been ten days since you posted, did you have a chance to compare and contrast TU-8900 to your Sunvalley - SV-S1645D and do you care to share your findings and current preferences with us? Inquiring minds want to know, Thx
Thanks for asking. I've been comparing and contrasting but it's still early days. Both are definitely keepers, that is clear.
I love the fact that the TU-8900 is at least two, if not four, amplifiers in one -- 300B with or without NFB, 2A3 the same. It's still breaking in but even fresh off the workbench it is a lovely sounding amplifier no matter what mode it's being operated in. I haven't developed a preference for 300B over 2A3 so far. I've got a couple of pair of NOS 2A3 to play with as well as the LinLai/Cossor 2A3 Western Electric-construction style tubes.
The Sunvalley SV-S1645D is something truly special and it might end up being my daily driver -- which is making it difficult to get the break-in hours on the Ele-kit. The 45 tube sound is really seductive and between my 107dB/w/m horns and two subwoofer stacks I'm finding there is no lack of volume when I want to turn it up (true for either amp).
But what is uncanny about the Sunvalley is how even at very low levels it has a clarity and vibrancy that most systems in my experience just can't duplicate. It is a late-night, intimate mood machine.
Steve Z