Removing the feedback opens up the sound-stage tremendously and brings a warmth that is well known with the ST70. There is a sharp (very narrow) spike at 14 kHz if you look with test equipment but as far as I remember it was never reported as being heard. I noticed no distortion or degradation through a pair of vertically reconfigured Quad electrostatic speakers, Audio Research tube preamp, Oracle Delphi turntable, ET-1 tonearm, and Koetzu Onyx MC cartridge. I do not know if this modification works with other tube amps but I do know that removing the feedback cap in the ST35 sounded terrible and made a lot of weird noise.
