Tube Preamp OT Question.

[Jatchley]

So if a preamp has both an unbalanced 1/4” output jack and a balanced XLR Output jack... how does the OT not get burned up if you only use the 1/4in Unbalanced output?

[PRR]

There are many ways.

Specific model? Circuit?

Preamps mostly do not have OTs.

If you are worried about voltage-spikes on an unloaded OT, add a dummy load.

[AmberB]

The OT on the preamp is just an impedance matching transformer.  It converts the high impedance of the tube circuit to a low impedance balanced output for the XLR line out, which is usually a 600 ohm balanced line out.  You're not going to hurt that by using the preamp without the low impedance line connected.