Freq setup is too bright with the Grados. I am gonna try the Freq Setup with my Edition 9, D2000 and HD600 tomorrow. Maybe it will be only the RS-1 that I don't like that way, in which case I will leave it that way.
I find the LM6172 in both opamp sockets to be too mids-centric, but in the ground channel it gave me many good combinations for main channel opamps. With the Freq Show I did try the LM4562 in the main amp today, and the sound was nice but I got some noise with it at low volumes (sounded like tube rush and quieted when I moved from 7 o'clock to 8 o'clock). The AD8397 was very nice, as was the LT1364 and ISL55002 and THS4032, when using one LM6172 in the ground channel socket. The AD8397 with LM6172 in ground is what the Lyrix uses.
I gave my LMH6643 and OPA2111 away with my D1 that I traded for Stax stuff, so I couldn't try them. The LMH6655 I had left over from the D1 was okay in the D2 ground channel but nothing special. I didn't bother to try my AD8656, AD8066, or ADA4841-2, also left over from my D1.
I did try the OPA627x2 on a SOIC to DIP in main, with THS4032 in the ground channel, and it was nice, but I couldn't close the D2 viper case with them. I also tried OPA627 in both main and ground opamp sockets, and it was also too mids-centric in the frequency balance, like when using two LM6172. I wanted to try my second set of AD743 in a DIP 2:1 on a riser, but couldn't find them until tonight - again, this would be a setup where the case could not be closed over the 2:1 board. The guy that made the OPA627AU SOIC soldered adapter decided to solder it onto a riser to clear the battery, based on photos I sent him, but that wasn't needed. I could cut the riser off the adapter, to lower it, and then I could close the case and spend more .