After using Sonosax pres for years, I now use the preamps in my MixPre exclusively on location for 4 mics or less, adding the Sonosax back in if I need six mics - the last time I used it was about 9 months ago on a 33-piece chamber orchestra. My Sonosax is 30-odd years old now - I first bought it on the recommendation of Dave royer when I bought two of the first R-121 ribbon mics made. He told me that was the preamp they used in their testing lab at Royer. The sonosax pres are the slightest bit more transparent than the SD, but only noticeable with very careful listening.
