Hi Dave, the externally cased volume control, frequently referred to as a passive preamp, will be fine with the mod.

It's the integrated amps with a maximum input voltage of 2Vrms on the CD input that could experience overload problems. It works fine on my integrated amp, but it might not on many others. So at this moment in time I am bordering on the cautious side until anyone else flouts my suggestions and proves me wrong .