Njs, the change in sound is fundamental, sweeping, an improvement in every parameter you wish to judge it, imo. When I first put them in and fired up the system I was expecting a marginal change. The difference was SO radical that in the first few seconds the disconnect between what I expected and heard had me thinking, "There's something wrong!" But after a few more seconds I became aware that my expectations had been dramatically surpassed, and realized that the performance parameters had been improved beyond my expectations. I have been highly motivated to have long listening sessions with this change, and have found no area which I would consider the difference to be worse than the original Opamp.
I am sure there will be some systems where this Opamp change will not be to the liking of the owner. I believe that will be rare since the improvements are to my ear across the board.
Mechans, I'm sure there are dozens to hundreds of variables involved in making such a design as a DAC or amp. A designer, and even a design team, has limited intellectual resources. They make a model of what sounds good, finalize it and sell it. The community has forever and vastly more resources to futz with the unit afterwards. I would not discount the work of designers because of those realities.
One can always determine at what quality level they feel the work of a designer/manufacturer is worth spending the money on. This experience opens my eyes to the fact that if Opamps were not soldered into most components likely a great number of them could be improved similarly. You and I both know there's a whole lot more going on that an $8 switch in a component. I recall buying the upsampler board for the Ah! Njoe Tjoeb 4000 and installing it. However, I believe the Opamp rolling of the EE DAC yields a proportionately larger change in sound. What was really shocking to me was the influence of the Opamps on the performance. That in no way discounts or diminishes the rest of the design. But it certainly does make me wonder if a different component might be a lot better if it had socketed Opamps to experiment!
Kijanki, "Amazing" is certainly a word that comes to mind in thinking about the influence of Opamps. I simply had no clue how sweeping their influence could be.
An aside regarding the tendency of people to dump more expensive upgrades for cheaper ones:
I'm certain people will be effusive in praise for the upgraded Maggie 3.7, the Kingsound King III (and many other marvelous new designs appearing at CES/T.H.E. Show), which I'm sure are lovely improvements over the previous designs. Here is a change which yields a profound difference for under $20. The great joy is that it's cheap, potent and marvelous sounding, imo - one of the most impressive tweaks I have ever experienced. But I'm not saying that it's a means of avoiding other upgrades in the system. It's economical thinking to say, "I'll do the Opamp thing instead of the speaker upgrade..." But that's not the way to build one's best system, nor to obtain the best listening experience. To obtain optimum results I would do efficacious tweaks as well as major upgrades.
I have found that one must pursue changes to every element of the system and thriftiness will ultimately not be paramount in every decision to upgrade if one's goal is building the ultimate system to one's taste. Even the most proportionately economical products rise in price substantially when they are an assault on the best sound attainable. In my experience at some point serious dollars (in the tens of thousands) must be spent to obtain a system that has any chance of being in the realm of SOTA. So, a person can do this tweak and call it quits, but I'm not saying here that it will nullify the need to pursue other changes/upgrades.
