Yeah the amplifier can only accept one input at a time as I switch them; I’m just not sure if having a tube preamplifier in the chain (even if its connection to the amp is switched off) is safe. I use TT2 in DAC mode only, and use my amp’s volume control.I don’t do this, and don’t use an external amplifier, but I do use both rear outputs to drive speakers and a sub. Remember that the XLRs and RCAs are both always active, so as long as the amplifier can only accept one input at a time and is designed to switch between the two inputs, it *should* be fine as far as I can tell. I would probably use low gain in dac mode, since you will probably want to use TT2 for volume control, unless your amp has a volume control, then amp mode would be better.
Will TT2 connection still be active if the tube preamp is turned on, and AMP connection is not active?