Regarding the SIT3, an important point to note is that it has an extremely low gain (for a power amp) of only 11.5 db. Power amp gains are typically in the mid to high 20s. Most Pass Labs amps have gains of 26 db for example, although most of the other First Watt amps have gains in the teens.
Consequently it can be calculated that the SIT3 will require a single-ended input (it does not provide a balanced input) of about 3.2 volts to be driven to its maximum power capability of 18 watts into 8 ohms. If a digital source having a volume control is used without an active preamp it will almost certainly not be able to provide that much voltage, even with the volume control at max. And in many and perhaps most cases vinyl or other analog sources won't be able to do so even when used in conjunction with an active preamp.
I considered purchasing a SIT3 recently, but that factor made it a non-starter for my system. I went with a Pass Labs XA25 instead, which I have been delighted with.
Best regards,
-- Al
Consequently it can be calculated that the SIT3 will require a single-ended input (it does not provide a balanced input) of about 3.2 volts to be driven to its maximum power capability of 18 watts into 8 ohms. If a digital source having a volume control is used without an active preamp it will almost certainly not be able to provide that much voltage, even with the volume control at max. And in many and perhaps most cases vinyl or other analog sources won't be able to do so even when used in conjunction with an active preamp.
I considered purchasing a SIT3 recently, but that factor made it a non-starter for my system. I went with a Pass Labs XA25 instead, which I have been delighted with.
Best regards,
-- Al