DAC Opamp Upgrade

I'm considering upgrading the Opamps in my MusicHall 25.3 DAC. Burson Media from Australia seems to make a good fit. Anyone has any experience doing this and what was the outcome ? I have replaced the original tube with a 1965 Mullard 6922 and I feel that was an improvement. 

If you are doing 6922's, the best tube out there is a Siemens CCA grey plate.  Telefunken grey plate is not bad either.  I used the Siemens in my TubeDAC that I used to make.  I tried all of the British tubes, found them to be too slow.

Steve N.

Empirical Audio

It entirely depends on what you want to accomplish.  The Burson op amps are FET based devices and have that rich FET like sound.  I auditioned the Burson V5 op amps.  While they are very resolving, they just did not sing in my system.  I found myself losing interest in the music halfway into a song.  It could have been because I had not upgraded the power supply at that time, but it seemed that other op amps just had more emotional engagement with me.  Other people have had more positive experience.  I suppose it is entirely personal taste.

The Sparkos discrete op amps are incredibly clean bipolar devices and they really sing.  However, they are biased very high into Class A and the sound can become too rich/warm/slow if too many Class A stages are in the audio chain.  You already have a tube output device in this DAC.  If you do try Sparkos, you might end up needing to upgrade the main power supply capacitor (put larger power supply capacitors in).  They do require a lot of current.  These are one of my favorite op amps and I love them.  They do have a large footprint, so you might have to get some additional 8-pin sockets to stack up high enough to clear those capacitors next to the op amps.

I have tried a ton of different op amps.  The only other two op amps that I think are good for audio are AD797 (bipolar) and OPA827 (FET).  These are mono op amps and can be mounted on a Browndog dual-adapter.  You can actually buy them from Browndog already mounted, so you just need to pop them into the sockets.  The OPA827 is a very nice op amp, slightly warm due to the FET inputs but it definitely has a nice magic to it.  Don't buy the more expensive OPA627, as the slew rate is too high and doesn't have enough bass (everything gets a little bright/shouty).  The AD797 is very neutral and is higher resolution than the OPA827.  Definitely a good op amp.  Not as clean sounding as Sparkos.

I really want to try the Sonic Imagery 994Enh.  This is another fully discrete Class A op amp, but it doesn't have as much Class A "richness" as the Sparkos.  It's more neutral/fast.  It is a HUGE op amp and may not fit in all circuit boards.

Dexa is an extremely clean sounding discrete bipolar op amp.  Almost like a Class D amp.  Lacked emotional engagement, but good if you want an extremely clean stage.

In my testing, discrete op amps (such as Sparkos) always beat the monolithic op amps in how clean the sound was.  While the monolithic op amps sounded good, they just had a dirty/messy character when compared to Sparkos/Dexa.

Probably any of these will be an upgrade to what is stock in the Music Hall DAC.


Thank you very much for your all your info. In my continued research I had also come across Sparko's and they certainly got my attention. Upon reading about your impression that too much Class A along the line might get things too warm I got a little concerned. I have a Cary SLP 98 preamp and 2 TAD 1000's ( Class A up to 10 watts then AB ) using a quad of KT 88's each. My speakers are Vienna Acoustic Strauss. Having said and based on my current sound I feel I have plenty of warmth and tubey action going on. I  have emailed with Burson and Sparko's and I can try either product 30 days for a full refund so thats great. I also ordered 2 XLR to RCA adapters that will be arriving today so I can play some with the outputs. The obvious question arises though...when do you stop dumping money into what I see as a low to mid hifi component ?. Here on A-gon there is a Cary DAC 100t going for $875 which to me seems like a good deal. However who doesn't love a good bout of tinkertitis. Which DAC(s) did you use for your opamp rolling if I may ask ?

Thanks again.
I am using an Emotiva XDA-2 DAC, but at this point I have completely rebuilt almost everything in the DAC, except for resistors.  All electrolytic capacitors have been upgraded.  Voltage regulators have been changed to Sparkos discrete regulators.  Film-on-foil negative feedback caps.  etc.etc.  It is pretty much a $1500+ DAC now.
Hi zipiv,

I've had a positive experience with Burson upgrades. I had an old Rotel RCD-991 which I couldn't listen to, (I have 7 spinners). After doing some research about 3 or 4 year ago I took the player to CVE (Melbourne, Aust.)who do the Burson mods/upgrades. They replaced the Op-Amps/Clock/Crystal. The improvement was staggering. I can now listen and enjoy the Rotel. All up it cost me $350, which I considered a bargain.
I will be trying this for sure. Traveling at the moment but will give it a go when I get home and report back with my findings.

I just replaced the Dexa output buffer op amps with some remaining Sparkos I still have. So now I have all Sparkos in both DAC and preamp. (3 stages in DAC and 2 stages in preamp). The sound is now the best I have heard it. I think it may need just a little bit more snap, but 5 stages of Sparkos definitely sounds great!

One thing I would advise, if you had the ability :


I have found that soldering a 47uf Nichicon Muse (50V) plus a 0.1uf MKP directly to the +/- power pins of the op amp significantly improves the sound quality. It gives more punch, smoother response, and removes the frizzy highs. It just sounds better.

Hey Auxinput 

Pardon my tardiness. I have and not to my surprise decided to keep the OpAmps. I feel I gained so much more soundstage up and to both sides. I have also spent a couple of bucks on treating my room. Curtains and DIY panels. I would almost go as far as saying as I feel I have a new system. Thanks for your input.