Details for bi-amping

If you are planning on passive crossovers, then unless the amps are identical, you will have gaps or mismatch is high/low output of the amp/speaker setup. Some speakers (Martin Logan's for instance) have switches that allow you to adjust the input of the amps to the speakers for just such an occurance.

However, it appears to me that if you want to bi-amp, then you can;
1) get identical amps for high/low inputs

2. Get an active crossover which allows you to adjust the levels of the amps.

There are some very good active crossovers out there and even your speaker manufacturer may have or suggest an active crossover for you also.

enjoy

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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Plan 'b' would of course be to can the biamp idea and get a single amp per speaker of high enough capability to render biamping unnecessary.

Maybe something like the Spectron offering? Or the kilowatt Pass amp?

Put any extra funds into a whole house lightning / surge protector, dedicated circuits to the amps and listening area and top it off with the appropriate room treatments and a couple 'o subs.

Back to the OP.
Before you even start choosing amps, I'd get the preamp thing sorted out. Some preamps have balanced AND single ended outputs which may allow use of both...simultaniously.
I'd like some additional information.
Where (frequency) is the proposed crossover? Are the speakers 2-way or more than 2-way?

Synergy will be critical and as others have pointed out, may be difficult to pull the trigger on.

Thanks, guys, for your help and instructive suggestions. Frankly I didn't expect so many advises which obviously is because the biamping option is highly attractive for many but also because it is a complicated issue. At least for me. I didn't post a single word since yesterday because of the 7 hours of time difference. But it gave me some time to think. So for sure I'll gonna go for a simple solution. Probably the use of 4 identical amps driven by a single pre-amp. Under this setup the advantage of the SS's in the lows will obviously be lost. (Just because I prefer tubes.) Another element of a simple solution seems to be the passive biamping but I am still doubtful to what extend it worths the effort - the result is modest compared to the investment. For summarizing - going for a simple solution I will loose the main advantages of the biamping option. The questions are 1) does it still worth the efforts and the money and 2) are the risks of messing up the things bigger than the modest output that can be expected.

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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