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what to look for when chosing a second power amp to bi-amp

theo cupier

Active Member
I'm toying with the idea of bi-amping my front l/r speakers. Are there any things in particular which I need to consider when chosing the second power amp in my set up to do this?

Ought both power amps have the same power rating per channel as each other? Are there any other technical points like this to consider?

Or is it important to match the tonal characteristics of the power amps (eg warm sound + warm sound) rather than the technical specs?

Any advice would be appreciated. Equally any recommendations for things which you think would work well alongside my RB985Mk2 would be greatfully received.

Cheers

Theo
 

Cliff

Distinguished Member
The only way to be sure is to use identical amplifiers. Phase differences between two different designs is your worst enemy.
 

gavp

Active Member
I've found there's varying advice in each hi-fi mag i've read, one argument is to match the wattage and ideally the maker to ensure compatability, but there's the argument that if one amp is driving the lower and one the higher it may be preferable to your ear to have less power going to the bass or vice versa, in an ideal world i'd like a set of speakers so kick ass they'd need a seperate amp driving all three sections :devil:
 
W

wookie

Guest
The most important thing that needs to be matched is the GAIN.

Both amps need identical gain, power output does not matter.
A 5w valve amp could be used with a 400w power amp for bi-amping as long as they both have the same gain.

Most amps are 29db ish
 

Steve Collier

Standard Member
wookie said:
The most important thing that needs to be matched is the GAIN.

Both amps need identical gain, power output does not matter.
A 5w valve amp could be used with a 400w power amp for bi-amping as long as they both have the same gain.

Most amps are 29db ish
Yes, that's right. Linn, who make a special thing of passive and active multi-amping, set the gain of their amps to 28.5 dB, even though the maximum power output of course varies between models. This makes mix and match practical. For example, I have run various combinations of LK280, LK100, LK140, AV5125 and 2250 Linn amps with Isobariks, Espeks, Trikan and Ekwal.

IMHO passive multi-amping is hardly worth it. Active amping is, though, if your manufacturer makes an active crossover to suit the speakers. Usually, the better quality (not necessarily the most powerful) amp is put on the treble.
 

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