I know that an external pre is usual treatment for a ribbon, but I'm wondering if one could record a ribbon without a boosting pre if amp volume was high.
Can you clarify?
If you have an interface with XLR input and gain knob, you already have a preamp.
Ribbon mics usually like a lot of gain, though, so often the budget interface built-in preamps aren't up to the job.
They'll still work just fine, but if your low quality, or low gain, preamp hisses like hell at 11, then it's going to hiss like hell.
With the exception of the Coles 4038, (-65dB/V/Pa) most modern ribbons have a sensitivity as high as most dynamics and some, Royer R2 e.g. a good deal higher at around -55dB/V/Pa. The snag is, ribbons are normally deployed at twice or more the distance from the sound source, to go in closer defeats much of the object of using a ribbon and in any case, most ribbons have a very pronounced proximity effect.
The result being that you will need at least another 6dB of gain in the pre amp and that with no increase in noise. There are exceptions of course, some folks like ribbons on gitamp cabs where pre amp noise is largely irrelevant.