Well, admittedly, "bass" is not what Hirsch "tuned" his amp to the R10's for. But I've had this discussion with him, and he's tried to get bass out of R10's, and the best he could do was LS3/5A bass (I.E. it may have been controlled, but it starts trailing off early, I wouldn't call it deep, although it was deeper than it appears on first listen). But he tries to get at least a semblance of full frequency response, and it's just not there.
Also, I don't think this is true -- Hirsch has two R10's, and I don't think he kept the bass-light versions in both cases -- one of the ones he has is definitely a later serial number R10, though I'm not sure if that's the balanced one or the single-ended one. It's the early models that are bass-light.
And unfortunately, I don't think he has the high-voltage switch -- that's just not an option on his amp, AFAIK.