I would like to thank Carlos from Burson Audio for making this review possible. I had been thinking about trying out some of the Burson opamps and saw on these pages that Burson would send opamp samples for an honest review and good to his word Carlos sent me 2 V5i-d opamps to try and review.
At the beginning of 2021, I bought a lightly used FAT DAC(FAT being a nickname for Firestone Audio Tobby) a DAC made in Taiwan with an excellent rep. and sound. Originally it came with 7 OPA2604 opamps. The unit as I received it, had LM4562NA installed though I received the original OPA2604s as well. As many know, the LM4562 is nicely detailed, has great specs and IMHO has a cold, unmusical sound. After a short time, I had enough and wanted to atleast hear what the creator of this unit heard and replaced all 7 slots (a dual mono machine with 4 slots for I/V, 2 for LPF and 1 for SE/output for those running unbalanced like myself)with the OPA2604 and for me it was a revelation it was musical, enjoyable and lightly detailed, I appreciated the sound. I enjoyed it for a while and now that I had successfully swapped opamps wanted to take the sound possibilities further.
Initially not wanting to spend too much, but willing to spend some money (7 opamp slots could get rather costly) I contemplated buying MUSES01. After a lot of reading of reviews I opted to start with 5 Muses 8920, 4 for the I/V slots and one for the output. Again a revelation...I now had a more detailed, musical and very nice sounding DAC one I could possibly live with for awhile.
I contemplated putting a couple of V5i in the LPF section(which had the original OPA 2604 there) after reading some reviews. Sure enough at this time I saw the post offering samples of the V5i which Carlos sent to me. I really looked forward to receiving them.
After receiving and placing the V5i's in the LPF section. The DAC sounded awful, truly awful. I was aware of the 100-150 hour burn in required and left them in hoping the sound would improve.. The vocals especially were very fuzzy and distorted sounding unlistenable, the V5i were not getting hot so I left them in hoping they would burn in...after 2 days I removed them, enough.
After some reflection I put the OPA2604 back into the LPF section and removed the MUSES8920 from the output buffer and in its place put a single V5i. Not an initial revelation but it worked, gone were the fuzzy distorted vocals and it was replaced by the sound of music and an opamp that still needed a few days to burn in. It took the better part of 5 more days of the unit playing music 24/7 until I could judge the sound.
After about 6 days total burn in time (150 hours) I was really pleased and surprised by the sound. In fact, I suspect the 1 V5i I used for the output was always the better choice then the LPF section. The DAC sounded great with the Muses 8920 in the output but with the V5i it became more, much more. I have read in some reviews the V5i it accentuates mids and it did but not to much but the guitars were more present, Jerry Garcia sounded like I never heard him before on my system, musically present guitar lines soaring as if Jerry was in the room. (yes a bit of live well recorded Good old Grateful Dead for this review) the highs were fully there like before but they had a more clear dimensional sound..I love the sound of cymbals and the pings, splashes and crashes sounded so natural and the decay as if they were live. I have read that the V5i has a noticeable cut off of the highs I didn’t find this. The highs are not greatly extended but they are fully there and very musically present with a nice clear sparkle the high hats and ride cymbal and bells are so nicely rendered. Besides losing the fuzziness the vocals had a very clear very real sound and tone. Lets not forget the bass a growling extended rumble with excellent differentiation of individual notes played on a system and speakers where one can appreciate such nuance just excellent. Dimensionality is a good word to describe what I heard everything sounded as if it was a rounder sound versus a flatter sound...hard to put into words but if you have tried the V5i you likely know what I mean. The surprise it was one v5i at the end of the output chain and it made an incredibly tangible change in the sound.
I listened to a lot of music throughout my time contemplating this review not just the GOGD, the ambient nature of Enya on her first (and I think best CD)was on full musical display a truly ambient experience with the music having a liquidity to it, just beautiful. Loving prog rock I listened to the new live Kansas as a high res recording and again wow the clarity, I closed my eyes and saw Kansas in the room though not as loud as seeing them live but with an incredible arrangement of instrumentation and soundstage. Sometimes I deliberately was listening to the changes and effects of the V5i and at other times I just was moved by the music my DAC was making….Not that I hadn’t heard the music at a very high level, but like I said before it sounded like more of it and I am still getting off on it..
I hope to settle in and enjoy the FAT DAC as it is now, it has a beautiful sound and I want to listen to the music not just the machine and its changes. I have no doubt that I will at some point explore further , perhaps with the V6’s if I can fit them in the cabinet, the sparkos and yes the MUSES01 and 02. But for now I am enjoying the shear musicality of the FAT DAC with some well placed opamp enhancements…and the very surprising upgrade the V5i has proven to be.
On a side note..I also burned in the 2nd V5i in the Output buffer for 6 days and then tried to place the 2 v5i’s in the LPF section again….Still a no go, just as fuzzy and distorted as before so it became clear that they don’t belong there..but as I hope I have conveyed in this review a stand out performance in the output buffer.
At the beginning of 2021, I bought a lightly used FAT DAC(FAT being a nickname for Firestone Audio Tobby) a DAC made in Taiwan with an excellent rep. and sound. Originally it came with 7 OPA2604 opamps. The unit as I received it, had LM4562NA installed though I received the original OPA2604s as well. As many know, the LM4562 is nicely detailed, has great specs and IMHO has a cold, unmusical sound. After a short time, I had enough and wanted to atleast hear what the creator of this unit heard and replaced all 7 slots (a dual mono machine with 4 slots for I/V, 2 for LPF and 1 for SE/output for those running unbalanced like myself)with the OPA2604 and for me it was a revelation it was musical, enjoyable and lightly detailed, I appreciated the sound. I enjoyed it for a while and now that I had successfully swapped opamps wanted to take the sound possibilities further.
Initially not wanting to spend too much, but willing to spend some money (7 opamp slots could get rather costly) I contemplated buying MUSES01. After a lot of reading of reviews I opted to start with 5 Muses 8920, 4 for the I/V slots and one for the output. Again a revelation...I now had a more detailed, musical and very nice sounding DAC one I could possibly live with for awhile.
I contemplated putting a couple of V5i in the LPF section(which had the original OPA 2604 there) after reading some reviews. Sure enough at this time I saw the post offering samples of the V5i which Carlos sent to me. I really looked forward to receiving them.
After receiving and placing the V5i's in the LPF section. The DAC sounded awful, truly awful. I was aware of the 100-150 hour burn in required and left them in hoping the sound would improve.. The vocals especially were very fuzzy and distorted sounding unlistenable, the V5i were not getting hot so I left them in hoping they would burn in...after 2 days I removed them, enough.
After some reflection I put the OPA2604 back into the LPF section and removed the MUSES8920 from the output buffer and in its place put a single V5i. Not an initial revelation but it worked, gone were the fuzzy distorted vocals and it was replaced by the sound of music and an opamp that still needed a few days to burn in. It took the better part of 5 more days of the unit playing music 24/7 until I could judge the sound.
After about 6 days total burn in time (150 hours) I was really pleased and surprised by the sound. In fact, I suspect the 1 V5i I used for the output was always the better choice then the LPF section. The DAC sounded great with the Muses 8920 in the output but with the V5i it became more, much more. I have read in some reviews the V5i it accentuates mids and it did but not to much but the guitars were more present, Jerry Garcia sounded like I never heard him before on my system, musically present guitar lines soaring as if Jerry was in the room. (yes a bit of live well recorded Good old Grateful Dead for this review) the highs were fully there like before but they had a more clear dimensional sound..I love the sound of cymbals and the pings, splashes and crashes sounded so natural and the decay as if they were live. I have read that the V5i has a noticeable cut off of the highs I didn’t find this. The highs are not greatly extended but they are fully there and very musically present with a nice clear sparkle the high hats and ride cymbal and bells are so nicely rendered. Besides losing the fuzziness the vocals had a very clear very real sound and tone. Lets not forget the bass a growling extended rumble with excellent differentiation of individual notes played on a system and speakers where one can appreciate such nuance just excellent. Dimensionality is a good word to describe what I heard everything sounded as if it was a rounder sound versus a flatter sound...hard to put into words but if you have tried the V5i you likely know what I mean. The surprise it was one v5i at the end of the output chain and it made an incredibly tangible change in the sound.
I listened to a lot of music throughout my time contemplating this review not just the GOGD, the ambient nature of Enya on her first (and I think best CD)was on full musical display a truly ambient experience with the music having a liquidity to it, just beautiful. Loving prog rock I listened to the new live Kansas as a high res recording and again wow the clarity, I closed my eyes and saw Kansas in the room though not as loud as seeing them live but with an incredible arrangement of instrumentation and soundstage. Sometimes I deliberately was listening to the changes and effects of the V5i and at other times I just was moved by the music my DAC was making….Not that I hadn’t heard the music at a very high level, but like I said before it sounded like more of it and I am still getting off on it..
I hope to settle in and enjoy the FAT DAC as it is now, it has a beautiful sound and I want to listen to the music not just the machine and its changes. I have no doubt that I will at some point explore further , perhaps with the V6’s if I can fit them in the cabinet, the sparkos and yes the MUSES01 and 02. But for now I am enjoying the shear musicality of the FAT DAC with some well placed opamp enhancements…and the very surprising upgrade the V5i has proven to be.
On a side note..I also burned in the 2nd V5i in the Output buffer for 6 days and then tried to place the 2 v5i’s in the LPF section again….Still a no go, just as fuzzy and distorted as before so it became clear that they don’t belong there..but as I hope I have conveyed in this review a stand out performance in the output buffer.