The only remaining question some purists may have about this is: Do its relay contacts affect the sound? I could not detect any sonic degradation whatsoever when I inserted the ABX between my Revox A-77 and the power amp it was feeding (sans preamp), but then it is impossible to make such a substitution instantaneously, for a direct comparison. So, I treated the ABX like a signal processor, and connected it into the Tape Monitor loop of my Berning TF-10 preamp. This allowed me to go either straight through the preamp, or insert the ABX's switches into the signal path. I could not hear the slightest difference, and I doubt that anyone else could under legitimate double-blind comparisons. Of course, it could be argued that the Tape-switch contacts in the Berning were obscuring any differences due to the switches in the ABX, to which I reply, What system doesn't have any switching in the signal circuits? If yours allows a choice between phono and any other input source, it has a switch in it. And now that I've called attention to it, just watch for the crop of "dedicated" (ie, single-input) preamps that will start to appear.

All cavils aside though, I feel that this is the first really significant contribution to the audio field in years—not because it is a "breakthrough" in sound reproduction, but because it makes possible listening comparisons that the most hardheaded skeptics of subjective testing are going to have to take seriously.

In 1981 (Stereophile, Vol.4 No.9), I observed that "subjective observations have no scientific respectability unless backed up by numbers." With the ABX comparator, we now have a way of gleaning those numbers.

I do not, however, feel that the present ABX Comparator is a "finished product." It leaves too many loose ends. The Logic and Display Module (the "heart" of the unit) plus the remote-control switcher are available without the $100 RM-1 relay box for $395, which allows one to put together any kind of relay switchers one wants—with input/output switching and heavy-duty relays for loudspeaker switching. But I fell that ABX is only doing half their job by not making such proper switchers available themselves, at least as extra-cost options.

For now, though, I can only hope ABX sells a lot of these, for the more people (and audio groups) who own them, the more overwhelming will be the evidence that trained listeners CAN hear things that Julian Hirsch can't measure. But God, how I'd like to put some "underground" reporters' claims to the test with this.