I ran humbucker guitars into a silverface twin for years, but that had separate pre and master volumes, so I would just turn down the pre and up the master to compensate, and it sounded great to my ears. You may need to attenuate the input signal using a compressor or EQ pedal (or just the volume knob on the guitar) if you can't get your DGT to hit softly enough to avoid unwanted distortion. I know my old twin could get a little "farty" in the lows if I hit the front end too hard.