The Jeff 625 stereo amp is one he'll of the best amp that Jeff ever produced. If it can get any better, it can only be their monoblock 925 released to the market here in Singapore soon. To start, with, it's a notch better than my Jeff 8ti. What goodness the 8ti can do, the 625 did it significantly better and did things that was unheard of on the 8ti. 3D soundstage, with vocals so liquid velvety and yet nor discolored warm character that u expect from tube. I m trying to say, the vocal is neutral. I find that most ss amps could give the muscle to power speakers, fastness and slam but not easeness of listening to vocals which tube amps do it better. The 625 has full control over the speaker squeezing out every bit of juice from my sonus faber amati homage anniversario. It sounded so musical playing from rock pieces like Bad Company and CCR with their electric guitars growling and the voices and the percussion all can be heard with high resolution. It's a quiet amp, THD of 0.005% at 1kHZ as compared to 0.1% over the 8ti. Perhaps that is why, the voices from the 8ti sounded a little warm and slow with slight hiss at the end of each vocal note especially on female voice. I believe the older design was meant to bridge the gap between ss and tube amp in its presentation. The 625 has the best of ss and tube amps. Simple as that. Marvelous for the fact that Jeff can reduce the size significantly from it's legendary class AB amps of the past like the model 7 and 8. The matching between the Jeff Critetion Preanp and the 625 is made un heaven. When switching to fulll battery mode (without charging from AC source), it improves subtileties which render music presentation from excellent to perfect. Playing music was never so lively in my listening room. Before I purchased the 625, I auditioned the newly release Goldmund Telos 250 and it sounded great with the Jeff Critetion. Very fast and excellent control over the speakers. High rise time and high slew rate?? I find that while the speed and control matches the Jeff or slightly better, the detail lnuances of a music passage especially the decay effect of piano notes or the strike of a drum lacks the 625. Jeff 625 is truly great. Bravo Mr Jeff.