Almost all preamps and amps have a tiny bit of DC offset. Maybe 5 mV or less for a pre, 60mV or less for an amp.
A preamp with 5 mV of DC at its output is rare. Our preamps have direct-coupled outputs and they have less DC Offset than that!
With **any** preamp, tube or solid state, it is advisable to turn on the preamp first and let it stabilize before turning on the amplifier. All preamps can exhibit turn-on thumps unless the manufacturer installed a mute relay.
Krell started the 'DC at the output' rumor with tube preamps; it was entirely false. Tube preamps usually have less DC at their outputs than solid state! This is mostly due to the output coupling capacitors used; tube preamps usually use a film cap at their output as stated earlier; solid state preamps often use electrolytic capacitors which are far more prone to leakage and failure.