Passive preamp and biamping

I don't have a lot to add to the prior posts on the terms that they addressed. I would just ask you if you love your front end?

I always closely examine the analog section of any CDP or DAC I'm considering. BTW, I have a CODA FET 04r (passive/buffered). It's true that one can only tell so much about a piece by determining the types of circuits used in the analog section and that the listening test is the bottom line. The thing is my ears have confirmed my theories on this point: a solid analog section on the front end is crucial in each and every system, but it may be even more important when a passive pre' is introduced to the equation. I have a balanced Theta DS Pro Gen Va (I just got the 24/96 upgrade--it dropped my jaw to the floor. I positively love it). Part of the reason I picked the Theta is because it has plenty of "umph," & the combo is, IMHO, truly outstanding.

So, I say again, how much do you love your front end? Is it time for an upgrade? If not, as others have already said, don't give that 1 o'clock thing a second thought. If it is as you narrow your choices give careful consideration to the analog section... it's what gets amplified throughout the rest of the system.

I hope I've been of some help. Happy listening.

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.

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.

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.

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.

So long as you can easily attain the listening level that you are seeking and it is clean, don't worry about where the volume control is set. If you had to turn an active preamp up to that level all the time, i might be slightly concerned. With a passive, it is not abnormal.

As to bi-amping with a passive, that could get REAL interesting in terms of impedances, drive levels, etc... Sean
>

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.