Dave, a question Sir---- If the 21196's were inferior to the XPL-909's why would every amp we upgrade get the 21196's. I don't understand the basis for that question. The XPL-909's , which are re-branded RCA-DTS-411's are more than 40 years old and were a transistor made initially for automotive CD ignition systems, where the 21196's are specifically made for audio use and are relatively new on the market.
If it's a matter of trust, please peruse the DIY section and PM every member whose amps I have converted, and ask them if they are satisfied with what was returned to them. I don't do this for a living, I do this because I love doing it and for the reaction of the people who listen to their amps for the first time after conversion, it's very fulfilling to hear their comments and impressions. I enjoy putting smiles on faces and delivering more value than they expect. Go ahead , make a few inquiries, I encourage it, then rephrase that question and I'll be glad to answer it, completely. If you've been burnt in audio deals before, I understand your paranoia, I haven't been and therefore that doesn't come to mind. Make some inquiries, do your homework, then PM me with your concerns.....