I just had to mention what a difference the Stratos Extreme makes over the Stratos with cap upgrade only (at least with the Lorelei's).
This isn't meant as a full review and I am not an audiophile. I have no technical/electronic/scientific background. I am not a musician, professional or amateur. I am just an aging hippie who loves music and spends far more time in front of his stereo than in front of his TV.
Years ago I owned a Stratos with cap upgrade. It was way overbuilt, sounded great, and couldn't be touched in it's price class. I finally sold it to try out tubes for a while though.
While I enjoyed some of the tubed stuff I listened to, I also missed what good ss could do. I also missed the simplicity (no biasing, etc.) of solid state.
I recently decided to return to an ss system. There was no question that within my budget, Odyssey was the way to go. Klaus provides exceptional quality and I think among the best value in audio.
I took delivery of my new Lorelei speakers but was still saving up for the amp. Klaus also delivered a loaner Stratos and and loaner preamp. This is unheard of customer service for most of you. For those of us fortunate enough to live local to Klaus Bunge, this is his common business practice. He really takes care of his customers and his reputation in that regard is well deserved.
The Lorelei's sounded great as all Odyssey products do. I saved my money and ordered another Stratos but decided to ask Klaus for his extreme mods if he still did them. I understand they are time consuming and he doesn't advertise his mods as he would not be able to keep up with the orders (I think he will still do them for members of this forum but keep it on the down low

).
I took delivery of the Stratos Extreme a couple of weeks ago. It is still breaking in but the whole point of my post here is that it really made a profound difference. From my limited experience I am used to degrees of "subtlety" when it comes to audio improvements. For what little Klaus charges for the Extreme mods, I expected some slight, subtle, improvement eventually, after the amp broke in.
I was taken aback at the immediate improvements between the Stratos Plus and the Stratos Extreme. I don't know if it has to do with a quieter background or what, but the already good soundstaging of the Lorelei's improved noticeably. The soundstage took on a bigger, more three-dimensional presentation, with the ability to pull a "ventriloquist" act on some recordings.
Bass was already good but articulation and weight improved noticeably.
The amp (and speakers for that matter) are still breaking in but with these kinds of immediate improvements, I just wanted to post a quick note. If you are considering an inexpensive (relatively speaking) upgrade in the near future, the Extreme mods are far more profound than I ever would have imagined. Highly recommended.
P.S. I think the mods add at least ten pounds to the amps weight so have fun moving it around!