Bi amplifier

Hello, I am using Nac282 and NAP250 + Hicap. Just purchased big B&W 800 Nautilus from early 2000. Need to increase power for LF and want to use second amplifier but not Naim.
Can somebody help me with appropriate wiring to have bi amplifier in this case?
Thks and Rgds, Alain

Use a sub?

First of all, don’t mix amplifier makes with passive bi-amping - not a good idea at all!

Secondly, that’s a lot of speaker to hang off the end of a NAC282/Hicap/250. What’s your source?

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Active or passive bi-amping? If passive then do the amps have thesame gain, and if not how will you balance levels (does the other amp have a volume/gain control?) Active would be much better though more complex and needs the active XO (and probably need tri- not bi- ?), otherwise passive but a single amp driving the whole speaker -maybe that other amp instead of the 250, or something else…

I have B&W803D3s which I originally biamped with a 250DR and Supernait 2 at 80W per channel apiece. Sadly they didn’t provide the drive the B&Ws needed. A much more satisfactory result was achieved by switching to a McIntosh amp at 300W per channel. 800 series speakers are a demanding drive that only really come on song at moderate volumes and above and powered by a high wattage amp (despite what B&Ws spec sheet says).

Alain,

Which Nautilus model have you got? I’d encourage you to have a look at the Stereophile reviews of B&W’s upper range speakers from around 1999/2000.

Their summary (for the 801) is that the then price of $11k is nothing compared to the spend on quality (powerful!) stereo/mono-bloc amplifiers which will be required to drive them properly. As @Althepo has stated (and I remember his queries at the time well), B&W are very power/current-hungry 'speakers, even though the technical specs may suggest otherwise.

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Yes my second amp have a gain/vol adjustment for each channel. At least I want to give a trial. If somebody can guide me with wiring appreciated. Thks Alain

Thks for your advices my nautilus are 800 from end 2001.
I completed the installation this weekend, bi-amp between my nap250 for M/H F and a LabGruppen FP3400 for L F. Both plug to the HiCap
As you can imagine power is not the pb with the LabGruppen.
First test is interesting but as mentioned you need a minimum volume to start to enjoy the BW.
Maybe to much in the HF, could come from my room need to do other trials.
Rgds Alain

I can’t advise on the connections - you need someone familiar with NAC 282 connections to a non-Naim power amp.

As for levels, I suggest using something like REW software and a measuring microphone to set up so that the levels either side of the crossover frequency are the same.

I hope you enjoy: I have quite fancied hearing the 800 (and the original Nautilus itself), but have never had a chance - I did audition the 802D2 a few years ago, but found it not as good as the similarly priced PMC MB2 I have now.

An interesting project! — although you may be finding a tonal/speed mis-match between the amps(?) and, whenever I’ve heard B&W speakers of this age, I’ve always found the top end (HF) to be bright with Naim amps, even screechy at times (of course all our ears differ).

With Naim amps and active systems, the guidance is normally to match the better quality/higher powered amp to the HF, but with B&W’s it has to be the other way.

The hi cap has two passive amp outputs.
Just find a din to rca cable connected to amp 2 socket. Easy

In fact, it has three, which enable easy bi or triamping.

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