ARC LS 25 Mk 11 Bypass

This whole discussion hints at a feature I have wanted from tube preamp manufacturers out there: implement HT pass-through WITHOUT the need for the tube unit to be powered on. Why is this so difficult? If all we want is to route a pair of inputs directly to the outputs, can't this be done through the use of one toggle switch? And in the other position, which perhaps is an open circuit, the preamp works in a normal way when powered on.

As for all the back-and-forth posts above, no matter how the Ref3 may differ from the LS25 sonically in "normal" mode, I gotta believe that they would NOT differ in HT pass-through if none of their active stages are in line for this mode. I suspect ARC's implementation (switches, wires and connectors) with HT pass-through is consistent from model to model. With that said however, it escapes me how insertion of any component (with its input and output connections and the additional IC) can result in NO kind of signal degradtion vs. the pre/pro's front channel outputs directly to the amp. In a high-resolution system, just that one extra pair of ICs can do far more damage than any inserted "pass-through" component. This may be a miniscule difference, and for the sake of HT usage, who cares, but I suspect there would certainly be a noticable change in dynamic contrasts even with the most linear ICs out there.

"If all we want is to route a pair of inputs directly to the outputs, can't this be done through the use of one toggle switch?"

you could do this yourself with a simple A/B switch and forget about a theater through pass input

you could do this yourself with a simple A/B switch and forget about a theater through pass input

True, but I still want the tube line stage there to make use of my 2-channel analog sources. And I do not want to fuss with disconnecting the IC-pair to the amp everytime I choose the line stage or the pre/pro as a purist might do. All I ask for is this simplistic "toggle function" wrapped in the line stage's implementation. And for days and days or weeks where only movies might be played, the line stage is powered off.

Billbench & Oneobgyn
Yes it does alter the sound, it has to because the signal passes through the tubes, but the Ref 3 is so good that I think it gives it a better sound stage. I have a Meridian G68 for HT.
I had a VAC Standard LE Tube Preamp by the way and it just passes the signal through wiring and not the tubes, it can be off while you are in HT mode.
AND tlg.
The stereo preamp that has HT mode either sets the output volume at a constant and repeatable level all the time or just pass the siganal straight though via wiring. Your HT is controlling the volume as if the stereo preamp was not there and it can also be calabrated correctly.
Also this stops you from having to set the volume on your stereo preamp. If you do not set the volume exactly same way everytime any calabration you have done will not be correct. A HT not calabrated is a waist off time and money.
As with most analog volome controls, because they work with resistance, being off a little can mean alot so you are much better off this HT passthrough.

I just ordered an LS 26 and spoke with Leonard at Audio Research. According to Leonard, the sound will be improved through the HT Pass through of the LS26. I will post a note when i try it myself next month. Happy listening!