I would like to start off by thanking Charles from SS-Audio for the sample for this review.
First impressions, amazing!
I am already using a Burson V5i in my Little Dot I+ and in my Xduoo XD-05 and the improvement was more than noticeable. With that in mind, I was expecting a lot from the big brother and it did not disappoint.
The first thing that I noticed was that the overall clarity and separation was significantly better. The left and right audio channels were much more distinct and the accuracy of the music was very vibrant and crisp.
While comparing the tracks listened to before and after, the mid range percussion stood out much better and I could distinguish beats and sounds that I didn't notice before. It seemed like un-muting another layer in the music to me. During female vocals I could actually hear the singer breath in between lines and was amazed by the new found details.
The bass did not seem to change much. It was very strong and pronounced both before and after.
The mids improved by far the most. They became much stronger and cleaner. It was more than like just boosting the mids on an EQ. It was hard to believe that I was listening to the same file because of how much more clarity I was now hearing. I was very impressed with the amount of detail that was now present.
The highs were also greatly improved, nicely bright with a good amount of detail as well. Some songs did become a tad bit overly bright, but generally not too fatiguing overall. That would be my only concern, but the benefits easily out weigh the concerns.
What I used for this review:
Custom PC > foobar2000 > Asus Xonar Essence STX > Beyerdynamic DT880 (600Ω)
Overall thoughts:
If you can find the room for the large size and have the money for the moderate price, these are a solidly good investment. By far the best improvement that I've heard from an OP AMP and I've at least tried a handful. Although not cheap, they are a bargain for what you get and the sound is impressive.