Details for bi-amping

Wow, what a bunch of nonreading and confused writing.

The OP first writes that he wants to use tubed amps on the top and SS amps on the bottom; later he writes that he wants to use indentical amps. Which is it? Tubed and SS or 4 identical amps? I suspect it's the former.

One preamps will do, and in fact the use of 2 preamps will complicate matters substantially. Y-connectors work just finely and are almost free. After you decide if you want to continue your experimant, you might look for a higher-resolution solution.

Stanwal is correct that you'll need some way to reduce the Voltage gain (NOT 'sensitivity') of the higher-gain amp(s). Of course, the easiest way to do that is to turn down the level of the higher-gain amp. However most poweramps don't have gain controls, so you'll be stuck having to use the passive attenuators that Ngjockey mentioned.

Good luck. I suspect that you'll decide that it's more trouble than it's worth.
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Sorry fot the misspellings; too bad this forum chooses not to have an Edit feature.
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"...what is commonly not realized is that much of the power capability of the solid state amp will not be utilizable, because how much of its power capability can be utilized will be limited by the clipping point of the lower powered amp."

Maybe so, but one still has more power available than if using only one pair of amp channels of whichever you had first, because each amp channel's power is not consumed driving a full-range signal.

Do understand that 'after filtering' (by the crossover's filters) is as effective in power saving as prefiltering, in that, for instance, the upper-frequency amp simply isn't able to/doesn't have to deliver current required by low-frequency signals. Said another way, if one starts this biamping (NOT 'bi-amping') process with a 50WPC tubed amp and adds a 100WPC amp for the bass, the 50WPC amp no longer has to consume the power of its powersupply driving low frequencies into the 'bottom half' of the speaker. So maybe we don't have 150WPC available, but we do have lots more than 50WPC available.

Passive biamping can be very effective, but it also can be excessively complex if one starts with the wrong amps and especially if one can't balance levels correctly.
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Have we noticed that Nikmilkov hasn't posted a word since the original message? Probably he's so confused and discouraged from our audiobabble that he'll either never try passive biamping or never ask a question here again! :-)

Nik, the biggest and IMO-only-important issue is gain matching the 2 different amps. Resolve that and you're well on your way.

And DO NOT--DO NOT--DO NOT combine passive biamping with an electronic crosover; ONE crossover network per speaker is just the right number.
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Well, now I'M confused, by your summary.

So you plan to biamp passively with 4 identical tubed monoamps?

Two STRONG advantages are that the gains will be identical and that you'll have 3dB more power. Another advantage will be slightly less IM and harmonic distortion.

Good luck.

One advantage not yet mentioned is that if your speakers split the frequencies between bass (NOT including midrange) and MR/treble, you can use a high-gage-but-inexpensive cable on the bass. If your speakers split the frequencies into bass/MR and treble--2-ways do this--I recommend equally-high-quality cable on both legs.
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"Contrastingly, if you bi-amp (SIC) with a passive crossover (e.g., use the crossovers built into the speakers), then each pair of monoblocks will amplify the full audio band. For example, the monoblocks for the woofer will be amplifying the full audio band but at the passive crossover, the mid/high freq's will be filtered out and essentially lost (the same thing happens for the monoblocks for the midrange/tweeter, except that the low freq's. will be filtered out and essentially lost)."

A common misconception. Yes, the entire frequency band is presented to each poweramp, but the 2 ends of the frequency band are NOT amplified equally, because the crossover presents a rapidly rising impedance within the filter (rolled-off) band. That's why one 'saves' amp power when passively biamping.
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