Passive preamp and biamping

Why is having to turn it up to 1:00 a problem?

Anyway, biamping will not change things too much but will actually lower the volume. Probably not enough to notice though. The gain of the amps would have to be the same to keep things balanced. So in that respect, the volume would stay the same. However, the input impedance of the second amp will be in parallel with the first. This will put a bigger load on the preamp and lower the volume. But probably not by much. Unless you use an active crossover that will act as a buffer and might actually increase the volume depending on the gain of the crossover.

Just to emphasis a valid point already made twice, with a passive preamp you're just throwing some of the signal away (letting it go to ground without going through the power amp) and throwing less of it away, or even none of it, can't possibly be a bad thing. In a series stepped attenuator, a high setting puts the "hot" signal through less solder joints than a lower setting, but does the opposite with the part of the signal that's getting thrown away. So maybe a higher setting is better, though I don't know enough to say. Moral: don't use a series stepped attenuator in a passive: it saves money but hurts transparency and detail badly, in comparison with a ladder type stepped attenuator or a shunt type. IMHO.

i agree with the points already made.....one additional issue is the length of the interconnects to and from your passive preamp. a passive attenuator is especially sensitive to anything over 1 meter between it and the amps. there will be considerable loss of body and bass performance if not keeping this short.

another consideration is the gain of your amp(s). you might check to see if there is more than 1 gain setting. i have a Rowland 112 that can be internally adjusted to either 26db or 32db of gain.

i love the passive approach....but it does require careful setup for best performance.

Playing through a passive at a very high setting means the output impedence of the passive is very high - therefore heightening the downsides of a passive. If you really love the passive, then I would look at a power amp with high gain and high input impedence, rather than doubling your investment in the existing amps. Power amps vary considerably in both regards. Tube amps can be best with passives as many have both high gain and high input impedence.

Granting the wisdom of Mikelavigne and Redkiwi on the desirability of (1) keeping interconnects from a passive short, and (2) having high input impedance in the power amp, one experience of mine would indicate that these principles should be seen as rules of thumb, not as written in stone. I used a 10K ohm passive with 8' interconnects into Pass Aleph 3's used as monoblocks, with inputs and outputs both paralleled. That would make the power amp input impedance 11.5K ohms, if I recall correctly that the Aleph 3 lists its input impedance at 23K ohms. Its gain is only 20 decibels. And I didn't notice lack of body or thin bass, though I was using the Aleph 3's with Quad ESL 63's, no deep bass at the best of times. When I told Nelson Pass that his Aleph 3's worked with a passive preamp, he said my experience had been reported by other Aleph 3 users. Do we all have tin ears? I don't rule out that possibility, at least for myself, and I'd certainly go by the rules of thumb if I had a choice. I wouldn't choose gear that violated those rules. But if I had it on hand anyway, I wouldn't hesitate to give it a try.