This is my current set up for the review. I use Pioneer DV-300 dvd player as digital source, because it was discovered by lampizator and others that it provides excellent waveform. Even Goldmund discovered that and parked little Pioneer inside bigger box and charged 10x more for it. Off course it has analog outputs, but the sound on this output is boring, bland, like from behind the curtain. External DAC is great improvement. I do have Schiit combo, but that will not be part of the review. First of all, it uses only smd parts with no socket, plus I am not going to open it. I have even better DAC, at least to my ears Cirrus Logic sounds more balanced. Schiit seems to have lifted treble, which may sound pleasing to some, but not good for review.
Besides, Cirrus Logic has one dual opamp on the output, conveniently in gold plated socket. Easy to replace. I have tried half a dozen of good opamps, many years ago, no need to repeat that. It came with 5532, but I tried 2134, 2604 and others. I believe 49720 is there for now. I will be comparing standard 49720 opamp to V6 Classic from Burson Audio.
When it comes to headphone amplifiers and headphones, I have quite a few, but I selected Lehmann audio amp and HE1000 headphones, as this combo provides clean well balanced sound. I believe the DAC should produce cleanest most accurate sound possible, and the headphone amp and headphones should provide pleasing non-fatiguing sound. I like B1 buffer and ACA combo, but ACA is not free of distortion, so I will be using cleaner amp. Other amps I have include Musical Fidelity tube headphone amp, Naim, ACP+, Schiit, and others.
Headphones I like include Sennheiser hd580, hd600 and hd598, HiFiman he400, he500 and he1000. I will be using he1000.
I would like to achieve the cleanest signal possible from the DAC, therefore I require treble to be as clean as possible. I can not stand sharp distorted highs. I do not like woolly mushy soft highs either. I like to have clean sparkly crystal clear highs. Bass lines needs to be deep but not overpowering. Mids easy to follow.
Second aspect of good sound I like is imaging. What I mean by imaging is that my brain does not have to work hard to follow any desired musical instrument or voice. If it is hard to follow separate instruments, music image collapsed and listening fatigue will follow.
I may not be able to explain what exactly I like when it comes to sound, but I know when I hear it.
So next I will be comparing sound of two output stages, one with LME49720 and second with V6 Burson Audio Classic.
I started listening comparison with Jesse Cook cd's. These are very dynamic recordings, plenty of guitars, and drums, not to mention nice triangles, chimes. I listened few best songs over and over, made few notes, then switched to Burson, listened again, and made notes again.
One thing I noted on 'free fall' recordings, songs 3 and 6, triangles were more standing out, easier to follow with Burson than with 49720. In vertigo recording, second song, Burson was clearly a winner, 49720 seemed little boring. Harmonica in third song was more real with Burson, three guitars seemed like in the air, much more enjoyable.
When it comes to stereo separation, both had the same impression. When it comes to dynamics, Burson seemed a little better than 49720. Bass lines were comparable.
When it comes to Bela Fleck, plenty of deep bass lines, especially 'flight of cosmic hippo' type. Perhaps 49720 may be better in bass department, but it may be just an impression because highs are a little less pronounces in 49720 than with Burson.
In separate session I listened to plenty of choral and early renaissance music. I like Hildegard Von Bingen for pure polyphony lines. When it comes to the sound quality, I must say both output stages, either with 49720 or V6 Classic sounded about the same. See, this type of music is happening mostly in the midrange. Not much to distinguish in sound quality. Both sounded great.
I like period instrument recordings, they offer window into that music era. Minstrelsy music group is using flutes, guitars and simple drums to accompany the vocals. Burson V6 Classic was a little more musical sounding then 49720, which was a little sterile. The difference was not big, but noticable and I was always looking forward to put V6 back in to enjoy the music more. Small, but noticeable improvement comes from V6 Classic.
Last listening session was done with bunch of Dire Straits and Mark Knopfler recordings. I like the music, always did, so it was fun. Granted, in some recordings they went overboard with loudness war and pushed it to the clipping and severe compression. I skipped those songs, what a pity. Luckily there is plenty of slow well recorded songs to listen and compare 49720 to V6 Classic.
Songs like 'telegraph road', 'love over gold', and 'private investigation' offer great spectrum of instruments, from acoustic guitar, steel guitar, keybords, synthesizers of all kind, to great drums, with plenty of hi-hats, cymbals and chimes...
I must say that V6 Classic excelled in these high pitched bells and whistles. Although 49720 is clean low distortion opamp, easy to listen to, it is on sterile side in comparison to V6 Classic. Burson is more musical, juicy and fun. Just listen cd 'on every street', song 6 'you and your friend' and you know what I mean. That steel guitar just brings shivers down the spine.
While 49720 can give you 95% of the recording, Burson V6 Classic can give you 98%.