I've been able to spend one or two hours with my Invicta each day for the past few days. I have only used the SD card mode and its integrated headphone amp. And my headphone is a newly acquired pair of HD800s with less than ten hours of usage, stock cable.
Overall, the DAC and integrated headphone amp of Invicta together pair with HD800s pretty well. In my opinion, it is easily on par with, if not better than, a Peachtree DAC/Bryston BHA-1 combo or a Northstar DAC32/Phonitor combo for driving the HD800s. I think this is remarkable given that the BHA-1, Phonitor, Northstar DAC32, and the Peachtree DAC (to a lesser extent) are all very capable dedicated amps and DACs. I'm under the impression that the Invicta sounds fuller and more musical without being less neutral or sacrificing any details compared with the Northstar DAC32/Phonitor combo, though I was not able to run a side-by-side comparison.
A few observations about the filters: Under the Minimum Phase IIR filter, Yanni' album Live At The Acropolis left me in awe last night. The soundstage was so realistic and 3D with great instrument separations, neutrality and musicality that I felt like I was there. For this specific album, I can hardly imagine it going any better. The Minimum Phase IIR filter also do a fantastic job for orchestral pieces because of its ability of truthfully reproducing the soundstage. Similar observation was mentioned earlier by Twsmith. However, the Minimum Phase IIR filter may sound a bit sibilant (to a lesser extent than the Phonitor) occasionally for vocals, for example when listening to the album This Left Feels Right by Bon Jovi. The Linear Phase Apodizing filter or the Linear Phase Slow Roll-Off filter does a better job taming the sibilance and therefore arguably works better for vocals, but may still sound a tad harsh to some. All available filters of the Invicta are able to produce tight and impactful bass.
Now I am looking for a dedicated amp to pair with the Invicta not because I am not very content with the Invicta as a DAC/AMP driving the HD800s, but because I'm curious to see how music will sound differently. After some intense searching, I find the Eddie Current Super 7 tempting at its price, and will probably get one soon. I don't expect the EC Super 7 to be superior than Invicta's integrated amp in every aspect or for every genre of music. Rather, I expect the Super 7 to be a nice complement to the integrated amp.
A couple of questions:
1) While the Invicta has both RCA unbalance output and XLR balanced output, the EC Super 7 only has a RCA unbalance input. Should I connect them with a RCA to RCA cable, or a XLR to RCA cable (or a XLR to XLR cable with a XLR to RCA adapter)? Will there be an audible difference (given that I will use a short cable in either case) ?
2) Any suggestions on the choices of RCA cable and/or XLR cable?
3) When using the Invicta with a dedicated amp, should I adjust the volume control on the Invicta or that on the dedicated amp to adjust the volume?
4) I found background noise in most old recordings. Is there anything we can do to reduce background noise that is in the records?
5) Dose anyone have experience changing the fuse(s) in the Invicta to change its voltage setting? According to Mark of the Resonessence Labs, the voltage setting can be easily changed by the user by changing the fuse in the fuse box. He set the Invicta for me for use under 115v in U.S., and also sent me a pair of additional fuses for use under 220v because I told him I might spent a few months abroad next year. And I just want to double check with you guys.
Edited by econparanoia - 12/28/12 at 1:45pm