I thought I would post this in case anyone else was considering modifying their 25.2 as I found little to no info on the net when I was looking. I don’t usually modify components for a couple of reasons including resale and the possibility of bad results. I did, however, decide to modify my Music Hall DAC 25.2 because I was very curios of the Burson audio discrete opamp modules and this isn’t a Mark Levinson, you can’t lose too much money on it. Also, when you inspect the unit you will find that everything is labelled; values and stages included. It is almost like the designer expects you to mod the DAC, and is trying to make it easier for you.

I contacted partsconnexion and they said they used the burson opamps in the DAC 25.2 as part of their level 3 mod package with extremely good results. I decided to make few other modifications to the output stage to take advantage of the cleaned up signal; I replaced the output resistors with caddocks and replaced the generic yellow caps in the output stage with some nice mundorfs. I stayed to the tried, tested and easy mods on the output stage only. Nothing too risky or hard.
The opamps in the 25.2 are socketed, so when I got my package in the mail I popped out the opamps and simply inserted the bursons to give it a whirl. The results were incredible right off the bat. Tone, soundstage, resolution, range and all with this incredible fluidity of sound. Things of course have improved more now that I have completed my mod with the caps and resistors, but the big daddy is the opamps. I would have to say that it is now amongst the best I have heard in digital, and I have heard, and even owned, a lot of them. I should mention that the 3 opamps I removed cost about $2 each and each of the 3 burson modules was $63 US on sale.
I still have to change the power coupling caps to double their size as per the instructions that came with the opamps. I missed that one when I made my order and will have to wait until I build up a list of things to order. This was a pretty simple upgrade with very large rewards, if anyone is interested I can pass on more detail and post a pic of the finished product.

I’ll post some more about it later when I have a bit of time, but you can take a look at the pic for an idea. Note the burson clock, a must have upgrade for any digital system. This was the big surprise for me as I was not expecting the results to be so dramatic. I guess it kind of makes sense though when you think how much money we have spent to make sure the speed on our vynil rigs is accurate, and we are surprised that our digital sounds harsh and grainy with a 2cent clock?

Original Post: http://www.canuckaudiomart.com/forum/viewtopic.php?t=12887