[I.Greyhound Fan]

I just had the op amps upgraded to the Burr Brown OPA627ap's in my one year old Ultra DAC by Frank this AM.

After listening for 1 hour my initial impressions are as follows: the pro's are a little more detail, more prominent bass, more pristine treble, and less grain.   Cymbals seem to be more prominent and forward. The cons are a slightly more over all forward and aggressive presentation ( I prefer a laid back airy sound) and possibly a slightly smaller sound stage and air.  I'm not sure if the bass is as refined or tight.  I have to do more listening to decide.  I actually found this more forward presentation when I modified my Music Hall 25.2 CDP by replacing the stock op amps to the same Burr Brown 627 op amps.

I'll post an update after a few more days of lisitening.

I was wondering if any one else has this upgrade and what their impressions are.

By the way, I did get to hear Franks new Hybrid preamp and DAC.  I'm thinking about selling my Ultra preamp and DAC so that I can buy the new versions. So if any one is interested in a 1yr old Ultra preamp and  DAC, let me know.

[Art_Chicago]

  I'm thinking about selling by Ultra preamp and DAC to that I can buy the new versions. so if any one is interested in a 1yr old Ultra preamp and  DAC, let me know.

I am sure you will find the buyers, but it is a matter of price. There are a couple of AVA DAC's (one Ultra) on the Trading post and a few preamps on A'gon. All of them are a bit overpriced, IMHO.

[I.Greyhound Fan]

Well I've done some more listening this evening, about 2hours and the upgrade was worth the money.  Again, I think the presentation is more forward, but there is definitely a little more detail and resolution at the expense of just a little air but not much.  I also think that bass has a touch more slam.  Over all it sounds better tonight.  I'm not sure if the op amps needed a little break in or that I'm just getting used to the sound.

[martyo]

Hey Grey. Here is what I posted last March:

I received and installed the chips in my Ultra DAC yesterday. There is certainly more transparency and detail and a more focused sound stage. Every upgrade Frank does seems to extend the frequency extremes, and here too. Probably the increased detail, but the low end is better again too.
Nice Frank

And then a couple weeks later I posted:

That was my initial post. Had my listening buddy over a few days later but didn't tell him about the chips. Right off the bat he commented on the bass and the soundstage. He then made the point of the soundstage improving left to right, but even more front to back.  (less noise) Maybe the very noticeable increase in bass definition is more apparent with the tubed units 

I was going to return to the originals at some point but that was last March and I still haven't.

Here is a link to the original thread: http://www.audiocircle.com/index.php?topic=65476.0

Happy listening